drivers/nvme/target/tcp.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * NVMe over Fabrics TCP target.
   4  * Copyright (c) 2018 Lightbits Labs. All rights reserved.
   5  */
   6 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   7 #include <linux/module.h>
   8 #include <linux/init.h>
   9 #include <linux/slab.h>
  10 #include <linux/err.h>
  11 #include <linux/nvme-tcp.h>
  12 #include <net/sock.h>
  13 #include <net/tcp.h>
  14 #include <linux/inet.h>
  15 #include <linux/llist.h>
  16 #include <crypto/hash.h>
  17
  18 #include "nvmet.h"
  19
  20 #define NVMET_TCP_DEF_INLINE_DATA_SIZE  (4 * PAGE_SIZE)
  21
  22 /* Define the socket priority to use for connections were it is desirable
  23  * that the NIC consider performing optimized packet processing or filtering.
  24  * A non-zero value being sufficient to indicate general consideration of any
  25  * possible optimization.  Making it a module param allows for alternative
  26  * values that may be unique for some NIC implementations.
  27  */
  28 static int so_priority;
  29 module_param(so_priority, int, 0644);
  30 MODULE_PARM_DESC(so_priority, "nvmet tcp socket optimize priority");
  31
  32 /* Define a time period (in usecs) that io_work() shall sample an activated
  33  * queue before determining it to be idle.  This optional module behavior
  34  * can enable NIC solutions that support socket optimized packet processing
  35  * using advanced interrupt moderation techniques.
  36  */
  37 static int idle_poll_period_usecs;
  38 module_param(idle_poll_period_usecs, int, 0644);
  39 MODULE_PARM_DESC(idle_poll_period_usecs,
  40                 "nvmet tcp io_work poll till idle time period in usecs");
  41
  42 #define NVMET_TCP_RECV_BUDGET           8
  43 #define NVMET_TCP_SEND_BUDGET           8
  44 #define NVMET_TCP_IO_WORK_BUDGET        64
  45
  46 enum nvmet_tcp_send_state {
  47         NVMET_TCP_SEND_DATA_PDU,
  48         NVMET_TCP_SEND_DATA,
  49         NVMET_TCP_SEND_R2T,
  50         NVMET_TCP_SEND_DDGST,
  51         NVMET_TCP_SEND_RESPONSE
  52 };
  53
  54 enum nvmet_tcp_recv_state {
  55         NVMET_TCP_RECV_PDU,
  56         NVMET_TCP_RECV_DATA,
  57         NVMET_TCP_RECV_DDGST,
  58         NVMET_TCP_RECV_ERR,
  59 };
  60
  61 enum {
  62         NVMET_TCP_F_INIT_FAILED = (1 << 0),
  63 };
  64
  65 struct nvmet_tcp_cmd {
  66         struct nvmet_tcp_queue          *queue;
  67         struct nvmet_req                req;
  68
  69         struct nvme_tcp_cmd_pdu         *cmd_pdu;
  70         struct nvme_tcp_rsp_pdu         *rsp_pdu;
  71         struct nvme_tcp_data_pdu        *data_pdu;
  72         struct nvme_tcp_r2t_pdu         *r2t_pdu;
  73
  74         u32                             rbytes_done;
  75         u32                             wbytes_done;
  76
  77         u32                             pdu_len;
  78         u32                             pdu_recv;
  79         int                             sg_idx;
  80         int                             nr_mapped;
  81         struct msghdr                   recv_msg;
  82         struct kvec                     *iov;
  83         u32                             flags;
  84
  85         struct list_head                entry;
  86         struct llist_node               lentry;
  87
  88         /* send state */
  89         u32                             offset;
  90         struct scatterlist              *cur_sg;
  91         enum nvmet_tcp_send_state       state;
  92
  93         __le32                          exp_ddgst;
  94         __le32                          recv_ddgst;
  95 };
  96
  97 enum nvmet_tcp_queue_state {
  98         NVMET_TCP_Q_CONNECTING,
  99         NVMET_TCP_Q_LIVE,
 100         NVMET_TCP_Q_DISCONNECTING,
 101 };
 102
 103 struct nvmet_tcp_queue {
 104         struct socket           *sock;
 105         struct nvmet_tcp_port   *port;
 106         struct work_struct      io_work;
 107         struct nvmet_cq         nvme_cq;
 108         struct nvmet_sq         nvme_sq;
 109
 110         /* send state */
 111         struct nvmet_tcp_cmd    *cmds;
 112         unsigned int            nr_cmds;
 113         struct list_head        free_list;
 114         struct llist_head       resp_list;
 115         struct list_head        resp_send_list;
 116         int                     send_list_len;
 117         struct nvmet_tcp_cmd    *snd_cmd;
 118
 119         /* recv state */
 120         int                     offset;
 121         int                     left;
 122         enum nvmet_tcp_recv_state rcv_state;
 123         struct nvmet_tcp_cmd    *cmd;
 124         union nvme_tcp_pdu      pdu;
 125
 126         /* digest state */
 127         bool                    hdr_digest;
 128         bool                    data_digest;
 129         struct ahash_request    *snd_hash;
 130         struct ahash_request    *rcv_hash;
 131
 132         unsigned long           poll_end;
 133
 134         spinlock_t              state_lock;
 135         enum nvmet_tcp_queue_state state;
 136
 137         struct sockaddr_storage sockaddr;
 138         struct sockaddr_storage sockaddr_peer;
 139         struct work_struct      release_work;
 140
 141         int                     idx;
 142         struct list_head        queue_list;
 143
 144         struct nvmet_tcp_cmd    connect;
 145
 146         struct page_frag_cache  pf_cache;
 147
 148         void (*data_ready)(struct sock *);
 149         void (*state_change)(struct sock *);
 150         void (*write_space)(struct sock *);
 151 };
 152
 153 struct nvmet_tcp_port {
 154         struct socket           *sock;
 155         struct work_struct      accept_work;
 156         struct nvmet_port       *nport;
 157         struct sockaddr_storage addr;
 158         void (*data_ready)(struct sock *);
 159 };
 160
 161 static DEFINE_IDA(nvmet_tcp_queue_ida);
 162 static LIST_HEAD(nvmet_tcp_queue_list);
 163 static DEFINE_MUTEX(nvmet_tcp_queue_mutex);
 164
 165 static struct workqueue_struct *nvmet_tcp_wq;
 166 static const struct nvmet_fabrics_ops nvmet_tcp_ops;
 167 static void nvmet_tcp_free_cmd(struct nvmet_tcp_cmd *c);
 168 static void nvmet_tcp_finish_cmd(struct nvmet_tcp_cmd *cmd);
 169
 170 static inline u16 nvmet_tcp_cmd_tag(struct nvmet_tcp_queue *queue,
 171                 struct nvmet_tcp_cmd *cmd)
 172 {
 173         if (unlikely(!queue->nr_cmds)) {
 174                 /* We didn't allocate cmds yet, send 0xffff */
 175                 return USHRT_MAX;
 176         }
 177
 178         return cmd - queue->cmds;
 179 }
 180
 181 static inline bool nvmet_tcp_has_data_in(struct nvmet_tcp_cmd *cmd)
 182 {
 183         return nvme_is_write(cmd->req.cmd) &&
 184                 cmd->rbytes_done < cmd->req.transfer_len;
 185 }
 186
 187 static inline bool nvmet_tcp_need_data_in(struct nvmet_tcp_cmd *cmd)
 188 {
 189         return nvmet_tcp_has_data_in(cmd) && !cmd->req.cqe->status;
 190 }
 191
 192 static inline bool nvmet_tcp_need_data_out(struct nvmet_tcp_cmd *cmd)
 193 {
 194         return !nvme_is_write(cmd->req.cmd) &&
 195                 cmd->req.transfer_len > 0 &&
 196                 !cmd->req.cqe->status;
 197 }
 198
 199 static inline bool nvmet_tcp_has_inline_data(struct nvmet_tcp_cmd *cmd)
 200 {
 201         return nvme_is_write(cmd->req.cmd) && cmd->pdu_len &&
 202                 !cmd->rbytes_done;
 203 }
 204
 205 static inline struct nvmet_tcp_cmd *
 206 nvmet_tcp_get_cmd(struct nvmet_tcp_queue *queue)
 207 {
 208         struct nvmet_tcp_cmd *cmd;
 209
 210         cmd = list_first_entry_or_null(&queue->free_list,
 211                                 struct nvmet_tcp_cmd, entry);
 212         if (!cmd)
