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 #ifdef __KERNEL__
  23
  24 #define RPC_MIN_SLOT_TABLE      (2U)
  25 #define RPC_DEF_SLOT_TABLE      (16U)
  26 #define RPC_MAX_SLOT_TABLE_LIMIT        (65536U)
  27 #define RPC_MAX_SLOT_TABLE      RPC_MAX_SLOT_TABLE_LIMIT
  28
  29 #define RPC_CWNDSHIFT           (8U)
  30 #define RPC_CWNDSCALE           (1U << RPC_CWNDSHIFT)
  31 #define RPC_INITCWND            RPC_CWNDSCALE
  32 #define RPC_MAXCWND(xprt)       ((xprt)->max_reqs << RPC_CWNDSHIFT)
  33 #define RPCXPRT_CONGESTED(xprt) ((xprt)->cong >= (xprt)->cwnd)
  34
  35 /*
  36  * This describes a timeout strategy
  37  */
  38 struct rpc_timeout {
  39         unsigned long           to_initval,             /* initial timeout */
  40                                 to_maxval,              /* max timeout */
  41                                 to_increment;           /* if !exponential */
  42         unsigned int            to_retries;             /* max # of retries */
  43         unsigned char           to_exponential;
  44 };
  45
  46 enum rpc_display_format_t {
  47         RPC_DISPLAY_ADDR = 0,
  48         RPC_DISPLAY_PORT,
  49         RPC_DISPLAY_PROTO,
  50         RPC_DISPLAY_HEX_ADDR,
  51         RPC_DISPLAY_HEX_PORT,
  52         RPC_DISPLAY_NETID,
  53         RPC_DISPLAY_MAX,
  54 };
  55
  56 struct rpc_task;
  57 struct rpc_xprt;
  58 struct seq_file;
  59 struct svc_serv;
  60 struct net;
  61
  62 /*
  63  * This describes a complete RPC request
  64  */
  65 struct rpc_rqst {
  66         /*
  67          * This is the user-visible part
  68          */
  69         struct rpc_xprt *       rq_xprt;                /* RPC client */
  70         struct xdr_buf          rq_snd_buf;             /* send buffer */
  71         struct xdr_buf          rq_rcv_buf;             /* recv buffer */
  72
  73         /*
  74          * This is the private part
  75          */
  76         struct rpc_task *       rq_task;        /* RPC task data */
  77         struct rpc_cred *       rq_cred;        /* Bound cred */
  78         __be32                  rq_xid;         /* request XID */
  79         int                     rq_cong;        /* has incremented xprt->cong */
  80         u32                     rq_seqno;       /* gss seq no. used on req. */
  81         int                     rq_enc_pages_num;
  82         struct page             **rq_enc_pages; /* scratch pages for use by
  83                                                    gss privacy code */
  84         void (*rq_release_snd_buf)(struct rpc_rqst *); /* release rq_enc_pages */
  85
  86         union {
  87                 struct list_head        rq_list;        /* Slot allocation list */
  88                 struct rb_node          rq_recv;        /* Receive queue */
  89         };
  90
  91         struct list_head        rq_xmit;        /* Send queue */
  92         struct list_head        rq_xmit2;       /* Send queue */
  93
  94         void                    *rq_buffer;     /* Call XDR encode buffer */
  95         size_t                  rq_callsize;
  96         void                    *rq_rbuffer;    /* Reply XDR decode buffer */
  97         size_t                  rq_rcvsize;
  98         size_t                  rq_xmit_bytes_sent;     /* total bytes sent */
  99         size_t                  rq_reply_bytes_recvd;   /* total reply bytes */
 100                                                         /* received */
 101
 102         struct xdr_buf          rq_private_buf;         /* The receive buffer
 103                                                          * used in the softirq.
