drivers/scsi/sg.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  History:
   4  *  Started: Aug 9 by Lawrence Foard (entropy@world.std.com),
   5  *           to allow user process control of SCSI devices.
   6  *  Development Sponsored by Killy Corp. NY NY
   7  *
   8  * Original driver (sg.c):
   9  *        Copyright (C) 1992 Lawrence Foard
  10  * Version 2 and 3 extensions to driver:
  11  *        Copyright (C) 1998 - 2014 Douglas Gilbert
  12  */
  13
  14 static int sg_version_num = 30536;      /* 2 digits for each component */
  15 #define SG_VERSION_STR "3.5.36"
  16
  17 /*
  18  *  D. P. Gilbert (dgilbert@interlog.com), notes:
  19  *      - scsi logging is available via SCSI_LOG_TIMEOUT macros. First
  20  *        the kernel/module needs to be built with CONFIG_SCSI_LOGGING
  21  *        (otherwise the macros compile to empty statements).
  22  *
  23  */
  24 #include <linux/module.h>
  25
  26 #include <linux/fs.h>
  27 #include <linux/kernel.h>
  28 #include <linux/sched.h>
  29 #include <linux/string.h>
  30 #include <linux/mm.h>
  31 #include <linux/errno.h>
  32 #include <linux/mtio.h>
  33 #include <linux/ioctl.h>
  34 #include <linux/slab.h>
  35 #include <linux/fcntl.h>
  36 #include <linux/init.h>
  37 #include <linux/poll.h>
  38 #include <linux/moduleparam.h>
  39 #include <linux/cdev.h>
  40 #include <linux/idr.h>
  41 #include <linux/seq_file.h>
  42 #include <linux/blkdev.h>
  43 #include <linux/delay.h>
  44 #include <linux/blktrace_api.h>
  45 #include <linux/mutex.h>
  46 #include <linux/atomic.h>
  47 #include <linux/ratelimit.h>
  48 #include <linux/uio.h>
  49 #include <linux/cred.h> /* for sg_check_file_access() */
  50
  51 #include "scsi.h"
  52 #include <scsi/scsi_dbg.h>
  53 #include <scsi/scsi_host.h>
  54 #include <scsi/scsi_driver.h>
  55 #include <scsi/scsi_ioctl.h>
  56 #include <scsi/sg.h>
  57
  58 #include "scsi_logging.h"
  59
  60 #ifdef CONFIG_SCSI_PROC_FS
  61 #include <linux/proc_fs.h>
  62 static char *sg_version_date = "20140603";
  63
  64 static int sg_proc_init(void);
  65 #endif
  66
  67 #define SG_ALLOW_DIO_DEF 0
  68
  69 #define SG_MAX_DEVS 32768
  70
  71 /* SG_MAX_CDB_SIZE should be 260 (spc4r37 section 3.1.30) however the type
  72  * of sg_io_hdr::cmd_len can only represent 255. All SCSI commands greater
  73  * than 16 bytes are "variable length" whose length is a multiple of 4
  74  */
  75 #define SG_MAX_CDB_SIZE 252
  76
  77 #define SG_DEFAULT_TIMEOUT mult_frac(SG_DEFAULT_TIMEOUT_USER, HZ, USER_HZ)
  78
  79 int sg_big_buff = SG_DEF_RESERVED_SIZE;
  80 /* N.B. This variable is readable and writeable via
  81    /proc/scsi/sg/def_reserved_size . Each time sg_open() is called a buffer
  82    of this size (or less if there is not enough memory) will be reserved
  83    for use by this file descriptor. [Deprecated usage: this variable is also
  84    readable via /proc/sys/kernel/sg-big-buff if the sg driver is built into
  85    the kernel (i.e. it is not a module).] */
  86 static int def_reserved_size = -1;      /* picks up init parameter */
  87 static int sg_allow_dio = SG_ALLOW_DIO_DEF;
  88
  89 static int scatter_elem_sz = SG_SCATTER_SZ;
  90 static int scatter_elem_sz_prev = SG_SCATTER_SZ;
  91
  92 #define SG_SECTOR_SZ 512
  93
  94 static int sg_add_device(struct device *, struct class_interface *);
  95 static void sg_remove_device(struct device *, struct class_interface *);
  96
  97 static DEFINE_IDR(sg_index_idr);
  98 static DEFINE_RWLOCK(sg_index_lock);    /* Also used to lock
  99                                                            file descriptor list for device */
 100
 101 static struct class_interface sg_interface = {
 102         .add_dev        = sg_add_device,
 103         .remove_dev     = sg_remove_device,
 104 };
 105
 106 typedef struct sg_scatter_hold { /* holding area for scsi scatter gather info */
 107         unsigned short k_use_sg; /* Count of kernel scatter-gather pieces */
 108         unsigned sglist_len; /* size of malloc'd scatter-gather list ++ */
 109         unsigned bufflen;       /* Size of (aggregate) data buffer */
 110         struct page **pages;
 111         int page_order;
 112         char dio_in_use;        /* 0->indirect IO (or mmap), 1->dio */
 113         unsigned char cmd_opcode; /* first byte of command */
 114 } Sg_scatter_hold;
 115
 116 struct sg_device;               /* forward declarations */
 117 struct sg_fd;
 118
 119 typedef struct sg_request {     /* SG_MAX_QUEUE requests outstanding per file */
 120         struct list_head entry; /* list entry */
 121         struct sg_fd *parentfp; /* NULL -> not in use */
 122         Sg_scatter_hold data;   /* hold buffer, perhaps scatter list */
 123         sg_io_hdr_t header;     /* scsi command+info, see <scsi/sg.h> */
 124         unsigned char sense_b[SCSI_SENSE_BUFFERSIZE];
 125         char res_used;          /* 1 -> using reserve buffer, 0 -> not ... */
 126         char orphan;            /* 1 -> drop on sight, 0 -> normal */
 127         char sg_io_owned;       /* 1 -> packet belongs to SG_IO */
 128         /* done protected by rq_list_lock */
 129         char done;              /* 0->before bh, 1->before read, 2->read */
 130         struct request *rq;
 131         struct bio *bio;
 132         struct execute_work ew;
 133 } Sg_request;
 134
 135 typedef struct sg_fd {          /* holds the state of a file descriptor */
 136         struct list_head sfd_siblings;  /* protected by device's sfd_lock */
 137         struct sg_device *parentdp;     /* owning device */
 138         wait_queue_head_t read_wait;    /* queue read until command done */
 139         rwlock_t rq_list_lock;  /* protect access to list in req_arr */
 140         struct mutex f_mutex;   /* protect against changes in this fd */
 141         int timeout;            /* defaults to SG_DEFAULT_TIMEOUT      */
 142         int timeout_user;       /* defaults to SG_DEFAULT_TIMEOUT_USER */
 143         Sg_scatter_hold reserve;        /* buffer held for this file descriptor */
 144         struct list_head rq_list; /* head of request list */
 145         struct fasync_struct *async_qp; /* used by asynchronous notification */
 146         Sg_request req_arr[SG_MAX_QUEUE];       /* used as singly-linked list */
 147         char force_packid;      /* 1 -> pack_id input to read(), 0 -> ignored */
 148         char cmd_q;             /* 1 -> allow command queuing, 0 -> don't */
 149         unsigned char next_cmd_len; /* 0: automatic, >0: use on next write() */
 150         char keep_orphan;       /* 0 -> drop orphan (def), 1 -> keep for read() */
 151         char mmap_called;       /* 0 -> mmap() never called on this fd */
 152         char res_in_use;        /* 1 -> 'reserve' array in use */
 153         struct kref f_ref;
 154         struct execute_work ew;
 155 } Sg_fd;
 156
 157 typedef struct sg_device { /* holds the state of each scsi generic device */
 158         struct scsi_device *device;
 159         wait_queue_head_t open_wait;    /* queue open() when O_EXCL present */
 160         struct mutex open_rel_lock;     /* held when in open() or release() */
 161         int sg_tablesize;       /* adapter's max scatter-gather table size */
 162         u32 index;              /* device index number */
 163         struct list_head sfds;
 164         rwlock_t sfd_lock;      /* protect access to sfd list */
 165         atomic_t detaching;     /* 0->device usable, 1->device detaching */
 166         bool exclude;           /* 1->open(O_EXCL) succeeded and is active */
 167         int open_cnt;           /* count of opens (perhaps < num(sfds) ) */
 168         char sgdebug;           /* 0->off, 1->sense, 9->dump dev, 10-> all devs */
 169         struct gendisk *disk;
 170         struct cdev * cdev;     /* char_dev [sysfs: /sys/cdev/major/sg<n>] */
 171         struct kref d_ref;
 172 } Sg_device;
 173
 174 /* tasklet or soft irq callback */
 175 static void sg_rq_end_io(struct request *rq, blk_status_t status);
 176 static int sg_start_req(Sg_request *srp, unsigned char *cmd);
 177 static int sg_finish_rem_req(Sg_request * srp);
 178 static int sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size);
 179 static ssize_t sg_new_read(Sg_fd * sfp, char __user *buf, size_t count,
 180                            Sg_request * srp);
 181 static ssize_t sg_new_write(Sg_fd *sfp, struct file *file,
 182                         const char __user *buf, size_t count, int blocking,
 183                         int read_only, int sg_io_owned, Sg_request **o_srp);
 184 static int sg_common_write(Sg_fd * sfp, Sg_request * srp,
 185                            unsigned char *cmnd, int timeout, int blocking);
 186 static int sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer);
 187 static void sg_remove_scat(Sg_fd * sfp, Sg_scatter_hold * schp);
 188 static void sg_build_reserve(Sg_fd * sfp, int req_size);
 189 static void sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size);
 190 static void sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp);
 191 static Sg_fd *sg_add_sfp(Sg_device * sdp);
 192 static void sg_remove_sfp(struct kref *);
 193 static Sg_request *sg_get_rq_mark(Sg_fd * sfp, int pack_id);
 194 static Sg_request *sg_add_request(Sg_fd * sfp);
 195 static int sg_remove_request(Sg_fd * sfp, Sg_request * srp);
 196 static Sg_device *sg_get_dev(int dev);
 197 static void sg_device_destroy(struct kref *kref);
 198
 199 #define SZ_SG_HEADER sizeof(struct sg_header)
 200 #define SZ_SG_IO_HDR sizeof(sg_io_hdr_t)
 201 #define SZ_SG_IOVEC sizeof(sg_iovec_t)
 202 #define SZ_SG_REQ_INFO sizeof(sg_req_info_t)
 203
 204 #define sg_printk(prefix, sdp, fmt, a...) \
 205         sdev_prefix_printk(prefix, (sdp)->device,               \
 206                            (sdp)->disk->disk_name, fmt, ##a)
 207
 208 /*
 209  * The SCSI interfaces that use read() and write() as an asynchronous variant of
 210  * ioctl(..., SG_IO, ...) are fundamentally unsafe, since there are lots of ways
 211  * to trigger read() and write() calls from various contexts with elevated
 212  * privileges. This can lead to kernel memory corruption (e.g. if these
 213  * interfaces are called through splice()) and privilege escalation inside
 214  * userspace (e.g. if a process with access to such a device passes a file
 215  * descriptor to a SUID binary as stdin/stdout/stderr).
 216  *
 217  * This function provides protection for the legacy API by restricting the
 218  * calling context.
