LXR linux/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 */
  38struct 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
  46enum 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
  56struct rpc_task;
  57struct rpc_xprt;
  58struct seq_file;
  59struct svc_serv;
  60struct net;
  61
  62/*
  63 * This describes a complete RPC request
  64 */
  65struct 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
 132struct 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)
 177enum 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
 186struct rpc_xprt {
 187        struct kref             kref;           /* Reference count */
 188        const struct rpc_xprt_ops *ops;         /* transport methods */
 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        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
 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        unsigned int            bc_alloc_max;
 256        unsigned int            bc_alloc_count; /* Total number of preallocs */
 257        atomic_t                bc_slot_count;  /* Number of allocated slots */
 258        spinlock_t              bc_pa_lock;     /* Protects the preallocated
 259                                                 * items */
 260        struct list_head        bc_pa_list;     /* List of preallocated
 261                                                 * backchannel rpc_rqst's */
 262#endif /* CONFIG_SUNRPC_BACKCHANNEL */
 263
 264        struct rb_root          recv_queue;     /* Receive queue */
 265
 266        struct {
 267                unsigned long           bind_count,     /* total number of binds */
 268                                        connect_count,  /* total number of connects */
 269                                        connect_start,  /* connect start timestamp */
 270                                        connect_time,   /* jiffies waiting for connect */
 271                                        sends,          /* how many complete requests */
 272                                        recvs,          /* how many complete requests */
 273                                        bad_xids,       /* lookup_rqst didn't find XID */
 274                                        max_slots;      /* max rpc_slots used */
 275
 276                unsigned long long      req_u,          /* average requests on the wire */
 277                                        bklog_u,        /* backlog queue utilization */
 278                                        sending_u,      /* send q utilization */
 279                                        pending_u;      /* pend q utilization */
 280        } stat;
 281
 282        struct net              *xprt_net;
 283        const char              *servername;
 284        const char              *address_strings[RPC_DISPLAY_MAX];
 285#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 286        struct dentry           *debugfs;               /* debugfs directory */
 287        atomic_t                inject_disconnect;
 288#endif
 289        struct rcu_head         rcu;
 290};
 291
 292#if defined(CONFIG_SUNRPC_BACKCHANNEL)
 293/*
 294 * Backchannel flags
 295 */
 296#define RPC_BC_PA_IN_USE        0x0001          /* Preallocated backchannel */
 297                                                /* buffer in use */
 298#endif /* CONFIG_SUNRPC_BACKCHANNEL */
 299
 300#if defined(CONFIG_SUNRPC_BACKCHANNEL)
 301static inline int bc_prealloc(struct rpc_rqst *req)
 302{
 303        return test_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state);
 304}
 305#else
 306static inline int bc_prealloc(struct rpc_rqst *req)
 307{
 308        return 0;
 309}
 310#endif /* CONFIG_SUNRPC_BACKCHANNEL */
 311
 312#define XPRT_CREATE_INFINITE_SLOTS      (1U)
 313#define XPRT_CREATE_NO_IDLE_TIMEOUT     (1U << 1)
 314
 315struct xprt_create {
 316        int                     ident;          /* XPRT_TRANSPORT identifier */
 317        struct net *            net;
 318        struct sockaddr *       srcaddr;        /* optional local address */
