v4.19.13 snapshot.
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
new file mode 100644
index 0000000..d066aae
--- /dev/null
+++ b/net/sunrpc/xprt.c
@@ -0,0 +1,1548 @@
+/*
+ * 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 <linux/rcupdate.h>
+
+#include <trace/events/sunrpc.h>
+
+#include "sunrpc.h"
+
+/*
+ * Local variables
+ */
+
+#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
+# define RPCDBG_FACILITY RPCDBG_XPRT
+#endif
+
+/*
+ * Local functions
+ */
+static void xprt_init(struct rpc_xprt *xprt, struct net *net);
+static __be32 xprt_alloc_xid(struct rpc_xprt *xprt);
+static void xprt_connect_status(struct rpc_task *task);
+static int __xprt_get_cong(struct rpc_xprt *, struct rpc_task *);
+static void __xprt_put_cong(struct rpc_xprt *, struct rpc_rqst *);
+static void xprt_destroy(struct rpc_xprt *xprt);
+
+static DEFINE_SPINLOCK(xprt_list_lock);
+static LIST_HEAD(xprt_list);
+
+/**
+ * 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_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_atomic();
+ clear_bit(XPRT_LOCKED, &xprt->state);
+ smp_mb__after_atomic();
+ } else
+ queue_work(xprtiod_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_ntrans++;
+ return 1;
+ }
+ xprt_clear_locked(xprt);
+out_sleep:
+ if (req)
+ __xprt_put_cong(xprt, req);
+ 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_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_on_wq(xprtiod_workqueue, &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_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_on_wq(xprtiod_workqueue, &xprt->sending,
+ __xprt_lock_write_cong_func, xprt))
+ return;
+out_unlock:
+ xprt_clear_locked(xprt);
+}
+
+static void xprt_task_clear_bytes_sent(struct rpc_task *task)
+{
+ if (task != NULL) {
+ struct rpc_rqst *req = task->tk_rqstp;
+ if (req != NULL)
+ req->rq_bytes_sent = 0;
+ }
+}
+
+/**
+ * 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_task_clear_bytes_sent(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_task_clear_bytes_sent(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
+ *
+ * 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.
+ */
+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_on_wq(xprtiod_workqueue,
+ &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);
+
+ clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
+ xprt->ops->close(xprt);
+ xprt_release_write(xprt, NULL);
+ wake_up_bit(&xprt->state, XPRT_LOCKED);
+}
+
+/**
+ * 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(xprtiod_workqueue, &xprt->task_cleanup);
+ xprt_wake_pending_tasks(xprt, -EAGAIN);
+ spin_unlock_bh(&xprt->transport_lock);
+}
+EXPORT_SYMBOL_GPL(xprt_force_disconnect);
+
+/**
+ * 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))
+ 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(xprtiod_workqueue, &xprt->task_cleanup);
+ xprt_wake_pending_tasks(xprt, -EAGAIN);
+out:
+ spin_unlock_bh(&xprt->transport_lock);
+}
+
+static bool
+xprt_has_timer(const struct rpc_xprt *xprt)
+{
+ return xprt->idle_timeout != 0;
+}
+
+static void
+xprt_schedule_autodisconnect(struct rpc_xprt *xprt)
+ __must_hold(&xprt->transport_lock)
+{
+ if (list_empty(&xprt->recv) && xprt_has_timer(xprt))