 213                 return NULL;
 214         list_del_init(&cmd->entry);
 215
 216         cmd->rbytes_done = cmd->wbytes_done = 0;
 217         cmd->pdu_len = 0;
 218         cmd->pdu_recv = 0;
 219         cmd->iov = NULL;
 220         cmd->flags = 0;
 221         return cmd;
 222 }
 223
 224 static inline void nvmet_tcp_put_cmd(struct nvmet_tcp_cmd *cmd)
 225 {
 226         if (unlikely(cmd == &cmd->queue->connect))
 227                 return;
 228
 229         list_add_tail(&cmd->entry, &cmd->queue->free_list);
 230 }
 231
 232 static inline int queue_cpu(struct nvmet_tcp_queue *queue)
 233 {
 234         return queue->sock->sk->sk_incoming_cpu;
 235 }
 236
 237 static inline u8 nvmet_tcp_hdgst_len(struct nvmet_tcp_queue *queue)
 238 {
 239         return queue->hdr_digest ? NVME_TCP_DIGEST_LENGTH : 0;
 240 }
 241
 242 static inline u8 nvmet_tcp_ddgst_len(struct nvmet_tcp_queue *queue)
 243 {
 244         return queue->data_digest ? NVME_TCP_DIGEST_LENGTH : 0;
 245 }
 246
 247 static inline void nvmet_tcp_hdgst(struct ahash_request *hash,
 248                 void *pdu, size_t len)
 249 {
 250         struct scatterlist sg;
 251
 252         sg_init_one(&sg, pdu, len);
 253         ahash_request_set_crypt(hash, &sg, pdu + len, len);
 254         crypto_ahash_digest(hash);
 255 }
 256
 257 static int nvmet_tcp_verify_hdgst(struct nvmet_tcp_queue *queue,
 258         void *pdu, size_t len)
 259 {
 260         struct nvme_tcp_hdr *hdr = pdu;
 261         __le32 recv_digest;
 262         __le32 exp_digest;
 263
 264         if (unlikely(!(hdr->flags & NVME_TCP_F_HDGST))) {
 265                 pr_err("queue %d: header digest enabled but no header digest\n",
 266                         queue->idx);
 267                 return -EPROTO;
 268         }
 269
 270         recv_digest = *(__le32 *)(pdu + hdr->hlen);
 271         nvmet_tcp_hdgst(queue->rcv_hash, pdu, len);
 272         exp_digest = *(__le32 *)(pdu + hdr->hlen);
 273         if (recv_digest != exp_digest) {
 274                 pr_err("queue %d: header digest error: recv %#x expected %#x\n",
 275                         queue->idx, le32_to_cpu(recv_digest),
 276                         le32_to_cpu(exp_digest));
 277                 return -EPROTO;
 278         }
 279
 280         return 0;
 281 }
 282
 283 static int nvmet_tcp_check_ddgst(struct nvmet_tcp_queue *queue, void *pdu)
 284 {
 285         struct nvme_tcp_hdr *hdr = pdu;
 286         u8 digest_len = nvmet_tcp_hdgst_len(queue);
 287         u32 len;
 288
 289         len = le32_to_cpu(hdr->plen) - hdr->hlen -
 290                 (hdr->flags & NVME_TCP_F_HDGST ? digest_len : 0);
 291
 292         if (unlikely(len && !(hdr->flags & NVME_TCP_F_DDGST))) {
 293                 pr_err("queue %d: data digest flag is cleared\n", queue->idx);
 294                 return -EPROTO;
 295         }
 296
 297         return 0;
 298 }
 299
 300 static void nvmet_tcp_unmap_pdu_iovec(struct nvmet_tcp_cmd *cmd)
 301 {
 302         struct scatterlist *sg;
 303         int i;
 304
 305         sg = &cmd->req.sg[cmd->sg_idx];
 306
 307         for (i = 0; i < cmd->nr_mapped; i++)
 308                 kunmap(sg_page(&sg[i]));
 309 }
 310
 311 static void nvmet_tcp_map_pdu_iovec(struct nvmet_tcp_cmd *cmd)
 312 {
 313         struct kvec *iov = cmd->iov;
 314         struct scatterlist *sg;
 315         u32 length, offset, sg_offset;
 316
 317         length = cmd->pdu_len;
 318         cmd->nr_mapped = DIV_ROUND_UP(length, PAGE_SIZE);
 319         offset = cmd->rbytes_done;
 320         cmd->sg_idx = offset / PAGE_SIZE;
 321         sg_offset = offset % PAGE_SIZE;
 322         sg = &cmd->req.sg[cmd->sg_idx];
 323
 324         while (length) {
 325                 u32 iov_len = min_t(u32, length, sg->length - sg_offset);
 326
 327                 iov->iov_base = kmap(sg_page(sg)) + sg->offset + sg_offset;
 328                 iov->iov_len = iov_len;
 329
 330                 length -= iov_len;
 331                 sg = sg_next(sg);
 332                 iov++;
 333                 sg_offset = 0;
 334         }
 335
 336         iov_iter_kvec(&cmd->recv_msg.msg_iter, READ, cmd->iov,
 337                 cmd->nr_mapped, cmd->pdu_len);
 338 }
 339
 340 static void nvmet_tcp_fatal_error(struct nvmet_tcp_queue *queue)
 341 {
 342         queue->rcv_state = NVMET_TCP_RECV_ERR;
 343         if (queue->nvme_sq.ctrl)
 344                 nvmet_ctrl_fatal_error(queue->nvme_sq.ctrl);
 345         else
 346                 kernel_sock_shutdown(queue->sock, SHUT_RDWR);
 347 }
 348
 349 static void nvmet_tcp_socket_error(struct nvmet_tcp_queue *queue, int status)
 350 {
 351         if (status == -EPIPE || status == -ECONNRESET)
 352                 kernel_sock_shutdown(queue->sock, SHUT_RDWR);
 353         else
 354                 nvmet_tcp_fatal_error(queue);
 355 }
 356
 357 static int nvmet_tcp_map_data(struct nvmet_tcp_cmd *cmd)
 358 {
 359         struct nvme_sgl_desc *sgl = &cmd->req.cmd->common.dptr.sgl;
 360         u32 len = le32_to_cpu(sgl->length);
 361
 362         if (!len)
 363                 return 0;
 364
 365         if (sgl->type == ((NVME_SGL_FMT_DATA_DESC << 4) |
 366                           NVME_SGL_FMT_OFFSET)) {
 367                 if (!nvme_is_write(cmd->req.cmd))
 368                         return NVME_SC_INVALID_FIELD | NVME_SC_DNR;
 369
 370                 if (len > cmd->req.port->inline_data_size)
 371                         return NVME_SC_SGL_INVALID_OFFSET | NVME_SC_DNR;
 372                 cmd->pdu_len = len;
 373         }
 374         cmd->req.transfer_len += len;
 375
 376         cmd->req.sg = sgl_alloc(len, GFP_KERNEL, &cmd->req.sg_cnt);
 377         if (!cmd->req.sg)
 378                 return NVME_SC_INTERNAL;
 379         cmd->cur_sg = cmd->req.sg;
 380
 381         if (nvmet_tcp_has_data_in(cmd)) {
 382                 cmd->iov = kmalloc_array(cmd->req.sg_cnt,
 383                                 sizeof(*cmd->iov), GFP_KERNEL);
 384                 if (!cmd->iov)
 385                         goto err;
 386         }
 387
 388         return 0;
 389 err:
 390         sgl_free(cmd->req.sg);
 391         return NVME_SC_INTERNAL;
 392 }
 393
 394 static void nvmet_tcp_send_ddgst(struct ahash_request *hash,
 395                 struct nvmet_tcp_cmd *cmd)
 396 {
 397         ahash_request_set_crypt(hash, cmd->req.sg,
 398                 (void *)&cmd->exp_ddgst, cmd->req.transfer_len);
 399         crypto_ahash_digest(hash);
 400 }
 401
 402 static void nvmet_tcp_recv_ddgst(struct ahash_request *hash,
 403                 struct nvmet_tcp_cmd *cmd)
 404 {
 405         struct scatterlist sg;
 406         struct kvec *iov;
 407         int i;
 408
 409         crypto_ahash_init(hash);
 410         for (i = 0, iov = cmd->iov; i < cmd->nr_mapped; i++, iov++) {
 411                 sg_init_one(&sg, iov->iov_base, iov->iov_len);
 412                 ahash_request_set_crypt(hash, &sg, NULL, iov->iov_len);
 413                 crypto_ahash_update(hash);
 414         }
 415         ahash_request_set_crypt(hash, NULL, (void *)&cmd->exp_ddgst, 0);
 416         crypto_ahash_final(hash);
 417 }
 418
 419 static void nvmet_setup_c2h_data_pdu(struct nvmet_tcp_cmd *cmd)
 420 {
 421         struct nvme_tcp_data_pdu *pdu = cmd->data_pdu;
 422         struct nvmet_tcp_queue *queue = cmd->queue;
 423         u8 hdgst = nvmet_tcp_hdgst_len(cmd->queue);
 424         u8 ddgst = nvmet_tcp_ddgst_len(cmd->queue);
 425
 426         cmd->offset = 0;
 427         cmd->state = NVMET_TCP_SEND_DATA_PDU;
 428
 429         pdu->hdr.type = nvme_tcp_c2h_data;
 430         pdu->hdr.flags = NVME_TCP_F_DATA_LAST | (queue->nvme_sq.sqhd_disabled ?
