1 files changed, 329 insertions, 208 deletions

diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index adc3c40cc733..016f16ca5779 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * linux/net/sunrpc/sched.c
  *
@@ -19,15 +20,13 @@
 #include <linux/spinlock.h>
 #include <linux/mutex.h>
 #include <linux/freezer.h>
+#include <linux/sched/mm.h>
 
 #include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/metrics.h>
 
 #include "sunrpc.h"
 
-#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
-#define RPCDBG_FACILITY		RPCDBG_SCHED
-#endif
-
 #define CREATE_TRACE_POINTS
 #include <trace/events/sunrpc.h>
 
@@ -44,7 +43,7 @@ static mempool_t	*rpc_buffer_mempool __read_mostly;
 
 static void			rpc_async_schedule(struct work_struct *);
 static void			 rpc_release_task(struct rpc_task *task);
-static void __rpc_queue_timer_fn(struct timer_list *t);
+static void __rpc_queue_timer_fn(struct work_struct *);
 
 /*
  * RPC tasks sit here while waiting for conditions to improve.
@@ -56,6 +55,36 @@ static struct rpc_wait_queue delay_queue;
  */
 struct workqueue_struct *rpciod_workqueue __read_mostly;
 struct workqueue_struct *xprtiod_workqueue __read_mostly;
+EXPORT_SYMBOL_GPL(xprtiod_workqueue);
+
+gfp_t rpc_task_gfp_mask(void)
+{
+	if (current->flags & PF_WQ_WORKER)
+		return GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN;
+	return GFP_KERNEL;
+}
+EXPORT_SYMBOL_GPL(rpc_task_gfp_mask);
+
+bool rpc_task_set_rpc_status(struct rpc_task *task, int rpc_status)
+{
+	if (cmpxchg(&task->tk_rpc_status, 0, rpc_status) == 0)
+		return true;
+	return false;
+}
+
+unsigned long
+rpc_task_timeout(const struct rpc_task *task)
+{
+	unsigned long timeout = READ_ONCE(task->tk_timeout);
+
+	if (timeout != 0) {
+		unsigned long now = jiffies;
+		if (time_before(now, timeout))
+			return timeout - now;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(rpc_task_timeout);
 
 /*
  * Disable the timer for a given RPC task. Should be called with
@@ -65,37 +94,36 @@ struct workqueue_struct *xprtiod_workqueue __read_mostly;
 static void
 __rpc_disable_timer(struct rpc_wait_queue *queue, struct rpc_task *task)
 {
-	if (task->tk_timeout == 0)
+	if (list_empty(&task->u.tk_wait.timer_list))
 		return;
-	dprintk("RPC: %5u disabling timer\n", task->tk_pid);
 	task->tk_timeout = 0;
 	list_del(&task->u.tk_wait.timer_list);
 	if (list_empty(&queue->timer_list.list))
-		del_timer(&queue->timer_list.timer);
+		cancel_delayed_work(&queue->timer_list.dwork);
 }
 
 static void
 rpc_set_queue_timer(struct rpc_wait_queue *queue, unsigned long expires)
 {
+	unsigned long now = jiffies;
 	queue->timer_list.expires = expires;
-	mod_timer(&queue->timer_list.timer, expires);
+	if (time_before_eq(expires, now))
+		expires = 0;
+	else
+		expires -= now;
+	mod_delayed_work(rpciod_workqueue, &queue->timer_list.dwork, expires);
 }
 
 /*
  * Set up a timer for the current task.
  */
 static void
-__rpc_add_timer(struct rpc_wait_queue *queue, struct rpc_task *task)
+__rpc_add_timer(struct rpc_wait_queue *queue, struct rpc_task *task,
+		unsigned long timeout)
 {
-	if (!task->tk_timeout)
-		return;
-
-	dprintk("RPC: %5u setting alarm for %u ms\n",
-		task->tk_pid, jiffies_to_msecs(task->tk_timeout));
-
-	task->u.tk_wait.expires = jiffies + task->tk_timeout;
-	if (list_empty(&queue->timer_list.list) || time_before(task->u.tk_wait.expires, queue->timer_list.expires))
-		rpc_set_queue_timer(queue, task->u.tk_wait.expires);
+	task->tk_timeout = timeout;
+	if (list_empty(&queue->timer_list.list) || time_before(timeout, queue->timer_list.expires))
+		rpc_set_queue_timer(queue, timeout);
 	list_add(&task->u.tk_wait.timer_list, &queue->timer_list.list);
 }
 