+ mod_timer(&xprt->timer, xprt->last_used + xprt->idle_timeout);
+}
+
+static void
+xprt_init_autodisconnect(struct timer_list *t)
+{
+ struct rpc_xprt *xprt = from_timer(xprt, t, timer);
+
+ spin_lock(&xprt->transport_lock);
+ if (!list_empty(&xprt->recv))
+ goto out_abort;
+ /* Reset xprt->last_used to avoid connect/autodisconnect cycling */
+ xprt->last_used = jiffies;
+ if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
+ goto out_abort;
+ spin_unlock(&xprt->transport_lock);
+ queue_work(xprtiod_workqueue, &xprt->task_cleanup);
+ return;
+out_abort:
+ spin_unlock(&xprt->transport_lock);
+}
+
+bool xprt_lock_connect(struct rpc_xprt *xprt,
+ struct rpc_task *task,
+ void *cookie)
+{
+ bool ret = false;
+
+ spin_lock_bh(&xprt->transport_lock);
+ if (!test_bit(XPRT_LOCKED, &xprt->state))
+ goto out;
+ if (xprt->snd_task != task)
+ goto out;
+ xprt_task_clear_bytes_sent(task);
+ xprt->snd_task = cookie;
+ ret = true;
+out:
+ spin_unlock_bh(&xprt->transport_lock);
+ return ret;
+}
+
+void xprt_unlock_connect(struct rpc_xprt *xprt, void *cookie)
+{
+ spin_lock_bh(&xprt->transport_lock);
+ if (xprt->snd_task != cookie)
+ goto out;
+ if (!test_bit(XPRT_LOCKED, &xprt->state))
+ goto out;
+ xprt->snd_task =NULL;
+ xprt->ops->release_xprt(xprt, NULL);
+ xprt_schedule_autodisconnect(xprt);
+out:
+ spin_unlock_bh(&xprt->transport_lock);
+ wake_up_bit(&xprt->state, XPRT_LOCKED);
+}
+
+/**
+ * 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)) {
+ task->tk_rqstp->rq_bytes_sent = 0;
+ task->tk_timeout = task->tk_rqstp->rq_timeout;
+ task->tk_rqstp->rq_connect_cookie = xprt->connect_cookie;
+ 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;
+ /* Race breaker */
+ if (!xprt_connected(xprt)) {
+ xprt->stat.connect_start = jiffies;
+ xprt->ops->connect(xprt, task);
+ } else {
+ xprt_clear_connecting(xprt);
+ task->tk_status = 0;
+ rpc_wake_up_queued_task(&xprt->pending, task);
+ }
+ }
+ xprt_release_write(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 -ECONNREFUSED:
+ case -ECONNRESET:
+ case -ECONNABORTED:
+ case -ENETUNREACH:
+ case -EHOSTUNREACH:
+ case -EPIPE:
+ 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);
+ 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
+ *
+ * Caller holds xprt->recv_lock.
+ */
+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) {
+ trace_xprt_lookup_rqst(xprt, xid, 0);
+ entry->rq_rtt = ktime_sub(ktime_get(), entry->rq_xtime);
+ return entry;
+ }
+
+ dprintk("RPC: xprt_lookup_rqst did not find xid %08x\n",
+ ntohl(xid));
+ trace_xprt_lookup_rqst(xprt, xid, -ENOENT);
+ xprt->stat.bad_xids++;
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(xprt_lookup_rqst);
+
+/**
+ * xprt_pin_rqst - Pin a request on the transport receive list
+ * @req: Request to pin
+ *
+ * Caller must ensure this is atomic with the call to xprt_lookup_rqst()
+ * so should be holding the xprt transport lock.
+ */
+void xprt_pin_rqst(struct rpc_rqst *req)
+{
+ set_bit(RPC_TASK_MSG_RECV, &req->rq_task->tk_runstate);
+}
+EXPORT_SYMBOL_GPL(xprt_pin_rqst);
+
+/**
+ * xprt_unpin_rqst - Unpin a request on the transport receive list
+ * @req: Request to pin
+ *
+ * Caller should be holding the xprt transport lock.
