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
 189         const struct rpc_timeout *timeout;      /* timeout parms */
 190         struct sockaddr_storage addr;           /* server address */
 191         size_t                  addrlen;        /* size of server address */
 192         int                     prot;           /* IP protocol */
 193
 194         unsigned long           cong;           /* current congestion */
 195         unsigned long           cwnd;           /* congestion window */
 196
 197         size_t                  max_payload;    /* largest RPC payload size,
 198                                                    in bytes */
 199
 200         struct rpc_wait_queue   binding;        /* requests waiting on rpcbind */
 201         struct rpc_wait_queue   sending;        /* requests waiting to send */
 202         struct rpc_wait_queue   pending;        /* requests in flight */
 203         struct rpc_wait_queue   backlog;        /* waiting for slot */
 204         struct list_head        free;           /* free slots */
 205         unsigned int            max_reqs;       /* max number of slots */
 206         unsigned int            min_reqs;       /* min number of slots */
 207         unsigned int            num_reqs;       /* total slots */
 208         unsigned long           state;          /* transport state */
 209         unsigned char           resvport   : 1, /* use a reserved port */
 210                                 reuseport  : 1; /* reuse port on reconnect */
 211         atomic_t                swapper;        /* we're swapping over this
 212                                                    transport */
 213         unsigned int            bind_index;     /* bind function index */
 214
 215         /*
 216          * Multipath
 217          */
 218         struct list_head        xprt_switch;
 219
 220         /*
 221          * Connection of transports
 222          */
 223         unsigned long           bind_timeout,
 224                                 reestablish_timeout;
 225         unsigned int            connect_cookie; /* A cookie that gets bumped
 226                                                    every time the transport
 227                                                    is reconnected */
 228
 229         /*
 230          * Disconnection of idle transports
 231          */
 232         struct work_struct      task_cleanup;
 233         struct timer_list       timer;
 234         unsigned long           last_used,
 235                                 idle_timeout,
 236                                 connect_timeout,
 237                                 max_reconnect_timeout;
 238
 239         /*
 240          * Send stuff
 241          */
 242         atomic_long_t           queuelen;
 243         spinlock_t              transport_lock; /* lock transport info */
 244         spinlock_t              reserve_lock;   /* lock slot table */
 245         spinlock_t              queue_lock;     /* send/receive queue lock */
 246         u32                     xid;            /* Next XID value to use */
 247         struct rpc_task *       snd_task;       /* Task blocked in send */
 248
 249         struct list_head        xmit_queue;     /* Send queue */
 250         atomic_long_t           xmit_queuelen;
 251
 252         struct svc_xprt         *bc_xprt;       /* NFSv4.1 backchannel */
 253 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
 254         struct svc_serv         *bc_serv;       /* The RPC service which will */
 255                                                 /* process the callback */
 256         unsigned int            bc_alloc_max;
 257         unsigned int            bc_alloc_count; /* Total number of preallocs */
 258         atomic_t                bc_slot_count;  /* Number of allocated slots */
 259         spinlock_t              bc_pa_lock;     /* Protects the preallocated
 260                                                  * items */
 261         struct list_head        bc_pa_list;     /* List of preallocated
 262                                                  * backchannel rpc_rqst's */
 263 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
 264
 265         struct rb_root          recv_queue;     /* Receive queue */
 266
 267         struct {
 268                 unsigned long           bind_count,     /* total number of binds */
 269                                         connect_count,  /* total number of connects */
 270                                         connect_start,  /* connect start timestamp */
 271                                         connect_time,   /* jiffies waiting for connect */
 272                                         sends,          /* how many complete requests */
 273                                         recvs,          /* how many complete requests */
 274                                         bad_xids,       /* lookup_rqst didn't find XID */
 275                                         max_slots;      /* max rpc_slots used */
 276
 277                 unsigned long long      req_u,          /* average requests on the wire */