@@ -173,24 +201,14 @@ static void __rpc_add_wait_queue_priority(struct rpc_wait_queue *queue,
 
 /*
  * Add new request to wait queue.
- *
- * Swapper tasks always get inserted at the head of the queue.
- * This should avoid many nasty memory deadlocks and hopefully
- * improve overall performance.
- * Everyone else gets appended to the queue to ensure proper FIFO behavior.
  */
 static void __rpc_add_wait_queue(struct rpc_wait_queue *queue,
 		struct rpc_task *task,
 		unsigned char queue_priority)
 {
-	WARN_ON_ONCE(RPC_IS_QUEUED(task));
-	if (RPC_IS_QUEUED(task))
-		return;
-
+	INIT_LIST_HEAD(&task->u.tk_wait.timer_list);
 	if (RPC_IS_PRIORITY(queue))
 		__rpc_add_wait_queue_priority(queue, task, queue_priority);
-	else if (RPC_IS_SWAPPER(task))
-		list_add(&task->u.tk_wait.list, &queue->tasks[0]);
 	else
 		list_add_tail(&task->u.tk_wait.list, &queue->tasks[0]);
 	task->tk_waitqueue = queue;
@@ -198,9 +216,6 @@ static void __rpc_add_wait_queue(struct rpc_wait_queue *queue,
 	/* barrier matches the read in rpc_wake_up_task_queue_locked() */
 	smp_wmb();
 	rpc_set_queued(task);
-
-	dprintk("RPC: %5u added to queue %p \"%s\"\n",
-			task->tk_pid, queue, rpc_qname(queue));
 }
 
 /*
@@ -223,8 +238,6 @@ static void __rpc_remove_wait_queue(struct rpc_wait_queue *queue, struct rpc_tas
 	else
 		list_del(&task->u.tk_wait.list);
 	queue->qlen--;
-	dprintk("RPC: %5u removed from queue %p \"%s\"\n",
-			task->tk_pid, queue, rpc_qname(queue));
 }
 
 static void __rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const char *qname, unsigned char nr_queues)
@@ -237,7 +250,8 @@ static void __rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const c
 	queue->maxpriority = nr_queues - 1;
 	rpc_reset_waitqueue_priority(queue);
 	queue->qlen = 0;
-	timer_setup(&queue->timer_list.timer, __rpc_queue_timer_fn, 0);
+	queue->timer_list.expires = 0;
+	INIT_DELAYED_WORK(&queue->timer_list.dwork, __rpc_queue_timer_fn);
 	INIT_LIST_HEAD(&queue->timer_list.list);
 	rpc_assign_waitqueue_name(queue, qname);
 }
@@ -256,13 +270,13 @@ EXPORT_SYMBOL_GPL(rpc_init_wait_queue);
 
 void rpc_destroy_wait_queue(struct rpc_wait_queue *queue)
 {
-	del_timer_sync(&queue->timer_list.timer);
+	cancel_delayed_work_sync(&queue->timer_list.dwork);
 }
 EXPORT_SYMBOL_GPL(rpc_destroy_wait_queue);
 
 static int rpc_wait_bit_killable(struct wait_bit_key *key, int mode)
 {
-	freezable_schedule_unsafe();
+	schedule();
 	if (signal_pending_state(mode, current))
 		return -ERESTARTSYS;
 	return 0;
@@ -271,9 +285,17 @@ static int rpc_wait_bit_killable(struct wait_bit_key *key, int mode)
 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG) || IS_ENABLED(CONFIG_TRACEPOINTS)
 static void rpc_task_set_debuginfo(struct rpc_task *task)
 {
-	static atomic_t rpc_pid;
+	struct rpc_clnt *clnt = task->tk_client;
+
+	/* Might be a task carrying a reverse-direction operation */
+	if (!clnt) {
+		static atomic_t rpc_pid;
 
