include/linux/sunrpc/xprt.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  *  linux/include/linux/sunrpc/xprt.h
   4  *
   5  *  Declarations for the RPC transport interface.
   6  *
   7  *  Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
   8  */
   9
  10 #ifndef _LINUX_SUNRPC_XPRT_H
  11 #define _LINUX_SUNRPC_XPRT_H
  12
  13 #include <linux/uio.h>
  14 #include <linux/socket.h>
  15 #include <linux/in.h>
  16 #include <linux/ktime.h>
  17 #include <linux/kref.h>
  18 #include <linux/sunrpc/sched.h>
  19 #include <linux/sunrpc/xdr.h>
  20 #include <linux/sunrpc/msg_prot.h>
  21
  22 #define RPC_MIN_SLOT_TABLE      (2U)
  23 #define RPC_DEF_SLOT_TABLE      (16U)
  24 #define RPC_MAX_SLOT_TABLE_LIMIT        (65536U)
  25 #define RPC_MAX_SLOT_TABLE      RPC_MAX_SLOT_TABLE_LIMIT
  26
  27 #define RPC_CWNDSHIFT           (8U)
  28 #define RPC_CWNDSCALE           (1U << RPC_CWNDSHIFT)
  29 #define RPC_INITCWND            RPC_CWNDSCALE
  30 #define RPC_MAXCWND(xprt)       ((xprt)->max_reqs << RPC_CWNDSHIFT)
  31 #define RPCXPRT_CONGESTED(xprt) ((xprt)->cong >= (xprt)->cwnd)
  32
  33 /*
  34  * This describes a timeout strategy
  35  */
  36 struct rpc_timeout {
  37         unsigned long           to_initval,             /* initial timeout */
  38                                 to_maxval,              /* max timeout */
  39                                 to_increment;           /* if !exponential */
  40         unsigned int            to_retries;             /* max # of retries */
  41         unsigned char           to_exponential;
  42 };
  43
  44 enum rpc_display_format_t {
  45         RPC_DISPLAY_ADDR = 0,
  46         RPC_DISPLAY_PORT,
  47         RPC_DISPLAY_PROTO,
  48         RPC_DISPLAY_HEX_ADDR,
  49         RPC_DISPLAY_HEX_PORT,
  50         RPC_DISPLAY_NETID,
  51         RPC_DISPLAY_MAX,
  52 };
  53
  54 struct rpc_task;
  55 struct rpc_xprt;
  56 struct xprt_class;
  57 struct seq_file;
  58 struct svc_serv;
  59 struct net;
  60
  61 /*
  62  * This describes a complete RPC request
  63  */
  64 struct rpc_rqst {
  65         /*
  66          * This is the user-visible part
  67          */
  68         struct rpc_xprt *       rq_xprt;                /* RPC client */
  69         struct xdr_buf          rq_snd_buf;             /* send buffer */
  70         struct xdr_buf          rq_rcv_buf;             /* recv buffer */
  71
  72         /*
  73          * This is the private part
  74          */
  75         struct rpc_task *       rq_task;        /* RPC task data */
  76         struct rpc_cred *       rq_cred;        /* Bound cred */
  77         __be32                  rq_xid;         /* request XID */
  78         int                     rq_cong;        /* has incremented xprt->cong */
  79         u32                     rq_seqno;       /* gss seq no. used on req. */
  80         int                     rq_enc_pages_num;
  81         struct page             **rq_enc_pages; /* scratch pages for use by
  82                                                    gss privacy code */
  83         void (*rq_release_snd_buf)(struct rpc_rqst *); /* release rq_enc_pages */
  84
  85         union {
  86                 struct list_head        rq_list;        /* Slot allocation list */
  87                 struct rb_node          rq_recv;        /* Receive queue */
  88         };
  89
  90         struct list_head        rq_xmit;        /* Send queue */
  91         struct list_head        rq_xmit2;       /* Send queue */
  92
  93         void                    *rq_buffer;     /* Call XDR encode buffer */
  94         size_t                  rq_callsize;
  95         void                    *rq_rbuffer;    /* Reply XDR decode buffer */
  96         size_t                  rq_rcvsize;
  97         size_t                  rq_xmit_bytes_sent;     /* total bytes sent */
  98         size_t                  rq_reply_bytes_recvd;   /* total reply bytes */
  99                                                         /* received */
 100
 101         struct xdr_buf          rq_private_buf;         /* The receive buffer
 102                                                          * used in the softirq.
