/* * linux/net/sunrpc/xprt.c * * This is a generic RPC call interface supporting congestion avoidance, * and asynchronous calls. * * The interface works like this: * * - When a process places a call, it allocates a request slot if * one is available. Otherwise, it sleeps on the backlog queue * (xprt_reserve). * - Next, the caller puts together the RPC message, stuffs it into * the request struct, and calls xprt_transmit(). * - xprt_transmit sends the message and installs the caller on the * transport's wait list. At the same time, if a reply is expected, * it installs a timer that is run after the packet's timeout has * expired. * - When a packet arrives, the data_ready handler walks the list of * pending requests for that transport. If a matching XID is found, the * caller is woken up, and the timer removed. * - When no reply arrives within the timeout interval, the timer is * fired by the kernel and runs xprt_timer(). It either adjusts the * timeout values (minor timeout) or wakes up the caller with a status * of -ETIMEDOUT. * - When the caller receives a notification from RPC that a reply arrived, * it should release the RPC slot, and process the reply. * If the call timed out, it may choose to retry the operation by * adjusting the initial timeout value, and simply calling rpc_call * again. * * Support for async RPC is done through a set of RPC-specific scheduling * primitives that `transparently' work for processes as well as async * tasks that rely on callbacks. * * Copyright (C) 1995-1997, Olaf Kirch <okir@monad.swb.de> * * Transport switch API copyright (C) 2005, Chuck Lever <cel@netapp.com> */ #include <linux/module.h> #include <linux/types.h> #include <linux/interrupt.h> #include <linux/workqueue.h> #include <linux/net.h> #include <linux/ktime.h> #include <linux/sunrpc/clnt.h> #include <linux/sunrpc/metrics.h> #include <linux/sunrpc/bc_xprt.h> #include "sunrpc.h" /* * Local variables */ #ifdef RPC_DEBUG # define RPCDBG_FACILITY RPCDBG_XPRT #endif /* * Local functions */ static void xprt_init(struct rpc_xprt *xprt, struct net *net); static void xprt_request_init(struct rpc_task *, struct rpc_xprt *); static void xprt_connect_status(struct rpc_task *task); static int __xprt_get_cong(struct rpc_xprt *, struct rpc_task *); static void xprt_destroy(struct rpc_xprt *xprt); static DEFINE_SPINLOCK(xprt_list_lock); static LIST_HEAD(xprt_list); /* * The transport code maintains an estimate on the maximum number of out- * standing RPC requests, using a smoothed version of the congestion * avoidance implemented in 44BSD. This is basically the Van Jacobson * congestion algorithm: If a retransmit occurs, the congestion window is * halved; otherwise, it is incremented by 1/cwnd when * * - a reply is received and * - a full number of requests are outstanding and * - the congestion window hasn't been updated recently. */ #define RPC_CWNDSHIFT (8U) #define RPC_CWNDSCALE (1U << RPC_CWNDSHIFT) #define RPC_INITCWND RPC_CWNDSCALE #define RPC_MAXCWND(xprt) ((xprt)->max_reqs << RPC_CWNDSHIFT) #define RPCXPRT_CONGESTED(xprt) ((xprt)->cong >= (xprt)->cwnd) /** * xprt_register_transport - register a transport implementation * @transport: transport to register * * If a transport implementation is loaded as a kernel module, it can * call this interface to make itself known to the RPC client. * * Returns: * 0: transport successfully registered * -EEXIST: transport already registered * -EINVAL: transport module being unloaded */ int xprt_register_transport(struct xprt_class *transport) { struct xprt_class *t; int result; result = -EEXIST; spin_lock(&xprt_list_lock); list_for_each_entry(t, &xprt_list, list) { /* don't register the same transport class twice */ if (t->ident == transport->ident) goto out; } list_add_tail(&transport->list, &xprt_list); printk(KERN_INFO "RPC: Registered %s transport module.\n", transport->name); result = 0; out: spin_unlock(&xprt_list_lock); return result; } EXPORT_SYMBOL_GPL(xprt_register_transport); /** * xprt_unregister_transport - unregister a transport implementation * @transport: transport to unregister * * Returns: * 0: transport successfully unregistered * -ENOENT: transport never registered */ int xprt_unregister_transport(struct xprt_class *transport) { struct xprt_class *t; int result; result = 0; spin_lock(&xprt_list_lock); list_for_each_entry(t, &xprt_list, list) { if (t == transport) { printk(KERN_INFO "RPC: Unregistered %s transport module.