-	task->tk_pid = atomic_inc_return(&rpc_pid);
+		task->tk_pid = atomic_inc_return(&rpc_pid);
+		return;
+	}
+
+	task->tk_pid = atomic_inc_return(&clnt->cl_pid);
 }
 #else
 static inline void rpc_task_set_debuginfo(struct rpc_task *task)
@@ -318,14 +340,12 @@ static int rpc_complete_task(struct rpc_task *task)
  * to enforce taking of the wq->lock and hence avoid races with
  * rpc_complete_task().
  */
-int __rpc_wait_for_completion_task(struct rpc_task *task, wait_bit_action_f *action)
+int rpc_wait_for_completion_task(struct rpc_task *task)
 {
-	if (action == NULL)
-		action = rpc_wait_bit_killable;
 	return out_of_line_wait_on_bit(&task->tk_runstate, RPC_TASK_ACTIVE,
-			action, TASK_KILLABLE);
+			rpc_wait_bit_killable, TASK_KILLABLE|TASK_FREEZABLE_UNSAFE);
 }
-EXPORT_SYMBOL_GPL(__rpc_wait_for_completion_task);
+EXPORT_SYMBOL_GPL(rpc_wait_for_completion_task);
 
 /*
  * Make an RPC task runnable.
@@ -349,8 +369,10 @@ static void rpc_make_runnable(struct workqueue_struct *wq,
 	if (RPC_IS_ASYNC(task)) {
 		INIT_WORK(&task->u.tk_work, rpc_async_schedule);
 		queue_work(wq, &task->u.tk_work);
-	} else
+	} else {
+		smp_mb__after_atomic();
 		wake_up_bit(&task->tk_runstate, RPC_TASK_QUEUED);
+	}
 }
 
 /*
@@ -359,60 +381,119 @@ static void rpc_make_runnable(struct workqueue_struct *wq,
  * NB: An RPC task will only receive interrupt-driven events as long
  * as it's on a wait queue.
  */
-static void __rpc_sleep_on_priority(struct rpc_wait_queue *q,
+static void __rpc_do_sleep_on_priority(struct rpc_wait_queue *q,
 		struct rpc_task *task,
-		rpc_action action,
 		unsigned char queue_priority)
 {
-	dprintk("RPC: %5u sleep_on(queue \"%s\" time %lu)\n",
-			task->tk_pid, rpc_qname(q), jiffies);
-
 	trace_rpc_task_sleep(task, q);
 
 	__rpc_add_wait_queue(q, task, queue_priority);
+}
+
+static void __rpc_sleep_on_priority(struct rpc_wait_queue *q,
+		struct rpc_task *task,
+		unsigned char queue_priority)
+{
+	if (WARN_ON_ONCE(RPC_IS_QUEUED(task)))
+		return;
+	__rpc_do_sleep_on_priority(q, task, queue_priority);
+}
 
-	WARN_ON_ONCE(task->tk_callback != NULL);
-	task->tk_callback = action;
-	__rpc_add_timer(q, task);
+static void __rpc_sleep_on_priority_timeout(struct rpc_wait_queue *q,
+		struct rpc_task *task, unsigned long timeout,
+		unsigned char queue_priority)
+{
+	if (WARN_ON_ONCE(RPC_IS_QUEUED(task)))
+		return;
+	if (time_is_after_jiffies(timeout)) {
+		__rpc_do_sleep_on_priority(q, task, queue_priority);
+		__rpc_add_timer(q, task, timeout);
+	} else
+		task->tk_status = -ETIMEDOUT;
 }
 
-void rpc_sleep_on(struct rpc_wait_queue *q, struct rpc_task *task,
-				rpc_action action)
+static void rpc_set_tk_callback(struct rpc_task *task, rpc_action action)
+{
+	if (action && !WARN_ON_ONCE(task->tk_callback != NULL))
+		task->tk_callback = action;
+}
+
+static bool rpc_sleep_check_activated(struct rpc_task *task)
 {
 	/* We shouldn't ever put an inactive task to sleep */
-	WARN_ON_ONCE(!RPC_IS_ACTIVATED(task));
-	if (!RPC_IS_ACTIVATED(task)) {
+	if (WARN_ON_ONCE(!RPC_IS_ACTIVATED(task))) {
 		task->tk_status = -EIO;
 		rpc_put_task_async(task);
-		return;
+		return false;
 	}
+	return true;
+}
+
+void rpc_sleep_on_timeout(struct rpc_wait_queue *q, struct rpc_task *task,
+				rpc_action action, unsigned long timeout)
+{
+	if (!rpc_sleep_check_activated(task))
+		return;
+
+	rpc_set_tk_callback(task, action);
+
+	/*
+	 * Protect the queue operations.
+	 */
+	spin_lock(&q->lock);
+	__rpc_sleep_on_priority_timeout(q, task, timeout, task->tk_priority);
+	spin_unlock(&q->lock);
+}
+EXPORT_SYMBOL_GPL(rpc_sleep_on_timeout);
+
+void rpc_sleep_on(struct rpc_wait_queue *q, struct rpc_task *task,
+				rpc_action action)
+{
+	if (!rpc_sleep_check_activated(task))
+		return;
+
+	rpc_set_tk_callback(task, action);
 