 219  */
 220 static int sg_check_file_access(struct file *filp, const char *caller)
 221 {
 222         if (filp->f_cred != current_real_cred()) {
 223                 pr_err_once("%s: process %d (%s) changed security contexts after opening file descriptor, this is not allowed.\n",
 224                         caller, task_tgid_vnr(current), current->comm);
 225                 return -EPERM;
 226         }
 227         if (uaccess_kernel()) {
 228                 pr_err_once("%s: process %d (%s) called from kernel context, this is not allowed.\n",
 229                         caller, task_tgid_vnr(current), current->comm);
 230                 return -EACCES;
 231         }
 232         return 0;
 233 }
 234
 235 static int sg_allow_access(struct file *filp, unsigned char *cmd)
 236 {
 237         struct sg_fd *sfp = filp->private_data;
 238
 239         if (sfp->parentdp->device->type == TYPE_SCANNER)
 240                 return 0;
 241
 242         return blk_verify_command(cmd, filp->f_mode);
 243 }
 244
 245 static int
 246 open_wait(Sg_device *sdp, int flags)
 247 {
 248         int retval = 0;
 249
 250         if (flags & O_EXCL) {
 251                 while (sdp->open_cnt > 0) {
 252                         mutex_unlock(&sdp->open_rel_lock);
 253                         retval = wait_event_interruptible(sdp->open_wait,
 254                                         (atomic_read(&sdp->detaching) ||
 255                                          !sdp->open_cnt));
 256                         mutex_lock(&sdp->open_rel_lock);
 257
 258                         if (retval) /* -ERESTARTSYS */
 259                                 return retval;
 260                         if (atomic_read(&sdp->detaching))
 261                                 return -ENODEV;
 262                 }
 263         } else {
 264                 while (sdp->exclude) {
 265                         mutex_unlock(&sdp->open_rel_lock);
 266                         retval = wait_event_interruptible(sdp->open_wait,
 267                                         (atomic_read(&sdp->detaching) ||
 268                                          !sdp->exclude));
 269                         mutex_lock(&sdp->open_rel_lock);
 270
 271                         if (retval) /* -ERESTARTSYS */
 272                                 return retval;
 273                         if (atomic_read(&sdp->detaching))
 274                                 return -ENODEV;
 275                 }
 276         }
 277
 278         return retval;
 279 }
 280
 281 /* Returns 0 on success, else a negated errno value */
 282 static int
 283 sg_open(struct inode *inode, struct file *filp)
 284 {
 285         int dev = iminor(inode);
 286         int flags = filp->f_flags;
 287         struct request_queue *q;
 288         Sg_device *sdp;
 289         Sg_fd *sfp;
 290         int retval;
 291
 292         nonseekable_open(inode, filp);
 293         if ((flags & O_EXCL) && (O_RDONLY == (flags & O_ACCMODE)))
 294                 return -EPERM; /* Can't lock it with read only access */
 295         sdp = sg_get_dev(dev);
 296         if (IS_ERR(sdp))
 297                 return PTR_ERR(sdp);
 298
 299         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
 300                                       "sg_open: flags=0x%x\n", flags));
 301
 302         /* This driver's module count bumped by fops_get in <linux/fs.h> */
 303         /* Prevent the device driver from vanishing while we sleep */
 304         retval = scsi_device_get(sdp->device);
 305         if (retval)
 306                 goto sg_put;
 307
 308         retval = scsi_autopm_get_device(sdp->device);
 309         if (retval)
 310                 goto sdp_put;
 311
 312         /* scsi_block_when_processing_errors() may block so bypass
 313          * check if O_NONBLOCK. Permits SCSI commands to be issued
 314          * during error recovery. Tread carefully. */
 315         if (!((flags & O_NONBLOCK) ||
 316               scsi_block_when_processing_errors(sdp->device))) {
 317                 retval = -ENXIO;
 318                 /* we are in error recovery for this device */
 319                 goto error_out;
 320         }
 321
 322         mutex_lock(&sdp->open_rel_lock);
 323         if (flags & O_NONBLOCK) {
 324                 if (flags & O_EXCL) {
 325                         if (sdp->open_cnt > 0) {
 326                                 retval = -EBUSY;
 327                                 goto error_mutex_locked;
 328                         }
 329                 } else {
 330                         if (sdp->exclude) {
 331                                 retval = -EBUSY;
 332                                 goto error_mutex_locked;
 333                         }
 334                 }
 335         } else {
 336                 retval = open_wait(sdp, flags);
 337                 if (retval) /* -ERESTARTSYS or -ENODEV */
 338                         goto error_mutex_locked;
 339         }
 340
 341         /* N.B. at this point we are holding the open_rel_lock */
 342         if (flags & O_EXCL)
 343                 sdp->exclude = true;
 344
 345         if (sdp->open_cnt < 1) {  /* no existing opens */
 346                 sdp->sgdebug = 0;
 347                 q = sdp->device->request_queue;
 348                 sdp->sg_tablesize = queue_max_segments(q);
 349         }
 350         sfp = sg_add_sfp(sdp);
 351         if (IS_ERR(sfp)) {
 352                 retval = PTR_ERR(sfp);
 353                 goto out_undo;
 354         }
 355
 356         filp->private_data = sfp;
 357         sdp->open_cnt++;
 358         mutex_unlock(&sdp->open_rel_lock);
 359
 360         retval = 0;
 361 sg_put:
 362         kref_put(&sdp->d_ref, sg_device_destroy);
 363         return retval;
 364
 365 out_undo:
 366         if (flags & O_EXCL) {
 367                 sdp->exclude = false;   /* undo if error */
 368                 wake_up_interruptible(&sdp->open_wait);
 369         }
 370 error_mutex_locked:
 371         mutex_unlock(&sdp->open_rel_lock);
 372 error_out:
 373         scsi_autopm_put_device(sdp->device);
 374 sdp_put:
 375         scsi_device_put(sdp->device);
 376         goto sg_put;
 377 }
 378
 379 /* Release resources associated with a successful sg_open()
 380  * Returns 0 on success, else a negated errno value */
 381 static int
 382 sg_release(struct inode *inode, struct file *filp)
 383 {
 384         Sg_device *sdp;
 385         Sg_fd *sfp;
 386
 387         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
 388                 return -ENXIO;
 389         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp, "sg_release\n"));
 390
 391         mutex_lock(&sdp->open_rel_lock);
 392         scsi_autopm_put_device(sdp->device);
 393         kref_put(&sfp->f_ref, sg_remove_sfp);
 394         sdp->open_cnt--;
 395
 396         /* possibly many open()s waiting on exlude clearing, start many;
 397          * only open(O_EXCL)s wait on 0==open_cnt so only start one */
 398         if (sdp->exclude) {
 399                 sdp->exclude = false;
 400                 wake_up_interruptible_all(&sdp->open_wait);
 401         } else if (0 == sdp->open_cnt) {
 402                 wake_up_interruptible(&sdp->open_wait);
 403         }
 404         mutex_unlock(&sdp->open_rel_lock);
 405         return 0;
 406 }
 407
 408 static ssize_t
 409 sg_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
 410 {
 411         Sg_device *sdp;
 412         Sg_fd *sfp;
 413         Sg_request *srp;
 414         int req_pack_id = -1;
 415         sg_io_hdr_t *hp;
 416         struct sg_header *old_hdr = NULL;
 417         int retval = 0;
 418
 419         /*
 420          * This could cause a response to be stranded. Close the associated
 421          * file descriptor to free up any resources being held.
 422          */
 423         retval = sg_check_file_access(filp, __func__);
 424         if (retval)
 425                 return retval;
 426
 427         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
 428                 return -ENXIO;
 429         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
 430                                       "sg_read: count=%d\n", (int) count));
 431
 432         if (sfp->force_packid && (count >= SZ_SG_HEADER)) {
 433                 old_hdr = memdup_user(buf, SZ_SG_HEADER);
 434                 if (IS_ERR(old_hdr))
 435                         return PTR_ERR(old_hdr);
 436                 if (old_hdr->reply_len < 0) {
 437                         if (count >= SZ_SG_IO_HDR) {
 438                                 /*
 439                                  * This is stupid.
 440                                  *
 441                                  * We're copying the whole sg_io_hdr_t from user
 442                                  * space just to get the 'pack_id' field. But the
 443                                  * field is at different offsets for the compat
 444                                  * case, so we'll use "get_sg_io_hdr()" to copy
 445                                  * the whole thing and convert it.
 446                                  *
 447                                  * We could do something like just calculating the
 448                                  * offset based of 'in_compat_syscall()', but the
 449                                  * 'compat_sg_io_hdr' definition is in the wrong
 450                                  * place for that.
 451                                  */
 452                                 sg_io_hdr_t *new_hdr;
 453                                 new_hdr = kmalloc(SZ_SG_IO_HDR, GFP_KERNEL);
 454                                 if (!new_hdr) {
 455                                         retval = -ENOMEM;
 456                                         goto free_old_hdr;
 457                                 }
 458                                 retval = get_sg_io_hdr(new_hdr, buf);
 459                                 req_pack_id = new_hdr->pack_id;
 460                                 kfree(new_hdr);
 461                                 if (retval) {
 462                                         retval = -EFAULT;
 463                                         goto free_old_hdr;
 464                                 }
 465                         }
 466                 } else
 467                         req_pack_id = old_hdr->pack_id;
 468         }
 469         srp = sg_get_rq_mark(sfp, req_pack_id);
 470         if (!srp) {             /* now wait on packet to arrive */
 471                 if (atomic_read(&sdp->detaching)) {
 472                         retval = -ENODEV;
 473                         goto free_old_hdr;
 474                 }
 475                 if (filp->f_flags & O_NONBLOCK) {
 476                         retval = -EAGAIN;
 477                         goto free_old_hdr;
 478                 }
 479                 retval = wait_event_interruptible(sfp->read_wait,
 480                         (atomic_read(&sdp->detaching) ||
 481                         (srp = sg_get_rq_mark(sfp, req_pack_id))));
 482                 if (atomic_read(&sdp->detaching)) {
 483                         retval = -ENODEV;
 484                         goto free_old_hdr;
 485                 }
 486                 if (retval) {
 487                         /* -ERESTARTSYS as signal hit process */
 488                         goto free_old_hdr;
 489                 }
 490         }
 491         if (srp->header.interface_id != '\0') {
 492                 retval = sg_new_read(sfp, buf, count, srp);
 493                 goto free_old_hdr;
 494         }
 495
 496         hp = &srp->header;
 497         if (old_hdr == NULL) {
 498                 old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL);
 499                 if (! old_hdr) {
 500                         retval = -ENOMEM;
 501                         goto free_old_hdr;
 502                 }
 503         }
 504         memset(old_hdr, 0, SZ_SG_HEADER);
 505         old_hdr->reply_len = (int) hp->timeout;
 506         old_hdr->pack_len = old_hdr->reply_len; /* old, strange behaviour */
 507         old_hdr->pack_id = hp->pack_id;
 508         old_hdr->twelve_byte =
 509             ((srp->data.cmd_opcode >= 0xc0) && (12 == hp->cmd_len)) ? 1 : 0;
 510         old_hdr->target_status = hp->masked_status;
 511         old_hdr->host_status = hp->host_status;
 512         old_hdr->driver_status = hp->driver_status;
 513         if ((CHECK_CONDITION & hp->masked_status) ||
 514             (DRIVER_SENSE & hp->driver_status))
 515                 memcpy(old_hdr->sense_buffer, srp->sense_b,
 516                        sizeof (old_hdr->sense_buffer));
 517         switch (hp->host_status) {
 518         /* This setup of 'result' is for backward compatibility and is best
 519            ignored by the user who should use target, host + driver status */
 520         case DID_OK:
 521         case DID_PASSTHROUGH:
 522         case DID_SOFT_ERROR:
 523                 old_hdr->result = 0;
 524                 break;
 525         case DID_NO_CONNECT:
 526         case DID_BUS_BUSY:
 527         case DID_TIME_OUT:
 528                 old_hdr->result = EBUSY;
 529                 break;
 530         case DID_BAD_TARGET:
 531         case DID_ABORT:
 532         case DID_PARITY:
 533         case DID_RESET:
 534         case DID_BAD_INTR:
 535                 old_hdr->result = EIO;
 536                 break;
 537         case DID_ERROR:
 538                 old_hdr->result = (srp->sense_b[0] == 0 &&
 539                                   hp->masked_status == GOOD) ? 0 : EIO;
 540                 break;
 541         default:
 542                 old_hdr->result = EIO;
 543                 break;
 544         }
 545
 546         /* Now copy the result back to the user buffer.  */
 547         if (count >= SZ_SG_HEADER) {
 548                 if (copy_to_user(buf, old_hdr, SZ_SG_HEADER)) {
 549                         retval = -EFAULT;
 550                         goto free_old_hdr;
 551                 }
 552                 buf += SZ_SG_HEADER;
 553                 if (count > old_hdr->reply_len)
 554                         count = old_hdr->reply_len;
 555                 if (count > SZ_SG_HEADER) {
 556                         if (sg_read_oxfer(srp, buf, count - SZ_SG_HEADER)) {
 557                                 retval = -EFAULT;
 558                                 goto free_old_hdr;
 559                         }
 560                 }
 561         } else
 562                 count = (old_hdr->result == 0) ? 0 : -EIO;
 563         sg_finish_rem_req(srp);
 564         sg_remove_request(sfp, srp);
 565         retval = count;
 566 free_old_hdr:
 567         kfree(old_hdr);
 568         return retval;
 569 }
 570
 571 static ssize_t
 572 sg_new_read(Sg_fd * sfp, char __user *buf, size_t count, Sg_request * srp)
 573 {
 574         sg_io_hdr_t *hp = &srp->header;
 575         int err = 0, err2;
 576         int len;
 577
 578         if (count < SZ_SG_IO_HDR) {
 579                 err = -EINVAL;
 580                 goto err_out;
 581         }
 582         hp->sb_len_wr = 0;
 583         if ((hp->mx_sb_len > 0) && hp->sbp) {
 584                 if ((CHECK_CONDITION & hp->masked_status) ||
 585                     (DRIVER_SENSE & hp->driver_status)) {
 586                         int sb_len = SCSI_SENSE_BUFFERSIZE;
 587                         sb_len = (hp->mx_sb_len > sb_len) ? sb_len : hp->mx_sb_len;
 588                         len = 8 + (int) srp->sense_b[7];        /* Additional sense length field */
 589                         len = (len > sb_len) ? sb_len : len;
 590                         if (copy_to_user(hp->sbp, srp->sense_b, len)) {
 591                                 err = -EFAULT;
 592                                 goto err_out;
 593                         }
 594                         hp->sb_len_wr = len;
 595                 }
 596         }
 597         if (hp->masked_status || hp->host_status || hp->driver_status)
 598                 hp->info |= SG_INFO_CHECK;
 599         err = put_sg_io_hdr(hp, buf);
 600 err_out:
 601         err2 = sg_finish_rem_req(srp);
 602         sg_remove_request(sfp, srp);
 603         return err ? : err2 ? : count;
 604 }
 605
 606 static ssize_t
 607 sg_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
 608 {
 609         int mxsize, cmd_size, k;
 610         int input_size, blocking;
 611         unsigned char opcode;
 612         Sg_device *sdp;
 613         Sg_fd *sfp;
 614         Sg_request *srp;
 615         struct sg_header old_hdr;
 616         sg_io_hdr_t *hp;
 617         unsigned char cmnd[SG_MAX_CDB_SIZE];
 618         int retval;
 619
 620         retval = sg_check_file_access(filp, __func__);
 621         if (retval)
 622                 return retval;
 623
 624         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
 625                 return -ENXIO;
 626         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
 627                                       "sg_write: count=%d\n", (int) count));
 628         if (atomic_read(&sdp->detaching))
 629                 return -ENODEV;
 630         if (!((filp->f_flags & O_NONBLOCK) ||
 631               scsi_block_when_processing_errors(sdp->device)))
 632                 return -ENXIO;
 633
 634         if (count < SZ_SG_HEADER)
 635                 return -EIO;
 636         if (copy_from_user(&old_hdr, buf, SZ_SG_HEADER))
 637                 return -EFAULT;
 638         blocking = !(filp->f_flags & O_NONBLOCK);
 639         if (old_hdr.reply_len < 0)
 640                 return sg_new_write(sfp, filp, buf, count,
 641                                     blocking, 0, 0, NULL);
 642         if (count < (SZ_SG_HEADER + 6))
 643                 return -EIO;    /* The minimum scsi command length is 6 bytes. */
 644
 645         buf += SZ_SG_HEADER;
 646         if (get_user(opcode, buf))
 647                 return -EFAULT;
 648
 649         if (!(srp = sg_add_request(sfp))) {
 650                 SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sdp,
 651                                               "sg_write: queue full\n"));
 652                 return -EDOM;
 653         }
 654         mutex_lock(&sfp->f_mutex);
 655         if (sfp->next_cmd_len > 0) {
 656                 cmd_size = sfp->next_cmd_len;
 657                 sfp->next_cmd_len = 0;  /* reset so only this write() effected */
 658         } else {
 659                 cmd_size = COMMAND_SIZE(opcode);        /* based on SCSI command group */
 660                 if ((opcode >= 0xc0) && old_hdr.twelve_byte)
 661                         cmd_size = 12;
 662         }
 663         mutex_unlock(&sfp->f_mutex);
 664         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sdp,
 665                 "sg_write:   scsi opcode=0x%02x, cmd_size=%d\n", (int) opcode, cmd_size));
 666 /* Determine buffer size.  */
 667         input_size = count - cmd_size;
 668         mxsize = (input_size > old_hdr.reply_len) ? input_size : old_hdr.reply_len;
 669         mxsize -= SZ_SG_HEADER;
 670         input_size -= SZ_SG_HEADER;
 671         if (input_size < 0) {
 672                 sg_remove_request(sfp, srp);
 673                 return -EIO;    /* User did not pass enough bytes for this command. */
 674         }
 675         hp = &srp->header;
 676         hp->interface_id = '\0';        /* indicator of old interface tunnelled */
 677         hp->cmd_len = (unsigned char) cmd_size;
 678         hp->iovec_count = 0;
 679         hp->mx_sb_len = 0;
 680         if (input_size > 0)
 681                 hp->dxfer_direction = (old_hdr.reply_len > SZ_SG_HEADER) ?