 431                                                 NVME_TCP_F_DATA_SUCCESS : 0);
 432         pdu->hdr.hlen = sizeof(*pdu);
 433         pdu->hdr.pdo = pdu->hdr.hlen + hdgst;
 434         pdu->hdr.plen =
 435                 cpu_to_le32(pdu->hdr.hlen + hdgst +
 436                                 cmd->req.transfer_len + ddgst);
 437         pdu->command_id = cmd->req.cqe->command_id;
 438         pdu->data_length = cpu_to_le32(cmd->req.transfer_len);
 439         pdu->data_offset = cpu_to_le32(cmd->wbytes_done);
 440
 441         if (queue->data_digest) {
 442                 pdu->hdr.flags |= NVME_TCP_F_DDGST;
 443                 nvmet_tcp_send_ddgst(queue->snd_hash, cmd);
 444         }
 445
 446         if (cmd->queue->hdr_digest) {
 447                 pdu->hdr.flags |= NVME_TCP_F_HDGST;
 448                 nvmet_tcp_hdgst(queue->snd_hash, pdu, sizeof(*pdu));
 449         }
 450 }
 451
 452 static void nvmet_setup_r2t_pdu(struct nvmet_tcp_cmd *cmd)
 453 {
 454         struct nvme_tcp_r2t_pdu *pdu = cmd->r2t_pdu;
 455         struct nvmet_tcp_queue *queue = cmd->queue;
 456         u8 hdgst = nvmet_tcp_hdgst_len(cmd->queue);
 457
 458         cmd->offset = 0;
 459         cmd->state = NVMET_TCP_SEND_R2T;
 460
 461         pdu->hdr.type = nvme_tcp_r2t;
 462         pdu->hdr.flags = 0;
 463         pdu->hdr.hlen = sizeof(*pdu);
 464         pdu->hdr.pdo = 0;
 465         pdu->hdr.plen = cpu_to_le32(pdu->hdr.hlen + hdgst);
 466
 467         pdu->command_id = cmd->req.cmd->common.command_id;
 468         pdu->ttag = nvmet_tcp_cmd_tag(cmd->queue, cmd);
 469         pdu->r2t_length = cpu_to_le32(cmd->req.transfer_len - cmd->rbytes_done);
 470         pdu->r2t_offset = cpu_to_le32(cmd->rbytes_done);
 471         if (cmd->queue->hdr_digest) {
 472                 pdu->hdr.flags |= NVME_TCP_F_HDGST;
 473                 nvmet_tcp_hdgst(queue->snd_hash, pdu, sizeof(*pdu));
 474         }
 475 }
 476
 477 static void nvmet_setup_response_pdu(struct nvmet_tcp_cmd *cmd)
 478 {
 479         struct nvme_tcp_rsp_pdu *pdu = cmd->rsp_pdu;
 480         struct nvmet_tcp_queue *queue = cmd->queue;
 481         u8 hdgst = nvmet_tcp_hdgst_len(cmd->queue);
 482
 483         cmd->offset = 0;
 484         cmd->state = NVMET_TCP_SEND_RESPONSE;
 485
 486         pdu->hdr.type = nvme_tcp_rsp;
 487         pdu->hdr.flags = 0;
 488         pdu->hdr.hlen = sizeof(*pdu);
 489         pdu->hdr.pdo = 0;
 490         pdu->hdr.plen = cpu_to_le32(pdu->hdr.hlen + hdgst);
 491         if (cmd->queue->hdr_digest) {
 492                 pdu->hdr.flags |= NVME_TCP_F_HDGST;
 493                 nvmet_tcp_hdgst(queue->snd_hash, pdu, sizeof(*pdu));
 494         }
 495 }
 496
 497 static void nvmet_tcp_process_resp_list(struct nvmet_tcp_queue *queue)
 498 {
 499         struct llist_node *node;
 500         struct nvmet_tcp_cmd *cmd;
 501
 502         for (node = llist_del_all(&queue->resp_list); node; node = node->next) {
 503                 cmd = llist_entry(node, struct nvmet_tcp_cmd, lentry);
 504                 list_add(&cmd->entry, &queue->resp_send_list);
 505                 queue->send_list_len++;
 506         }
 507 }
 508
 509 static struct nvmet_tcp_cmd *nvmet_tcp_fetch_cmd(struct nvmet_tcp_queue *queue)
 510 {
 511         queue->snd_cmd = list_first_entry_or_null(&queue->resp_send_list,
 512                                 struct nvmet_tcp_cmd, entry);
 513         if (!queue->snd_cmd) {
 514                 nvmet_tcp_process_resp_list(queue);
 515                 queue->snd_cmd =
 516                         list_first_entry_or_null(&queue->resp_send_list,
 517                                         struct nvmet_tcp_cmd, entry);
 518                 if (unlikely(!queue->snd_cmd))
 519                         return NULL;
 520         }
 521
 522         list_del_init(&queue->snd_cmd->entry);
 523         queue->send_list_len--;
 524
 525         if (nvmet_tcp_need_data_out(queue->snd_cmd))
 526                 nvmet_setup_c2h_data_pdu(queue->snd_cmd);
 527         else if (nvmet_tcp_need_data_in(queue->snd_cmd))
 528                 nvmet_setup_r2t_pdu(queue->snd_cmd);
 529         else
 530                 nvmet_setup_response_pdu(queue->snd_cmd);
 531
 532         return queue->snd_cmd;
 533 }
 534
 535 static void nvmet_tcp_queue_response(struct nvmet_req *req)
 536 {
 537         struct nvmet_tcp_cmd *cmd =
 538                 container_of(req, struct nvmet_tcp_cmd, req);
 539         struct nvmet_tcp_queue  *queue = cmd->queue;
 540         struct nvme_sgl_desc *sgl;
 541         u32 len;
 542
 543         if (unlikely(cmd == queue->cmd)) {
 544                 sgl = &cmd->req.cmd->common.dptr.sgl;
 545                 len = le32_to_cpu(sgl->length);
 546
 547                 /*
 548                  * Wait for inline data before processing the response.
 549                  * Avoid using helpers, this might happen before
 550                  * nvmet_req_init is completed.
 551                  */
 552                 if (queue->rcv_state == NVMET_TCP_RECV_PDU &&
 553                     len && len <= cmd->req.port->inline_data_size &&
 554                     nvme_is_write(cmd->req.cmd))
 555                         return;
 556         }
 557
 558         llist_add(&cmd->lentry, &queue->resp_list);
 559         queue_work_on(queue_cpu(queue), nvmet_tcp_wq, &cmd->queue->io_work);
 560 }
 561
 562 static void nvmet_tcp_execute_request(struct nvmet_tcp_cmd *cmd)
 563 {
 564         if (unlikely(cmd->flags & NVMET_TCP_F_INIT_FAILED))
 565                 nvmet_tcp_queue_response(&cmd->req);
 566         else
 567                 cmd->req.execute(&cmd->req);
 568 }
 569
 570 static int nvmet_try_send_data_pdu(struct nvmet_tcp_cmd *cmd)
 571 {
 572         u8 hdgst = nvmet_tcp_hdgst_len(cmd->queue);
 573         int left = sizeof(*cmd->data_pdu) - cmd->offset + hdgst;
 574         int ret;
 575
 576         ret = kernel_sendpage(cmd->queue->sock, virt_to_page(cmd->data_pdu),
 577                         offset_in_page(cmd->data_pdu) + cmd->offset,
 578                         left, MSG_DONTWAIT | MSG_MORE | MSG_SENDPAGE_NOTLAST);
 579         if (ret <= 0)
 580                 return ret;
 581
 582         cmd->offset += ret;
 583         left -= ret;
 584
 585         if (left)
 586                 return -EAGAIN;
 587
 588         cmd->state = NVMET_TCP_SEND_DATA;
 589         cmd->offset  = 0;
 590         return 1;
 591 }
 592
 593 static int nvmet_try_send_data(struct nvmet_tcp_cmd *cmd, bool last_in_batch)
 594 {
 595         struct nvmet_tcp_queue *queue = cmd->queue;
 596         int ret;
 597
 598         while (cmd->cur_sg) {
 599                 struct page *page = sg_page(cmd->cur_sg);
 600                 u32 left = cmd->cur_sg->length - cmd->offset;
 601                 int flags = MSG_DONTWAIT;
 602
 603                 if ((!last_in_batch && cmd->queue->send_list_len) ||
 604                     cmd->wbytes_done + left < cmd->req.transfer_len ||
 605                     queue->data_digest || !queue->nvme_sq.sqhd_disabled)
 606                         flags |= MSG_MORE | MSG_SENDPAGE_NOTLAST;
 607
 608                 ret = kernel_sendpage(cmd->queue->sock, page, cmd->offset,
 609                                         left, flags);
 610                 if (ret <= 0)
 611                         return ret;
 612
 613                 cmd->offset += ret;
 614                 cmd->wbytes_done += ret;
 615
 616                 /* Done with sg?*/
 617                 if (cmd->offset == cmd->cur_sg->length) {
 618                         cmd->cur_sg = sg_next(cmd->cur_sg);
 619                         cmd->offset = 0;
 620                 }
 621         }
 622
 623         if (queue->data_digest) {
 624                 cmd->state = NVMET_TCP_SEND_DDGST;
 625                 cmd->offset = 0;
 626         } else {
 627                 if (queue->nvme_sq.sqhd_disabled) {
 628                         cmd->queue->snd_cmd = NULL;
 629                         nvmet_tcp_put_cmd(cmd);
 630                 } else {
 631                         nvmet_setup_response_pdu(cmd);
 632                 }
 633         }
 634
 635         if (queue->nvme_sq.sqhd_disabled) {
 636                 kfree(cmd->iov);
 637                 sgl_free(cmd->req.sg);
 638         }
 639
 640         return 1;
 641
 642 }
 643
 644 static int nvmet_try_send_response(struct nvmet_tcp_cmd *cmd,
 645                 bool last_in_batch)
 646 {
 647         u8 hdgst = nvmet_tcp_hdgst_len(cmd->queue);
 648         int left = sizeof(*cmd->rsp_pdu) - cmd->offset + hdgst;
 649         int flags = MSG_DONTWAIT;