+ */
+void xprt_unpin_rqst(struct rpc_rqst *req)
+{
+ struct rpc_task *task = req->rq_task;
+
+ clear_bit(RPC_TASK_MSG_RECV, &task->tk_runstate);
+ if (test_bit(RPC_TASK_MSG_RECV_WAIT, &task->tk_runstate))
+ wake_up_bit(&task->tk_runstate, RPC_TASK_MSG_RECV);
+}
+EXPORT_SYMBOL_GPL(xprt_unpin_rqst);
+
+static void xprt_wait_on_pinned_rqst(struct rpc_rqst *req)
+__must_hold(&req->rq_xprt->recv_lock)
+{
+ struct rpc_task *task = req->rq_task;
+
+ if (task && test_bit(RPC_TASK_MSG_RECV, &task->tk_runstate)) {
+ spin_unlock(&req->rq_xprt->recv_lock);
+ set_bit(RPC_TASK_MSG_RECV_WAIT, &task->tk_runstate);
+ wait_on_bit(&task->tk_runstate, RPC_TASK_MSG_RECV,
+ TASK_UNINTERRUPTIBLE);
+ clear_bit(RPC_TASK_MSG_RECV_WAIT, &task->tk_runstate);
+ spin_lock(&req->rq_xprt->recv_lock);
+ }
+}
+
+/**
+ * xprt_update_rtt - Update RPC RTT statistics
+ * @task: RPC request that recently completed
+ *
+ * Caller holds xprt->recv_lock.
+ */
+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);
+ }
+}
+EXPORT_SYMBOL_GPL(xprt_update_rtt);
+
+/**
+ * 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 xprt->recv_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);
+ trace_xprt_complete_rqst(xprt, req->rq_xid, copied);
+
+ xprt->stat.recvs++;
+
+ 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;
+
+ trace_xprt_timer(xprt, req->rq_xid, task->tk_status);
+ if (!req->rq_reply_bytes_recvd) {
+ if (xprt->ops->timer)
+ xprt->ops->timer(xprt, task);
+ } else
+ task->tk_status = 0;
+}
+
+/**
+ * xprt_prepare_transmit - reserve the transport before sending a request
+ * @task: RPC task about to send a request
+ *
+ */
+bool xprt_prepare_transmit(struct rpc_task *task)
+{
+ struct rpc_rqst *req = task->tk_rqstp;
+ struct rpc_xprt *xprt = req->rq_xprt;
+ bool ret = false;
+
+ dprintk("RPC: %5u xprt_prepare_transmit\n", task->tk_pid);
+
+ spin_lock_bh(&xprt->transport_lock);
+ if (!req->rq_bytes_sent) {
+ if (req->rq_reply_bytes_recvd) {
+ task->tk_status = req->rq_reply_bytes_recvd;
+ goto out_unlock;
+ }
+ if ((task->tk_flags & RPC_TASK_NO_RETRANS_TIMEOUT)
+ && xprt_connected(xprt)
+ && req->rq_connect_cookie == xprt->connect_cookie) {
+ xprt->ops->set_retrans_timeout(task);
+ rpc_sleep_on(&xprt->pending, task, xprt_timer);
+ goto out_unlock;
+ }
+ }
+ if (!xprt->ops->reserve_xprt(xprt, task)) {
+ task->tk_status = -EAGAIN;
+ goto out_unlock;
+ }
+ ret = true;
+out_unlock:
+ spin_unlock_bh(&xprt->transport_lock);
+ return ret;
+}
+
+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;
+ unsigned int connect_cookie;
+ int status;
+
+ 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
+ */
+ /* 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 */
+ spin_lock(&xprt->recv_lock);
+ list_add_tail(&req->rq_list, &xprt->recv);
+ spin_unlock(&xprt->recv_lock);
+ xprt_reset_majortimeo(req);
+ /* Turn off autodisconnect */
+ del_singleshot_timer_sync(&xprt->timer);
+ }
+ } else if (!req->rq_bytes_sent)
+ return;
+
+ connect_cookie = xprt->connect_cookie;
+ status = xprt->ops->send_request(task);
+ trace_xprt_transmit(xprt, req->rq_xid, status);
+ if (status != 0) {
+ task->tk_status = status;
+ return;
+ }
+ xprt_inject_disconnect(xprt);
+
+ 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);
+
+ 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;
+ spin_unlock_bh(&xprt->transport_lock);
+
+ req->rq_connect_cookie = connect_cookie;
+ if (rpc_reply_expected(task) && !READ_ONCE(req->rq_reply_bytes_recvd)) {
+ /*
+ * Sleep on the pending queue if we're expecting a reply.