 104                                                          */
 105         unsigned long           rq_majortimeo;  /* major 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            (*set_retrans_timeout)(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         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         unsigned int            tsh_size;       /* size of transport specific
 200                                                    header */
 201
 202         struct rpc_wait_queue   binding;        /* requests waiting on rpcbind */
 203         struct rpc_wait_queue   sending;        /* requests waiting to send */
 204         struct rpc_wait_queue   pending;        /* requests in flight */
 205         struct rpc_wait_queue   backlog;        /* waiting for slot */
 206         struct list_head        free;           /* free slots */
 207         unsigned int            max_reqs;       /* max number of slots */
 208         unsigned int            min_reqs;       /* min number of slots */
 209         unsigned int            num_reqs;       /* total slots */
 210         unsigned long           state;          /* transport state */
 211         unsigned char           resvport   : 1; /* use a reserved port */
 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         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
 251         struct svc_xprt         *bc_xprt;       /* NFSv4.1 backchannel */
 252 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
 253         struct svc_serv         *bc_serv;       /* The RPC service which will */
 254                                                 /* process the callback */
 255         int                     bc_alloc_count; /* Total number of preallocs */
 256         atomic_t                bc_free_slots;
 257         spinlock_t              bc_pa_lock;     /* Protects the preallocated
 258                                                  * items */
 259         struct list_head        bc_pa_list;     /* List of preallocated
 260                                                  * backchannel rpc_rqst's */
 261 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
 262
 263         struct rb_root          recv_queue;     /* Receive queue */
 264
 265         struct {
 266                 unsigned long           bind_count,     /* total number of binds */
 267                                         connect_count,  /* total number of connects */
 268                                         connect_start,  /* connect start timestamp */
 269                                         connect_time,   /* jiffies waiting for connect */
 270                                         sends,          /* how many complete requests */
 271                                         recvs,          /* how many complete requests */
 272                                         bad_xids,       /* lookup_rqst didn't find XID */
 273                                         max_slots;      /* max rpc_slots used */
 274
 275                 unsigned long long      req_u,          /* average requests on the wire */
 276                                         bklog_u,        /* backlog queue utilization */
 277                                         sending_u,      /* send q utilization */
 278                                         pending_u;      /* pend q utilization */
 279         } stat;
 280
 281         struct net              *xprt_net;
 282         const char              *servername;
 283         const char              *address_strings[RPC_DISPLAY_MAX];
 284 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 285         struct dentry           *debugfs;               /* debugfs directory */
 286         atomic_t                inject_disconnect;
 287 #endif
 288         struct rcu_head         rcu;
 289 };
 290
 291 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
 292 /*
 293  * Backchannel flags
 294  */
 295 #define RPC_BC_PA_IN_USE        0x0001          /* Preallocated backchannel */
 296                                                 /* buffer in use */
 297 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
 298
 299 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
 300 static inline int bc_prealloc(struct rpc_rqst *req)
 301 {
 302         return test_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state);