 103                                                          */
 104         unsigned long           rq_majortimeo;  /* major timeout alarm */
 105         unsigned long           rq_minortimeo;  /* minor timeout alarm */
 106         unsigned long           rq_timeout;     /* Current timeout value */
 107         ktime_t                 rq_rtt;         /* round-trip time */
 108         unsigned int            rq_retries;     /* # of retries */
 109         unsigned int            rq_connect_cookie;
 110                                                 /* A cookie used to track the
 111                                                    state of the transport
 112                                                    connection */
 113         atomic_t                rq_pin;
 114
 115         /*
 116          * Partial send handling
 117          */
 118         u32                     rq_bytes_sent;  /* Bytes we have sent */
 119
 120         ktime_t                 rq_xtime;       /* transmit time stamp */
 121         int                     rq_ntrans;
 122
 123 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
 124         struct list_head        rq_bc_list;     /* Callback service list */
 125         unsigned long           rq_bc_pa_state; /* Backchannel prealloc state */
 126         struct list_head        rq_bc_pa_list;  /* Backchannel prealloc list */
 127 #endif /* CONFIG_SUNRPC_BACKCHANEL */
 128 };
 129 #define rq_svec                 rq_snd_buf.head
 130 #define rq_slen                 rq_snd_buf.len
 131
 132 struct rpc_xprt_ops {
 133         void            (*set_buffer_size)(struct rpc_xprt *xprt, size_t sndsize, size_t rcvsize);
 134         int             (*reserve_xprt)(struct rpc_xprt *xprt, struct rpc_task *task);
 135         void            (*release_xprt)(struct rpc_xprt *xprt, struct rpc_task *task);
 136         void            (*alloc_slot)(struct rpc_xprt *xprt, struct rpc_task *task);
 137         void            (*free_slot)(struct rpc_xprt *xprt,
 138                                      struct rpc_rqst *req);
 139         void            (*rpcbind)(struct rpc_task *task);
 140         void            (*set_port)(struct rpc_xprt *xprt, unsigned short port);
 141         void            (*connect)(struct rpc_xprt *xprt, struct rpc_task *task);
 142         int             (*buf_alloc)(struct rpc_task *task);
 143         void            (*buf_free)(struct rpc_task *task);
 144         void            (*prepare_request)(struct rpc_rqst *req);
 145         int             (*send_request)(struct rpc_rqst *req);
 146         void            (*wait_for_reply_request)(struct rpc_task *task);
 147         void            (*timer)(struct rpc_xprt *xprt, struct rpc_task *task);
 148         void            (*release_request)(struct rpc_task *task);
 149         void            (*close)(struct rpc_xprt *xprt);
 150         void            (*destroy)(struct rpc_xprt *xprt);
 151         void            (*set_connect_timeout)(struct rpc_xprt *xprt,
 152                                         unsigned long connect_timeout,
 153                                         unsigned long reconnect_timeout);
 154         void            (*print_stats)(struct rpc_xprt *xprt, struct seq_file *seq);
 155         int             (*enable_swap)(struct rpc_xprt *xprt);
 156         void            (*disable_swap)(struct rpc_xprt *xprt);
 157         void            (*inject_disconnect)(struct rpc_xprt *xprt);
 158         int             (*bc_setup)(struct rpc_xprt *xprt,
 159                                     unsigned int min_reqs);
 160         size_t          (*bc_maxpayload)(struct rpc_xprt *xprt);
 161         unsigned int    (*bc_num_slots)(struct rpc_xprt *xprt);
 162         void            (*bc_free_rqst)(struct rpc_rqst *rqst);
 163         void            (*bc_destroy)(struct rpc_xprt *xprt,
 164                                       unsigned int max_reqs);
 165 };
 166
 167 /*
 168  * RPC transport identifiers
 169  *
 170  * To preserve compatibility with the historical use of raw IP protocol
 171  * id's for transport selection, UDP and TCP identifiers are specified
 172  * with the previous values. No such restriction exists for new transports,
 173  * except that they may not collide with these values (17 and 6,
 174  * respectively).