\n", transport->name); list_del_init(&transport->list); goto out; } } result = -ENOENT; out: spin_unlock(&xprt_list_lock); return result; } EXPORT_SYMBOL_GPL(xprt_unregister_transport); /** * xprt_load_transport - load a transport implementation * @transport_name: transport to load * * Returns: * 0: transport successfully loaded * -ENOENT: transport module not available */ int xprt_load_transport(const char *transport_name) { struct xprt_class *t; int result; result = 0; spin_lock(&xprt_list_lock); list_for_each_entry(t, &xprt_list, list) { if (strcmp(t->name, transport_name) == 0) { spin_unlock(&xprt_list_lock); goto out; } } spin_unlock(&xprt_list_lock); result = request_module("xprt%s", transport_name); out: return result; } EXPORT_SYMBOL_GPL(xprt_load_transport); /** * xprt_reserve_xprt - serialize write access to transports * @task: task that is requesting access to the transport * @xprt: pointer to the target transport * * This prevents mixing the payload of separate requests, and prevents * transport connects from colliding with writes. No congestion control * is provided. */ int xprt_reserve_xprt(struct rpc_xprt *xprt, struct rpc_task *task) { struct rpc_rqst *req = task->tk_rqstp; int priority; if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) { if (task == xprt->snd_task) return 1; goto out_sleep; } xprt->snd_task = task; if (req != NULL) { req->rq_bytes_sent = 0; req->rq_ntrans++; } return 1; out_sleep: dprintk("RPC: %5u failed to lock transport %p\n", task->tk_pid, xprt); task->tk_timeout = 0; task->tk_status = -EAGAIN; if (req == NULL) priority = RPC_PRIORITY_LOW; else if (!req->rq_ntrans) priority = RPC_PRIORITY_NORMAL; else priority = RPC_PRIORITY_HIGH; rpc_sleep_on_priority(&xprt->sending, task, NULL, priority); return 0; } EXPORT_SYMBOL_GPL(xprt_reserve_xprt); static void xprt_clear_locked(struct rpc_xprt *xprt) { xprt->snd_task = NULL; if (!test_bit(XPRT_CLOSE_WAIT, &xprt->state)) { smp_mb__before_clear_bit(); clear_bit(XPRT_LOCKED, &xprt->state); smp_mb__after_clear_bit(); } else queue_work(rpciod_workqueue, &xprt->task_cleanup); } /* * xprt_reserve_xprt_cong - serialize write access to transports * @task: task that is requesting access to the transport * * Same as xprt_reserve_xprt, but Van Jacobson congestion control is * integrated into the decision of whether a request is allowed to be * woken up and given access to the transport. */ int xprt_reserve_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task) { struct rpc_rqst *req = task->tk_rqstp; int priority; if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) { if (task == xprt->snd_task) return 1; goto out_sleep; } if (req == NULL) { xprt->snd_task = task; return 1; } if (__xprt_get_cong(xprt, task)) { xprt->snd_task = task; req->rq_bytes_sent = 0; req->rq_ntrans++; return 1; } xprt_clear_locked(xprt); out_sleep: dprintk("RPC: %5u failed to lock transport %p\n", task->tk_pid, xprt); task->tk_timeout = 0; task->tk_status = -EAGAIN; if (req == NULL) priority = RPC_PRIORITY_LOW; else if (!req->rq_ntrans) priority = RPC_PRIORITY_NORMAL; else priority = RPC_PRIORITY_HIGH; rpc_sleep_on_priority(&xprt->sending, task, NULL, priority); return 0; } EXPORT_SYMBOL_GPL(xprt_reserve_xprt_cong); static inline int xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task) { int retval; spin_lock_bh(&xprt->transport_lock); retval = xprt->ops->reserve_xprt(xprt, task); spin_unlock_bh(&xprt->transport_lock); return retval; } static bool __xprt_lock_write_func(struct rpc_task *task, void *data) { struct rpc_xprt *xprt = data; struct rpc_rqst *req; req = task->tk_rqstp; xprt->snd_task = task; if (req) { req->rq_bytes_sent = 0; req->rq_ntrans++; } return true; } static void __xprt_lock_write_next(struct rpc_xprt *xprt) { if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) return; if (rpc_wake_up_first(&xprt->sending, __xprt_lock_write_func, xprt)) return; xprt_clear_locked(xprt); } static bool __xprt_lock_write_cong_func(struct rpc_task *task, void *data) { struct rpc_xprt *xprt = data; struct rpc_rqst *req; req = task->tk_rqstp; if (req == NULL) { xprt->snd_task = task; return true; } if (__xprt_get_cong(xprt, task)) { xprt->snd_task = task; req->rq_bytes_sent = 0; req->rq_ntrans++; return true; } return false; } static void __xprt_lock_write_next_cong(struct rpc_xprt *xprt) { if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) return; if (RPCXPRT_CONGESTED(xprt)) goto out_unlock; if (rpc_wake_up_first(&xprt->sending, __xprt_lock_write_cong_func, xprt)) return; out_unlock: xprt_clear_locked(xprt); } /** * xprt_release_xprt - allow other requests to use a transport * @xprt: transport with other tasks potentially waiting * @task: task that is releasing access to the transport * * Note that "task" can be NULL. No congestion control is provided. */ void xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task) { if (xprt->snd_task == task) { xprt_clear_locked(xprt); __xprt_lock_write_next(xprt); } } EXPORT_SYMBOL_GPL(xprt_release_xprt); /** * xprt_release_xprt_cong - allow other requests to use a transport * @xprt: transport with other tasks potentially waiting * @task: task that is releasing access to the transport * * Note that "task" can be NULL. Another task is awoken to use the * transport if the transport's congestion window allows it. */ void xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task) { if (xprt->snd_task == task) { xprt_clear_locked(xprt); __xprt_lock_write_next_cong(xprt); } } EXPORT_SYMBOL_GPL(xprt_release_xprt_cong); static inline void xprt_release_write(struct rpc_xprt *xprt, struct rpc_task *task) { spin_lock_bh(&xprt->transport_lock); xprt->ops->release_xprt(xprt, task); spin_unlock_bh(&xprt->transport_lock); } /* * Van Jacobson congestion avoidance. Check if the congestion window * overflowed. Put the task to sleep if this is the case. */ static int __xprt_get_cong(struct rpc_xprt *xprt, struct rpc_task *task) { struct rpc_rqst *req = task->tk_rqstp; if (req->rq_cong) return 1; dprintk("RPC: %5u xprt_cwnd_limited cong = %lu cwnd = %lu\n", task->tk_pid, xprt->cong, xprt->cwnd); if (RPCXPRT_CONGESTED(xprt)) return 0; req->rq_cong = 1; xprt->cong += RPC_CWNDSCALE; return 1; } /* * Adjust the congestion window, and wake up the next task * that has been sleeping due to congestion */ static void __xprt_put_cong(struct rpc_xprt *xprt, struct rpc_rqst *req) { if (!req->rq_cong) return; req->rq_cong = 0; xprt->cong -= RPC_CWNDSCALE; __xprt_lock_write_next_cong(xprt); } /** * xprt_release_rqst_cong - housekeeping when request is complete * @task: RPC request that recently completed * * Useful for transports that require congestion control. */ void xprt_release_rqst_cong(struct rpc_task *task) { struct rpc_rqst *req = task->tk_rqstp; __xprt_put_cong(req->rq_xprt, req); } EXPORT_SYMBOL_GPL(xprt_release_rqst_cong); /** * xprt_adjust_cwnd - adjust transport congestion window * @xprt: pointer to xprt * @task: recently completed RPC request used to adjust window * @result: result code of completed RPC request * * We use a time-smoothed congestion estimator to avoid heavy oscillation. */ void xprt_adjust_cwnd(struct rpc_xprt *xprt, struct rpc_task *task, int result) { struct rpc_rqst *req = task->tk_rqstp; unsigned long cwnd = xprt->cwnd; if (result >= 0 && cwnd <= xprt->cong) { /* The (cwnd >> 1) term makes sure * the result gets rounded properly. */ cwnd += (RPC_CWNDSCALE * RPC_CWNDSCALE + (cwnd >> 1)) / cwnd; if (cwnd > RPC_MAXCWND(xprt)) cwnd = RPC_MAXCWND(xprt); __xprt_lock_write_next_cong(xprt); } else if (result == -ETIMEDOUT) { cwnd >>= 1; if (cwnd < RPC_CWNDSCALE) cwnd = RPC_CWNDSCALE; } dprintk("RPC: cong %ld, cwnd was %ld, now %ld\n", xprt->cong, xprt->cwnd, cwnd); xprt->cwnd = cwnd; __xprt_put_cong(xprt, req); } EXPORT_SYMBOL_GPL(xprt_adjust_cwnd); /** * xprt_wake_pending_tasks - wake all tasks on a transport's pending queue * @xprt: transport with waiting tasks * @status: result code to plant in each task before waking it * */ void xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status) { if (status < 0) rpc_wake_up_status(&xprt->pending, status); else rpc_wake_up(&xprt->pending); } EXPORT_SYMBOL_GPL(xprt_wake_pending_tasks); /** * xprt_wait_for_buffer_space - wait for transport output buffer to clear * @task: task to be put to sleep * @action: function pointer to be executed after wait * * Note that we only set the timer for the case of RPC_IS_SOFT(), since * we don't in general want to force a socket disconnection due to * an incomplete RPC call transmission. */ void xprt_wait_for_buffer_space(struct rpc_task *task, rpc_action action) { struct rpc_rqst *req = task->tk_rqstp; struct rpc_xprt *xprt = req->rq_xprt; task->tk_timeout = RPC_IS_SOFT(task) ? req->rq_timeout : 