 650         int ret;
 651
 652         if (!last_in_batch && cmd->queue->send_list_len)
 653                 flags |= MSG_MORE | MSG_SENDPAGE_NOTLAST;
 654         else
 655                 flags |= MSG_EOR;
 656
 657         ret = kernel_sendpage(cmd->queue->sock, virt_to_page(cmd->rsp_pdu),
 658                 offset_in_page(cmd->rsp_pdu) + cmd->offset, left, flags);
 659         if (ret <= 0)
 660                 return ret;
 661         cmd->offset += ret;
 662         left -= ret;
 663
 664         if (left)
 665                 return -EAGAIN;
 666
 667         kfree(cmd->iov);
 668         sgl_free(cmd->req.sg);
 669         cmd->queue->snd_cmd = NULL;
 670         nvmet_tcp_put_cmd(cmd);
 671         return 1;
 672 }
 673
 674 static int nvmet_try_send_r2t(struct nvmet_tcp_cmd *cmd, bool last_in_batch)
 675 {
 676         u8 hdgst = nvmet_tcp_hdgst_len(cmd->queue);
 677         int left = sizeof(*cmd->r2t_pdu) - cmd->offset + hdgst;
 678         int flags = MSG_DONTWAIT;
 679         int ret;
 680
 681         if (!last_in_batch && cmd->queue->send_list_len)
 682                 flags |= MSG_MORE | MSG_SENDPAGE_NOTLAST;
 683         else
 684                 flags |= MSG_EOR;
 685
 686         ret = kernel_sendpage(cmd->queue->sock, virt_to_page(cmd->r2t_pdu),
 687                 offset_in_page(cmd->r2t_pdu) + cmd->offset, left, flags);
 688         if (ret <= 0)
 689                 return ret;
 690         cmd->offset += ret;
 691         left -= ret;
 692
 693         if (left)
 694                 return -EAGAIN;
 695
 696         cmd->queue->snd_cmd = NULL;
 697         return 1;
 698 }
 699
 700 static int nvmet_try_send_ddgst(struct nvmet_tcp_cmd *cmd, bool last_in_batch)
 701 {
 702         struct nvmet_tcp_queue *queue = cmd->queue;
 703         struct msghdr msg = { .msg_flags = MSG_DONTWAIT };
 704         struct kvec iov = {
 705                 .iov_base = &cmd->exp_ddgst + cmd->offset,
 706                 .iov_len = NVME_TCP_DIGEST_LENGTH - cmd->offset
 707         };
 708         int ret;
 709
 710         if (!last_in_batch && cmd->queue->send_list_len)
 711                 msg.msg_flags |= MSG_MORE;
 712         else
 713                 msg.msg_flags |= MSG_EOR;
 714
 715         ret = kernel_sendmsg(queue->sock, &msg, &iov, 1, iov.iov_len);
 716         if (unlikely(ret <= 0))
 717                 return ret;
 718
 719         cmd->offset += ret;
 720
 721         if (queue->nvme_sq.sqhd_disabled) {
 722                 cmd->queue->snd_cmd = NULL;
 723                 nvmet_tcp_put_cmd(cmd);
 724         } else {
 725                 nvmet_setup_response_pdu(cmd);
 726         }
 727         return 1;
 728 }
 729
 730 static int nvmet_tcp_try_send_one(struct nvmet_tcp_queue *queue,
 731                 bool last_in_batch)
 732 {
 733         struct nvmet_tcp_cmd *cmd = queue->snd_cmd;
 734         int ret = 0;
 735
 736         if (!cmd || queue->state == NVMET_TCP_Q_DISCONNECTING) {
 737                 cmd = nvmet_tcp_fetch_cmd(queue);
 738                 if (unlikely(!cmd))
 739                         return 0;
 740         }
 741
 742         if (cmd->state == NVMET_TCP_SEND_DATA_PDU) {
 743                 ret = nvmet_try_send_data_pdu(cmd);
 744                 if (ret <= 0)
 745                         goto done_send;
 746         }
 747
 748         if (cmd->state == NVMET_TCP_SEND_DATA) {
 749                 ret = nvmet_try_send_data(cmd, last_in_batch);
 750                 if (ret <= 0)
 751                         goto done_send;
 752         }
 753
 754         if (cmd->state == NVMET_TCP_SEND_DDGST) {
 755                 ret = nvmet_try_send_ddgst(cmd, last_in_batch);
 756                 if (ret <= 0)
 757                         goto done_send;
 758         }
 759
 760         if (cmd->state == NVMET_TCP_SEND_R2T) {
 761                 ret = nvmet_try_send_r2t(cmd, last_in_batch);
 762                 if (ret <= 0)
 763                         goto done_send;
 764         }
 765
 766         if (cmd->state == NVMET_TCP_SEND_RESPONSE)
 767                 ret = nvmet_try_send_response(cmd, last_in_batch);
 768
 769 done_send:
 770         if (ret < 0) {
 771                 if (ret == -EAGAIN)
 772                         return 0;
 773                 return ret;
 774         }
 775
 776         return 1;
 777 }
 778
 779 static int nvmet_tcp_try_send(struct nvmet_tcp_queue *queue,
 780                 int budget, int *sends)
 781 {
 782         int i, ret = 0;
 783
 784         for (i = 0; i < budget; i++) {
 785                 ret = nvmet_tcp_try_send_one(queue, i == budget - 1);
 786                 if (unlikely(ret < 0)) {
 787                         nvmet_tcp_socket_error(queue, ret);
 788                         goto done;
 789                 } else if (ret == 0) {
 790                         break;
 791                 }
 792                 (*sends)++;
 793         }
 794 done:
 795         return ret;
 796 }
 797
 798 static void nvmet_prepare_receive_pdu(struct nvmet_tcp_queue *queue)
 799 {
 800         queue->offset = 0;
 801         queue->left = sizeof(struct nvme_tcp_hdr);
 802         queue->cmd = NULL;
 803         queue->rcv_state = NVMET_TCP_RECV_PDU;
 804 }
 805
 806 static void nvmet_tcp_free_crypto(struct nvmet_tcp_queue *queue)
 807 {
 808         struct crypto_ahash *tfm = crypto_ahash_reqtfm(queue->rcv_hash);
 809
 810         ahash_request_free(queue->rcv_hash);
 811         ahash_request_free(queue->snd_hash);
 812         crypto_free_ahash(tfm);
 813 }
 814
 815 static int nvmet_tcp_alloc_crypto(struct nvmet_tcp_queue *queue)
 816 {
 817         struct crypto_ahash *tfm;
 818
 819         tfm = crypto_alloc_ahash("crc32c", 0, CRYPTO_ALG_ASYNC);
 820         if (IS_ERR(tfm))
 821                 return PTR_ERR(tfm);
 822
 823         queue->snd_hash = ahash_request_alloc(tfm, GFP_KERNEL);
 824         if (!queue->snd_hash)
 825                 goto free_tfm;
 826         ahash_request_set_callback(queue->snd_hash, 0, NULL, NULL);
 827
 828         queue->rcv_hash = ahash_request_alloc(tfm, GFP_KERNEL);
 829         if (!queue->rcv_hash)
 830                 goto free_snd_hash;
 831         ahash_request_set_callback(queue->rcv_hash, 0, NULL, NULL);
 832
 833         return 0;
 834 free_snd_hash:
 835         ahash_request_free(queue->snd_hash);
 836 free_tfm:
 837         crypto_free_ahash(tfm);
 838         return -ENOMEM;
 839 }
 840
 841
 842 static int nvmet_tcp_handle_icreq(struct nvmet_tcp_queue *queue)
 843 {
 844         struct nvme_tcp_icreq_pdu *icreq = &queue->pdu.icreq;
 845         struct nvme_tcp_icresp_pdu *icresp = &queue->pdu.icresp;
 846         struct msghdr msg = {};
 847         struct kvec iov;
 848         int ret;
 849
 850         if (le32_to_cpu(icreq->hdr.plen) != sizeof(struct nvme_tcp_icreq_pdu)) {
 851                 pr_err("bad nvme-tcp pdu length (%d)\n",
 852                         le32_to_cpu(icreq->hdr.plen));
 853                 nvmet_tcp_fatal_error(queue);
 854         }
 855
 856         if (icreq->pfv != NVME_TCP_PFV_1_0) {
 857                 pr_err("queue %d: bad pfv %d\n", queue->idx, icreq->pfv);
 858                 return -EPROTO;
 859         }
 860
 861         if (icreq->hpda != 0) {
 862                 pr_err("queue %d: unsupported hpda %d\n", queue->idx,
 863                         icreq->hpda);
 864                 return -EPROTO;
 865         }
 866
 867         queue->hdr_digest = !!(icreq->digest & NVME_TCP_HDR_DIGEST_ENABLE);
 868         queue->data_digest = !!(icreq->digest & NVME_TCP_DATA_DIGEST_ENABLE);
 869         if (queue->hdr_digest || queue->data_digest) {
 870                 ret = nvmet_tcp_alloc_crypto(queue);
 871                 if (ret)
 872                         return ret;
 873         }
 874
 875         memset(icresp, 0, sizeof(*icresp));
 876         icresp->hdr.type = nvme_tcp_icresp;
 877         icresp->hdr.hlen = sizeof(*icresp);
 878         icresp->hdr.pdo = 0;
 879         icresp->hdr.plen = cpu_to_le32(icresp->hdr.hlen);
 880         icresp->pfv = cpu_to_le16(NVME_TCP_PFV_1_0);
 881         icresp->maxdata = cpu_to_le32(0x400000); /* 16M arbitrary limit */
 882         icresp->cpda = 0;
 883         if (queue->hdr_digest)
 884                 icresp->digest |= NVME_TCP_HDR_DIGEST_ENABLE;
 885         if (queue->data_digest)
 886                 icresp->digest |= NVME_TCP_DATA_DIGEST_ENABLE;
 887
 888         iov.iov_base = icresp;
 889         iov.iov_len = sizeof(*icresp);
 890         ret = kernel_sendmsg(queue->sock, &msg, &iov, 1, iov.iov_len);
 891         if (ret < 0)