 682                     SG_DXFER_TO_FROM_DEV : SG_DXFER_TO_DEV;
 683         else
 684                 hp->dxfer_direction = (mxsize > 0) ? SG_DXFER_FROM_DEV : SG_DXFER_NONE;
 685         hp->dxfer_len = mxsize;
 686         if ((hp->dxfer_direction == SG_DXFER_TO_DEV) ||
 687             (hp->dxfer_direction == SG_DXFER_TO_FROM_DEV))
 688                 hp->dxferp = (char __user *)buf + cmd_size;
 689         else
 690                 hp->dxferp = NULL;
 691         hp->sbp = NULL;
 692         hp->timeout = old_hdr.reply_len;        /* structure abuse ... */
 693         hp->flags = input_size; /* structure abuse ... */
 694         hp->pack_id = old_hdr.pack_id;
 695         hp->usr_ptr = NULL;
 696         if (copy_from_user(cmnd, buf, cmd_size))
 697                 return -EFAULT;
 698         /*
 699          * SG_DXFER_TO_FROM_DEV is functionally equivalent to SG_DXFER_FROM_DEV,
 700          * but is is possible that the app intended SG_DXFER_TO_DEV, because there
 701          * is a non-zero input_size, so emit a warning.
 702          */
 703         if (hp->dxfer_direction == SG_DXFER_TO_FROM_DEV) {
 704                 printk_ratelimited(KERN_WARNING
 705                                    "sg_write: data in/out %d/%d bytes "
 706                                    "for SCSI command 0x%x-- guessing "
 707                                    "data in;\n   program %s not setting "
 708                                    "count and/or reply_len properly\n",
 709                                    old_hdr.reply_len - (int)SZ_SG_HEADER,
 710                                    input_size, (unsigned int) cmnd[0],
 711                                    current->comm);
 712         }
 713         k = sg_common_write(sfp, srp, cmnd, sfp->timeout, blocking);
 714         return (k < 0) ? k : count;
 715 }
 716
 717 static ssize_t
 718 sg_new_write(Sg_fd *sfp, struct file *file, const char __user *buf,
 719                  size_t count, int blocking, int read_only, int sg_io_owned,
 720                  Sg_request **o_srp)
 721 {
 722         int k;
 723         Sg_request *srp;
 724         sg_io_hdr_t *hp;
 725         unsigned char cmnd[SG_MAX_CDB_SIZE];
 726         int timeout;
 727         unsigned long ul_timeout;
 728
 729         if (count < SZ_SG_IO_HDR)
 730                 return -EINVAL;
 731
 732         sfp->cmd_q = 1; /* when sg_io_hdr seen, set command queuing on */
 733         if (!(srp = sg_add_request(sfp))) {
 734                 SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sfp->parentdp,
 735                                               "sg_new_write: queue full\n"));
 736                 return -EDOM;
 737         }
 738         srp->sg_io_owned = sg_io_owned;
 739         hp = &srp->header;
 740         if (get_sg_io_hdr(hp, buf)) {
 741                 sg_remove_request(sfp, srp);
 742                 return -EFAULT;
 743         }
 744         if (hp->interface_id != 'S') {
 745                 sg_remove_request(sfp, srp);
 746                 return -ENOSYS;
 747         }
 748         if (hp->flags & SG_FLAG_MMAP_IO) {
 749                 if (hp->dxfer_len > sfp->reserve.bufflen) {
 750                         sg_remove_request(sfp, srp);
 751                         return -ENOMEM; /* MMAP_IO size must fit in reserve buffer */
 752                 }
 753                 if (hp->flags & SG_FLAG_DIRECT_IO) {
 754                         sg_remove_request(sfp, srp);
 755                         return -EINVAL; /* either MMAP_IO or DIRECT_IO (not both) */
 756                 }
 757                 if (sfp->res_in_use) {
 758                         sg_remove_request(sfp, srp);
 759                         return -EBUSY;  /* reserve buffer already being used */
 760                 }
 761         }
 762         ul_timeout = msecs_to_jiffies(srp->header.timeout);
 763         timeout = (ul_timeout < INT_MAX) ? ul_timeout : INT_MAX;
 764         if ((!hp->cmdp) || (hp->cmd_len < 6) || (hp->cmd_len > sizeof (cmnd))) {
 765                 sg_remove_request(sfp, srp);
 766                 return -EMSGSIZE;
 767         }
 768         if (copy_from_user(cmnd, hp->cmdp, hp->cmd_len)) {
 769                 sg_remove_request(sfp, srp);
 770                 return -EFAULT;
 771         }
 772         if (read_only && sg_allow_access(file, cmnd)) {
 773                 sg_remove_request(sfp, srp);
 774                 return -EPERM;
 775         }
 776         k = sg_common_write(sfp, srp, cmnd, timeout, blocking);
 777         if (k < 0)
 778                 return k;
 779         if (o_srp)
 780                 *o_srp = srp;
 781         return count;
 782 }
 783
 784 static int
 785 sg_common_write(Sg_fd * sfp, Sg_request * srp,
 786                 unsigned char *cmnd, int timeout, int blocking)
 787 {
 788         int k, at_head;
 789         Sg_device *sdp = sfp->parentdp;
 790         sg_io_hdr_t *hp = &srp->header;
 791
 792         srp->data.cmd_opcode = cmnd[0]; /* hold opcode of command */
 793         hp->status = 0;
 794         hp->masked_status = 0;
 795         hp->msg_status = 0;
 796         hp->info = 0;
 797         hp->host_status = 0;
 798         hp->driver_status = 0;
 799         hp->resid = 0;
 800         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
 801                         "sg_common_write:  scsi opcode=0x%02x, cmd_size=%d\n",
 802                         (int) cmnd[0], (int) hp->cmd_len));
 803
 804         if (hp->dxfer_len >= SZ_256M)
 805                 return -EINVAL;
 806
 807         k = sg_start_req(srp, cmnd);
 808         if (k) {
 809                 SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sfp->parentdp,
 810                         "sg_common_write: start_req err=%d\n", k));
 811                 sg_finish_rem_req(srp);
 812                 sg_remove_request(sfp, srp);
 813                 return k;       /* probably out of space --> ENOMEM */
 814         }
 815         if (atomic_read(&sdp->detaching)) {
 816                 if (srp->bio) {
 817                         scsi_req_free_cmd(scsi_req(srp->rq));
 818                         blk_put_request(srp->rq);
 819                         srp->rq = NULL;
 820                 }
 821
 822                 sg_finish_rem_req(srp);
 823                 sg_remove_request(sfp, srp);
 824                 return -ENODEV;
 825         }
 826
 827         hp->duration = jiffies_to_msecs(jiffies);
 828         if (hp->interface_id != '\0' && /* v3 (or later) interface */
 829             (SG_FLAG_Q_AT_TAIL & hp->flags))
 830                 at_head = 0;
 831         else
 832                 at_head = 1;
 833
 834         srp->rq->timeout = timeout;
 835         kref_get(&sfp->f_ref); /* sg_rq_end_io() does kref_put(). */
 836         blk_execute_rq_nowait(sdp->device->request_queue, sdp->disk,
 837                               srp->rq, at_head, sg_rq_end_io);
 838         return 0;
 839 }
 840
 841 static int srp_done(Sg_fd *sfp, Sg_request *srp)
 842 {
 843         unsigned long flags;
 844         int ret;
 845
 846         read_lock_irqsave(&sfp->rq_list_lock, flags);
 847         ret = srp->done;
 848         read_unlock_irqrestore(&sfp->rq_list_lock, flags);
 849         return ret;
 850 }
 851
 852 static int max_sectors_bytes(struct request_queue *q)
 853 {
 854         unsigned int max_sectors = queue_max_sectors(q);
 855
 856         max_sectors = min_t(unsigned int, max_sectors, INT_MAX >> 9);
 857
 858         return max_sectors << 9;
 859 }
 860
 861 static void
 862 sg_fill_request_table(Sg_fd *sfp, sg_req_info_t *rinfo)
 863 {
 864         Sg_request *srp;
 865         int val;
 866         unsigned int ms;
 867
 868         val = 0;
 869         list_for_each_entry(srp, &sfp->rq_list, entry) {
 870                 if (val >= SG_MAX_QUEUE)
 871                         break;
 872                 rinfo[val].req_state = srp->done + 1;
 873                 rinfo[val].problem =
 874                         srp->header.masked_status &
 875                         srp->header.host_status &
 876                         srp->header.driver_status;
 877                 if (srp->done)
 878                         rinfo[val].duration =
 879                                 srp->header.duration;
 880                 else {
 881                         ms = jiffies_to_msecs(jiffies);
 882                         rinfo[val].duration =
 883                                 (ms > srp->header.duration) ?
 884                                 (ms - srp->header.duration) : 0;
 885                 }
 886                 rinfo[val].orphan = srp->orphan;
 887                 rinfo[val].sg_io_owned = srp->sg_io_owned;
 888                 rinfo[val].pack_id = srp->header.pack_id;
 889                 rinfo[val].usr_ptr = srp->header.usr_ptr;
 890                 val++;
 891         }
 892 }
 893
 894 #ifdef CONFIG_COMPAT
 895 struct compat_sg_req_info { /* used by SG_GET_REQUEST_TABLE ioctl() */
 896         char req_state;
 897         char orphan;
 898         char sg_io_owned;
 899         char problem;
 900         int pack_id;
 901         compat_uptr_t usr_ptr;
 902         unsigned int duration;
 903         int unused;
 904 };
 905
 906 static int put_compat_request_table(struct compat_sg_req_info __user *o,
 907                                     struct sg_req_info *rinfo)
 908 {
 909         int i;
 910         for (i = 0; i < SG_MAX_QUEUE; i++) {
 911                 if (copy_to_user(o + i, rinfo + i, offsetof(sg_req_info_t, usr_ptr)) ||
 912                     put_user((uintptr_t)rinfo[i].usr_ptr, &o[i].usr_ptr) ||
 913                     put_user(rinfo[i].duration, &o[i].duration) ||
 914                     put_user(rinfo[i].unused, &o[i].unused))
 915                         return -EFAULT;
 916         }
 917         return 0;
 918 }
 919 #endif
 920
 921 static long
 922 sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
 923 {
 924         void __user *p = (void __user *)arg;
 925         int __user *ip = p;
 926         int result, val, read_only;
 927         Sg_device *sdp;
 928         Sg_fd *sfp;
 929         Sg_request *srp;
 930         unsigned long iflags;
 931
 932         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
 933                 return -ENXIO;
 934
 935         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
 936                                    "sg_ioctl: cmd=0x%x\n", (int) cmd_in));
 937         read_only = (O_RDWR != (filp->f_flags & O_ACCMODE));
 938
 939         switch (cmd_in) {
 940         case SG_IO:
 941                 if (atomic_read(&sdp->detaching))
 942                         return -ENODEV;
 943                 if (!scsi_block_when_processing_errors(sdp->device))
 944                         return -ENXIO;
 945                 result = sg_new_write(sfp, filp, p, SZ_SG_IO_HDR,
 946                                  1, read_only, 1, &srp);
 947                 if (result < 0)
 948                         return result;
 949                 result = wait_event_interruptible(sfp->read_wait,
 950                         (srp_done(sfp, srp) || atomic_read(&sdp->detaching)));
 951                 if (atomic_read(&sdp->detaching))
 952                         return -ENODEV;
 953                 write_lock_irq(&sfp->rq_list_lock);
 954                 if (srp->done) {
 955                         srp->done = 2;
 956                         write_unlock_irq(&sfp->rq_list_lock);
 957                         result = sg_new_read(sfp, p, SZ_SG_IO_HDR, srp);
 958                         return (result < 0) ? result : 0;
 959                 }
 960                 srp->orphan = 1;
 961                 write_unlock_irq(&sfp->rq_list_lock);
 962                 return result;  /* -ERESTARTSYS because signal hit process */
 963         case SG_SET_TIMEOUT:
 964                 result = get_user(val, ip);
 965                 if (result)
 966                         return result;
 967                 if (val < 0)
 968                         return -EIO;
 969                 if (val >= mult_frac((s64)INT_MAX, USER_HZ, HZ))
 970                         val = min_t(s64, mult_frac((s64)INT_MAX, USER_HZ, HZ),
 971                                     INT_MAX);
 972                 sfp->timeout_user = val;
 973                 sfp->timeout = mult_frac(val, HZ, USER_HZ);
 974
 975                 return 0;
 976         case SG_GET_TIMEOUT:    /* N.B. User receives timeout as return value */
 977                                 /* strange ..., for backward compatibility */
 978                 return sfp->timeout_user;
 979         case SG_SET_FORCE_LOW_DMA:
 980                 /*
 981                  * N.B. This ioctl never worked properly, but failed to
 982                  * return an error value. So returning '0' to keep compability
 983                  * with legacy applications.