 278                                         bklog_u,        /* backlog queue utilization */
 279                                         sending_u,      /* send q utilization */
 280                                         pending_u;      /* pend q utilization */
 281         } stat;
 282
 283         struct net              *xprt_net;
 284         const char              *servername;
 285         const char              *address_strings[RPC_DISPLAY_MAX];
 286 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 287         struct dentry           *debugfs;               /* debugfs directory */
 288         atomic_t                inject_disconnect;
 289 #endif
 290         struct rcu_head         rcu;
 291 };
 292
 293 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
 294 /*
 295  * Backchannel flags
 296  */
 297 #define RPC_BC_PA_IN_USE        0x0001          /* Preallocated backchannel */
 298                                                 /* buffer in use */
 299 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
 300
 301 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
 302 static inline int bc_prealloc(struct rpc_rqst *req)
 303 {
 304         return test_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state);
 305 }
 306 #else
 307 static inline int bc_prealloc(struct rpc_rqst *req)
 308 {
 309         return 0;
 310 }
 311 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
 312
 313 #define XPRT_CREATE_INFINITE_SLOTS      (1U)
 314 #define XPRT_CREATE_NO_IDLE_TIMEOUT     (1U << 1)
 315
 316 struct xprt_create {
 317         int                     ident;          /* XPRT_TRANSPORT identifier */
 318         struct net *            net;
 319         struct sockaddr *       srcaddr;        /* optional local address */
 320         struct sockaddr *       dstaddr;        /* remote peer address */
 321         size_t                  addrlen;
 322         const char              *servername;
 323         struct svc_xprt         *bc_xprt;       /* NFSv4.1 backchannel */
 324         struct rpc_xprt_switch  *bc_xps;
 325         unsigned int            flags;
 326 };
 327
 328 struct xprt_class {
 329         struct list_head        list;
 330         int                     ident;          /* XPRT_TRANSPORT identifier */
 331         struct rpc_xprt *       (*setup)(struct xprt_create *);
 332         struct module           *owner;
 333         char                    name[32];
 334         const char *            netid[];
 335 };
 336
 337 /*
 338  * Generic internal transport functions
 339  */
 340 struct rpc_xprt         *xprt_create_transport(struct xprt_create *args);
 341 void                    xprt_connect(struct rpc_task *task);
 342 unsigned long           xprt_reconnect_delay(const struct rpc_xprt *xprt);
 343 void                    xprt_reconnect_backoff(struct rpc_xprt *xprt,
 344                                                unsigned long init_to);
 345 void                    xprt_reserve(struct rpc_task *task);
 346 void                    xprt_retry_reserve(struct rpc_task *task);
 347 int                     xprt_reserve_xprt(struct rpc_xprt *xprt, struct rpc_task *task);
 348 int                     xprt_reserve_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task);
 349 void                    xprt_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task);
 350 void                    xprt_free_slot(struct rpc_xprt *xprt,
 351                                        struct rpc_rqst *req);
 352 void                    xprt_request_prepare(struct rpc_rqst *req);
 353 bool                    xprt_prepare_transmit(struct rpc_task *task);
 354 void                    xprt_request_enqueue_transmit(struct rpc_task *task);
 355 void                    xprt_request_enqueue_receive(struct rpc_task *task);
 356 void                    xprt_request_wait_receive(struct rpc_task *task);
 357 void                    xprt_request_dequeue_xprt(struct rpc_task *task);
 358 bool                    xprt_request_need_retransmit(struct rpc_task *task);
 359 void                    xprt_transmit(struct rpc_task *task);
 360 void                    xprt_end_transmit(struct rpc_task *task);
 361 int                     xprt_adjust_timeout(struct rpc_rqst *req);
 362 void                    xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task);
 363 void                    xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task);
 364 void                    xprt_release(struct rpc_task *task);
 365 struct rpc_xprt *       xprt_get(struct rpc_xprt *xprt);
 366 void                    xprt_put(struct rpc_xprt *xprt);
 367 struct rpc_xprt *       xprt_alloc(struct net *net, size_t size,
 368                                 unsigned int num_prealloc,
 369                                 unsigned int max_req);
 370 void                    xprt_free(struct rpc_xprt *);
 371 void                    xprt_add_backlog(struct rpc_xprt *xprt, struct rpc_task *task);
 372 bool                    xprt_wake_up_backlog(struct rpc_xprt *xprt, struct rpc_rqst *req);
 373
 374 static inline int