 892                 goto free_crypto;
 893
 894         queue->state = NVMET_TCP_Q_LIVE;
 895         nvmet_prepare_receive_pdu(queue);
 896         return 0;
 897 free_crypto:
 898         if (queue->hdr_digest || queue->data_digest)
 899                 nvmet_tcp_free_crypto(queue);
 900         return ret;
 901 }
 902
 903 static void nvmet_tcp_handle_req_failure(struct nvmet_tcp_queue *queue,
 904                 struct nvmet_tcp_cmd *cmd, struct nvmet_req *req)
 905 {
 906         size_t data_len = le32_to_cpu(req->cmd->common.dptr.sgl.length);
 907         int ret;
 908
 909         if (!nvme_is_write(cmd->req.cmd) ||
 910             data_len > cmd->req.port->inline_data_size) {
 911                 nvmet_prepare_receive_pdu(queue);
 912                 return;
 913         }
 914
 915         ret = nvmet_tcp_map_data(cmd);
 916         if (unlikely(ret)) {
 917                 pr_err("queue %d: failed to map data\n", queue->idx);
 918                 nvmet_tcp_fatal_error(queue);
 919                 return;
 920         }
 921
 922         queue->rcv_state = NVMET_TCP_RECV_DATA;
 923         nvmet_tcp_map_pdu_iovec(cmd);
 924         cmd->flags |= NVMET_TCP_F_INIT_FAILED;
 925 }
 926
 927 static int nvmet_tcp_handle_h2c_data_pdu(struct nvmet_tcp_queue *queue)
 928 {
 929         struct nvme_tcp_data_pdu *data = &queue->pdu.data;
 930         struct nvmet_tcp_cmd *cmd;
 931
 932         if (likely(queue->nr_cmds))
 933                 cmd = &queue->cmds[data->ttag];
 934         else
 935                 cmd = &queue->connect;
 936
 937         if (le32_to_cpu(data->data_offset) != cmd->rbytes_done) {
 938                 pr_err("ttag %u unexpected data offset %u (expected %u)\n",
 939                         data->ttag, le32_to_cpu(data->data_offset),
 940                         cmd->rbytes_done);
 941                 /* FIXME: use path and transport errors */
 942                 nvmet_req_complete(&cmd->req,
 943                         NVME_SC_INVALID_FIELD | NVME_SC_DNR);
 944                 return -EPROTO;
 945         }
 946
 947         cmd->pdu_len = le32_to_cpu(data->data_length);
 948         cmd->pdu_recv = 0;
 949         nvmet_tcp_map_pdu_iovec(cmd);
 950         queue->cmd = cmd;
 951         queue->rcv_state = NVMET_TCP_RECV_DATA;
 952
 953         return 0;
 954 }
 955
 956 static int nvmet_tcp_done_recv_pdu(struct nvmet_tcp_queue *queue)
 957 {
 958         struct nvme_tcp_hdr *hdr = &queue->pdu.cmd.hdr;
 959         struct nvme_command *nvme_cmd = &queue->pdu.cmd.cmd;
 960         struct nvmet_req *req;
 961         int ret;
 962
 963         if (unlikely(queue->state == NVMET_TCP_Q_CONNECTING)) {
 964                 if (hdr->type != nvme_tcp_icreq) {
 965                         pr_err("unexpected pdu type (%d) before icreq\n",
 966                                 hdr->type);
 967                         nvmet_tcp_fatal_error(queue);
 968                         return -EPROTO;
 969                 }
 970                 return nvmet_tcp_handle_icreq(queue);
 971         }
 972
 973         if (hdr->type == nvme_tcp_h2c_data) {
 974                 ret = nvmet_tcp_handle_h2c_data_pdu(queue);
 975                 if (unlikely(ret))
 976                         return ret;
 977                 return 0;
 978         }
 979
 980         queue->cmd = nvmet_tcp_get_cmd(queue);
 981         if (unlikely(!queue->cmd)) {
 982                 /* This should never happen */
 983                 pr_err("queue %d: out of commands (%d) send_list_len: %d, opcode: %d",
 984                         queue->idx, queue->nr_cmds, queue->send_list_len,
 985                         nvme_cmd->common.opcode);
 986                 nvmet_tcp_fatal_error(queue);
 987                 return -ENOMEM;
 988         }
 989
 990         req = &queue->cmd->req;
 991         memcpy(req->cmd, nvme_cmd, sizeof(*nvme_cmd));
 992
 993         if (unlikely(!nvmet_req_init(req, &queue->nvme_cq,
 994                         &queue->nvme_sq, &nvmet_tcp_ops))) {
 995                 pr_err("failed cmd %p id %d opcode %d, data_len: %d\n",
 996                         req->cmd, req->cmd->common.command_id,
 997                         req->cmd->common.opcode,
 998                         le32_to_cpu(req->cmd->common.dptr.sgl.length));
 999
1000                 nvmet_tcp_handle_req_failure(queue, queue->cmd, req);
1001                 return 0;
1002         }
1003
1004         ret = nvmet_tcp_map_data(queue->cmd);
1005         if (unlikely(ret)) {
1006                 pr_err("queue %d: failed to map data\n", queue->idx);
1007                 if (nvmet_tcp_has_inline_data(queue->cmd))
1008                         nvmet_tcp_fatal_error(queue);
1009                 else
1010                         nvmet_req_complete(req, ret);
1011                 ret = -EAGAIN;
1012                 goto out;
1013         }
1014
1015         if (nvmet_tcp_need_data_in(queue->cmd)) {
1016                 if (nvmet_tcp_has_inline_data(queue->cmd)) {
1017                         queue->rcv_state = NVMET_TCP_RECV_DATA;
1018                         nvmet_tcp_map_pdu_iovec(queue->cmd);
1019                         return 0;
1020                 }
1021                 /* send back R2T */
1022                 nvmet_tcp_queue_response(&queue->cmd->req);
1023                 goto out;
1024         }
1025
1026         queue->cmd->req.execute(&queue->cmd->req);
1027 out:
1028         nvmet_prepare_receive_pdu(queue);
1029         return ret;
1030 }
1031
1032 static const u8 nvme_tcp_pdu_sizes[] = {
1033         [nvme_tcp_icreq]        = sizeof(struct nvme_tcp_icreq_pdu),
1034         [nvme_tcp_cmd]          = sizeof(struct nvme_tcp_cmd_pdu),
1035         [nvme_tcp_h2c_data]     = sizeof(struct nvme_tcp_data_pdu),
1036 };
1037
1038 static inline u8 nvmet_tcp_pdu_size(u8 type)
1039 {
1040         size_t idx = type;
1041
1042         return (idx < ARRAY_SIZE(nvme_tcp_pdu_sizes) &&
1043                 nvme_tcp_pdu_sizes[idx]) ?
1044                         nvme_tcp_pdu_sizes[idx] : 0;
1045 }
1046
1047 static inline bool nvmet_tcp_pdu_valid(u8 type)
1048 {
1049         switch (type) {
1050         case nvme_tcp_icreq:
1051         case nvme_tcp_cmd:
1052         case nvme_tcp_h2c_data:
1053                 /* fallthru */
1054                 return true;
1055         }
1056
1057         return false;
1058 }
1059
1060 static int nvmet_tcp_try_recv_pdu(struct nvmet_tcp_queue *queue)
1061 {
1062         struct nvme_tcp_hdr *hdr = &queue->pdu.cmd.hdr;
1063         int len;
1064         struct kvec iov;
1065         struct msghdr msg = { .msg_flags = MSG_DONTWAIT };
1066
1067 recv:
1068         iov.iov_base = (void *)&queue->pdu + queue->offset;
1069         iov.iov_len = queue->left;
1070         len = kernel_recvmsg(queue->sock, &msg, &iov, 1,
1071                         iov.iov_len, msg.msg_flags);
1072         if (unlikely(len < 0))
1073                 return len;
1074
1075         queue->offset += len;
1076         queue->left -= len;
1077         if (queue->left)
1078                 return -EAGAIN;
1079
1080         if (queue->offset == sizeof(struct nvme_tcp_hdr)) {
1081                 u8 hdgst = nvmet_tcp_hdgst_len(queue);
1082
1083                 if (unlikely(!nvmet_tcp_pdu_valid(hdr->type))) {
1084                         pr_err("unexpected pdu type %d\n", hdr->type);
1085                         nvmet_tcp_fatal_error(queue);
1086                         return -EIO;
1087                 }
1088
1089                 if (unlikely(hdr->hlen != nvmet_tcp_pdu_size(hdr->type))) {
1090                         pr_err("pdu %d bad hlen %d\n", hdr->type, hdr->hlen);
1091                         return -EIO;
1092                 }
1093
1094                 queue->left = hdr->hlen - queue->offset + hdgst;
1095                 goto recv;
1096         }
1097
1098         if (queue->hdr_digest &&
1099             nvmet_tcp_verify_hdgst(queue, &queue->pdu, queue->offset)) {
1100                 nvmet_tcp_fatal_error(queue); /* fatal */
1101                 return -EPROTO;
1102         }
1103
1104         if (queue->data_digest &&
1105             nvmet_tcp_check_ddgst(queue, &queue->pdu)) {
1106                 nvmet_tcp_fatal_error(queue); /* fatal */
1107                 return -EPROTO;
1108         }
1109
1110         return nvmet_tcp_done_recv_pdu(queue);
1111 }
1112
1113 static void nvmet_tcp_prep_recv_ddgst(struct nvmet_tcp_cmd *cmd)
1114 {
1115         struct nvmet_tcp_queue *queue = cmd->queue;
1116
1117         nvmet_tcp_recv_ddgst(queue->rcv_hash, cmd);
1118         queue->offset = 0;
1119         queue->left = NVME_TCP_DIGEST_LENGTH;