 984                  */
 985                 return 0;
 986         case SG_GET_LOW_DMA:
 987                 return put_user((int) sdp->device->host->unchecked_isa_dma, ip);
 988         case SG_GET_SCSI_ID:
 989                 {
 990                         sg_scsi_id_t v;
 991
 992                         if (atomic_read(&sdp->detaching))
 993                                 return -ENODEV;
 994                         memset(&v, 0, sizeof(v));
 995                         v.host_no = sdp->device->host->host_no;
 996                         v.channel = sdp->device->channel;
 997                         v.scsi_id = sdp->device->id;
 998                         v.lun = sdp->device->lun;
 999                         v.scsi_type = sdp->device->type;
1000                         v.h_cmd_per_lun = sdp->device->host->cmd_per_lun;
1001                         v.d_queue_depth = sdp->device->queue_depth;
1002                         if (copy_to_user(p, &v, sizeof(sg_scsi_id_t)))
1003                                 return -EFAULT;
1004                         return 0;
1005                 }
1006         case SG_SET_FORCE_PACK_ID:
1007                 result = get_user(val, ip);
1008                 if (result)
1009                         return result;
1010                 sfp->force_packid = val ? 1 : 0;
1011                 return 0;
1012         case SG_GET_PACK_ID:
1013                 read_lock_irqsave(&sfp->rq_list_lock, iflags);
1014                 list_for_each_entry(srp, &sfp->rq_list, entry) {
1015                         if ((1 == srp->done) && (!srp->sg_io_owned)) {
1016                                 read_unlock_irqrestore(&sfp->rq_list_lock,
1017                                                        iflags);
1018                                 return put_user(srp->header.pack_id, ip);
1019                         }
1020                 }
1021                 read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1022                 return put_user(-1, ip);
1023         case SG_GET_NUM_WAITING:
1024                 read_lock_irqsave(&sfp->rq_list_lock, iflags);
1025                 val = 0;
1026                 list_for_each_entry(srp, &sfp->rq_list, entry) {
1027                         if ((1 == srp->done) && (!srp->sg_io_owned))
1028                                 ++val;
1029                 }
1030                 read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1031                 return put_user(val, ip);
1032         case SG_GET_SG_TABLESIZE:
1033                 return put_user(sdp->sg_tablesize, ip);
1034         case SG_SET_RESERVED_SIZE:
1035                 result = get_user(val, ip);
1036                 if (result)
1037                         return result;
1038                 if (val < 0)
1039                         return -EINVAL;
1040                 val = min_t(int, val,
1041                             max_sectors_bytes(sdp->device->request_queue));
1042                 mutex_lock(&sfp->f_mutex);
1043                 if (val != sfp->reserve.bufflen) {
1044                         if (sfp->mmap_called ||
1045                             sfp->res_in_use) {
1046                                 mutex_unlock(&sfp->f_mutex);
1047                                 return -EBUSY;
1048                         }
1049
1050                         sg_remove_scat(sfp, &sfp->reserve);
1051                         sg_build_reserve(sfp, val);
1052                 }
1053                 mutex_unlock(&sfp->f_mutex);
1054                 return 0;
1055         case SG_GET_RESERVED_SIZE:
1056                 val = min_t(int, sfp->reserve.bufflen,
1057                             max_sectors_bytes(sdp->device->request_queue));
1058                 return put_user(val, ip);
1059         case SG_SET_COMMAND_Q:
1060                 result = get_user(val, ip);
1061                 if (result)
1062                         return result;
1063                 sfp->cmd_q = val ? 1 : 0;
1064                 return 0;
1065         case SG_GET_COMMAND_Q:
1066                 return put_user((int) sfp->cmd_q, ip);
1067         case SG_SET_KEEP_ORPHAN:
1068                 result = get_user(val, ip);
1069                 if (result)
1070                         return result;
1071                 sfp->keep_orphan = val;
1072                 return 0;
1073         case SG_GET_KEEP_ORPHAN:
1074                 return put_user((int) sfp->keep_orphan, ip);
1075         case SG_NEXT_CMD_LEN:
1076                 result = get_user(val, ip);
1077                 if (result)
1078                         return result;
1079                 if (val > SG_MAX_CDB_SIZE)
1080                         return -ENOMEM;
1081                 sfp->next_cmd_len = (val > 0) ? val : 0;
1082                 return 0;
1083         case SG_GET_VERSION_NUM:
1084                 return put_user(sg_version_num, ip);
1085         case SG_GET_ACCESS_COUNT:
1086                 /* faked - we don't have a real access count anymore */
1087                 val = (sdp->device ? 1 : 0);
1088                 return put_user(val, ip);
1089         case SG_GET_REQUEST_TABLE:
1090                 {
1091                         sg_req_info_t *rinfo;
1092
1093                         rinfo = kcalloc(SG_MAX_QUEUE, SZ_SG_REQ_INFO,
1094                                         GFP_KERNEL);
1095                         if (!rinfo)
1096                                 return -ENOMEM;
1097                         read_lock_irqsave(&sfp->rq_list_lock, iflags);
1098                         sg_fill_request_table(sfp, rinfo);
1099                         read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1100         #ifdef CONFIG_COMPAT
1101                         if (in_compat_syscall())
1102                                 result = put_compat_request_table(p, rinfo);
1103                         else
1104         #endif
1105                                 result = copy_to_user(p, rinfo,
1106                                                       SZ_SG_REQ_INFO * SG_MAX_QUEUE);
1107                         result = result ? -EFAULT : 0;
1108                         kfree(rinfo);
1109                         return result;
1110                 }
1111         case SG_EMULATED_HOST:
1112                 if (atomic_read(&sdp->detaching))
1113                         return -ENODEV;
1114                 return put_user(sdp->device->host->hostt->emulated, ip);
1115         case SCSI_IOCTL_SEND_COMMAND:
1116                 if (atomic_read(&sdp->detaching))
1117                         return -ENODEV;
1118                 return sg_scsi_ioctl(sdp->device->request_queue, NULL, filp->f_mode, p);
1119         case SG_SET_DEBUG:
1120                 result = get_user(val, ip);
1121                 if (result)
1122                         return result;
1123                 sdp->sgdebug = (char) val;
1124                 return 0;
1125         case BLKSECTGET:
1126                 return put_user(max_sectors_bytes(sdp->device->request_queue),
1127                                 ip);
1128         case BLKTRACESETUP:
1129                 return blk_trace_setup(sdp->device->request_queue,
1130                                        sdp->disk->disk_name,
1131                                        MKDEV(SCSI_GENERIC_MAJOR, sdp->index),
1132                                        NULL, p);
1133         case BLKTRACESTART:
1134                 return blk_trace_startstop(sdp->device->request_queue, 1);
1135         case BLKTRACESTOP:
1136                 return blk_trace_startstop(sdp->device->request_queue, 0);
1137         case BLKTRACETEARDOWN:
1138                 return blk_trace_remove(sdp->device->request_queue);
1139         case SCSI_IOCTL_GET_IDLUN:
1140         case SCSI_IOCTL_GET_BUS_NUMBER:
1141         case SCSI_IOCTL_PROBE_HOST:
1142         case SG_GET_TRANSFORM:
1143         case SG_SCSI_RESET:
1144                 if (atomic_read(&sdp->detaching))
1145                         return -ENODEV;
1146                 break;
1147         default:
1148                 if (read_only)
1149                         return -EPERM;  /* don't know so take safe approach */
1150                 break;
1151         }
1152
1153         result = scsi_ioctl_block_when_processing_errors(sdp->device,
1154                         cmd_in, filp->f_flags & O_NDELAY);
1155         if (result)
1156                 return result;
1157         return scsi_ioctl(sdp->device, cmd_in, p);
1158 }
1159
1160 #ifdef CONFIG_COMPAT
1161 static long sg_compat_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
1162 {
1163         Sg_device *sdp;
1164         Sg_fd *sfp;
1165         struct scsi_device *sdev;
1166
1167         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1168                 return -ENXIO;
1169
1170         sdev = sdp->device;
1171         if (sdev->host->hostt->compat_ioctl) {
1172                 int ret;
1173
1174                 ret = sdev->host->hostt->compat_ioctl(sdev, cmd_in, (void __user *)arg);
1175
1176                 return ret;
1177         }
1178
1179         return -ENOIOCTLCMD;
1180 }
1181 #endif
1182
1183 static __poll_t
1184 sg_poll(struct file *filp, poll_table * wait)
1185 {
1186         __poll_t res = 0;
1187         Sg_device *sdp;
1188         Sg_fd *sfp;
1189         Sg_request *srp;
1190         int count = 0;
1191         unsigned long iflags;
1192
1193         sfp = filp->private_data;
1194         if (!sfp)
1195                 return EPOLLERR;
1196         sdp = sfp->parentdp;
1197         if (!sdp)
1198                 return EPOLLERR;
1199         poll_wait(filp, &sfp->read_wait, wait);
1200         read_lock_irqsave(&sfp->rq_list_lock, iflags);
1201         list_for_each_entry(srp, &sfp->rq_list, entry) {
1202                 /* if any read waiting, flag it */
1203                 if ((0 == res) && (1 == srp->done) && (!srp->sg_io_owned))
1204                         res = EPOLLIN | EPOLLRDNORM;
1205                 ++count;
1206         }
1207         read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1208
1209         if (atomic_read(&sdp->detaching))
1210                 res |= EPOLLHUP;
1211         else if (!sfp->cmd_q) {
1212                 if (0 == count)
1213                         res |= EPOLLOUT | EPOLLWRNORM;
1214         } else if (count < SG_MAX_QUEUE)
1215                 res |= EPOLLOUT | EPOLLWRNORM;
1216         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
1217                                       "sg_poll: res=0x%x\n", (__force u32) res));
1218         return res;
1219 }
1220
1221 static int
1222 sg_fasync(int fd, struct file *filp, int mode)
1223 {
1224         Sg_device *sdp;
1225         Sg_fd *sfp;
1226
1227         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1228                 return -ENXIO;
1229         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
1230                                       "sg_fasync: mode=%d\n", mode));
1231
1232         return fasync_helper(fd, filp, mode, &sfp->async_qp);
1233 }
1234
1235 static vm_fault_t
1236 sg_vma_fault(struct vm_fault *vmf)
1237 {
1238         struct vm_area_struct *vma = vmf->vma;
1239         Sg_fd *sfp;
1240         unsigned long offset, len, sa;
1241         Sg_scatter_hold *rsv_schp;
1242         int k, length;
1243
1244         if ((NULL == vma) || (!(sfp = (Sg_fd *) vma->vm_private_data)))
1245                 return VM_FAULT_SIGBUS;
1246         rsv_schp = &sfp->reserve;
1247         offset = vmf->pgoff << PAGE_SHIFT;
1248         if (offset >= rsv_schp->bufflen)
1249                 return VM_FAULT_SIGBUS;
1250         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sfp->parentdp,
1251                                       "sg_vma_fault: offset=%lu, scatg=%d\n",
1252                                       offset, rsv_schp->k_use_sg));
1253         sa = vma->vm_start;
1254         length = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1255         for (k = 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) {
1256                 len = vma->vm_end - sa;
1257                 len = (len < length) ? len : length;
1258                 if (offset < len) {
1259                         struct page *page = nth_page(rsv_schp->pages[k],
1260                                                      offset >> PAGE_SHIFT);
1261                         get_page(page); /* increment page count */
1262                         vmf->page = page;
1263                         return 0; /* success */
1264                 }
1265                 sa += len;
1266                 offset -= len;
1267         }
1268
1269         return VM_FAULT_SIGBUS;
1270 }
1271
1272 static const struct vm_operations_struct sg_mmap_vm_ops = {
1273         .fault = sg_vma_fault,
1274 };
1275
1276 static int
1277 sg_mmap(struct file *filp, struct vm_area_struct *vma)
1278 {
1279         Sg_fd *sfp;
1280         unsigned long req_sz, len, sa;
1281         Sg_scatter_hold *rsv_schp;
1282         int k, length;
1283         int ret = 0;
1284
1285         if ((!filp) || (!vma) || (!(sfp = (Sg_fd *) filp->private_data)))
1286                 return -ENXIO;
1287         req_sz = vma->vm_end - vma->vm_start;
1288         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sfp->parentdp,
1289                                       "sg_mmap starting, vm_start=%p, len=%d\n",
1290                                       (void *) vma->vm_start, (int) req_sz));
1291         if (vma->vm_pgoff)
1292                 return -EINVAL; /* want no offset */
1293         rsv_schp = &sfp->reserve;
1294         mutex_lock(&sfp->f_mutex);
1295         if (req_sz > rsv_schp->bufflen) {
1296                 ret = -ENOMEM;  /* cannot map more than reserved buffer */
1297                 goto out;
1298         }
1299
1300         sa = vma->vm_start;
1301         length = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1302         for (k = 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) {
1303                 len = vma->vm_end - sa;
1304                 len = (len < length) ? len : length;
1305                 sa += len;
1306         }
1307
1308         sfp->mmap_called = 1;
1309         vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP;
1310         vma->vm_private_data = sfp;
1311         vma->vm_ops = &sg_mmap_vm_ops;
1312 out:
1313         mutex_unlock(&sfp->f_mutex);
1314         return ret;
1315 }
1316
1317 static void
1318 sg_rq_end_io_usercontext(struct work_struct *work)
1319 {
1320         struct sg_request *srp = container_of(work, struct sg_request, ew.work);
1321         struct sg_fd *sfp = srp->parentfp;
1322
1323         sg_finish_rem_req(srp);
1324         sg_remove_request(sfp, srp);
1325         kref_put(&sfp->f_ref, sg_remove_sfp);
1326 }
1327
1328 /*
1329  * This function is a "bottom half" handler that is called by the mid
1330  * level when a command is completed (or has failed).