+ * The spinlock ensures atomicity between the test of
+ * req->rq_reply_bytes_recvd, and the call to rpc_sleep_on().
+ */
+ spin_lock(&xprt->recv_lock);
+ if (!req->rq_reply_bytes_recvd) {
+ rpc_sleep_on(&xprt->pending, task, xprt_timer);
+ /*
+ * Send an extra queue wakeup call if the
+ * connection was dropped in case the call to
+ * rpc_sleep_on() raced.
+ */
+ if (!xprt_connected(xprt))
+ xprt_wake_pending_tasks(xprt, -ENOTCONN);
+ }
+ spin_unlock(&xprt->recv_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)
+{
+ struct rpc_rqst *req = ERR_PTR(-EAGAIN);
+
+ if (xprt->num_reqs >= xprt->max_reqs)
+ goto out;
+ ++xprt->num_reqs;
+ spin_unlock(&xprt->reserve_lock);
+ req = kzalloc(sizeof(struct rpc_rqst), GFP_NOFS);
+ spin_lock(&xprt->reserve_lock);
+ if (req != NULL)
+ goto out;
+ --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 (xprt->num_reqs > xprt->min_reqs) {
+ --xprt->num_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);
+ 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");
+ /* fall through */
+ default:
+ task->tk_status = -EAGAIN;
+ }
+ spin_unlock(&xprt->reserve_lock);
+ return;
+out_init_req:
+ xprt->stat.max_slots = max_t(unsigned int, xprt->stat.max_slots,
+ xprt->num_reqs);
+ spin_unlock(&xprt->reserve_lock);
+
+ task->tk_status = 0;
+ task->tk_rqstp = req;
+}
+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);
+
+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);
+}
+EXPORT_SYMBOL_GPL(xprt_free_slot);
+
+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)
+ goto out_free;
+ list_add(&req->rq_list, &xprt->free);
+ }
+ if (max_alloc > num_prealloc)
+ xprt->max_reqs = max_alloc;
+ else
+ xprt->max_reqs = num_prealloc;
+ xprt->min_reqs = num_prealloc;
+ 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_rcu(xprt, rcu);
+}
+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_xprt;
+
+ task->tk_status = 0;
+ if (task->tk_rqstp != NULL)
+ return;
+
+ task->tk_timeout = 0;
+ task->tk_status = -EAGAIN;
+ if (!xprt_throttle_congested(xprt, task))
+ xprt->ops->alloc_slot(xprt, task);
+}
+
+/**
+ * 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_xprt;
+
+ task->tk_status = 0;
+ if (task->tk_rqstp != NULL)
+ return;
+
+ task->tk_timeout = 0;
+ task->tk_status = -EAGAIN;
+ xprt->ops->alloc_slot(xprt, task);
+}
+
+static inline __be32 xprt_alloc_xid(struct rpc_xprt *xprt)
+{
+ __be32 xid;
+
+ spin_lock(&xprt->reserve_lock);
+ xid = (__force __be32)xprt->xid++;
+ spin_unlock(&xprt->reserve_lock);
+ return xid;
+}
+
+static inline void xprt_init_xid(struct rpc_xprt *xprt)
+{
+ xprt->xid = prandom_u32();
+}
+
+void xprt_request_init(struct rpc_task *task)
+{
+ struct rpc_xprt *xprt = task->tk_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_connect_cookie = xprt->connect_cookie - 1;
+ req->rq_bytes_sent = 0;
+ req->rq_snd_buf.len = 0;
+ req->rq_snd_buf.buflen = 0;
+ req->rq_rcv_buf.len = 0;
+ req->rq_rcv_buf.buflen = 0;
+ 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) {
+ xprt = task->tk_xprt;
+ if (xprt->snd_task == task)