0; rpc_sleep_on(&xprt->pending, task, action); } EXPORT_SYMBOL_GPL(xprt_wait_for_buffer_space); /** * xprt_write_space - wake the task waiting for transport output buffer space * @xprt: transport with waiting tasks * * Can be called in a soft IRQ context, so xprt_write_space never sleeps. */ void xprt_write_space(struct rpc_xprt *xprt) { spin_lock_bh(&xprt->transport_lock); if (xprt->snd_task) { dprintk("RPC: write space: waking waiting task on " "xprt %p\n", xprt); rpc_wake_up_queued_task(&xprt->pending, xprt->snd_task); } spin_unlock_bh(&xprt->transport_lock); } EXPORT_SYMBOL_GPL(xprt_write_space); /** * xprt_set_retrans_timeout_def - set a request's retransmit timeout * @task: task whose timeout is to be set * * Set a request's retransmit timeout based on the transport's * default timeout parameters. Used by transports that don't adjust * the retransmit timeout based on round-trip time estimation. */ void xprt_set_retrans_timeout_def(struct rpc_task *task) { task->tk_timeout = task->tk_rqstp->rq_timeout; } EXPORT_SYMBOL_GPL(xprt_set_retrans_timeout_def); /** * xprt_set_retrans_timeout_rtt - set a request's retransmit timeout * @task: task whose timeout is to be set * * Set a request's retransmit timeout using the RTT estimator. */ void xprt_set_retrans_timeout_rtt(struct rpc_task *task) { int timer = task->tk_msg.rpc_proc->p_timer; struct rpc_clnt *clnt = task->tk_client; struct rpc_rtt *rtt = clnt->cl_rtt; struct rpc_rqst *req = task->tk_rqstp; unsigned long max_timeout = clnt->cl_timeout->to_maxval; task->tk_timeout = rpc_calc_rto(rtt, timer); task->tk_timeout <<= rpc_ntimeo(rtt, timer) + req->rq_retries; if (task->tk_timeout > max_timeout || task->tk_timeout == 0) task->tk_timeout = max_timeout; } EXPORT_SYMBOL_GPL(xprt_set_retrans_timeout_rtt); static void xprt_reset_majortimeo(struct rpc_rqst *req) { const struct rpc_timeout *to = req->rq_task->tk_client->cl_timeout; req->rq_majortimeo = req->rq_timeout; if (to->to_exponential) req->rq_majortimeo <<= to->to_retries; else req->rq_majortimeo += to->to_increment * to->to_retries; if (req->rq_majortimeo > to->to_maxval || req->rq_majortimeo == 0) req->rq_majortimeo = to->to_maxval; req->rq_majortimeo += jiffies; } /** * xprt_adjust_timeout - adjust timeout values for next retransmit * @req: RPC request containing parameters to use for the adjustment * */ int xprt_adjust_timeout(struct rpc_rqst *req) { struct rpc_xprt *xprt = req->rq_xprt; const struct rpc_timeout *to = req->rq_task->tk_client->cl_timeout; int status = 0; if (time_before(jiffies, req->rq_majortimeo)) { if (to->to_exponential) req->rq_timeout <<= 1; else req->rq_timeout += to->to_increment; if (to->to_maxval && req->rq_timeout >= to->to_maxval) req->rq_timeout = to->to_maxval; req->rq_retries++; } else { req->rq_timeout = to->to_initval; req->rq_retries = 0; xprt_reset_majortimeo(req); /* Reset the RTT counters == "slow start" */ spin_lock_bh(&xprt->transport_lock); rpc_init_rtt(req->rq_task->tk_client->cl_rtt, to->to_initval); spin_unlock_bh(&xprt->transport_lock); status = -ETIMEDOUT; } if (req->rq_timeout == 0) { printk(KERN_WARNING "xprt_adjust_timeout: rq_timeout = 0!\n"); req->rq_timeout = 5 * HZ; } return status; } static void xprt_autoclose(struct work_struct *work) { struct rpc_xprt *xprt = container_of(work, struct rpc_xprt, task_cleanup); xprt->ops->close(xprt); clear_bit(XPRT_CLOSE_WAIT, &xprt->state); xprt_release_write(xprt, NULL); } /** * xprt_disconnect_done - mark a transport as disconnected * @xprt: transport to flag for disconnect * */ void xprt_disconnect_done(struct rpc_xprt *xprt) { dprintk("RPC: disconnected transport %p\n", xprt); spin_lock_bh(&xprt->transport_lock); xprt_clear_connected(xprt); xprt_wake_pending_tasks(xprt, -EAGAIN); spin_unlock_bh(&xprt->transport_lock); } EXPORT_SYMBOL_GPL(xprt_disconnect_done); /** * xprt_force_disconnect - force a transport to disconnect * @xprt: transport to disconnect * */ void xprt_force_disconnect(struct rpc_xprt *xprt) { /* Don't race with the test_bit() in xprt_clear_locked() */ spin_lock_bh(&xprt->transport_lock); set_bit(XPRT_CLOSE_WAIT, &xprt->state); /* Try to schedule an autoclose RPC call */ if (test_and_set_bit(XPRT_LOCKED, &xprt->state) == 0) queue_work(rpciod_workqueue, &xprt->task_cleanup); xprt_wake_pending_tasks(xprt, -EAGAIN); spin_unlock_bh(&xprt->transport_lock); } /** * xprt_conditional_disconnect - force a transport to disconnect * @xprt: transport