1331  */
1332 static void
1333 sg_rq_end_io(struct request *rq, blk_status_t status)
1334 {
1335         struct sg_request *srp = rq->end_io_data;
1336         struct scsi_request *req = scsi_req(rq);
1337         Sg_device *sdp;
1338         Sg_fd *sfp;
1339         unsigned long iflags;
1340         unsigned int ms;
1341         char *sense;
1342         int result, resid, done = 1;
1343
1344         if (WARN_ON(srp->done != 0))
1345                 return;
1346
1347         sfp = srp->parentfp;
1348         if (WARN_ON(sfp == NULL))
1349                 return;
1350
1351         sdp = sfp->parentdp;
1352         if (unlikely(atomic_read(&sdp->detaching)))
1353                 pr_info("%s: device detaching\n", __func__);
1354
1355         sense = req->sense;
1356         result = req->result;
1357         resid = req->resid_len;
1358
1359         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sdp,
1360                                       "sg_cmd_done: pack_id=%d, res=0x%x\n",
1361                                       srp->header.pack_id, result));
1362         srp->header.resid = resid;
1363         ms = jiffies_to_msecs(jiffies);
1364         srp->header.duration = (ms > srp->header.duration) ?
1365                                 (ms - srp->header.duration) : 0;
1366         if (0 != result) {
1367                 struct scsi_sense_hdr sshdr;
1368
1369                 srp->header.status = 0xff & result;
1370                 srp->header.masked_status = status_byte(result);
1371                 srp->header.msg_status = msg_byte(result);
1372                 srp->header.host_status = host_byte(result);
1373                 srp->header.driver_status = driver_byte(result);
1374                 if ((sdp->sgdebug > 0) &&
1375                     ((CHECK_CONDITION == srp->header.masked_status) ||
1376                      (COMMAND_TERMINATED == srp->header.masked_status)))
1377                         __scsi_print_sense(sdp->device, __func__, sense,
1378                                            SCSI_SENSE_BUFFERSIZE);
1379
1380                 /* Following if statement is a patch supplied by Eric Youngdale */
1381                 if (driver_byte(result) != 0
1382                     && scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, &sshdr)
1383                     && !scsi_sense_is_deferred(&sshdr)
1384                     && sshdr.sense_key == UNIT_ATTENTION
1385                     && sdp->device->removable) {
1386                         /* Detected possible disc change. Set the bit - this */
1387                         /* may be used if there are filesystems using this device */
1388                         sdp->device->changed = 1;
1389                 }
1390         }
1391
1392         if (req->sense_len)
1393                 memcpy(srp->sense_b, req->sense, SCSI_SENSE_BUFFERSIZE);
1394
1395         /* Rely on write phase to clean out srp status values, so no "else" */
1396
1397         /*
1398          * Free the request as soon as it is complete so that its resources
1399          * can be reused without waiting for userspace to read() the
1400          * result.  But keep the associated bio (if any) around until
1401          * blk_rq_unmap_user() can be called from user context.
1402          */
1403         srp->rq = NULL;
1404         scsi_req_free_cmd(scsi_req(rq));
1405         blk_put_request(rq);
1406
1407         write_lock_irqsave(&sfp->rq_list_lock, iflags);
1408         if (unlikely(srp->orphan)) {
1409                 if (sfp->keep_orphan)
1410                         srp->sg_io_owned = 0;
1411                 else
1412                         done = 0;
1413         }
1414         srp->done = done;
1415         write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1416
1417         if (likely(done)) {
1418                 /* Now wake up any sg_read() that is waiting for this
1419                  * packet.
1420                  */
1421                 wake_up_interruptible(&sfp->read_wait);
1422                 kill_fasync(&sfp->async_qp, SIGPOLL, POLL_IN);
1423                 kref_put(&sfp->f_ref, sg_remove_sfp);
1424         } else {
1425                 INIT_WORK(&srp->ew.work, sg_rq_end_io_usercontext);
1426                 schedule_work(&srp->ew.work);
1427         }
1428 }
1429
1430 static const struct file_operations sg_fops = {
1431         .owner = THIS_MODULE,
1432         .read = sg_read,
1433         .write = sg_write,
1434         .poll = sg_poll,
1435         .unlocked_ioctl = sg_ioctl,
1436 #ifdef CONFIG_COMPAT
1437         .compat_ioctl = sg_compat_ioctl,
1438 #endif
1439         .open = sg_open,
1440         .mmap = sg_mmap,
1441         .release = sg_release,
1442         .fasync = sg_fasync,
1443         .llseek = no_llseek,
1444 };
1445
1446 static struct class *sg_sysfs_class;
1447
1448 static int sg_sysfs_valid = 0;
1449
1450 static Sg_device *
1451 sg_alloc(struct gendisk *disk, struct scsi_device *scsidp)
1452 {
1453         struct request_queue *q = scsidp->request_queue;
1454         Sg_device *sdp;
1455         unsigned long iflags;
1456         int error;
1457         u32 k;
1458
1459         sdp = kzalloc(sizeof(Sg_device), GFP_KERNEL);
1460         if (!sdp) {
1461                 sdev_printk(KERN_WARNING, scsidp, "%s: kmalloc Sg_device "
1462                             "failure\n", __func__);
1463                 return ERR_PTR(-ENOMEM);
1464         }
1465
1466         idr_preload(GFP_KERNEL);
1467         write_lock_irqsave(&sg_index_lock, iflags);
1468
1469         error = idr_alloc(&sg_index_idr, sdp, 0, SG_MAX_DEVS, GFP_NOWAIT);
1470         if (error < 0) {
1471                 if (error == -ENOSPC) {
1472                         sdev_printk(KERN_WARNING, scsidp,
1473                                     "Unable to attach sg device type=%d, minor number exceeds %d\n",
1474                                     scsidp->type, SG_MAX_DEVS - 1);
1475                         error = -ENODEV;
1476                 } else {
1477                         sdev_printk(KERN_WARNING, scsidp, "%s: idr "
1478                                     "allocation Sg_device failure: %d\n",
1479                                     __func__, error);
1480                 }
1481                 goto out_unlock;
1482         }
1483         k = error;
1484
1485         SCSI_LOG_TIMEOUT(3, sdev_printk(KERN_INFO, scsidp,
1486                                         "sg_alloc: dev=%d \n", k));
1487         sprintf(disk->disk_name, "sg%d", k);
1488         disk->first_minor = k;
1489         sdp->disk = disk;
1490         sdp->device = scsidp;
1491         mutex_init(&sdp->open_rel_lock);
1492         INIT_LIST_HEAD(&sdp->sfds);
1493         init_waitqueue_head(&sdp->open_wait);
1494         atomic_set(&sdp->detaching, 0);
1495         rwlock_init(&sdp->sfd_lock);
1496         sdp->sg_tablesize = queue_max_segments(q);
1497         sdp->index = k;
1498         kref_init(&sdp->d_ref);
1499         error = 0;
1500
1501 out_unlock:
1502         write_unlock_irqrestore(&sg_index_lock, iflags);
1503         idr_preload_end();
1504
1505         if (error) {
1506                 kfree(sdp);
1507                 return ERR_PTR(error);
1508         }
1509         return sdp;
1510 }
1511
1512 static int
1513 sg_add_device(struct device *cl_dev, struct class_interface *cl_intf)
1514 {
1515         struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
1516         struct gendisk *disk;
1517         Sg_device *sdp = NULL;
1518         struct cdev * cdev = NULL;
1519         int error;
1520         unsigned long iflags;
1521
1522         disk = alloc_disk(1);
1523         if (!disk) {
1524                 pr_warn("%s: alloc_disk failed\n", __func__);
1525                 return -ENOMEM;
1526         }
1527         disk->major = SCSI_GENERIC_MAJOR;
1528
1529         error = -ENOMEM;
1530         cdev = cdev_alloc();
1531         if (!cdev) {
1532                 pr_warn("%s: cdev_alloc failed\n", __func__);
1533                 goto out;
1534         }
1535         cdev->owner = THIS_MODULE;
1536         cdev->ops = &sg_fops;
1537
1538         sdp = sg_alloc(disk, scsidp);
1539         if (IS_ERR(sdp)) {
1540                 pr_warn("%s: sg_alloc failed\n", __func__);
1541                 error = PTR_ERR(sdp);
1542                 goto out;
1543         }
1544
1545         error = cdev_add(cdev, MKDEV(SCSI_GENERIC_MAJOR, sdp->index), 1);
1546         if (error)
1547                 goto cdev_add_err;
1548
1549         sdp->cdev = cdev;
1550         if (sg_sysfs_valid) {
1551                 struct device *sg_class_member;
1552
1553                 sg_class_member = device_create(sg_sysfs_class, cl_dev->parent,
1554                                                 MKDEV(SCSI_GENERIC_MAJOR,
1555                                                       sdp->index),
1556                                                 sdp, "%s", disk->disk_name);
1557                 if (IS_ERR(sg_class_member)) {
1558                         pr_err("%s: device_create failed\n", __func__);
1559                         error = PTR_ERR(sg_class_member);
1560                         goto cdev_add_err;
1561                 }
1562                 error = sysfs_create_link(&scsidp->sdev_gendev.kobj,
1563                                           &sg_class_member->kobj, "generic");
1564                 if (error)
1565                         pr_err("%s: unable to make symlink 'generic' back "
1566                                "to sg%d\n", __func__, sdp->index);
1567         } else
1568                 pr_warn("%s: sg_sys Invalid\n", __func__);
1569
1570         sdev_printk(KERN_NOTICE, scsidp, "Attached scsi generic sg%d "
1571                     "type %d\n", sdp->index, scsidp->type);
1572
1573         dev_set_drvdata(cl_dev, sdp);
1574
1575         return 0;
1576
1577 cdev_add_err:
1578         write_lock_irqsave(&sg_index_lock, iflags);
1579         idr_remove(&sg_index_idr, sdp->index);
1580         write_unlock_irqrestore(&sg_index_lock, iflags);
1581         kfree(sdp);
1582
1583 out:
1584         put_disk(disk);
1585         if (cdev)
1586                 cdev_del(cdev);
1587         return error;
1588 }
1589
1590 static void
1591 sg_device_destroy(struct kref *kref)
1592 {
1593         struct sg_device *sdp = container_of(kref, struct sg_device, d_ref);
1594         unsigned long flags;
1595
1596         /* CAUTION!  Note that the device can still be found via idr_find()
1597          * even though the refcount is 0.  Therefore, do idr_remove() BEFORE
1598          * any other cleanup.
