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