 175  */
 176 #define XPRT_TRANSPORT_BC       (1 << 31)
 177 enum xprt_transports {
 178         XPRT_TRANSPORT_UDP      = IPPROTO_UDP,
 179         XPRT_TRANSPORT_TCP      = IPPROTO_TCP,
 180         XPRT_TRANSPORT_BC_TCP   = IPPROTO_TCP | XPRT_TRANSPORT_BC,
 181         XPRT_TRANSPORT_RDMA     = 256,
 182         XPRT_TRANSPORT_BC_RDMA  = XPRT_TRANSPORT_RDMA | XPRT_TRANSPORT_BC,
 183         XPRT_TRANSPORT_LOCAL    = 257,
 184 };
 185
 186 struct rpc_sysfs_xprt;
 187 struct rpc_xprt {
 188         struct kref             kref;           /* Reference count */
 189         const struct rpc_xprt_ops *ops;         /* transport methods */
 190         unsigned int            id;             /* transport id */
 191
 192         const struct rpc_timeout *timeout;      /* timeout parms */
 193         struct sockaddr_storage addr;           /* server address */
 194         size_t                  addrlen;        /* size of server address */
 195         int                     prot;           /* IP protocol */
 196
 197         unsigned long           cong;           /* current congestion */
 198         unsigned long           cwnd;           /* congestion window */
 199
 200         size_t                  max_payload;    /* largest RPC payload size,
 201                                                    in bytes */
 202
 203         struct rpc_wait_queue   binding;        /* requests waiting on rpcbind */
 204         struct rpc_wait_queue   sending;        /* requests waiting to send */
 205         struct rpc_wait_queue   pending;        /* requests in flight */
 206         struct rpc_wait_queue   backlog;        /* waiting for slot */
 207         struct list_head        free;           /* free slots */
 208         unsigned int            max_reqs;       /* max number of slots */
 209         unsigned int            min_reqs;       /* min number of slots */
 210         unsigned int            num_reqs;       /* total slots */
 211         unsigned long           state;          /* transport state */
 212         unsigned char           resvport   : 1, /* use a reserved port */
 213                                 reuseport  : 1; /* reuse port on reconnect */
 214         atomic_t                swapper;        /* we're swapping over this
 215                                                    transport */
 216         unsigned int            bind_index;     /* bind function index */
 217
 218         /*
 219          * Multipath
 220          */
 221         struct list_head        xprt_switch;
 222
 223         /*
 224          * Connection of transports
 225          */
 226         unsigned long           bind_timeout,
 227                                 reestablish_timeout;
 228         unsigned int            connect_cookie; /* A cookie that gets bumped
 229                                                    every time the transport
 230                                                    is reconnected */
 231
 232         /*
 233          * Disconnection of idle transports
 234          */
 235         struct work_struct      task_cleanup;
 236         struct timer_list       timer;
 237         unsigned long           last_used,
 238                                 idle_timeout,
 239                                 connect_timeout,
 240                                 max_reconnect_timeout;
 241
 242         /*
 243          * Send stuff
 244          */
 245         atomic_long_t           queuelen;
 246         spinlock_t              transport_lock; /* lock transport info */
 247         spinlock_t              reserve_lock;   /* lock slot table */
 248         spinlock_t              queue_lock;     /* send/receive queue lock */
 249         u32                     xid;            /* Next XID value to use */
 250         struct rpc_task *       snd_task;       /* Task blocked in send */
 251
 252         struct list_head        xmit_queue;     /* Send queue */
 253         atomic_long_t           xmit_queuelen;
 254
 255         struct svc_xprt         *bc_xprt;       /* NFSv4.1 backchannel */
 256 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