to disconnect * @cookie: 'connection cookie' * * This attempts to break the connection if and only if 'cookie' matches * the current transport 'connection cookie'. It ensures that we don't * try to break the connection more than once when we need to retransmit * a batch of RPC requests. * */ void xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie) { /* Don't race with the test_bit() in xprt_clear_locked() */ spin_lock_bh(&xprt->transport_lock); if (cookie != xprt->connect_cookie) goto out; if (test_bit(XPRT_CLOSING, &xprt->state) || !xprt_connected(xprt)) goto out; set_bit(XPRT_CLOSE_WAIT, &xprt->state); /* Try to schedule an autoclose RPC call */ if (test_and_set_bit(XPRT_LOCKED, &xprt->state) == 0) queue_work(rpciod_workqueue, &xprt->task_cleanup); xprt_wake_pending_tasks(xprt, -EAGAIN); out: spin_unlock_bh(&xprt->transport_lock); } static void xprt_init_autodisconnect(unsigned long data) { struct rpc_xprt *xprt = (struct rpc_xprt *)data; spin_lock(&xprt->transport_lock); if (!list_empty(&xprt->recv)) goto out_abort; if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) goto out_abort; spin_unlock(&xprt->transport_lock); set_bit(XPRT_CONNECTION_CLOSE, &xprt->state); queue_work(rpciod_workqueue, &xprt->task_cleanup); return; out_abort: spin_unlock(&xprt->transport_lock); } /** * xprt_connect - schedule a transport connect operation * @task: RPC task that is requesting the connect * */ void xprt_connect(struct rpc_task *task) { struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt; dprintk("RPC: %5u xprt_connect xprt %p %s connected\n", task->tk_pid, xprt, (xprt_connected(xprt) ? "is" : "is not")); if (!xprt_bound(xprt)) { task->tk_status = -EAGAIN; return; } if (!xprt_lock_write(xprt, task)) return; if (test_and_clear_bit(XPRT_CLOSE_WAIT, &xprt->state)) xprt->ops->close(xprt); if (xprt_connected(xprt)) xprt_release_write(xprt, task); else { task->tk_rqstp->rq_bytes_sent = 0; task->tk_timeout = task->tk_rqstp->rq_timeout; rpc_sleep_on(&xprt->pending, task, xprt_connect_status); if (test_bit(XPRT_CLOSING, &xprt->state)) return; if (xprt_test_and_set_connecting(xprt)) return; xprt->stat.connect_start = jiffies; xprt->ops->connect(xprt, task); } } static void xprt_connect_status(struct rpc_task *task) { struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt; if (task->tk_status == 0) { xprt->stat.connect_count++; xprt->stat.connect_time += (long)jiffies - xprt->stat.connect_start; dprintk("RPC: %5u xprt_connect_status: connection established\n", task->tk_pid); return; } switch (task->tk_status) { case -EAGAIN: dprintk("RPC: %5u xprt_connect_status: retrying\n", task->tk_pid); break; case -ETIMEDOUT: dprintk("RPC: %5u xprt_connect_status: connect attempt timed " "out\n", task->tk_pid); break; default: dprintk("RPC: %5u xprt_connect_status: error %d connecting to " "server %s\n", task->tk_pid, -task->tk_status, xprt->servername); xprt_release_write(xprt, task); task->tk_status = -EIO; } } /** * xprt_lookup_rqst - find an RPC request corresponding to an XID * @xprt: transport on which the original request was transmitted * @xid: RPC XID of incoming reply * */ struct rpc_rqst *xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid) { struct rpc_rqst *entry; list_for_each_entry(entry, &xprt->recv, rq_list) if (entry->rq_xid == xid) return entry; dprintk("RPC: xprt_lookup_rqst did not find xid %08x\n", ntohl(xid)); xprt->stat.bad_xids++; return NULL; } EXPORT_SYMBOL_GPL(xprt_lookup_rqst); static void xprt_update_rtt(struct rpc_task *task) { struct rpc_rqst *req = task->tk_rqstp; struct rpc_rtt *rtt = task->tk_client->cl_rtt; unsigned int timer = task->tk_msg.rpc_proc->p_timer; long m = usecs_to_jiffies(ktime_to_us(req->rq_rtt)); if (timer) { if (req->rq_ntrans == 1) rpc_update_rtt(rtt, timer, m); rpc_set_timeo(rtt, timer, req->rq_ntrans - 1); } } /** * xprt_complete_rqst - called when reply processing is complete * @task: RPC request that recently completed * @copied: actual number of bytes received from the transport * * Caller holds transport lock. */ void xprt_complete_rqst(struct rpc_task *task, int copied) { struct rpc_rqst *req = task->tk_rqstp; struct rpc_xprt *xprt = req->rq_xprt; dprintk("RPC: %5u xid %08x complete (%d bytes received)\n", task->tk_pid, ntohl(req->rq_xid), copied); xprt->stat.recvs++; req->rq_rtt = ktime_sub(ktime_get(), req->rq_xtime); if (xprt->ops->timer != NULL) xprt_update_rtt(task); list_del_init(&req->rq_list); req->rq_private_buf.len = copied; /* Ensure all writes are done before we update */ /* req->rq_reply_bytes_recvd */ smp_wmb(); req->rq_reply_bytes_recvd = copied; rpc_wake_up_queued_task(&xprt->pending, task); } EXPORT_SYMBOL_GPL(xprt_complete_rqst); static void xprt_timer(struct rpc_task *task) { struct rpc_rqst *req = task->tk_rqstp; struct rpc_xprt *xprt = req->rq_xprt; if (task->tk_status != -ETIMEDOUT) return; dprintk("RPC: %5u xprt_timer\n", task->tk_pid); spin_lock_bh(&xprt->transport_lock); if (!req->rq_reply_bytes_recvd) { if (xprt->ops->timer) xprt->ops->timer(xprt, task); } else task->tk_status = 0; spin_unlock_bh(&xprt->transport_lock); } static inline int xprt_has_timer(struct rpc_xprt *xprt) { return xprt->idle_timeout != 0; } /** * xprt_prepare_transmit - reserve the transport before sending a request * @task: RPC task about to send a request * */ int xprt_prepare_transmit(struct rpc_task *task) { struct rpc_rqst *req = task->tk_rqstp; struct rpc_xprt *xprt = req->rq_xprt; int err = 0; dprintk("RPC: %5u xprt_prepare_transmit\n", task->tk_pid); spin_lock_bh(&xprt->transport_lock); if (req->rq_reply_bytes_recvd && !req->rq_bytes_sent) { err = req->rq_reply_bytes_recvd; goto out_unlock; } if (!xprt->ops->reserve_xprt(xprt, task)) err = -EAGAIN; out_unlock: spin_unlock_bh(&xprt->transport_lock); return err; } void xprt_end_transmit(struct rpc_task *task) { xprt_release_write(task->tk_rqstp->rq_xprt, task); } /** * xprt_transmit - send an RPC request on a transport * @task: controlling RPC task * * We have to copy the iovec because sendmsg fiddles with its contents. */ void xprt_transmit(struct rpc_task *task) { struct rpc_rqst *req = task->tk_rqstp; struct rpc_xprt *xprt = req->rq_xprt; int status, numreqs; dprintk("RPC: %5u xprt_transmit(%u)\n", task->tk_pid, req->rq_slen); if (!req->rq_reply_bytes_recvd) { if (list_empty(&req->rq_list) && rpc_reply_expected(task)) { /* * Add to the list only if we're expecting a reply */ spin_lock_bh(&xprt->transport_lock); /* Update the softirq receive buffer */ memcpy(&req->rq_private_buf, &req->rq_rcv_buf, sizeof(req->rq_private_buf)); /* Add request to the receive list */ list_add_tail(&req->rq_list, &xprt->recv); spin_unlock_bh(&xprt->transport_lock); xprt_reset_majortimeo(req); /* Turn off autodisconnect */ del_singleshot_timer_sync(&xprt->timer); } } else if (!req->rq_bytes_sent) return; req->rq_connect_cookie = xprt->connect_cookie; req->rq_xtime = ktime_get(); status = xprt->ops->send_request(task); if (status != 0) { task->tk_status = status; return; } dprintk("RPC: %5u xmit complete\n", task->tk_pid); task->tk_flags |= RPC_TASK_SENT; spin_lock_bh(&xprt->transport_lock); xprt->ops->set_retrans_timeout(task); numreqs = atomic_read(&xprt->num_reqs); if (numreqs > xprt->stat.max_slots) xprt->stat.max_slots = numreqs; xprt->stat.sends++; xprt->stat.req_u += xprt->stat.sends - xprt->stat.recvs; xprt->stat.bklog_u += xprt->backlog.qlen; xprt->stat.sending_u += xprt->sending.qlen; xprt->stat.pending_u += xprt->pending.qlen; /* Don't race with disconnect */ if (!xprt_connected(xprt)) task->tk_status = -ENOTCONN; else if (!req->rq_reply_bytes_recvd && rpc_reply_expected(task)) { /* * Sleep on the pending queue since * we're expecting a reply. */ rpc_sleep_on(&xprt->pending, task, xprt_timer); } spin_unlock_bh(&xprt->transport_lock); } static void xprt_add_backlog(struct rpc_xprt *xprt, struct rpc_task *task) { set_bit(XPRT_CONGESTED, &xprt->state); rpc_sleep_on(&xprt->backlog, task, NULL); } static void xprt_wake_up_backlog(struct rpc_xprt *xprt) { if (rpc_wake_up_next(&xprt->backlog) == NULL) clear_bit(XPRT_CONGESTED, &xprt->state); } static bool xprt_throttle_congested(struct rpc_xprt *xprt, struct rpc_task *task) { bool ret = false; if (!test_bit(XPRT_CONGESTED, &xprt->state)) goto out; spin_lock(&xprt->reserve_lock); if (test_bit(XPRT_CONGESTED, &xprt->state)) { rpc_sleep_on(&xprt->backlog, task, NULL); ret = true; } spin_unlock(&xprt->reserve_lock); out: return ret; } static struct rpc_rqst *xprt_dynamic_alloc_slot(struct rpc_xprt *xprt, gfp_t gfp_flags) { struct rpc_rqst *req = ERR_PTR(-EAGAIN); if (!atomic_add_unless(&xprt->num_reqs, 1, xprt->max_reqs)) goto out; req = kzalloc(sizeof(struct rpc_rqst), gfp_flags); if (req != NULL) goto out; atomic_dec(&xprt->num_reqs); req = ERR_PTR(-ENOMEM); out: return req; } static bool