1599          */
1600
1601         write_lock_irqsave(&sg_index_lock, flags);
1602         idr_remove(&sg_index_idr, sdp->index);
1603         write_unlock_irqrestore(&sg_index_lock, flags);
1604
1605         SCSI_LOG_TIMEOUT(3,
1606                 sg_printk(KERN_INFO, sdp, "sg_device_destroy\n"));
1607
1608         put_disk(sdp->disk);
1609         kfree(sdp);
1610 }
1611
1612 static void
1613 sg_remove_device(struct device *cl_dev, struct class_interface *cl_intf)
1614 {
1615         struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
1616         Sg_device *sdp = dev_get_drvdata(cl_dev);
1617         unsigned long iflags;
1618         Sg_fd *sfp;
1619         int val;
1620
1621         if (!sdp)
1622                 return;
1623         /* want sdp->detaching non-zero as soon as possible */
1624         val = atomic_inc_return(&sdp->detaching);
1625         if (val > 1)
1626                 return; /* only want to do following once per device */
1627
1628         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
1629                                       "%s\n", __func__));
1630
1631         read_lock_irqsave(&sdp->sfd_lock, iflags);
1632         list_for_each_entry(sfp, &sdp->sfds, sfd_siblings) {
1633                 wake_up_interruptible_all(&sfp->read_wait);
1634                 kill_fasync(&sfp->async_qp, SIGPOLL, POLL_HUP);
1635         }
1636         wake_up_interruptible_all(&sdp->open_wait);
1637         read_unlock_irqrestore(&sdp->sfd_lock, iflags);
1638
1639         sysfs_remove_link(&scsidp->sdev_gendev.kobj, "generic");
1640         device_destroy(sg_sysfs_class, MKDEV(SCSI_GENERIC_MAJOR, sdp->index));
1641         cdev_del(sdp->cdev);
1642         sdp->cdev = NULL;
1643
1644         kref_put(&sdp->d_ref, sg_device_destroy);
1645 }
1646
1647 module_param_named(scatter_elem_sz, scatter_elem_sz, int, S_IRUGO | S_IWUSR);
1648 module_param_named(def_reserved_size, def_reserved_size, int,
1649                    S_IRUGO | S_IWUSR);
1650 module_param_named(allow_dio, sg_allow_dio, int, S_IRUGO | S_IWUSR);
1651
1652 MODULE_AUTHOR("Douglas Gilbert");
1653 MODULE_DESCRIPTION("SCSI generic (sg) driver");
1654 MODULE_LICENSE("GPL");
1655 MODULE_VERSION(SG_VERSION_STR);
1656 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_GENERIC_MAJOR);
1657
1658 MODULE_PARM_DESC(scatter_elem_sz, "scatter gather element "
1659                 "size (default: max(SG_SCATTER_SZ, PAGE_SIZE))");
1660 MODULE_PARM_DESC(def_reserved_size, "size of buffer reserved for each fd");
1661 MODULE_PARM_DESC(allow_dio, "allow direct I/O (default: 0 (disallow))");
1662
1663 static int __init
1664 init_sg(void)
1665 {
1666         int rc;
1667
1668         if (scatter_elem_sz < PAGE_SIZE) {
1669                 scatter_elem_sz = PAGE_SIZE;
1670                 scatter_elem_sz_prev = scatter_elem_sz;
1671         }
1672         if (def_reserved_size >= 0)
1673                 sg_big_buff = def_reserved_size;
1674         else
1675                 def_reserved_size = sg_big_buff;
1676
1677         rc = register_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1678                                     SG_MAX_DEVS, "sg");
1679         if (rc)
1680                 return rc;
1681         sg_sysfs_class = class_create(THIS_MODULE, "scsi_generic");
1682         if ( IS_ERR(sg_sysfs_class) ) {
1683                 rc = PTR_ERR(sg_sysfs_class);
1684                 goto err_out;
1685         }
1686         sg_sysfs_valid = 1;
1687         rc = scsi_register_interface(&sg_interface);
1688         if (0 == rc) {
1689 #ifdef CONFIG_SCSI_PROC_FS
1690                 sg_proc_init();
1691 #endif                          /* CONFIG_SCSI_PROC_FS */
1692                 return 0;
1693         }
1694         class_destroy(sg_sysfs_class);
1695 err_out:
1696         unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0), SG_MAX_DEVS);
1697         return rc;
1698 }
1699
1700 static void __exit
1701 exit_sg(void)
1702 {
1703 #ifdef CONFIG_SCSI_PROC_FS
1704         remove_proc_subtree("scsi/sg", NULL);
1705 #endif                          /* CONFIG_SCSI_PROC_FS */
1706         scsi_unregister_interface(&sg_interface);
1707         class_destroy(sg_sysfs_class);
1708         sg_sysfs_valid = 0;
1709         unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1710                                  SG_MAX_DEVS);
1711         idr_destroy(&sg_index_idr);
1712 }
1713
1714 static int
1715 sg_start_req(Sg_request *srp, unsigned char *cmd)
1716 {
1717         int res;
1718         struct request *rq;
1719         struct scsi_request *req;
1720         Sg_fd *sfp = srp->parentfp;
1721         sg_io_hdr_t *hp = &srp->header;
1722         int dxfer_len = (int) hp->dxfer_len;
1723         int dxfer_dir = hp->dxfer_direction;
1724         unsigned int iov_count = hp->iovec_count;
1725         Sg_scatter_hold *req_schp = &srp->data;
1726         Sg_scatter_hold *rsv_schp = &sfp->reserve;
1727         struct request_queue *q = sfp->parentdp->device->request_queue;
1728         struct rq_map_data *md, map_data;
1729         int rw = hp->dxfer_direction == SG_DXFER_TO_DEV ? WRITE : READ;
1730         unsigned char *long_cmdp = NULL;
1731
1732         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1733                                       "sg_start_req: dxfer_len=%d\n",
1734                                       dxfer_len));
1735
1736         if (hp->cmd_len > BLK_MAX_CDB) {
1737                 long_cmdp = kzalloc(hp->cmd_len, GFP_KERNEL);
1738                 if (!long_cmdp)
1739                         return -ENOMEM;
1740         }
1741
1742         /*
1743          * NOTE
1744          *
1745          * With scsi-mq enabled, there are a fixed number of preallocated
1746          * requests equal in number to shost->can_queue.  If all of the
1747          * preallocated requests are already in use, then blk_get_request()
1748          * will sleep until an active command completes, freeing up a request.
1749          * Although waiting in an asynchronous interface is less than ideal, we
1750          * do not want to use BLK_MQ_REQ_NOWAIT here because userspace might
1751          * not expect an EWOULDBLOCK from this condition.
1752          */
1753         rq = blk_get_request(q, hp->dxfer_direction == SG_DXFER_TO_DEV ?
1754                         REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, 0);
1755         if (IS_ERR(rq)) {
1756                 kfree(long_cmdp);
1757                 return PTR_ERR(rq);
1758         }
1759         req = scsi_req(rq);
1760
1761         if (hp->cmd_len > BLK_MAX_CDB)
1762                 req->cmd = long_cmdp;
1763         memcpy(req->cmd, cmd, hp->cmd_len);
1764         req->cmd_len = hp->cmd_len;
1765
1766         srp->rq = rq;
1767         rq->end_io_data = srp;
1768         req->retries = SG_DEFAULT_RETRIES;
1769
1770         if ((dxfer_len <= 0) || (dxfer_dir == SG_DXFER_NONE))
1771                 return 0;
1772
1773         if (sg_allow_dio && hp->flags & SG_FLAG_DIRECT_IO &&
1774             dxfer_dir != SG_DXFER_UNKNOWN && !iov_count &&
1775             !sfp->parentdp->device->host->unchecked_isa_dma &&
1776             blk_rq_aligned(q, (unsigned long)hp->dxferp, dxfer_len))
1777                 md = NULL;
1778         else
1779                 md = &map_data;
1780
1781         if (md) {
1782                 mutex_lock(&sfp->f_mutex);
1783                 if (dxfer_len <= rsv_schp->bufflen &&
1784                     !sfp->res_in_use) {
1785                         sfp->res_in_use = 1;
1786                         sg_link_reserve(sfp, srp, dxfer_len);
1787                 } else if (hp->flags & SG_FLAG_MMAP_IO) {
1788                         res = -EBUSY; /* sfp->res_in_use == 1 */
1789                         if (dxfer_len > rsv_schp->bufflen)
1790                                 res = -ENOMEM;
1791                         mutex_unlock(&sfp->f_mutex);
1792                         return res;
1793                 } else {
1794                         res = sg_build_indirect(req_schp, sfp, dxfer_len);
1795                         if (res) {
1796                                 mutex_unlock(&sfp->f_mutex);
1797                                 return res;
1798                         }
1799                 }
1800                 mutex_unlock(&sfp->f_mutex);
1801
1802                 md->pages = req_schp->pages;
1803                 md->page_order = req_schp->page_order;
1804                 md->nr_entries = req_schp->k_use_sg;
1805                 md->offset = 0;
1806                 md->null_mapped = hp->dxferp ? 0 : 1;
1807                 if (dxfer_dir == SG_DXFER_TO_FROM_DEV)
1808                         md->from_user = 1;
1809                 else
1810                         md->from_user = 0;
1811         }
1812
1813         if (iov_count) {
1814                 struct iovec *iov = NULL;
1815                 struct iov_iter i;
1816
1817 #ifdef CONFIG_COMPAT
1818                 if (in_compat_syscall())
1819                         res = compat_import_iovec(rw, hp->dxferp, iov_count,
1820                                                   0, &iov, &i);
1821                 else
1822 #endif
1823                         res = import_iovec(rw, hp->dxferp, iov_count,
1824                                            0, &iov, &i);
1825                 if (res < 0)
1826                         return res;
1827
1828                 iov_iter_truncate(&i, hp->dxfer_len);
1829                 if (!iov_iter_count(&i)) {
1830                         kfree(iov);
1831                         return -EINVAL;
1832                 }
1833
1834                 res = blk_rq_map_user_iov(q, rq, md, &i, GFP_ATOMIC);
1835                 kfree(iov);
1836         } else
1837                 res = blk_rq_map_user(q, rq, md, hp->dxferp,
1838                                       hp->dxfer_len, GFP_ATOMIC);
1839
1840         if (!res) {
1841                 srp->bio = rq->bio;
1842
1843                 if (!md) {
1844                         req_schp->dio_in_use = 1;
1845                         hp->info |= SG_INFO_DIRECT_IO;
1846                 }
1847         }
1848         return res;
1849 }
1850
1851 static int
1852 sg_finish_rem_req(Sg_request *srp)
1853 {
1854         int ret = 0;
1855
1856         Sg_fd *sfp = srp->parentfp;
1857         Sg_scatter_hold *req_schp = &srp->data;
1858
1859         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1860                                       "sg_finish_rem_req: res_used=%d\n",
1861                                       (int) srp->res_used));
1862         if (srp->bio)
1863                 ret = blk_rq_unmap_user(srp->bio);
1864
1865         if (srp->rq) {
1866                 scsi_req_free_cmd(scsi_req(srp->rq));
1867                 blk_put_request(srp->rq);
1868         }
1869
1870         if (srp->res_used)
1871                 sg_unlink_reserve(sfp, srp);
1872         else
1873                 sg_remove_scat(sfp, req_schp);
1874
1875         return ret;
1876 }
1877
1878 static int
1879 sg_build_sgat(Sg_scatter_hold * schp, const Sg_fd * sfp, int tablesize)
1880 {
1881         int sg_bufflen = tablesize * sizeof(struct page *);
1882         gfp_t gfp_flags = GFP_ATOMIC | __GFP_NOWARN;
1883
1884         schp->pages = kzalloc(sg_bufflen, gfp_flags);
1885         if (!schp->pages)
1886                 return -ENOMEM;
1887         schp->sglist_len = sg_bufflen;
1888         return tablesize;       /* number of scat_gath elements allocated */
1889 }
1890
1891 static int
1892 sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size)
1893 {
1894         int ret_sz = 0, i, k, rem_sz, num, mx_sc_elems;
1895         int sg_tablesize = sfp->parentdp->sg_tablesize;
1896         int blk_size = buff_size, order;
1897         gfp_t gfp_mask = GFP_ATOMIC | __GFP_COMP | __GFP_NOWARN | __GFP_ZERO;
1898         struct sg_device *sdp = sfp->parentdp;
1899
1900         if (blk_size < 0)
1901                 return -EFAULT;
1902         if (0 == blk_size)
1903                 ++blk_size;     /* don't know why */
1904         /* round request up to next highest SG_SECTOR_SZ byte boundary */
1905         blk_size = ALIGN(blk_size, SG_SECTOR_SZ);
1906         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1907                 "sg_build_indirect: buff_size=%d, blk_size=%d\n",
1908                 buff_size, blk_size));
1909
1910         /* N.B. ret_sz carried into this block ... */
1911         mx_sc_elems = sg_build_sgat(schp, sfp, sg_tablesize);
1912         if (mx_sc_elems < 0)
1913                 return mx_sc_elems;     /* most likely -ENOMEM */
1914
1915         num = scatter_elem_sz;
1916         if (unlikely(num != scatter_elem_sz_prev)) {
1917                 if (num < PAGE_SIZE) {
1918                         scatter_elem_sz = PAGE_SIZE;
1919                         scatter_elem_sz_prev = PAGE_SIZE;
1920                 } else
1921                         scatter_elem_sz_prev = num;
1922         }
1923
1924         if (sdp->device->host->unchecked_isa_dma)
1925                 gfp_mask |= GFP_DMA;
1926
1927         order = get_order(num);
1928 retry:
1929         ret_sz = 1 << (PAGE_SHIFT + order);
1930
1931         for (k = 0, rem_sz = blk_size; rem_sz > 0 && k < mx_sc_elems;
1932              k++, rem_sz -= ret_sz) {
1933
1934                 num = (rem_sz > scatter_elem_sz_prev) ?