+ xprt_release_write(xprt, task);
+ }
+ 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(&xprt->recv_lock);
+ if (!list_empty(&req->rq_list)) {
+ list_del_init(&req->rq_list);
+ xprt_wait_on_pinned_rqst(req);
+ }
+ spin_unlock(&xprt->recv_lock);
+ spin_lock_bh(&xprt->transport_lock);
+ xprt->ops->release_xprt(xprt, task);
+ if (xprt->ops->release_request)
+ xprt->ops->release_request(task);
+ xprt->last_used = jiffies;
+ xprt_schedule_autodisconnect(xprt);
+ spin_unlock_bh(&xprt->transport_lock);
+ if (req->rq_buffer)
+ xprt->ops->buf_free(task);
+ xprt_inject_disconnect(xprt);
+ 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->ops->free_slot(xprt, req);
+ else
+ xprt_free_bc_request(req);
+}
+
+static void xprt_init(struct rpc_xprt *xprt, struct net *net)
+{
+ kref_init(&xprt->kref);
+
+ spin_lock_init(&xprt->transport_lock);
+ spin_lock_init(&xprt->reserve_lock);
+ spin_lock_init(&xprt->recv_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 */
+ INIT_LIST_HEAD(&xprt->xprt_switch);
+
+ 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);
+ dprintk("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))
+ timer_setup(&xprt->timer, xprt_init_autodisconnect, 0);
+ else
+ timer_setup(&xprt->timer, NULL, 0);
+
+ 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);
+ }
+
+ rpc_xprt_debugfs_register(xprt);
+
+ dprintk("RPC: created transport %p with %u slots\n", xprt,
+ xprt->max_reqs);
+out:
+ return xprt;
+}
+
+static void xprt_destroy_cb(struct work_struct *work)
+{
+ struct rpc_xprt *xprt =
+ container_of(work, struct rpc_xprt, task_cleanup);
+
+ rpc_xprt_debugfs_unregister(xprt);
+ rpc_destroy_wait_queue(&xprt->binding);
+ rpc_destroy_wait_queue(&xprt->pending);
+ rpc_destroy_wait_queue(&xprt->sending);
+ rpc_destroy_wait_queue(&xprt->backlog);
+ kfree(xprt->servername);
+ /*
+ * Tear down transport state and free the rpc_xprt
+ */
+ xprt->ops->destroy(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);
+
+ /*
+ * Exclude transport connect/disconnect handlers and autoclose
+ */
+ wait_on_bit_lock(&xprt->state, XPRT_LOCKED, TASK_UNINTERRUPTIBLE);
+
+ del_timer_sync(&xprt->timer);
+
+ /*
+ * Destroy sockets etc from the system workqueue so they can
+ * safely flush receive work running on rpciod.
+ */
+ INIT_WORK(&xprt->task_cleanup, xprt_destroy_cb);
+ schedule_work(&xprt->task_cleanup);
+}
+
+static void xprt_destroy_kref(struct kref *kref)
+{
+ xprt_destroy(container_of(kref, struct rpc_xprt, kref));
+}
+
+/**
+ * xprt_get - return a reference to an RPC transport.
+ * @xprt: pointer to the transport
+ *
+ */
+struct rpc_xprt *xprt_get(struct rpc_xprt *xprt)
+{
+ if (xprt != NULL && kref_get_unless_zero(&xprt->kref))
+ return xprt;
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(xprt_get);
+
+/**
+ * xprt_put - release a reference to an RPC transport.
+ * @xprt: pointer to the transport
+ *
+ */
+void xprt_put(struct rpc_xprt *xprt)
+{
+ if (xprt != NULL)
+ kref_put(&xprt->kref, xprt_destroy_kref);
+}
+EXPORT_SYMBOL_GPL(xprt_put);