 375 xprt_enable_swap(struct rpc_xprt *xprt)
 376 {
 377         return xprt->ops->enable_swap(xprt);
 378 }
 379
 380 static inline void
 381 xprt_disable_swap(struct rpc_xprt *xprt)
 382 {
 383         xprt->ops->disable_swap(xprt);
 384 }
 385
 386 /*
 387  * Transport switch helper functions
 388  */
 389 int                     xprt_register_transport(struct xprt_class *type);
 390 int                     xprt_unregister_transport(struct xprt_class *type);
 391 int                     xprt_find_transport_ident(const char *);
 392 void                    xprt_wait_for_reply_request_def(struct rpc_task *task);
 393 void                    xprt_wait_for_reply_request_rtt(struct rpc_task *task);
 394 void                    xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status);
 395 void                    xprt_wait_for_buffer_space(struct rpc_xprt *xprt);
 396 bool                    xprt_write_space(struct rpc_xprt *xprt);
 397 void                    xprt_adjust_cwnd(struct rpc_xprt *xprt, struct rpc_task *task, int result);
 398 struct rpc_rqst *       xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid);
 399 void                    xprt_update_rtt(struct rpc_task *task);
 400 void                    xprt_complete_rqst(struct rpc_task *task, int copied);
 401 void                    xprt_pin_rqst(struct rpc_rqst *req);
 402 void                    xprt_unpin_rqst(struct rpc_rqst *req);
 403 void                    xprt_release_rqst_cong(struct rpc_task *task);
 404 bool                    xprt_request_get_cong(struct rpc_xprt *xprt, struct rpc_rqst *req);
 405 void                    xprt_disconnect_done(struct rpc_xprt *xprt);
 406 void                    xprt_force_disconnect(struct rpc_xprt *xprt);
 407 void                    xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie);
 408
 409 bool                    xprt_lock_connect(struct rpc_xprt *, struct rpc_task *, void *);
 410 void                    xprt_unlock_connect(struct rpc_xprt *, void *);
 411
 412 /*
 413  * Reserved bit positions in xprt->state
 414  */
 415 #define XPRT_LOCKED             (0)
 416 #define XPRT_CONNECTED          (1)
 417 #define XPRT_CONNECTING         (2)
 418 #define XPRT_CLOSE_WAIT         (3)
 419 #define XPRT_BOUND              (4)
 420 #define XPRT_BINDING            (5)
 421 #define XPRT_CLOSING            (6)
 422 #define XPRT_CONGESTED          (9)
 423 #define XPRT_CWND_WAIT          (10)
 424 #define XPRT_WRITE_SPACE        (11)
 425
 426 static inline void xprt_set_connected(struct rpc_xprt *xprt)
 427 {
 428         set_bit(XPRT_CONNECTED, &xprt->state);
 429 }
 430
 431 static inline void xprt_clear_connected(struct rpc_xprt *xprt)
 432 {
 433         clear_bit(XPRT_CONNECTED, &xprt->state);
 434 }
 435
 436 static inline int xprt_connected(struct rpc_xprt *xprt)
 437 {
 438         return test_bit(XPRT_CONNECTED, &xprt->state);
 439 }
 440
 441 static inline int xprt_test_and_set_connected(struct rpc_xprt *xprt)
 442 {
 443         return test_and_set_bit(XPRT_CONNECTED, &xprt->state);
 444 }
 445
 446 static inline int xprt_test_and_clear_connected(struct rpc_xprt *xprt)
 447 {
 448         return test_and_clear_bit(XPRT_CONNECTED, &xprt->state);
 449 }
 450
 451 static inline void xprt_clear_connecting(struct rpc_xprt *xprt)
 452 {
 453         smp_mb__before_atomic();
 454         clear_bit(XPRT_CONNECTING, &xprt->state);
 455         smp_mb__after_atomic();
 456 }
 457
 458 static inline int xprt_connecting(struct rpc_xprt *xprt)
 459 {
 460         return test_bit(XPRT_CONNECTING, &xprt->state);
 461 }
 462
 463 static inline int xprt_test_and_set_connecting(struct rpc_xprt *xprt)
 464 {
 465         return test_and_set_bit(XPRT_CONNECTING, &xprt->state);
 466 }
 467
 468 static inline void xprt_set_bound(struct rpc_xprt *xprt)
 469 {
 470         test_and_set_bit(XPRT_BOUND, &xprt->state);
 471 }
 472
 473 static inline int xprt_bound(struct rpc_xprt *xprt)
 474 {
 475         return test_bit(XPRT_BOUND, &xprt->state);
 476 }
 477
 478 static inline void xprt_clear_bound(struct rpc_xprt *xprt)
 479 {
 480         clear_bit(XPRT_BOUND, &xprt->state);
 481 }
 482
 483 static inline void xprt_clear_binding(struct rpc_xprt *xprt)
 484 {
 485         smp_mb__before_atomic();
 486         clear_bit(XPRT_BINDING, &xprt->state);
 487         smp_mb__after_atomic();
 488 }
 489
 490 static inline int xprt_test_and_set_binding(struct rpc_xprt *xprt)
 491 {
 492         return test_and_set_bit(XPRT_BINDING, &xprt->state);
 493 }
 494
 495 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 496 extern unsigned int rpc_inject_disconnect;
 497 static inline void xprt_inject_disconnect(struct rpc_xprt *xprt)
 498 {
 499         if (!rpc_inject_disconnect)
 500                 return;
 501         if (atomic_dec_return(&xprt->inject_disconnect))
 502                 return;
 503         atomic_set(&xprt->inject_disconnect, rpc_inject_disconnect);
 504         xprt->ops->inject_disconnect(xprt);
 505 }
 506 #else
 507 static inline void xprt_inject_disconnect(struct rpc_xprt *xprt)
 508 {
 509 }
 510 #endif
 511
 512 #endif /* _LINUX_SUNRPC_XPRT_H */