xprt_dynamic_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *req) { if (atomic_add_unless(&xprt->num_reqs, -1, xprt->min_reqs)) { kfree(req); return true; } return false; } void xprt_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task) { struct rpc_rqst *req; spin_lock(&xprt->reserve_lock); if (!list_empty(&xprt->free)) { req = list_entry(xprt->free.next, struct rpc_rqst, rq_list); list_del(&req->rq_list); goto out_init_req; } req = xprt_dynamic_alloc_slot(xprt, GFP_NOWAIT|__GFP_NOWARN); if (!IS_ERR(req)) goto out_init_req; switch (PTR_ERR(req)) { case -ENOMEM: dprintk("RPC: dynamic allocation of request slot " "failed! Retrying\n"); task->tk_status = -ENOMEM; break; case -EAGAIN: xprt_add_backlog(xprt, task); dprintk("RPC: waiting for request slot\n"); default: task->tk_status = -EAGAIN; } spin_unlock(&xprt->reserve_lock); return; out_init_req: task->tk_status = 0; task->tk_rqstp = req; xprt_request_init(task, xprt); spin_unlock(&xprt->reserve_lock); } EXPORT_SYMBOL_GPL(xprt_alloc_slot); void xprt_lock_and_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task) { /* Note: grabbing the xprt_lock_write() ensures that we throttle * new slot allocation if the transport is congested (i.e. when * reconnecting a stream transport or when out of socket write * buffer space). */ if (xprt_lock_write(xprt, task)) { xprt_alloc_slot(xprt, task); xprt_release_write(xprt, task); } } EXPORT_SYMBOL_GPL(xprt_lock_and_alloc_slot); static void xprt_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *req) { spin_lock(&xprt->reserve_lock); if (!xprt_dynamic_free_slot(xprt, req)) { memset(req, 0, sizeof(*req)); /* mark unused */ list_add(&req->rq_list, &xprt->free); } xprt_wake_up_backlog(xprt); spin_unlock(&xprt->reserve_lock); } static void xprt_free_all_slots(struct rpc_xprt *xprt) { struct rpc_rqst *req; while (!list_empty(&xprt->free)) { req = list_first_entry(&xprt->free, struct rpc_rqst, rq_list); list_del(&req->rq_list); kfree(req); } } struct rpc_xprt *xprt_alloc(struct net *net, size_t size, unsigned int num_prealloc, unsigned int max_alloc) { struct rpc_xprt *xprt; struct rpc_rqst *req; int i; xprt = kzalloc(size, GFP_KERNEL); if (xprt == NULL) goto out; xprt_init(xprt, net); for (i = 0; i < num_prealloc; i++) { req = kzalloc(sizeof(struct rpc_rqst), GFP_KERNEL); if (!req) break; list_add(&req->rq_list, &xprt->free); } if (i < num_prealloc) goto out_free; if (max_alloc > num_prealloc) xprt->max_reqs = max_alloc; else xprt->max_reqs = num_prealloc; xprt->min_reqs = num_prealloc; atomic_set(&xprt->num_reqs, num_prealloc); return xprt; out_free: xprt_free(xprt); out: return NULL; } EXPORT_SYMBOL_GPL(xprt_alloc); void xprt_free(struct rpc_xprt *xprt) { put_net(xprt->xprt_net); xprt_free_all_slots(xprt); kfree(xprt); } EXPORT_SYMBOL_GPL(xprt_free); /** * xprt_reserve - allocate an RPC request slot * @task: RPC task requesting a slot allocation * * If the transport is marked as being congested, or if no more * slots are available, place the task on the transport's * backlog queue. */ void xprt_reserve(struct rpc_task *task) { struct rpc_xprt *xprt; task->tk_status = 0; if (task->tk_rqstp != NULL) return; task->tk_timeout = 0; task->tk_status = -EAGAIN; rcu_read_lock(); xprt = rcu_dereference(task->tk_client->cl_xprt); if (!xprt_throttle_congested(xprt, task)) xprt->ops->alloc_slot(xprt, task); rcu_read_unlock(); } /** * xprt_retry_reserve - allocate an RPC request slot * @task: RPC task requesting a slot allocation * * If no more slots are available, place the task on the transport's * backlog queue. * Note that the only difference with xprt_reserve is that we now * ignore the value of the XPRT_CONGESTED flag. */ void xprt_retry_reserve(struct rpc_task *task) { struct rpc_xprt *xprt; task->tk_status = 0; if (task->tk_rqstp != NULL) return; task->tk_timeout = 0; task->tk_status = -EAGAIN; rcu_read_lock(); xprt = rcu_dereference(task->tk_client->cl_xprt); xprt->ops->alloc_slot(xprt, task); rcu_read_unlock(); } static inline __be32 xprt_alloc_xid(struct rpc_xprt *xprt) { return (__force __be32)xprt->xid++; } static inline void xprt_init_xid(struct rpc_xprt *xprt) { xprt->xid = net_random(); } static void xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt) { struct rpc_rqst *req = task->tk_rqstp; INIT_LIST_HEAD(&req->rq_list); req->rq_timeout = task->tk_client->cl_timeout->to_initval; req->rq_task = task; req->rq_xprt = xprt; req->rq_buffer = NULL; req->rq_xid = xprt_alloc_xid(xprt); req->rq_release_snd_buf = NULL; xprt_reset_majortimeo(req); dprintk("RPC: %5u reserved req %p xid %08x\n", task->tk_pid, req, ntohl(req->rq_xid)); } /** * xprt_release - release an RPC request slot * @task: task which is finished with the slot * */ void xprt_release(struct rpc_task *task) { struct rpc_xprt *xprt; struct rpc_rqst *req = task->tk_rqstp; if (req == NULL) { if (task->tk_client) { rcu_read_lock(); xprt = rcu_dereference(task->tk_client->cl_xprt); if (xprt->snd_task == task) xprt_release_write(xprt, task); rcu_read_unlock(); } return; } xprt = req->rq_xprt; if (task->tk_ops->rpc_count_stats != NULL) task->tk_ops->rpc_count_stats(task, task->tk_calldata); else if (task->tk_client) rpc_count_iostats(task, task->tk_client->cl_metrics); spin_lock_bh(&xprt->transport_lock); xprt->ops->release_xprt(xprt, task); if (xprt->ops->release_request) xprt->ops->release_request(task); if (!list_empty(&req->rq_list)) list_del(&req->rq_list); xprt->last_used = jiffies; if (list_empty(&xprt->recv) && xprt_has_timer(xprt)) mod_timer(&xprt->timer, xprt->last_used + xprt->idle_timeout); spin_unlock_bh(&xprt->transport_lock); if (req->rq_buffer) xprt->ops->buf_free(req->rq_buffer); if (req->rq_cred != NULL) put_rpccred(req->rq_cred); task->tk_rqstp = NULL; if (req->rq_release_snd_buf) req->rq_release_snd_buf(req); dprintk("RPC: %5u release request %p\n", task->tk_pid, req); if (likely(!bc_prealloc(req))) xprt_free_slot(xprt, req); else xprt_free_bc_request(req); } static void xprt_init(struct rpc_xprt *xprt, struct net *net) { atomic_set(&xprt->count, 1); spin_lock_init(&xprt->transport_lock); spin_lock_init(&xprt->reserve_lock); INIT_LIST_HEAD(&xprt->free); INIT_LIST_HEAD(&xprt->recv); #if defined(CONFIG_SUNRPC_BACKCHANNEL) spin_lock_init(&xprt->bc_pa_lock); INIT_LIST_HEAD(&xprt->bc_pa_list); #endif /* CONFIG_SUNRPC_BACKCHANNEL */ xprt->last_used = jiffies; xprt->cwnd = RPC_INITCWND; xprt->bind_index = 0; rpc_init_wait_queue(&xprt->binding, "xprt_binding"); rpc_init_wait_queue(&xprt->pending, "xprt_pending"); rpc_init_priority_wait_queue(&xprt->sending, "xprt_sending"); rpc_init_priority_wait_queue(&xprt->backlog, "xprt_backlog"); xprt_init_xid(xprt); xprt->xprt_net = get_net(net); } /** * xprt_create_transport - create an RPC transport * @args: rpc transport creation arguments * */ struct rpc_xprt *xprt_create_transport(struct xprt_create *args) { struct rpc_xprt *xprt; struct xprt_class *t; spin_lock(&xprt_list_lock); list_for_each_entry(t, &xprt_list, list) { if (t->ident == args->ident) { spin_unlock(&xprt_list_lock); goto found; } } spin_unlock(&xprt_list_lock); printk(KERN_ERR "RPC: transport (%d) not supported\n", args->ident); return ERR_PTR(-EIO); found: xprt = t->setup(args); if (IS_ERR(xprt)) { dprintk("RPC: xprt_create_transport: failed, %ld\n", -PTR_ERR(xprt)); goto out; } if (args->flags & XPRT_CREATE_NO_IDLE_TIMEOUT) xprt->idle_timeout = 0; INIT_WORK(&xprt->task_cleanup, xprt_autoclose); if (xprt_has_timer(xprt)) setup_timer(&xprt->timer, xprt_init_autodisconnect, (unsigned long)xprt); else init_timer(&xprt->timer); if (strlen(args->servername) > RPC_MAXNETNAMELEN) { xprt_destroy(xprt); return ERR_PTR(-EINVAL); } xprt->servername = kstrdup(args->servername, GFP_KERNEL); if (xprt->servername == NULL) { xprt_destroy(xprt); return ERR_PTR(-ENOMEM); } dprintk("RPC: created transport %p with %u slots\n", xprt, xprt->max_reqs); out: return xprt; } /** * xprt_destroy - destroy an RPC transport, killing off all requests. * @xprt: transport to destroy * */ static void xprt_destroy(struct rpc_xprt *xprt) { dprintk("RPC: destroying transport %p\n", xprt); del_timer_sync(&xprt->timer); rpc_destroy_wait_queue(&xprt->binding); rpc_destroy_wait_queue(&xprt->pending); rpc_destroy_wait_queue(&xprt->sending); rpc_destroy_wait_queue(&xprt->backlog); cancel_work_sync(&xprt->task_cleanup); kfree(xprt->servername); /* * Tear down transport state and free the rpc_xprt */ xprt->ops->destroy(xprt); } /** * xprt_put - release a reference to an RPC transport. * @xprt: pointer to the transport * */ void xprt_put(struct rpc_xprt *xprt) { if (atomic_dec_and_test(&xprt->count)) xprt_destroy(xprt); } /** * xprt_get - return a reference to an RPC transport. * @xprt: pointer to the transport * */ struct rpc_xprt *xprt_get(struct rpc_xprt *xprt) { if (atomic_inc_not_zero(&xprt->count)) return xprt; return NULL; }