+	WARN_ON_ONCE(task->tk_timeout != 0);
 	/*
 	 * Protect the queue operations.
 	 */
-	spin_lock_bh(&q->lock);
-	__rpc_sleep_on_priority(q, task, action, task->tk_priority);
-	spin_unlock_bh(&q->lock);
+	spin_lock(&q->lock);
+	__rpc_sleep_on_priority(q, task, task->tk_priority);
+	spin_unlock(&q->lock);
 }
 EXPORT_SYMBOL_GPL(rpc_sleep_on);
 
+void rpc_sleep_on_priority_timeout(struct rpc_wait_queue *q,
+		struct rpc_task *task, unsigned long timeout, int priority)
+{
+	if (!rpc_sleep_check_activated(task))
+		return;
+
+	priority -= RPC_PRIORITY_LOW;
+	/*
+	 * Protect the queue operations.
+	 */
+	spin_lock(&q->lock);
+	__rpc_sleep_on_priority_timeout(q, task, timeout, priority);
+	spin_unlock(&q->lock);
+}
+EXPORT_SYMBOL_GPL(rpc_sleep_on_priority_timeout);
+
 void rpc_sleep_on_priority(struct rpc_wait_queue *q, struct rpc_task *task,
-		rpc_action action, int priority)
+		int priority)
 {
-	/* We shouldn't ever put an inactive task to sleep */
-	WARN_ON_ONCE(!RPC_IS_ACTIVATED(task));
-	if (!RPC_IS_ACTIVATED(task)) {
-		task->tk_status = -EIO;
-		rpc_put_task_async(task);
+	if (!rpc_sleep_check_activated(task))
 		return;
-	}
 
+	WARN_ON_ONCE(task->tk_timeout != 0);
+	priority -= RPC_PRIORITY_LOW;
 	/*
 	 * Protect the queue operations.
 	 */
-	spin_lock_bh(&q->lock);
-	__rpc_sleep_on_priority(q, task, action, priority - RPC_PRIORITY_LOW);
-	spin_unlock_bh(&q->lock);
+	spin_lock(&q->lock);
+	__rpc_sleep_on_priority(q, task, priority);
+	spin_unlock(&q->lock);
 }
 EXPORT_SYMBOL_GPL(rpc_sleep_on_priority);
 
@@ -428,9 +509,6 @@ static void __rpc_do_wake_up_task_on_wq(struct workqueue_struct *wq,
 		struct rpc_wait_queue *queue,
 		struct rpc_task *task)
 {
-	dprintk("RPC: %5u __rpc_wake_up_task (now %lu)\n",
-			task->tk_pid, jiffies);
-
 	/* Has the task been executed yet? If not, we cannot wake it up! */
 	if (!RPC_IS_ACTIVATED(task)) {
 		printk(KERN_ERR "RPC: Inactive task (%p) being woken up!\n", task);
@@ -442,8 +520,6 @@ static void __rpc_do_wake_up_task_on_wq(struct workqueue_struct *wq,
 	__rpc_remove_wait_queue(queue, task);
 
 	rpc_make_runnable(wq, task);
-
-	dprintk("RPC:       __rpc_wake_up_task done\n");
 }
 
 /*
@@ -466,33 +542,14 @@ rpc_wake_up_task_on_wq_queue_action_locked(struct workqueue_struct *wq,
 	return NULL;
 }
 
-static void
-rpc_wake_up_task_on_wq_queue_locked(struct workqueue_struct *wq,
-		struct rpc_wait_queue *queue, struct rpc_task *task)
-{
-	rpc_wake_up_task_on_wq_queue_action_locked(wq, queue, task, NULL, NULL);
-}
-
 /*
  * Wake up a queued task while the queue lock is being held
  */
-static void rpc_wake_up_task_queue_locked(struct rpc_wait_queue *queue, struct rpc_task *task)
-{
-	rpc_wake_up_task_on_wq_queue_locked(rpciod_workqueue, queue, task);
-}
-
-/*
- * Wake up a task on a specific queue
- */
-void rpc_wake_up_queued_task_on_wq(struct workqueue_struct *wq,
-		struct rpc_wait_queue *queue,
-		struct rpc_task *task)
+static void rpc_wake_up_task_queue_locked(struct rpc_wait_queue *queue,
+					  struct rpc_task *task)
 {
-	if (!RPC_IS_QUEUED(task))
-		return;
-	spin_lock_bh(&queue->lock);
-	rpc_wake_up_task_on_wq_queue_locked(wq, queue, task);
-	spin_unlock_bh(&queue->lock);
+	rpc_wake_up_task_on_wq_queue_action_locked(rpciod_workqueue, queue,
+						   task, NULL, NULL);
 }
 