 319        struct sockaddr *       dstaddr;        /* remote peer address */
 320        size_t                  addrlen;
 321        const char              *servername;
 322        struct svc_xprt         *bc_xprt;       /* NFSv4.1 backchannel */
 323        struct rpc_xprt_switch  *bc_xps;
 324        unsigned int            flags;
 325};
 326
 327struct xprt_class {
 328        struct list_head        list;
 329        int                     ident;          /* XPRT_TRANSPORT identifier */
 330        struct rpc_xprt *       (*setup)(struct xprt_create *);
 331        struct module           *owner;
 332        char                    name[32];
 333};
 334
 335/*
 336 * Generic internal transport functions
 337 */
 338struct rpc_xprt         *xprt_create_transport(struct xprt_create *args);
 339void                    xprt_connect(struct rpc_task *task);
 340unsigned long           xprt_reconnect_delay(const struct rpc_xprt *xprt);
 341void                    xprt_reconnect_backoff(struct rpc_xprt *xprt,
 342                                               unsigned long init_to);
 343void                    xprt_reserve(struct rpc_task *task);
 344void                    xprt_retry_reserve(struct rpc_task *task);
 345int                     xprt_reserve_xprt(struct rpc_xprt *xprt, struct rpc_task *task);
 346int                     xprt_reserve_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task);
 347void                    xprt_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task);
 348void                    xprt_free_slot(struct rpc_xprt *xprt,
 349                                       struct rpc_rqst *req);
 350void                    xprt_request_prepare(struct rpc_rqst *req);
 351bool                    xprt_prepare_transmit(struct rpc_task *task);
 352void                    xprt_request_enqueue_transmit(struct rpc_task *task);
 353void                    xprt_request_enqueue_receive(struct rpc_task *task);
 354void                    xprt_request_wait_receive(struct rpc_task *task);
 355bool                    xprt_request_need_retransmit(struct rpc_task *task);
 356void                    xprt_transmit(struct rpc_task *task);
 357void                    xprt_end_transmit(struct rpc_task *task);
 358int                     xprt_adjust_timeout(struct rpc_rqst *req);
 359void                    xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task);
 360void                    xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task);
 361void                    xprt_release(struct rpc_task *task);
 362struct rpc_xprt *       xprt_get(struct rpc_xprt *xprt);
 363void                    xprt_put(struct rpc_xprt *xprt);
 364struct rpc_xprt *       xprt_alloc(struct net *net, size_t size,
 365                                unsigned int num_prealloc,
 366                                unsigned int max_req);
 367void                    xprt_free(struct rpc_xprt *);
 368
 369static inline int
 370xprt_enable_swap(struct rpc_xprt *xprt)
 371{
 372        return xprt->ops->enable_swap(xprt);
 373}
 374
 375static inline void
 376xprt_disable_swap(struct rpc_xprt *xprt)
 377{
 378        xprt->ops->disable_swap(xprt);
 379}
 380
 381/*
 382 * Transport switch helper functions
 383 */
 384int                     xprt_register_transport(struct xprt_class *type);
 385int                     xprt_unregister_transport(struct xprt_class *type);
 386int                     xprt_load_transport(const char *);
 387void                    xprt_wait_for_reply_request_def(struct rpc_task *task);
 388void                    xprt_wait_for_reply_request_rtt(struct rpc_task *task);
 389void                    xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status);
 390void                    xprt_wait_for_buffer_space(struct rpc_xprt *xprt);
 391bool                    xprt_write_space(struct rpc_xprt *xprt);
 392void                    xprt_adjust_cwnd(struct rpc_xprt *xprt, struct rpc_task *task, int result);