1120         queue->rcv_state = NVMET_TCP_RECV_DDGST;
1121 }
1122
1123 static int nvmet_tcp_try_recv_data(struct nvmet_tcp_queue *queue)
1124 {
1125         struct nvmet_tcp_cmd  *cmd = queue->cmd;
1126         int ret;
1127
1128         while (msg_data_left(&cmd->recv_msg)) {
1129                 ret = sock_recvmsg(cmd->queue->sock, &cmd->recv_msg,
1130                         cmd->recv_msg.msg_flags);
1131                 if (ret <= 0)
1132                         return ret;
1133
1134                 cmd->pdu_recv += ret;
1135                 cmd->rbytes_done += ret;
1136         }
1137
1138         nvmet_tcp_unmap_pdu_iovec(cmd);
1139         if (queue->data_digest) {
1140                 nvmet_tcp_prep_recv_ddgst(cmd);
1141                 return 0;
1142         }
1143
1144         if (cmd->rbytes_done == cmd->req.transfer_len)
1145                 nvmet_tcp_execute_request(cmd);
1146
1147         nvmet_prepare_receive_pdu(queue);
1148         return 0;
1149 }
1150
1151 static int nvmet_tcp_try_recv_ddgst(struct nvmet_tcp_queue *queue)
1152 {
1153         struct nvmet_tcp_cmd *cmd = queue->cmd;
1154         int ret;
1155         struct msghdr msg = { .msg_flags = MSG_DONTWAIT };
1156         struct kvec iov = {
1157                 .iov_base = (void *)&cmd->recv_ddgst + queue->offset,
1158                 .iov_len = queue->left
1159         };
1160
1161         ret = kernel_recvmsg(queue->sock, &msg, &iov, 1,
1162                         iov.iov_len, msg.msg_flags);
1163         if (unlikely(ret < 0))
1164                 return ret;
1165
1166         queue->offset += ret;
1167         queue->left -= ret;
1168         if (queue->left)
1169                 return -EAGAIN;
1170
1171         if (queue->data_digest && cmd->exp_ddgst != cmd->recv_ddgst) {
1172                 pr_err("queue %d: cmd %d pdu (%d) data digest error: recv %#x expected %#x\n",
1173                         queue->idx, cmd->req.cmd->common.command_id,
1174                         queue->pdu.cmd.hdr.type, le32_to_cpu(cmd->recv_ddgst),
1175                         le32_to_cpu(cmd->exp_ddgst));
1176                 nvmet_tcp_finish_cmd(cmd);
1177                 nvmet_tcp_fatal_error(queue);
1178                 ret = -EPROTO;
1179                 goto out;
1180         }
1181
1182         if (cmd->rbytes_done == cmd->req.transfer_len)
1183                 nvmet_tcp_execute_request(cmd);
1184
1185         ret = 0;
1186 out:
1187         nvmet_prepare_receive_pdu(queue);
1188         return ret;
1189 }
1190
1191 static int nvmet_tcp_try_recv_one(struct nvmet_tcp_queue *queue)
1192 {
1193         int result = 0;
1194
1195         if (unlikely(queue->rcv_state == NVMET_TCP_RECV_ERR))
1196                 return 0;
1197
1198         if (queue->rcv_state == NVMET_TCP_RECV_PDU) {
1199                 result = nvmet_tcp_try_recv_pdu(queue);
1200                 if (result != 0)
1201                         goto done_recv;
1202         }
1203
1204         if (queue->rcv_state == NVMET_TCP_RECV_DATA) {
1205                 result = nvmet_tcp_try_recv_data(queue);
1206                 if (result != 0)
1207                         goto done_recv;
1208         }
1209
1210         if (queue->rcv_state == NVMET_TCP_RECV_DDGST) {
1211                 result = nvmet_tcp_try_recv_ddgst(queue);
1212                 if (result != 0)
1213                         goto done_recv;
1214         }
1215
1216 done_recv:
1217         if (result < 0) {
1218                 if (result == -EAGAIN)
1219                         return 0;
1220                 return result;
1221         }
1222         return 1;
1223 }
1224
1225 static int nvmet_tcp_try_recv(struct nvmet_tcp_queue *queue,
1226                 int budget, int *recvs)
1227 {
1228         int i, ret = 0;
1229
1230         for (i = 0; i < budget; i++) {
1231                 ret = nvmet_tcp_try_recv_one(queue);
1232                 if (unlikely(ret < 0)) {
1233                         nvmet_tcp_socket_error(queue, ret);
1234                         goto done;
1235                 } else if (ret == 0) {
1236                         break;
1237                 }
1238                 (*recvs)++;
1239         }
1240 done:
1241         return ret;
1242 }
1243
1244 static void nvmet_tcp_schedule_release_queue(struct nvmet_tcp_queue *queue)
1245 {
1246         spin_lock(&queue->state_lock);
1247         if (queue->state != NVMET_TCP_Q_DISCONNECTING) {
1248                 queue->state = NVMET_TCP_Q_DISCONNECTING;
1249                 schedule_work(&queue->release_work);
1250         }
1251         spin_unlock(&queue->state_lock);
1252 }
1253
1254 static inline void nvmet_tcp_arm_queue_deadline(struct nvmet_tcp_queue *queue)
1255 {
1256         queue->poll_end = jiffies + usecs_to_jiffies(idle_poll_period_usecs);
1257 }
1258
1259 static bool nvmet_tcp_check_queue_deadline(struct nvmet_tcp_queue *queue,
1260                 int ops)
1261 {
1262         if (!idle_poll_period_usecs)
1263                 return false;
1264
1265         if (ops)
1266                 nvmet_tcp_arm_queue_deadline(queue);
1267
1268         return !time_after(jiffies, queue->poll_end);
1269 }
1270
1271 static void nvmet_tcp_io_work(struct work_struct *w)
1272 {
1273         struct nvmet_tcp_queue *queue =
1274                 container_of(w, struct nvmet_tcp_queue, io_work);
1275         bool pending;
1276         int ret, ops = 0;
1277
1278         do {
1279                 pending = false;
1280
1281                 ret = nvmet_tcp_try_recv(queue, NVMET_TCP_RECV_BUDGET, &ops);
1282                 if (ret > 0)
1283                         pending = true;
1284                 else if (ret < 0)
1285                         return;
1286
1287                 ret = nvmet_tcp_try_send(queue, NVMET_TCP_SEND_BUDGET, &ops);
1288                 if (ret > 0)
1289                         pending = true;
1290                 else if (ret < 0)
1291                         return;
1292
1293         } while (pending && ops < NVMET_TCP_IO_WORK_BUDGET);
1294
1295         /*
1296          * Requeue the worker if idle deadline period is in progress or any
1297          * ops activity was recorded during the do-while loop above.
1298          */
1299         if (nvmet_tcp_check_queue_deadline(queue, ops) || pending)
1300                 queue_work_on(queue_cpu(queue), nvmet_tcp_wq, &queue->io_work);
1301 }
1302
1303 static int nvmet_tcp_alloc_cmd(struct nvmet_tcp_queue *queue,
1304                 struct nvmet_tcp_cmd *c)
1305 {
1306         u8 hdgst = nvmet_tcp_hdgst_len(queue);
1307
1308         c->queue = queue;
1309         c->req.port = queue->port->nport;
1310
1311         c->cmd_pdu = page_frag_alloc(&queue->pf_cache,
1312                         sizeof(*c->cmd_pdu) + hdgst, GFP_KERNEL | __GFP_ZERO);
1313         if (!c->cmd_pdu)
1314                 return -ENOMEM;
1315         c->req.cmd = &c->cmd_pdu->cmd;
1316
1317         c->rsp_pdu = page_frag_alloc(&queue->pf_cache,
1318                         sizeof(*c->rsp_pdu) + hdgst, GFP_KERNEL | __GFP_ZERO);
1319         if (!c->rsp_pdu)
1320                 goto out_free_cmd;
1321         c->req.cqe = &c->rsp_pdu->cqe;
1322
1323         c->data_pdu = page_frag_alloc(&queue->pf_cache,
1324                         sizeof(*c->data_pdu) + hdgst, GFP_KERNEL | __GFP_ZERO);
1325         if (!c->data_pdu)
1326                 goto out_free_rsp;
1327
1328         c->r2t_pdu = page_frag_alloc(&queue->pf_cache,
1329                         sizeof(*c->r2t_pdu) + hdgst, GFP_KERNEL | __GFP_ZERO);
1330         if (!c->r2t_pdu)
1331                 goto out_free_data;
1332
1333         c->recv_msg.msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL;
1334
1335         list_add_tail(&c->entry, &queue->free_list);
1336
1337         return 0;
1338 out_free_data:
1339         page_frag_free(c->data_pdu);
1340 out_free_rsp:
1341         page_frag_free(c->rsp_pdu);
1342 out_free_cmd:
1343         page_frag_free(c->cmd_pdu);
1344         return -ENOMEM;
1345 }
1346
1347 static void nvmet_tcp_free_cmd(struct nvmet_tcp_cmd *c)
1348 {
1349         page_frag_free(c->r2t_pdu);
1350         page_frag_free(c->data_pdu);
1351         page_frag_free(c->rsp_pdu);
1352         page_frag_free(c->cmd_pdu);
1353 }
1354
1355 static int nvmet_tcp_alloc_cmds(struct nvmet_tcp_queue *queue)
1356 {
1357         struct nvmet_tcp_cmd *cmds;
1358         int i, ret = -EINVAL, nr_cmds = queue->nr_cmds;
1359
1360         cmds = kcalloc(nr_cmds, sizeof(struct nvmet_tcp_cmd), GFP_KERNEL);
1361         if (!cmds)
1362                 goto out;
1363
1364         for (i = 0; i < nr_cmds; i++) {