 /*
@@ -502,9 +559,9 @@ void rpc_wake_up_queued_task(struct rpc_wait_queue *queue, struct rpc_task *task
 {
 	if (!RPC_IS_QUEUED(task))
 		return;
-	spin_lock_bh(&queue->lock);
+	spin_lock(&queue->lock);
 	rpc_wake_up_task_queue_locked(queue, task);
-	spin_unlock_bh(&queue->lock);
+	spin_unlock(&queue->lock);
 }
 EXPORT_SYMBOL_GPL(rpc_wake_up_queued_task);
 
@@ -537,9 +594,9 @@ rpc_wake_up_queued_task_set_status(struct rpc_wait_queue *queue,
 {
 	if (!RPC_IS_QUEUED(task))
 		return;
-	spin_lock_bh(&queue->lock);
+	spin_lock(&queue->lock);
 	rpc_wake_up_task_queue_set_status_locked(queue, task, status);
-	spin_unlock_bh(&queue->lock);
+	spin_unlock(&queue->lock);
 }
 
 /*
@@ -551,10 +608,20 @@ static struct rpc_task *__rpc_find_next_queued_priority(struct rpc_wait_queue *q
 	struct rpc_task *task;
 
 	/*
+	 * Service the privileged queue.
+	 */
+	q = &queue->tasks[RPC_NR_PRIORITY - 1];
+	if (queue->maxpriority > RPC_PRIORITY_PRIVILEGED && !list_empty(q)) {
+		task = list_first_entry(q, struct rpc_task, u.tk_wait.list);
+		goto out;
+	}
+
+	/*
 	 * Service a batch of tasks from a single owner.
 	 */
 	q = &queue->tasks[queue->priority];
-	if (!list_empty(q) && --queue->nr) {
+	if (!list_empty(q) && queue->nr) {
+		queue->nr--;
 		task = list_first_entry(q, struct rpc_task, u.tk_wait.list);
 		goto out;
 	}
@@ -600,14 +667,12 @@ struct rpc_task *rpc_wake_up_first_on_wq(struct workqueue_struct *wq,
 {
 	struct rpc_task	*task = NULL;
 
-	dprintk("RPC:       wake_up_first(%p \"%s\")\n",
-			queue, rpc_qname(queue));
-	spin_lock_bh(&queue->lock);
+	spin_lock(&queue->lock);
 	task = __rpc_find_next_queued(queue);
 	if (task != NULL)
 		task = rpc_wake_up_task_on_wq_queue_action_locked(wq, queue,
 				task, func, data);
-	spin_unlock_bh(&queue->lock);
+	spin_unlock(&queue->lock);
 
 	return task;
 }
@@ -637,6 +702,23 @@ struct rpc_task *rpc_wake_up_next(struct rpc_wait_queue *queue)
 EXPORT_SYMBOL_GPL(rpc_wake_up_next);
 
 /**
+ * rpc_wake_up_locked - wake up all rpc_tasks
+ * @queue: rpc_wait_queue on which the tasks are sleeping
+ *
+ */
+static void rpc_wake_up_locked(struct rpc_wait_queue *queue)
+{
+	struct rpc_task *task;
+
+	for (;;) {
+		task = __rpc_find_next_queued(queue);
+		if (task == NULL)
+			break;
+		rpc_wake_up_task_queue_locked(queue, task);
+	}
+}
+
+/**
  * rpc_wake_up - wake up all rpc_tasks
  * @queue: rpc_wait_queue on which the tasks are sleeping
  *
@@ -644,25 +726,28 @@ EXPORT_SYMBOL_GPL(rpc_wake_up_next);
  */
 void rpc_wake_up(struct rpc_wait_queue *queue)
 {
-	struct list_head *head;
+	spin_lock(&queue->lock);
+	rpc_wake_up_locked(queue);
+	spin_unlock(&queue->lock);
+}
+EXPORT_SYMBOL_GPL(rpc_wake_up);
+
+/**
+ * rpc_wake_up_status_locked - wake up all rpc_tasks and set their status value.
+ * @queue: rpc_wait_queue on which the tasks are sleeping
+ * @status: status value to set
+ */
+static void rpc_wake_up_status_locked(struct rpc_wait_queue *queue, int status)
+{
+	struct rpc_task *task;
 