1935                         scatter_elem_sz_prev : rem_sz;
1936
1937                 schp->pages[k] = alloc_pages(gfp_mask, order);
1938                 if (!schp->pages[k])
1939                         goto out;
1940
1941                 if (num == scatter_elem_sz_prev) {
1942                         if (unlikely(ret_sz > scatter_elem_sz_prev)) {
1943                                 scatter_elem_sz = ret_sz;
1944                                 scatter_elem_sz_prev = ret_sz;
1945                         }
1946                 }
1947
1948                 SCSI_LOG_TIMEOUT(5, sg_printk(KERN_INFO, sfp->parentdp,
1949                                  "sg_build_indirect: k=%d, num=%d, ret_sz=%d\n",
1950                                  k, num, ret_sz));
1951         }               /* end of for loop */
1952
1953         schp->page_order = order;
1954         schp->k_use_sg = k;
1955         SCSI_LOG_TIMEOUT(5, sg_printk(KERN_INFO, sfp->parentdp,
1956                          "sg_build_indirect: k_use_sg=%d, rem_sz=%d\n",
1957                          k, rem_sz));
1958
1959         schp->bufflen = blk_size;
1960         if (rem_sz > 0) /* must have failed */
1961                 return -ENOMEM;
1962         return 0;
1963 out:
1964         for (i = 0; i < k; i++)
1965                 __free_pages(schp->pages[i], order);
1966
1967         if (--order >= 0)
1968                 goto retry;
1969
1970         return -ENOMEM;
1971 }
1972
1973 static void
1974 sg_remove_scat(Sg_fd * sfp, Sg_scatter_hold * schp)
1975 {
1976         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1977                          "sg_remove_scat: k_use_sg=%d\n", schp->k_use_sg));
1978         if (schp->pages && schp->sglist_len > 0) {
1979                 if (!schp->dio_in_use) {
1980                         int k;
1981
1982                         for (k = 0; k < schp->k_use_sg && schp->pages[k]; k++) {
1983                                 SCSI_LOG_TIMEOUT(5,
1984                                         sg_printk(KERN_INFO, sfp->parentdp,
1985                                         "sg_remove_scat: k=%d, pg=0x%p\n",
1986                                         k, schp->pages[k]));
1987                                 __free_pages(schp->pages[k], schp->page_order);
1988                         }
1989
1990                         kfree(schp->pages);
1991                 }
1992         }
1993         memset(schp, 0, sizeof (*schp));
1994 }
1995
1996 static int
1997 sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer)
1998 {
1999         Sg_scatter_hold *schp = &srp->data;
2000         int k, num;
2001
2002         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, srp->parentfp->parentdp,
2003                          "sg_read_oxfer: num_read_xfer=%d\n",
2004                          num_read_xfer));
2005         if ((!outp) || (num_read_xfer <= 0))
2006                 return 0;
2007
2008         num = 1 << (PAGE_SHIFT + schp->page_order);
2009         for (k = 0; k < schp->k_use_sg && schp->pages[k]; k++) {
2010                 if (num > num_read_xfer) {
2011                         if (copy_to_user(outp, page_address(schp->pages[k]),
2012                                            num_read_xfer))
2013                                 return -EFAULT;
2014                         break;
2015                 } else {
2016                         if (copy_to_user(outp, page_address(schp->pages[k]),
2017                                            num))
2018                                 return -EFAULT;
2019                         num_read_xfer -= num;
2020                         if (num_read_xfer <= 0)
2021                                 break;
2022                         outp += num;
2023                 }
2024         }
2025
2026         return 0;
2027 }
2028
2029 static void
2030 sg_build_reserve(Sg_fd * sfp, int req_size)
2031 {
2032         Sg_scatter_hold *schp = &sfp->reserve;
2033
2034         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
2035                          "sg_build_reserve: req_size=%d\n", req_size));
2036         do {
2037                 if (req_size < PAGE_SIZE)
2038                         req_size = PAGE_SIZE;
2039                 if (0 == sg_build_indirect(schp, sfp, req_size))
2040                         return;
2041                 else
2042                         sg_remove_scat(sfp, schp);
2043                 req_size >>= 1; /* divide by 2 */
2044         } while (req_size > (PAGE_SIZE / 2));
2045 }
2046
2047 static void
2048 sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size)
2049 {
2050         Sg_scatter_hold *req_schp = &srp->data;
2051         Sg_scatter_hold *rsv_schp = &sfp->reserve;
2052         int k, num, rem;
2053
2054         srp->res_used = 1;
2055         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
2056                          "sg_link_reserve: size=%d\n", size));
2057         rem = size;
2058
2059         num = 1 << (PAGE_SHIFT + rsv_schp->page_order);
2060         for (k = 0; k < rsv_schp->k_use_sg; k++) {
2061                 if (rem <= num) {
2062                         req_schp->k_use_sg = k + 1;
2063                         req_schp->sglist_len = rsv_schp->sglist_len;
2064                         req_schp->pages = rsv_schp->pages;
2065
2066                         req_schp->bufflen = size;
2067                         req_schp->page_order = rsv_schp->page_order;
2068                         break;
2069                 } else
2070                         rem -= num;
2071         }
2072
2073         if (k >= rsv_schp->k_use_sg)
2074                 SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sfp->parentdp,
2075                                  "sg_link_reserve: BAD size\n"));
2076 }
2077
2078 static void
2079 sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp)
2080 {
2081         Sg_scatter_hold *req_schp = &srp->data;
2082
2083         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, srp->parentfp->parentdp,
2084                                       "sg_unlink_reserve: req->k_use_sg=%d\n",
2085                                       (int) req_schp->k_use_sg));
2086         req_schp->k_use_sg = 0;
2087         req_schp->bufflen = 0;
2088         req_schp->pages = NULL;
2089         req_schp->page_order = 0;
2090         req_schp->sglist_len = 0;
2091         srp->res_used = 0;
2092         /* Called without mutex lock to avoid deadlock */
2093         sfp->res_in_use = 0;
2094 }
2095
2096 static Sg_request *
2097 sg_get_rq_mark(Sg_fd * sfp, int pack_id)
2098 {
2099         Sg_request *resp;
2100         unsigned long iflags;
2101
2102         write_lock_irqsave(&sfp->rq_list_lock, iflags);
2103         list_for_each_entry(resp, &sfp->rq_list, entry) {
2104                 /* look for requests that are ready + not SG_IO owned */
2105                 if ((1 == resp->done) && (!resp->sg_io_owned) &&
2106                     ((-1 == pack_id) || (resp->header.pack_id == pack_id))) {
2107                         resp->done = 2; /* guard against other readers */
2108                         write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2109                         return resp;
2110                 }
2111         }
2112         write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2113         return NULL;
2114 }
2115
2116 /* always adds to end of list */
2117 static Sg_request *
2118 sg_add_request(Sg_fd * sfp)
2119 {
2120         int k;
2121         unsigned long iflags;
2122         Sg_request *rp = sfp->req_arr;
2123
2124         write_lock_irqsave(&sfp->rq_list_lock, iflags);
2125         if (!list_empty(&sfp->rq_list)) {
2126                 if (!sfp->cmd_q)
2127                         goto out_unlock;
2128
2129                 for (k = 0; k < SG_MAX_QUEUE; ++k, ++rp) {
2130                         if (!rp->parentfp)
2131                                 break;
2132                 }
2133                 if (k >= SG_MAX_QUEUE)
2134                         goto out_unlock;
2135         }
2136         memset(rp, 0, sizeof (Sg_request));
2137         rp->parentfp = sfp;
2138         rp->header.duration = jiffies_to_msecs(jiffies);
2139         list_add_tail(&rp->entry, &sfp->rq_list);
2140         write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2141         return rp;
2142 out_unlock:
2143         write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2144         return NULL;
2145 }
2146
2147 /* Return of 1 for found; 0 for not found */
2148 static int
2149 sg_remove_request(Sg_fd * sfp, Sg_request * srp)
2150 {
2151         unsigned long iflags;
2152         int res = 0;
2153
2154         if (!sfp || !srp || list_empty(&sfp->rq_list))
2155                 return res;
2156         write_lock_irqsave(&sfp->rq_list_lock, iflags);
2157         if (!list_empty(&srp->entry)) {
2158                 list_del(&srp->entry);
2159                 srp->parentfp = NULL;
2160                 res = 1;
2161         }
2162         write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2163         return res;
2164 }
2165
2166 static Sg_fd *
2167 sg_add_sfp(Sg_device * sdp)
2168 {
2169         Sg_fd *sfp;
2170         unsigned long iflags;
2171         int bufflen;
2172
2173         sfp = kzalloc(sizeof(*sfp), GFP_ATOMIC | __GFP_NOWARN);
2174         if (!sfp)
2175                 return ERR_PTR(-ENOMEM);
2176
2177         init_waitqueue_head(&sfp->read_wait);
2178         rwlock_init(&sfp->rq_list_lock);
2179         INIT_LIST_HEAD(&sfp->rq_list);
2180         kref_init(&sfp->f_ref);
2181         mutex_init(&sfp->f_mutex);
2182         sfp->timeout = SG_DEFAULT_TIMEOUT;
2183         sfp->timeout_user = SG_DEFAULT_TIMEOUT_USER;
2184         sfp->force_packid = SG_DEF_FORCE_PACK_ID;
2185         sfp->cmd_q = SG_DEF_COMMAND_Q;
2186         sfp->keep_orphan = SG_DEF_KEEP_ORPHAN;
2187         sfp->parentdp = sdp;
2188         write_lock_irqsave(&sdp->sfd_lock, iflags);
2189         if (atomic_read(&sdp->detaching)) {
2190                 write_unlock_irqrestore(&sdp->sfd_lock, iflags);
2191                 kfree(sfp);
2192                 return ERR_PTR(-ENODEV);
2193         }
2194         list_add_tail(&sfp->sfd_siblings, &sdp->sfds);
2195         write_unlock_irqrestore(&sdp->sfd_lock, iflags);
2196         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
2197                                       "sg_add_sfp: sfp=0x%p\n", sfp));
2198         if (unlikely(sg_big_buff != def_reserved_size))
2199                 sg_big_buff = def_reserved_size;
2200
2201         bufflen = min_t(int, sg_big_buff,
2202                         max_sectors_bytes(sdp->device->request_queue));
2203         sg_build_reserve(sfp, bufflen);
2204         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
2205                                       "sg_add_sfp: bufflen=%d, k_use_sg=%d\n",
2206                                       sfp->reserve.bufflen,
2207                                       sfp->reserve.k_use_sg));
2208
2209         kref_get(&sdp->d_ref);
2210         __module_get(THIS_MODULE);
2211         return sfp;
2212 }
2213
2214 static void
2215 sg_remove_sfp_usercontext(struct work_struct *work)
2216 {
2217         struct sg_fd *sfp = container_of(work, struct sg_fd, ew.work);
2218         struct sg_device *sdp = sfp->parentdp;
2219         Sg_request *srp;
2220         unsigned long iflags;
2221
2222         /* Cleanup any responses which were never read(). */
2223         write_lock_irqsave(&sfp->rq_list_lock, iflags);
2224         while (!list_empty(&sfp->rq_list)) {
2225                 srp = list_first_entry(&sfp->rq_list, Sg_request, entry);
2226                 sg_finish_rem_req(srp);
2227                 list_del(&srp->entry);
2228                 srp->parentfp = NULL;
2229         }
2230         write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2231
2232         if (sfp->reserve.bufflen > 0) {
2233                 SCSI_LOG_TIMEOUT(6, sg_printk(KERN_INFO, sdp,
2234                                 "sg_remove_sfp:    bufflen=%d, k_use_sg=%d\n",
2235                                 (int) sfp->reserve.bufflen,
2236                                 (int) sfp->reserve.k_use_sg));
2237                 sg_remove_scat(sfp, &sfp->reserve);
2238         }
2239
2240         SCSI_LOG_TIMEOUT(6, sg_printk(KERN_INFO, sdp,
2241                         "sg_remove_sfp: sfp=0x%p\n", sfp));
2242         kfree(sfp);
2243
2244         scsi_device_put(sdp->device);
2245         kref_put(&sdp->d_ref, sg_device_destroy);
2246         module_put(THIS_MODULE);
2247 }
2248
2249 static void
2250 sg_remove_sfp(struct kref *kref)
2251 {
2252         struct sg_fd *sfp = container_of(kref, struct sg_fd, f_ref);
2253         struct sg_device *sdp = sfp->parentdp;
2254         unsigned long iflags;
2255
2256         write_lock_irqsave(&sdp->sfd_lock, iflags);
2257         list_del(&sfp->sfd_siblings);
2258         write_unlock_irqrestore(&sdp->sfd_lock, iflags);
2259
2260         INIT_WORK(&sfp->ew.work, sg_remove_sfp_usercontext);
2261         schedule_work(&sfp->ew.work);
2262 }
2263
2264 #ifdef CONFIG_SCSI_PROC_FS
2265 static int
2266 sg_idr_max_id(int id, void *p, void *data)
2267 {
2268         int *k = data;
2269
2270         if (*k < id)
2271                 *k = id;
2272
2273         return 0;
2274 }
2275
2276 static int
2277 sg_last_dev(void)
2278 {
2279         int k = -1;
2280         unsigned long iflags;
2281
2282         read_lock_irqsave(&sg_index_lock, iflags);
2283         idr_for_each(&sg_index_idr, sg_idr_max_id, &k);
2284         read_unlock_irqrestore(&sg_index_lock, iflags);
2285         return k + 1;           /* origin 1 */
2286 }
2287 #endif
2288
2289 /* must be called with sg_index_lock held */
2290 static Sg_device *sg_lookup_dev(int dev)
2291 {
2292         return idr_find(&sg_index_idr, dev);
2293 }
2294
2295 static Sg_device *
2296 sg_get_dev(int dev)
2297 {
2298         struct sg_device *sdp;
2299         unsigned long flags;
2300
2301         read_lock_irqsave(&sg_index_lock, flags);
2302         sdp = sg_lookup_dev(dev);
2303         if (!sdp)
2304                 sdp = ERR_PTR(-ENXIO);
2305         else if (atomic_read(&sdp->detaching)) {
2306                 /* If sdp->detaching, then the refcount may already be 0, in
2307                  * which case it would be a bug to do kref_get().