 303 }
 304 #else
 305 static inline int bc_prealloc(struct rpc_rqst *req)
 306 {
 307         return 0;
 308 }
 309 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
 310
 311 #define XPRT_CREATE_INFINITE_SLOTS      (1U)
 312 #define XPRT_CREATE_NO_IDLE_TIMEOUT     (1U << 1)
 313
 314 struct xprt_create {
 315         int                     ident;          /* XPRT_TRANSPORT identifier */
 316         struct net *            net;
 317         struct sockaddr *       srcaddr;        /* optional local address */
 318         struct sockaddr *       dstaddr;        /* remote peer address */
 319         size_t                  addrlen;
 320         const char              *servername;
 321         struct svc_xprt         *bc_xprt;       /* NFSv4.1 backchannel */
 322         struct rpc_xprt_switch  *bc_xps;
 323         unsigned int            flags;
 324 };
 325
 326 struct xprt_class {
 327         struct list_head        list;
 328         int                     ident;          /* XPRT_TRANSPORT identifier */
 329         struct rpc_xprt *       (*setup)(struct xprt_create *);
 330         struct module           *owner;
 331         char                    name[32];
 332 };
 333
 334 /*
 335  * Generic internal transport functions
 336  */
 337 struct rpc_xprt         *xprt_create_transport(struct xprt_create *args);
 338 void                    xprt_connect(struct rpc_task *task);
 339 void                    xprt_reserve(struct rpc_task *task);
 340 void                    xprt_retry_reserve(struct rpc_task *task);
 341 int                     xprt_reserve_xprt(struct rpc_xprt *xprt, struct rpc_task *task);
 342 int                     xprt_reserve_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task);
 343 void                    xprt_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task);
 344 void                    xprt_free_slot(struct rpc_xprt *xprt,
 345                                        struct rpc_rqst *req);
 346 void                    xprt_request_prepare(struct rpc_rqst *req);
 347 bool                    xprt_prepare_transmit(struct rpc_task *task);
 348 void                    xprt_request_enqueue_transmit(struct rpc_task *task);
 349 void                    xprt_request_enqueue_receive(struct rpc_task *task);
 350 void                    xprt_request_wait_receive(struct rpc_task *task);
 351 bool                    xprt_request_need_retransmit(struct rpc_task *task);
 352 void                    xprt_transmit(struct rpc_task *task);
 353 void                    xprt_end_transmit(struct rpc_task *task);
 354 int                     xprt_adjust_timeout(struct rpc_rqst *req);
 355 void                    xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task);
 356 void                    xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task);
 357 void                    xprt_release(struct rpc_task *task);
 358 struct rpc_xprt *       xprt_get(struct rpc_xprt *xprt);
 359 void                    xprt_put(struct rpc_xprt *xprt);
 360 struct rpc_xprt *       xprt_alloc(struct net *net, size_t size,
 361                                 unsigned int num_prealloc,
 362                                 unsigned int max_req);
 363 void                    xprt_free(struct rpc_xprt *);
 364
 365 static inline __be32 *xprt_skip_transport_header(struct rpc_xprt *xprt, __be32 *p)
 366 {
 367         return p + xprt->tsh_size;
 368 }
 369
 370 static inline int
 371 xprt_enable_swap(struct rpc_xprt *xprt)
 372 {
 373         return xprt->ops->enable_swap(xprt);
 374 }
 375
 376 static inline void
 377 xprt_disable_swap(struct rpc_xprt *xprt)
 378 {
 379         xprt->ops->disable_swap(xprt);
 380 }
 381
 382 /*
 383  * Transport switch helper functions
 384  */
 385 int                     xprt_register_transport(struct xprt_class *type);
 386 int                     xprt_unregister_transport(struct xprt_class *type);
 387 int                     xprt_load_transport(const char *);
 388 void                    xprt_set_retrans_timeout_def(struct rpc_task *task);
 389 void                    xprt_set_retrans_timeout_rtt(struct rpc_task *task);
 390 void                    xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status);
 391 void                    xprt_wait_for_buffer_space(struct rpc_xprt *xprt);