 257         struct svc_serv         *bc_serv;       /* The RPC service which will */
 258                                                 /* process the callback */
 259         unsigned int            bc_alloc_max;
 260         unsigned int            bc_alloc_count; /* Total number of preallocs */
 261         atomic_t                bc_slot_count;  /* Number of allocated slots */
 262         spinlock_t              bc_pa_lock;     /* Protects the preallocated
 263                                                  * items */
 264         struct list_head        bc_pa_list;     /* List of preallocated
 265                                                  * backchannel rpc_rqst's */
 266 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
 267
 268         struct rb_root          recv_queue;     /* Receive queue */
 269
 270         struct {
 271                 unsigned long           bind_count,     /* total number of binds */
 272                                         connect_count,  /* total number of connects */
 273                                         connect_start,  /* connect start timestamp */
 274                                         connect_time,   /* jiffies waiting for connect */
 275                                         sends,          /* how many complete requests */
 276                                         recvs,          /* how many complete requests */
 277                                         bad_xids,       /* lookup_rqst didn't find XID */
 278                                         max_slots;      /* max rpc_slots used */
 279
 280                 unsigned long long      req_u,          /* average requests on the wire */
 281                                         bklog_u,        /* backlog queue utilization */
 282                                         sending_u,      /* send q utilization */
 283                                         pending_u;      /* pend q utilization */
 284         } stat;
 285
 286         struct net              *xprt_net;
 287         const char              *servername;
 288         const char              *address_strings[RPC_DISPLAY_MAX];
 289 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 290         struct dentry           *debugfs;               /* debugfs directory */
 291         atomic_t                inject_disconnect;
 292 #endif
 293         struct rcu_head         rcu;
 294         const struct xprt_class *xprt_class;
 295         struct rpc_sysfs_xprt   *xprt_sysfs;
 296         bool                    main; /*mark if this is the 1st transport */
 297 };
 298
 299 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
 300 /*
 301  * Backchannel flags
 302  */
 303 #define RPC_BC_PA_IN_USE        0x0001          /* Preallocated backchannel */
 304                                                 /* buffer in use */
 305 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
 306
 307 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
 308 static inline int bc_prealloc(struct rpc_rqst *req)
 309 {
 310         return test_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state);
 311 }
 312 #else
 313 static inline int bc_prealloc(struct rpc_rqst *req)
 314 {
 315         return 0;
 316 }
 317 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
 318
 319 #define XPRT_CREATE_INFINITE_SLOTS      (1U)
 320 #define XPRT_CREATE_NO_IDLE_TIMEOUT     (1U << 1)
 321
 322 struct xprt_create {
 323         int                     ident;          /* XPRT_TRANSPORT identifier */
 324         struct net *            net;
 325         struct sockaddr *       srcaddr;        /* optional local address */
 326         struct sockaddr *       dstaddr;        /* remote peer address */
 327         size_t                  addrlen;
 328         const char              *servername;
 329         struct svc_xprt         *bc_xprt;       /* NFSv4.1 backchannel */
 330         struct rpc_xprt_switch  *bc_xps;
 331         unsigned int            flags;
 332 };
 333
 334 struct xprt_class {
 335         struct list_head        list;