2308                  */
2309                 sdp = ERR_PTR(-ENODEV);
2310         } else
2311                 kref_get(&sdp->d_ref);
2312         read_unlock_irqrestore(&sg_index_lock, flags);
2313
2314         return sdp;
2315 }
2316
2317 #ifdef CONFIG_SCSI_PROC_FS
2318 static int sg_proc_seq_show_int(struct seq_file *s, void *v);
2319
2320 static int sg_proc_single_open_adio(struct inode *inode, struct file *file);
2321 static ssize_t sg_proc_write_adio(struct file *filp, const char __user *buffer,
2322                                   size_t count, loff_t *off);
2323 static const struct file_operations adio_fops = {
2324         .owner = THIS_MODULE,
2325         .open = sg_proc_single_open_adio,
2326         .read = seq_read,
2327         .llseek = seq_lseek,
2328         .write = sg_proc_write_adio,
2329         .release = single_release,
2330 };
2331
2332 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file);
2333 static ssize_t sg_proc_write_dressz(struct file *filp,
2334                 const char __user *buffer, size_t count, loff_t *off);
2335 static const struct file_operations dressz_fops = {
2336         .owner = THIS_MODULE,
2337         .open = sg_proc_single_open_dressz,
2338         .read = seq_read,
2339         .llseek = seq_lseek,
2340         .write = sg_proc_write_dressz,
2341         .release = single_release,
2342 };
2343
2344 static int sg_proc_seq_show_version(struct seq_file *s, void *v);
2345 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v);
2346 static int sg_proc_seq_show_dev(struct seq_file *s, void *v);
2347 static void * dev_seq_start(struct seq_file *s, loff_t *pos);
2348 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos);
2349 static void dev_seq_stop(struct seq_file *s, void *v);
2350 static const struct seq_operations dev_seq_ops = {
2351         .start = dev_seq_start,
2352         .next  = dev_seq_next,
2353         .stop  = dev_seq_stop,
2354         .show  = sg_proc_seq_show_dev,
2355 };
2356
2357 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v);
2358 static const struct seq_operations devstrs_seq_ops = {
2359         .start = dev_seq_start,
2360         .next  = dev_seq_next,
2361         .stop  = dev_seq_stop,
2362         .show  = sg_proc_seq_show_devstrs,
2363 };
2364
2365 static int sg_proc_seq_show_debug(struct seq_file *s, void *v);
2366 static const struct seq_operations debug_seq_ops = {
2367         .start = dev_seq_start,
2368         .next  = dev_seq_next,
2369         .stop  = dev_seq_stop,
2370         .show  = sg_proc_seq_show_debug,
2371 };
2372
2373 static int
2374 sg_proc_init(void)
2375 {
2376         struct proc_dir_entry *p;
2377
2378         p = proc_mkdir("scsi/sg", NULL);
2379         if (!p)
2380                 return 1;
2381
2382         proc_create("allow_dio", S_IRUGO | S_IWUSR, p, &adio_fops);
2383         proc_create_seq("debug", S_IRUGO, p, &debug_seq_ops);
2384         proc_create("def_reserved_size", S_IRUGO | S_IWUSR, p, &dressz_fops);
2385         proc_create_single("device_hdr", S_IRUGO, p, sg_proc_seq_show_devhdr);
2386         proc_create_seq("devices", S_IRUGO, p, &dev_seq_ops);
2387         proc_create_seq("device_strs", S_IRUGO, p, &devstrs_seq_ops);
2388         proc_create_single("version", S_IRUGO, p, sg_proc_seq_show_version);
2389         return 0;
2390 }
2391
2392
2393 static int sg_proc_seq_show_int(struct seq_file *s, void *v)
2394 {
2395         seq_printf(s, "%d\n", *((int *)s->private));
2396         return 0;
2397 }
2398
2399 static int sg_proc_single_open_adio(struct inode *inode, struct file *file)
2400 {
2401         return single_open(file, sg_proc_seq_show_int, &sg_allow_dio);
2402 }
2403
2404 static ssize_t
2405 sg_proc_write_adio(struct file *filp, const char __user *buffer,
2406                    size_t count, loff_t *off)
2407 {
2408         int err;
2409         unsigned long num;
2410
2411         if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2412                 return -EACCES;
2413         err = kstrtoul_from_user(buffer, count, 0, &num);
2414         if (err)
2415                 return err;
2416         sg_allow_dio = num ? 1 : 0;
2417         return count;
2418 }
2419
2420 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file)
2421 {
2422         return single_open(file, sg_proc_seq_show_int, &sg_big_buff);
2423 }
2424
2425 static ssize_t
2426 sg_proc_write_dressz(struct file *filp, const char __user *buffer,
2427                      size_t count, loff_t *off)
2428 {
2429         int err;
2430         unsigned long k = ULONG_MAX;
2431
2432         if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2433                 return -EACCES;
2434
2435         err = kstrtoul_from_user(buffer, count, 0, &k);
2436         if (err)
2437                 return err;
2438         if (k <= 1048576) {     /* limit "big buff" to 1 MB */
2439                 sg_big_buff = k;
2440                 return count;
2441         }
2442         return -ERANGE;
2443 }
2444
2445 static int sg_proc_seq_show_version(struct seq_file *s, void *v)
2446 {
2447         seq_printf(s, "%d\t%s [%s]\n", sg_version_num, SG_VERSION_STR,
2448                    sg_version_date);
2449         return 0;
2450 }
2451
2452 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v)
2453 {
2454         seq_puts(s, "host\tchan\tid\tlun\ttype\topens\tqdepth\tbusy\tonline\n");
2455         return 0;
2456 }
2457
2458 struct sg_proc_deviter {
2459         loff_t  index;
2460         size_t  max;
2461 };
2462
2463 static void * dev_seq_start(struct seq_file *s, loff_t *pos)
2464 {
2465         struct sg_proc_deviter * it = kmalloc(sizeof(*it), GFP_KERNEL);
2466
2467         s->private = it;
2468         if (! it)
2469                 return NULL;
2470
2471         it->index = *pos;
2472         it->max = sg_last_dev();
2473         if (it->index >= it->max)
2474                 return NULL;
2475         return it;
2476 }
2477
2478 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos)
2479 {
2480         struct sg_proc_deviter * it = s->private;
2481
2482         *pos = ++it->index;
2483         return (it->index < it->max) ? it : NULL;
2484 }
2485
2486 static void dev_seq_stop(struct seq_file *s, void *v)
2487 {
2488         kfree(s->private);
2489 }
2490
2491 static int sg_proc_seq_show_dev(struct seq_file *s, void *v)
2492 {
2493         struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2494         Sg_device *sdp;
2495         struct scsi_device *scsidp;
2496         unsigned long iflags;
2497
2498         read_lock_irqsave(&sg_index_lock, iflags);
2499         sdp = it ? sg_lookup_dev(it->index) : NULL;
2500         if ((NULL == sdp) || (NULL == sdp->device) ||
2501             (atomic_read(&sdp->detaching)))
2502                 seq_puts(s, "-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\n");
2503         else {
2504                 scsidp = sdp->device;
2505                 seq_printf(s, "%d\t%d\t%d\t%llu\t%d\t%d\t%d\t%d\t%d\n",
2506                               scsidp->host->host_no, scsidp->channel,
2507                               scsidp->id, scsidp->lun, (int) scsidp->type,
2508                               1,
2509                               (int) scsidp->queue_depth,
2510                               (int) atomic_read(&scsidp->device_busy),
2511                               (int) scsi_device_online(scsidp));
2512         }
2513         read_unlock_irqrestore(&sg_index_lock, iflags);
2514         return 0;
2515 }
2516
2517 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v)
2518 {
2519         struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2520         Sg_device *sdp;
2521         struct scsi_device *scsidp;
2522         unsigned long iflags;
2523
2524         read_lock_irqsave(&sg_index_lock, iflags);
2525         sdp = it ? sg_lookup_dev(it->index) : NULL;
2526         scsidp = sdp ? sdp->device : NULL;
2527         if (sdp && scsidp && (!atomic_read(&sdp->detaching)))
2528                 seq_printf(s, "%8.8s\t%16.16s\t%4.4s\n",
2529                            scsidp->vendor, scsidp->model, scsidp->rev);
2530         else
2531                 seq_puts(s, "<no active device>\n");
2532         read_unlock_irqrestore(&sg_index_lock, iflags);
2533         return 0;
2534 }
2535
2536 /* must be called while holding sg_index_lock */
2537 static void sg_proc_debug_helper(struct seq_file *s, Sg_device * sdp)
2538 {
2539         int k, new_interface, blen, usg;
2540         Sg_request *srp;
2541         Sg_fd *fp;
2542         const sg_io_hdr_t *hp;
2543         const char * cp;
2544         unsigned int ms;
2545
2546         k = 0;
2547         list_for_each_entry(fp, &sdp->sfds, sfd_siblings) {
2548                 k++;
2549                 read_lock(&fp->rq_list_lock); /* irqs already disabled */
2550                 seq_printf(s, "   FD(%d): timeout=%dms bufflen=%d "
2551                            "(res)sgat=%d low_dma=%d\n", k,
2552                            jiffies_to_msecs(fp->timeout),
2553                            fp->reserve.bufflen,
2554                            (int) fp->reserve.k_use_sg,
2555                            (int) sdp->device->host->unchecked_isa_dma);
2556                 seq_printf(s, "   cmd_q=%d f_packid=%d k_orphan=%d closed=0\n",
2557                            (int) fp->cmd_q, (int) fp->force_packid,
2558                            (int) fp->keep_orphan);
2559                 list_for_each_entry(srp, &fp->rq_list, entry) {
2560                         hp = &srp->header;
2561                         new_interface = (hp->interface_id == '\0') ? 0 : 1;
2562                         if (srp->res_used) {
2563                                 if (new_interface &&
2564                                     (SG_FLAG_MMAP_IO & hp->flags))
2565                                         cp = "     mmap>> ";
2566                                 else
2567                                         cp = "     rb>> ";
2568                         } else {
2569                                 if (SG_INFO_DIRECT_IO_MASK & hp->info)
2570                                         cp = "     dio>> ";
2571                                 else
2572                                         cp = "     ";
2573                         }
2574                         seq_puts(s, cp);
2575                         blen = srp->data.bufflen;
2576                         usg = srp->data.k_use_sg;
2577                         seq_puts(s, srp->done ?
2578                                  ((1 == srp->done) ?  "rcv:" : "fin:")
2579                                   : "act:");
2580                         seq_printf(s, " id=%d blen=%d",
2581                                    srp->header.pack_id, blen);
2582                         if (srp->done)
2583                                 seq_printf(s, " dur=%d", hp->duration);
2584                         else {
2585                                 ms = jiffies_to_msecs(jiffies);
2586                                 seq_printf(s, " t_o/elap=%d/%d",
2587                                         (new_interface ? hp->timeout :
2588                                                   jiffies_to_msecs(fp->timeout)),
2589                                         (ms > hp->duration ? ms - hp->duration : 0));
2590                         }
2591                         seq_printf(s, "ms sgat=%d op=0x%02x\n", usg,
2592                                    (int) srp->data.cmd_opcode);
2593                 }
2594                 if (list_empty(&fp->rq_list))
2595                         seq_puts(s, "     No requests active\n");
2596                 read_unlock(&fp->rq_list_lock);
2597         }
2598 }
2599
2600 static int sg_proc_seq_show_debug(struct seq_file *s, void *v)
2601 {
2602         struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2603         Sg_device *sdp;
2604         unsigned long iflags;
2605
2606         if (it && (0 == it->index))
2607                 seq_printf(s, "max_active_device=%d  def_reserved_size=%d\n",
2608                            (int)it->max, sg_big_buff);
2609
2610         read_lock_irqsave(&sg_index_lock, iflags);
2611         sdp = it ? sg_lookup_dev(it->index) : NULL;
2612         if (NULL == sdp)
2613                 goto skip;
2614         read_lock(&sdp->sfd_lock);
2615         if (!list_empty(&sdp->sfds)) {
2616                 seq_printf(s, " >>> device=%s ", sdp->disk->disk_name);
2617                 if (atomic_read(&sdp->detaching))
2618                         seq_puts(s, "detaching pending close ");
2619                 else if (sdp->device) {
2620                         struct scsi_device *scsidp = sdp->device;
2621
2622                         seq_printf(s, "%d:%d:%d:%llu   em=%d",
2623                                    scsidp->host->host_no,
2624                                    scsidp->channel, scsidp->id,
2625                                    scsidp->lun,
2626                                    scsidp->host->hostt->emulated);
2627                 }
2628                 seq_printf(s, " sg_tablesize=%d excl=%d open_cnt=%d\n",
2629                            sdp->sg_tablesize, sdp->exclude, sdp->open_cnt);
2630                 sg_proc_debug_helper(s, sdp);
2631         }
2632         read_unlock(&sdp->sfd_lock);
2633 skip:
2634         read_unlock_irqrestore(&sg_index_lock, iflags);
2635         return 0;
2636 }
2637
2638 #endif                          /* CONFIG_SCSI_PROC_FS */
2639
2640 module_init(init_sg);
2641 module_exit(exit_sg);