 392 bool                    xprt_write_space(struct rpc_xprt *xprt);
 393 void                    xprt_adjust_cwnd(struct rpc_xprt *xprt, struct rpc_task *task, int result);
 394 struct rpc_rqst *       xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid);
 395 void                    xprt_update_rtt(struct rpc_task *task);
 396 void                    xprt_complete_rqst(struct rpc_task *task, int copied);
 397 void                    xprt_pin_rqst(struct rpc_rqst *req);
 398 void                    xprt_unpin_rqst(struct rpc_rqst *req);
 399 void                    xprt_release_rqst_cong(struct rpc_task *task);
 400 bool                    xprt_request_get_cong(struct rpc_xprt *xprt, struct rpc_rqst *req);
 401 void                    xprt_disconnect_done(struct rpc_xprt *xprt);
 402 void                    xprt_force_disconnect(struct rpc_xprt *xprt);
 403 void                    xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie);
 404
 405 bool                    xprt_lock_connect(struct rpc_xprt *, struct rpc_task *, void *);
 406 void                    xprt_unlock_connect(struct rpc_xprt *, void *);
 407
 408 /*
 409  * Reserved bit positions in xprt->state
 410  */
 411 #define XPRT_LOCKED             (0)
 412 #define XPRT_CONNECTED          (1)
 413 #define XPRT_CONNECTING         (2)
 414 #define XPRT_CLOSE_WAIT         (3)
 415 #define XPRT_BOUND              (4)
 416 #define XPRT_BINDING            (5)
 417 #define XPRT_CLOSING            (6)
 418 #define XPRT_CONGESTED          (9)
 419 #define XPRT_CWND_WAIT          (10)
 420 #define XPRT_WRITE_SPACE        (11)
 421
 422 static inline void xprt_set_connected(struct rpc_xprt *xprt)
 423 {
 424         set_bit(XPRT_CONNECTED, &xprt->state);
 425 }
 426
 427 static inline void xprt_clear_connected(struct rpc_xprt *xprt)
 428 {
 429         clear_bit(XPRT_CONNECTED, &xprt->state);
 430 }
 431
 432 static inline int xprt_connected(struct rpc_xprt *xprt)
 433 {
 434         return test_bit(XPRT_CONNECTED, &xprt->state);
 435 }
 436
 437 static inline int xprt_test_and_set_connected(struct rpc_xprt *xprt)
 438 {
 439         return test_and_set_bit(XPRT_CONNECTED, &xprt->state);
 440 }
 441
 442 static inline int xprt_test_and_clear_connected(struct rpc_xprt *xprt)
 443 {
 444         return test_and_clear_bit(XPRT_CONNECTED, &xprt->state);
 445 }
 446
 447 static inline void xprt_clear_connecting(struct rpc_xprt *xprt)
 448 {
 449         smp_mb__before_atomic();
 450         clear_bit(XPRT_CONNECTING, &xprt->state);
 451         smp_mb__after_atomic();
 452 }
 453
 454 static inline int xprt_connecting(struct rpc_xprt *xprt)
 455 {
 456         return test_bit(XPRT_CONNECTING, &xprt->state);
 457 }
 458
 459 static inline int xprt_test_and_set_connecting(struct rpc_xprt *xprt)
 460 {
 461         return test_and_set_bit(XPRT_CONNECTING, &xprt->state);
 462 }
 463
 464 static inline void xprt_set_bound(struct rpc_xprt *xprt)
 465 {
 466         test_and_set_bit(XPRT_BOUND, &xprt->state);
 467 }
 468
 469 static inline int xprt_bound(struct rpc_xprt *xprt)
 470 {
 471         return test_bit(XPRT_BOUND, &xprt->state);
 472 }
 473
 474 static inline void xprt_clear_bound(struct rpc_xprt *xprt)
 475 {
 476         clear_bit(XPRT_BOUND, &xprt->state);
 477 }
 478
 479 static inline void xprt_clear_binding(struct rpc_xprt *xprt)
 480 {
 481         smp_mb__before_atomic();
 482         clear_bit(XPRT_BINDING, &xprt->state);
 483         smp_mb__after_atomic();
 484 }
 485
 486 static inline int xprt_test_and_set_binding(struct rpc_xprt *xprt)
 487 {
 488         return test_and_set_bit(XPRT_BINDING, &xprt->state);
 489 }
 490
 491 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 492 extern unsigned int rpc_inject_disconnect;
 493 static inline void xprt_inject_disconnect(struct rpc_xprt *xprt)
 494 {
 495         if (!rpc_inject_disconnect)
 496                 return;
 497         if (atomic_dec_return(&xprt->inject_disconnect))
 498                 return;
 499         atomic_set(&xprt->inject_disconnect, rpc_inject_disconnect);
 500         xprt->ops->inject_disconnect(xprt);
 501 }
 502 #else
 503 static inline void xprt_inject_disconnect(struct rpc_xprt *xprt)
 504 {
 505 }
 506 #endif
 507
 508 #endif /* __KERNEL__*/
 509
 510 #endif /* _LINUX_SUNRPC_XPRT_H */