 336         int                     ident;          /* XPRT_TRANSPORT identifier */
 337         struct rpc_xprt *       (*setup)(struct xprt_create *);
 338         struct module           *owner;
 339         char                    name[32];
 340         const char *            netid[];
 341 };
 342
 343 /*
 344  * Generic internal transport functions
 345  */
 346 struct rpc_xprt         *xprt_create_transport(struct xprt_create *args);
 347 void                    xprt_connect(struct rpc_task *task);
 348 unsigned long           xprt_reconnect_delay(const struct rpc_xprt *xprt);
 349 void                    xprt_reconnect_backoff(struct rpc_xprt *xprt,
 350                                                unsigned long init_to);
 351 void                    xprt_reserve(struct rpc_task *task);
 352 void                    xprt_retry_reserve(struct rpc_task *task);
 353 int                     xprt_reserve_xprt(struct rpc_xprt *xprt, struct rpc_task *task);
 354 int                     xprt_reserve_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task);
 355 void                    xprt_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task);
 356 void                    xprt_free_slot(struct rpc_xprt *xprt,
 357                                        struct rpc_rqst *req);
 358 void                    xprt_request_prepare(struct rpc_rqst *req);
 359 bool                    xprt_prepare_transmit(struct rpc_task *task);
 360 void                    xprt_request_enqueue_transmit(struct rpc_task *task);
 361 void                    xprt_request_enqueue_receive(struct rpc_task *task);
 362 void                    xprt_request_wait_receive(struct rpc_task *task);
 363 void                    xprt_request_dequeue_xprt(struct rpc_task *task);
 364 bool                    xprt_request_need_retransmit(struct rpc_task *task);
 365 void                    xprt_transmit(struct rpc_task *task);
 366 void                    xprt_end_transmit(struct rpc_task *task);
 367 int                     xprt_adjust_timeout(struct rpc_rqst *req);
 368 void                    xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task);
 369 void                    xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task);
 370 void                    xprt_release(struct rpc_task *task);
 371 struct rpc_xprt *       xprt_get(struct rpc_xprt *xprt);
 372 void                    xprt_put(struct rpc_xprt *xprt);
 373 struct rpc_xprt *       xprt_alloc(struct net *net, size_t size,
 374                                 unsigned int num_prealloc,
 375                                 unsigned int max_req);
 376 void                    xprt_free(struct rpc_xprt *);
 377 void                    xprt_add_backlog(struct rpc_xprt *xprt, struct rpc_task *task);
 378 bool                    xprt_wake_up_backlog(struct rpc_xprt *xprt, struct rpc_rqst *req);
 379 void                    xprt_cleanup_ids(void);
 380
 381 static inline int
 382 xprt_enable_swap(struct rpc_xprt *xprt)
 383 {
 384         return xprt->ops->enable_swap(xprt);
 385 }
 386
 387 static inline void
 388 xprt_disable_swap(struct rpc_xprt *xprt)
 389 {
 390         xprt->ops->disable_swap(xprt);
 391 }
 392
 393 /*
 394  * Transport switch helper functions
 395  */
 396 int                     xprt_register_transport(struct xprt_class *type);
 397 int                     xprt_unregister_transport(struct xprt_class *type);
 398 int                     xprt_find_transport_ident(const char *);
 399 void                    xprt_wait_for_reply_request_def(struct rpc_task *task);
 400 void                    xprt_wait_for_reply_request_rtt(struct rpc_task *task);
 401 void                    xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status);
 402 void                    xprt_wait_for_buffer_space(struct rpc_xprt *xprt);
 403 bool                    xprt_write_space(struct rpc_xprt *xprt);
 404 void                    xprt_adjust_cwnd(struct rpc_xprt *xprt, struct rpc_task *task, int result);
 405 struct rpc_rqst *       xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid);
 406 void                    xprt_update_rtt(struct rpc_task *task);