 393struct rpc_rqst *       xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid);
 394void                    xprt_update_rtt(struct rpc_task *task);
 395void                    xprt_complete_rqst(struct rpc_task *task, int copied);
 396void                    xprt_pin_rqst(struct rpc_rqst *req);
 397void                    xprt_unpin_rqst(struct rpc_rqst *req);
 398void                    xprt_release_rqst_cong(struct rpc_task *task);
 399bool                    xprt_request_get_cong(struct rpc_xprt *xprt, struct rpc_rqst *req);
 400void                    xprt_disconnect_done(struct rpc_xprt *xprt);
 401void                    xprt_force_disconnect(struct rpc_xprt *xprt);
 402void                    xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie);
 403
 404bool                    xprt_lock_connect(struct rpc_xprt *, struct rpc_task *, void *);
 405void                    xprt_unlock_connect(struct rpc_xprt *, void *);
 406
 407/*
 408 * Reserved bit positions in xprt->state
 409 */
 410#define XPRT_LOCKED             (0)
 411#define XPRT_CONNECTED          (1)
 412#define XPRT_CONNECTING         (2)
 413#define XPRT_CLOSE_WAIT         (3)
 414#define XPRT_BOUND              (4)
 415#define XPRT_BINDING            (5)
 416#define XPRT_CLOSING            (6)
 417#define XPRT_CONGESTED          (9)
 418#define XPRT_CWND_WAIT          (10)
 419#define XPRT_WRITE_SPACE        (11)
 420
 421static inline void xprt_set_connected(struct rpc_xprt *xprt)
 422{
 423        set_bit(XPRT_CONNECTED, &xprt->state);
 424}
 425
 426static inline void xprt_clear_connected(struct rpc_xprt *xprt)
 427{
 428        clear_bit(XPRT_CONNECTED, &xprt->state);
 429}
 430
 431static inline int xprt_connected(struct rpc_xprt *xprt)
 432{
 433        return test_bit(XPRT_CONNECTED, &xprt->state);
 434}
 435
 436static inline int xprt_test_and_set_connected(struct rpc_xprt *xprt)
 437{
 438        return test_and_set_bit(XPRT_CONNECTED, &xprt->state);
 439}
 440
 441static inline int xprt_test_and_clear_connected(struct rpc_xprt *xprt)
 442{
 443        return test_and_clear_bit(XPRT_CONNECTED, &xprt->state);
 444}
 445
 446static inline void xprt_clear_connecting(struct rpc_xprt *xprt)
 447{
 448        smp_mb__before_atomic();
 449        clear_bit(XPRT_CONNECTING, &xprt->state);
 450        smp_mb__after_atomic();
 451}
 452
 453static inline int xprt_connecting(struct rpc_xprt *xprt)
 454{
 455        return test_bit(XPRT_CONNECTING, &xprt->state);
 456}
 457
 458static inline int xprt_test_and_set_connecting(struct rpc_xprt *xprt)
 459{
 460        return test_and_set_bit(XPRT_CONNECTING, &xprt->state);
 461}
 462
 463static inline void xprt_set_bound(struct rpc_xprt *xprt)
 464{
 465        test_and_set_bit(XPRT_BOUND, &xprt->state);
 466}
 467
 468static inline int xprt_bound(struct rpc_xprt *xprt)
 469{
 470        return test_bit(XPRT_BOUND, &xprt->state);
 471}
 472
 473static inline void xprt_clear_bound(struct rpc_xprt *xprt)
 474{
 475        clear_bit(XPRT_BOUND, &xprt->state);
 476}
 477
 478static inline void xprt_clear_binding(struct rpc_xprt *xprt)
 479{
 480        smp_mb__before_atomic();
 481        clear_bit(XPRT_BINDING, &xprt->state);
 482        smp_mb__after_atomic();
 483}
 484
 485static inline int xprt_test_and_set_binding(struct rpc_xprt *xprt)
 486{
 487        return test_and_set_bit(XPRT_BINDING, &xprt->state);
 488}
 489
 490#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 491extern unsigned int rpc_inject_disconnect;
 492static inline void xprt_inject_disconnect(struct rpc_xprt *xprt)
 493{
 494        if (!rpc_inject_disconnect)
 495                return;
 496        if (atomic_dec_return(&xprt->inject_disconnect))
 497                return;
 498        atomic_set(&xprt->inject_disconnect, rpc_inject_disconnect);
 499        xprt->ops->inject_disconnect(xprt);
 500}
 501#else
 502static inline void xprt_inject_disconnect(struct rpc_xprt *xprt)
 503{
 504}
 505#endif
 506
 507#endif /* __KERNEL__*/
 508
 509#endif /* _LINUX_SUNRPC_XPRT_H */
 510