1365                 ret = nvmet_tcp_alloc_cmd(queue, cmds + i);
1366                 if (ret)
1367                         goto out_free;
1368         }
1369
1370         queue->cmds = cmds;
1371
1372         return 0;
1373 out_free:
1374         while (--i >= 0)
1375                 nvmet_tcp_free_cmd(cmds + i);
1376         kfree(cmds);
1377 out:
1378         return ret;
1379 }
1380
1381 static void nvmet_tcp_free_cmds(struct nvmet_tcp_queue *queue)
1382 {
1383         struct nvmet_tcp_cmd *cmds = queue->cmds;
1384         int i;
1385
1386         for (i = 0; i < queue->nr_cmds; i++)
1387                 nvmet_tcp_free_cmd(cmds + i);
1388
1389         nvmet_tcp_free_cmd(&queue->connect);
1390         kfree(cmds);
1391 }
1392
1393 static void nvmet_tcp_restore_socket_callbacks(struct nvmet_tcp_queue *queue)
1394 {
1395         struct socket *sock = queue->sock;
1396
1397         write_lock_bh(&sock->sk->sk_callback_lock);
1398         sock->sk->sk_data_ready =  queue->data_ready;
1399         sock->sk->sk_state_change = queue->state_change;
1400         sock->sk->sk_write_space = queue->write_space;
1401         sock->sk->sk_user_data = NULL;
1402         write_unlock_bh(&sock->sk->sk_callback_lock);
1403 }
1404
1405 static void nvmet_tcp_finish_cmd(struct nvmet_tcp_cmd *cmd)
1406 {
1407         nvmet_req_uninit(&cmd->req);
1408         nvmet_tcp_unmap_pdu_iovec(cmd);
1409         kfree(cmd->iov);
1410         sgl_free(cmd->req.sg);
1411 }
1412
1413 static void nvmet_tcp_uninit_data_in_cmds(struct nvmet_tcp_queue *queue)
1414 {
1415         struct nvmet_tcp_cmd *cmd = queue->cmds;
1416         int i;
1417
1418         for (i = 0; i < queue->nr_cmds; i++, cmd++) {
1419                 if (nvmet_tcp_need_data_in(cmd))
1420                         nvmet_tcp_finish_cmd(cmd);
1421         }
1422
1423         if (!queue->nr_cmds && nvmet_tcp_need_data_in(&queue->connect)) {
1424                 /* failed in connect */
1425                 nvmet_tcp_finish_cmd(&queue->connect);
1426         }
1427 }
1428
1429 static void nvmet_tcp_release_queue_work(struct work_struct *w)
1430 {
1431         struct nvmet_tcp_queue *queue =
1432                 container_of(w, struct nvmet_tcp_queue, release_work);
1433
1434         mutex_lock(&nvmet_tcp_queue_mutex);
1435         list_del_init(&queue->queue_list);
1436         mutex_unlock(&nvmet_tcp_queue_mutex);
1437
1438         nvmet_tcp_restore_socket_callbacks(queue);
1439         flush_work(&queue->io_work);
1440
1441         nvmet_tcp_uninit_data_in_cmds(queue);
1442         nvmet_sq_destroy(&queue->nvme_sq);
1443         cancel_work_sync(&queue->io_work);
1444         sock_release(queue->sock);
1445         nvmet_tcp_free_cmds(queue);
1446         if (queue->hdr_digest || queue->data_digest)
1447                 nvmet_tcp_free_crypto(queue);
1448         ida_simple_remove(&nvmet_tcp_queue_ida, queue->idx);
1449
1450         kfree(queue);
1451 }
1452
1453 static void nvmet_tcp_data_ready(struct sock *sk)
1454 {
1455         struct nvmet_tcp_queue *queue;
1456
1457         read_lock_bh(&sk->sk_callback_lock);
1458         queue = sk->sk_user_data;
1459         if (likely(queue))
1460                 queue_work_on(queue_cpu(queue), nvmet_tcp_wq, &queue->io_work);
1461         read_unlock_bh(&sk->sk_callback_lock);
1462 }
1463
1464 static void nvmet_tcp_write_space(struct sock *sk)
1465 {
1466         struct nvmet_tcp_queue *queue;
1467
1468         read_lock_bh(&sk->sk_callback_lock);
1469         queue = sk->sk_user_data;
1470         if (unlikely(!queue))
1471                 goto out;
1472
1473         if (unlikely(queue->state == NVMET_TCP_Q_CONNECTING)) {
1474                 queue->write_space(sk);
1475                 goto out;
1476         }
1477
1478         if (sk_stream_is_writeable(sk)) {
1479                 clear_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1480                 queue_work_on(queue_cpu(queue), nvmet_tcp_wq, &queue->io_work);
1481         }
1482 out:
1483         read_unlock_bh(&sk->sk_callback_lock);
1484 }
1485
1486 static void nvmet_tcp_state_change(struct sock *sk)
1487 {
1488         struct nvmet_tcp_queue *queue;
1489
1490         read_lock_bh(&sk->sk_callback_lock);
1491         queue = sk->sk_user_data;
1492         if (!queue)
1493                 goto done;
1494
1495         switch (sk->sk_state) {
1496         case TCP_FIN_WAIT1:
1497         case TCP_CLOSE_WAIT:
1498         case TCP_CLOSE:
1499                 /* FALLTHRU */
1500                 nvmet_tcp_schedule_release_queue(queue);
1501                 break;
1502         default:
1503                 pr_warn("queue %d unhandled state %d\n",
1504                         queue->idx, sk->sk_state);
1505         }
1506 done:
1507         read_unlock_bh(&sk->sk_callback_lock);
1508 }
1509
1510 static int nvmet_tcp_set_queue_sock(struct nvmet_tcp_queue *queue)
1511 {
1512         struct socket *sock = queue->sock;
1513         struct inet_sock *inet = inet_sk(sock->sk);
1514         int ret;
1515
1516         ret = kernel_getsockname(sock,
1517                 (struct sockaddr *)&queue->sockaddr);
1518         if (ret < 0)
1519                 return ret;
1520
1521         ret = kernel_getpeername(sock,
1522                 (struct sockaddr *)&queue->sockaddr_peer);
1523         if (ret < 0)
1524                 return ret;
1525
1526         /*
1527          * Cleanup whatever is sitting in the TCP transmit queue on socket
1528          * close. This is done to prevent stale data from being sent should
1529          * the network connection be restored before TCP times out.
1530          */
1531         sock_no_linger(sock->sk);
1532
1533         if (so_priority > 0)
1534                 sock_set_priority(sock->sk, so_priority);
1535
1536         /* Set socket type of service */
1537         if (inet->rcv_tos > 0)
1538                 ip_sock_set_tos(sock->sk, inet->rcv_tos);
1539
1540         ret = 0;
1541         write_lock_bh(&sock->sk->sk_callback_lock);
1542         if (sock->sk->sk_state != TCP_ESTABLISHED) {
1543                 /*
1544                  * If the socket is already closing, don't even start
1545                  * consuming it
1546                  */
1547                 ret = -ENOTCONN;
1548         } else {
1549                 sock->sk->sk_user_data = queue;
1550                 queue->data_ready = sock->sk->sk_data_ready;
1551                 sock->sk->sk_data_ready = nvmet_tcp_data_ready;
1552                 queue->state_change = sock->sk->sk_state_change;
1553                 sock->sk->sk_state_change = nvmet_tcp_state_change;
1554                 queue->write_space = sock->sk->sk_write_space;
1555                 sock->sk->sk_write_space = nvmet_tcp_write_space;
1556                 if (idle_poll_period_usecs)
1557                         nvmet_tcp_arm_queue_deadline(queue);
1558                 queue_work_on(queue_cpu(queue), nvmet_tcp_wq, &queue->io_work);
1559         }
1560         write_unlock_bh(&sock->sk->sk_callback_lock);
1561
1562         return ret;
1563 }
1564
1565 static int nvmet_tcp_alloc_queue(struct nvmet_tcp_port *port,
1566                 struct socket *newsock)
1567 {
1568         struct nvmet_tcp_queue *queue;
1569         int ret;
1570
1571         queue = kzalloc(sizeof(*queue), GFP_KERNEL);
1572         if (!queue)
1573                 return -ENOMEM;
1574
1575         INIT_WORK(&queue->release_work, nvmet_tcp_release_queue_work);
1576         INIT_WORK(&queue->io_work, nvmet_tcp_io_work);
1577         queue->sock = newsock;
1578         queue->port = port;
1579         queue->nr_cmds = 0;
1580         spin_lock_init(&queue->state_lock);
1581         queue->state = NVMET_TCP_Q_CONNECTING;
1582         INIT_LIST_HEAD(&queue->free_list);
1583         init_llist_head(&queue->resp_list);
1584         INIT_LIST_HEAD(&queue->resp_send_list);
1585
1586         queue->idx = ida_simple_get(&nvmet_tcp_queue_ida, 0, 0, GFP_KERNEL);
1587         if (queue->idx < 0) {
1588                 ret = queue->idx;
1589                 goto out_free_queue;
1590         }
1591
1592         ret = nvmet_tcp_alloc_cmd(queue, &queue->connect);
1593         if (ret)
1594                 goto out_ida_remove;
1595
1596         ret = nvmet_sq_init(&queue->nvme_sq);
1597         if (ret)
1598                 goto out_free_connect;
1599
1600         nvmet_prepare_receive_pdu(queue);
1601
1602         mutex_lock(&nvmet_tcp_queue_mutex);
1603         list_add_tail(&queue->queue_list, &nvmet_tcp_queue_list);
1604         mutex_unlock(&nvmet_tcp_queue_mutex);
1605
1606         ret = nvmet_tcp_set_queue_sock(queue);