 407 void                    xprt_complete_rqst(struct rpc_task *task, int copied);
 408 void                    xprt_pin_rqst(struct rpc_rqst *req);
 409 void                    xprt_unpin_rqst(struct rpc_rqst *req);
 410 void                    xprt_release_rqst_cong(struct rpc_task *task);
 411 bool                    xprt_request_get_cong(struct rpc_xprt *xprt, struct rpc_rqst *req);
 412 void                    xprt_disconnect_done(struct rpc_xprt *xprt);
 413 void                    xprt_force_disconnect(struct rpc_xprt *xprt);
 414 void                    xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie);
 415
 416 bool                    xprt_lock_connect(struct rpc_xprt *, struct rpc_task *, void *);
 417 void                    xprt_unlock_connect(struct rpc_xprt *, void *);
 418 void                    xprt_release_write(struct rpc_xprt *, struct rpc_task *);
 419
 420 /*
 421  * Reserved bit positions in xprt->state
 422  */
 423 #define XPRT_LOCKED             (0)
 424 #define XPRT_CONNECTED          (1)
 425 #define XPRT_CONNECTING         (2)
 426 #define XPRT_CLOSE_WAIT         (3)
 427 #define XPRT_BOUND              (4)
 428 #define XPRT_BINDING            (5)
 429 #define XPRT_CLOSING            (6)
 430 #define XPRT_OFFLINE            (7)
 431 #define XPRT_REMOVE             (8)
 432 #define XPRT_CONGESTED          (9)
 433 #define XPRT_CWND_WAIT          (10)
 434 #define XPRT_WRITE_SPACE        (11)
 435
 436 static inline void xprt_set_connected(struct rpc_xprt *xprt)
 437 {
 438         set_bit(XPRT_CONNECTED, &xprt->state);
 439 }
 440
 441 static inline void xprt_clear_connected(struct rpc_xprt *xprt)
 442 {
 443         clear_bit(XPRT_CONNECTED, &xprt->state);
 444 }
 445
 446 static inline int xprt_connected(struct rpc_xprt *xprt)
 447 {
 448         return test_bit(XPRT_CONNECTED, &xprt->state);
 449 }
 450
 451 static inline int xprt_test_and_set_connected(struct rpc_xprt *xprt)
 452 {
 453         return test_and_set_bit(XPRT_CONNECTED, &xprt->state);
 454 }
 455
 456 static inline int xprt_test_and_clear_connected(struct rpc_xprt *xprt)
 457 {
 458         return test_and_clear_bit(XPRT_CONNECTED, &xprt->state);
 459 }
 460
 461 static inline void xprt_clear_connecting(struct rpc_xprt *xprt)
 462 {
 463         smp_mb__before_atomic();
 464         clear_bit(XPRT_CONNECTING, &xprt->state);
 465         smp_mb__after_atomic();
 466 }
 467
 468 static inline int xprt_connecting(struct rpc_xprt *xprt)
 469 {
 470         return test_bit(XPRT_CONNECTING, &xprt->state);
 471 }
 472
 473 static inline int xprt_test_and_set_connecting(struct rpc_xprt *xprt)
 474 {
 475         return test_and_set_bit(XPRT_CONNECTING, &xprt->state);
 476 }
 477
 478 static inline void xprt_set_bound(struct rpc_xprt *xprt)
 479 {
 480         test_and_set_bit(XPRT_BOUND, &xprt->state);
 481 }
 482
 483 static inline int xprt_bound(struct rpc_xprt *xprt)
 484 {
 485         return test_bit(XPRT_BOUND, &xprt->state);
 486 }
 487
 488 static inline void xprt_clear_bound(struct rpc_xprt *xprt)
 489 {
 490         clear_bit(XPRT_BOUND, &xprt->state);
 491 }
 492
 493 static inline void xprt_clear_binding(struct rpc_xprt *xprt)
 494 {
 495         smp_mb__before_atomic();
 496         clear_bit(XPRT_BINDING, &xprt->state);
 497         smp_mb__after_atomic();
 498 }
 499
 500 static inline int xprt_test_and_set_binding(struct rpc_xprt *xprt)
 501 {
 502         return test_and_set_bit(XPRT_BINDING, &xprt->state);
 503 }
 504
 505 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 506 extern unsigned int rpc_inject_disconnect;
 507 static inline void xprt_inject_disconnect(struct rpc_xprt *xprt)
 508 {
 509         if (!rpc_inject_disconnect)
 510                 return;
 511         if (atomic_dec_return(&xprt->inject_disconnect))
 512                 return;
 513         atomic_set(&xprt->inject_disconnect, rpc_inject_disconnect);
 514         xprt->ops->inject_disconnect(xprt);
 515 }
 516 #else
 517 static inline void xprt_inject_disconnect(struct rpc_xprt *xprt)
 518 {
 519 }
 520 #endif
 521
 522 #endif /* _LINUX_SUNRPC_XPRT_H */