1607         if (ret)
1608                 goto out_destroy_sq;
1609
1610         return 0;
1611 out_destroy_sq:
1612         mutex_lock(&nvmet_tcp_queue_mutex);
1613         list_del_init(&queue->queue_list);
1614         mutex_unlock(&nvmet_tcp_queue_mutex);
1615         nvmet_sq_destroy(&queue->nvme_sq);
1616 out_free_connect:
1617         nvmet_tcp_free_cmd(&queue->connect);
1618 out_ida_remove:
1619         ida_simple_remove(&nvmet_tcp_queue_ida, queue->idx);
1620 out_free_queue:
1621         kfree(queue);
1622         return ret;
1623 }
1624
1625 static void nvmet_tcp_accept_work(struct work_struct *w)
1626 {
1627         struct nvmet_tcp_port *port =
1628                 container_of(w, struct nvmet_tcp_port, accept_work);
1629         struct socket *newsock;
1630         int ret;
1631
1632         while (true) {
1633                 ret = kernel_accept(port->sock, &newsock, O_NONBLOCK);
1634                 if (ret < 0) {
1635                         if (ret != -EAGAIN)
1636                                 pr_warn("failed to accept err=%d\n", ret);
1637                         return;
1638                 }
1639                 ret = nvmet_tcp_alloc_queue(port, newsock);
1640                 if (ret) {
1641                         pr_err("failed to allocate queue\n");
1642                         sock_release(newsock);
1643                 }
1644         }
1645 }
1646
1647 static void nvmet_tcp_listen_data_ready(struct sock *sk)
1648 {
1649         struct nvmet_tcp_port *port;
1650
1651         read_lock_bh(&sk->sk_callback_lock);
1652         port = sk->sk_user_data;
1653         if (!port)
1654                 goto out;
1655
1656         if (sk->sk_state == TCP_LISTEN)
1657                 schedule_work(&port->accept_work);
1658 out:
1659         read_unlock_bh(&sk->sk_callback_lock);
1660 }
1661
1662 static int nvmet_tcp_add_port(struct nvmet_port *nport)
1663 {
1664         struct nvmet_tcp_port *port;
1665         __kernel_sa_family_t af;
1666         int ret;
1667
1668         port = kzalloc(sizeof(*port), GFP_KERNEL);
1669         if (!port)
1670                 return -ENOMEM;
1671
1672         switch (nport->disc_addr.adrfam) {
1673         case NVMF_ADDR_FAMILY_IP4:
1674                 af = AF_INET;
1675                 break;
1676         case NVMF_ADDR_FAMILY_IP6:
1677                 af = AF_INET6;
1678                 break;
1679         default:
1680                 pr_err("address family %d not supported\n",
1681                                 nport->disc_addr.adrfam);
1682                 ret = -EINVAL;
1683                 goto err_port;
1684         }
1685
1686         ret = inet_pton_with_scope(&init_net, af, nport->disc_addr.traddr,
1687                         nport->disc_addr.trsvcid, &port->addr);
1688         if (ret) {
1689                 pr_err("malformed ip/port passed: %s:%s\n",
1690                         nport->disc_addr.traddr, nport->disc_addr.trsvcid);
1691                 goto err_port;
1692         }
1693
1694         port->nport = nport;
1695         INIT_WORK(&port->accept_work, nvmet_tcp_accept_work);
1696         if (port->nport->inline_data_size < 0)
1697                 port->nport->inline_data_size = NVMET_TCP_DEF_INLINE_DATA_SIZE;
1698
1699         ret = sock_create(port->addr.ss_family, SOCK_STREAM,
1700                                 IPPROTO_TCP, &port->sock);
1701         if (ret) {
1702                 pr_err("failed to create a socket\n");
1703                 goto err_port;
1704         }
1705
1706         port->sock->sk->sk_user_data = port;
1707         port->data_ready = port->sock->sk->sk_data_ready;
1708         port->sock->sk->sk_data_ready = nvmet_tcp_listen_data_ready;
1709         sock_set_reuseaddr(port->sock->sk);
1710         tcp_sock_set_nodelay(port->sock->sk);
1711         if (so_priority > 0)
1712                 sock_set_priority(port->sock->sk, so_priority);
1713
1714         ret = kernel_bind(port->sock, (struct sockaddr *)&port->addr,
1715                         sizeof(port->addr));
1716         if (ret) {
1717                 pr_err("failed to bind port socket %d\n", ret);
1718                 goto err_sock;
1719         }
1720
1721         ret = kernel_listen(port->sock, 128);
1722         if (ret) {
1723                 pr_err("failed to listen %d on port sock\n", ret);
1724                 goto err_sock;
1725         }
1726
1727         nport->priv = port;
1728         pr_info("enabling port %d (%pISpc)\n",
1729                 le16_to_cpu(nport->disc_addr.portid), &port->addr);
1730
1731         return 0;
1732
1733 err_sock:
1734         sock_release(port->sock);
1735 err_port:
1736         kfree(port);
1737         return ret;
1738 }
1739
1740 static void nvmet_tcp_remove_port(struct nvmet_port *nport)
1741 {
1742         struct nvmet_tcp_port *port = nport->priv;
1743
1744         write_lock_bh(&port->sock->sk->sk_callback_lock);
1745         port->sock->sk->sk_data_ready = port->data_ready;
1746         port->sock->sk->sk_user_data = NULL;
1747         write_unlock_bh(&port->sock->sk->sk_callback_lock);
1748         cancel_work_sync(&port->accept_work);
1749
1750         sock_release(port->sock);
1751         kfree(port);
1752 }
1753
1754 static void nvmet_tcp_delete_ctrl(struct nvmet_ctrl *ctrl)
1755 {
1756         struct nvmet_tcp_queue *queue;
1757
1758         mutex_lock(&nvmet_tcp_queue_mutex);
1759         list_for_each_entry(queue, &nvmet_tcp_queue_list, queue_list)
1760                 if (queue->nvme_sq.ctrl == ctrl)
1761                         kernel_sock_shutdown(queue->sock, SHUT_RDWR);
1762         mutex_unlock(&nvmet_tcp_queue_mutex);
1763 }
1764
1765 static u16 nvmet_tcp_install_queue(struct nvmet_sq *sq)
1766 {
1767         struct nvmet_tcp_queue *queue =
1768                 container_of(sq, struct nvmet_tcp_queue, nvme_sq);
1769
1770         if (sq->qid == 0) {
1771                 /* Let inflight controller teardown complete */
1772                 flush_scheduled_work();
1773         }
1774
1775         queue->nr_cmds = sq->size * 2;
1776         if (nvmet_tcp_alloc_cmds(queue))
1777                 return NVME_SC_INTERNAL;
1778         return 0;
1779 }
1780
1781 static void nvmet_tcp_disc_port_addr(struct nvmet_req *req,
1782                 struct nvmet_port *nport, char *traddr)
1783 {
1784         struct nvmet_tcp_port *port = nport->priv;
1785
1786         if (inet_addr_is_any((struct sockaddr *)&port->addr)) {
1787                 struct nvmet_tcp_cmd *cmd =
1788                         container_of(req, struct nvmet_tcp_cmd, req);
1789                 struct nvmet_tcp_queue *queue = cmd->queue;
1790
1791                 sprintf(traddr, "%pISc", (struct sockaddr *)&queue->sockaddr);
1792         } else {
1793                 memcpy(traddr, nport->disc_addr.traddr, NVMF_TRADDR_SIZE);
1794         }
1795 }
1796
1797 static const struct nvmet_fabrics_ops nvmet_tcp_ops = {
1798         .owner                  = THIS_MODULE,
1799         .type                   = NVMF_TRTYPE_TCP,
1800         .msdbd                  = 1,
1801         .add_port               = nvmet_tcp_add_port,
1802         .remove_port            = nvmet_tcp_remove_port,
1803         .queue_response         = nvmet_tcp_queue_response,
1804         .delete_ctrl            = nvmet_tcp_delete_ctrl,
1805         .install_queue          = nvmet_tcp_install_queue,
1806         .disc_traddr            = nvmet_tcp_disc_port_addr,
1807 };
1808
1809 static int __init nvmet_tcp_init(void)
1810 {
1811         int ret;
1812
1813         nvmet_tcp_wq = alloc_workqueue("nvmet_tcp_wq", WQ_HIGHPRI, 0);
1814         if (!nvmet_tcp_wq)
1815                 return -ENOMEM;
1816
1817         ret = nvmet_register_transport(&nvmet_tcp_ops);
1818         if (ret)
1819                 goto err;
1820
1821         return 0;
1822 err:
1823         destroy_workqueue(nvmet_tcp_wq);
1824         return ret;
1825 }
1826
1827 static void __exit nvmet_tcp_exit(void)
1828 {
1829         struct nvmet_tcp_queue *queue;
1830
1831         nvmet_unregister_transport(&nvmet_tcp_ops);
1832
1833         flush_scheduled_work();
1834         mutex_lock(&nvmet_tcp_queue_mutex);
1835         list_for_each_entry(queue, &nvmet_tcp_queue_list, queue_list)
1836                 kernel_sock_shutdown(queue->sock, SHUT_RDWR);
1837         mutex_unlock(&nvmet_tcp_queue_mutex);
1838         flush_scheduled_work();
1839
1840         destroy_workqueue(nvmet_tcp_wq);
1841 }
1842
1843 module_init(nvmet_tcp_init);
1844 module_exit(nvmet_tcp_exit);
1845
1846 MODULE_LICENSE("GPL v2");
1847 MODULE_ALIAS("nvmet-transport-3"); /* 3 == NVMF_TRTYPE_TCP */