-	spin_lock_bh(&queue->lock);
-	head = &queue->tasks[queue->maxpriority];
 	for (;;) {
-		while (!list_empty(head)) {
-			struct rpc_task *task;
-			task = list_first_entry(head,
-					struct rpc_task,
-					u.tk_wait.list);
-			rpc_wake_up_task_queue_locked(queue, task);
-		}
-		if (head == &queue->tasks[0])
+		task = __rpc_find_next_queued(queue);
+		if (task == NULL)
 			break;
-		head--;
+		rpc_wake_up_task_queue_set_status_locked(queue, task, status);
 	}
-	spin_unlock_bh(&queue->lock);
 }
-EXPORT_SYMBOL_GPL(rpc_wake_up);
 
 /**
  * rpc_wake_up_status - wake up all rpc_tasks and set their status value.
@@ -673,39 +758,26 @@ EXPORT_SYMBOL_GPL(rpc_wake_up);
  */
 void rpc_wake_up_status(struct rpc_wait_queue *queue, int status)
 {
-	struct list_head *head;
-
-	spin_lock_bh(&queue->lock);
-	head = &queue->tasks[queue->maxpriority];
-	for (;;) {
-		while (!list_empty(head)) {
-			struct rpc_task *task;
-			task = list_first_entry(head,
-					struct rpc_task,
-					u.tk_wait.list);
-			task->tk_status = status;
-			rpc_wake_up_task_queue_locked(queue, task);
-		}
-		if (head == &queue->tasks[0])
-			break;
-		head--;
-	}
-	spin_unlock_bh(&queue->lock);
+	spin_lock(&queue->lock);
+	rpc_wake_up_status_locked(queue, status);
+	spin_unlock(&queue->lock);
 }
 EXPORT_SYMBOL_GPL(rpc_wake_up_status);
 
-static void __rpc_queue_timer_fn(struct timer_list *t)
+static void __rpc_queue_timer_fn(struct work_struct *work)
 {
-	struct rpc_wait_queue *queue = from_timer(queue, t, timer_list.timer);
+	struct rpc_wait_queue *queue = container_of(work,
+			struct rpc_wait_queue,
+			timer_list.dwork.work);
 	struct rpc_task *task, *n;
 	unsigned long expires, now, timeo;
 
 	spin_lock(&queue->lock);
 	expires = now = jiffies;
 	list_for_each_entry_safe(task, n, &queue->timer_list.list, u.tk_wait.timer_list) {
-		timeo = task->u.tk_wait.expires;
+		timeo = task->tk_timeout;
 		if (time_after_eq(now, timeo)) {
-			dprintk("RPC: %5u timeout\n", task->tk_pid);
+			trace_rpc_task_timeout(task, task->tk_action);
 			task->tk_status = -ETIMEDOUT;
 			rpc_wake_up_task_queue_locked(queue, task);
 			continue;
@@ -729,8 +801,7 @@ static void __rpc_atrun(struct rpc_task *task)
  */
 void rpc_delay(struct rpc_task *task, unsigned long delay)
 {
-	task->tk_timeout = delay;
-	rpc_sleep_on(&delay_queue, task, __rpc_atrun);
+	rpc_sleep_on_timeout(&delay_queue, task, __rpc_atrun, jiffies + delay);
 }
 EXPORT_SYMBOL_GPL(rpc_delay);
 
@@ -748,7 +819,6 @@ rpc_init_task_statistics(struct rpc_task *task)
 	/* Initialize retry counters */
 	task->tk_garb_retry = 2;
 	task->tk_cred_retry = 2;
-	task->tk_rebind_retry = 2;
 
 	/* starting timestamp */
 	task->tk_start = ktime_get();
@@ -758,8 +828,7 @@ static void
 rpc_reset_task_statistics(struct rpc_task *task)
 {
 	task->tk_timeouts = 0;
-	task->tk_flags &= ~(RPC_CALL_MAJORSEEN|RPC_TASK_KILLED|RPC_TASK_SENT);
-
+	task->tk_flags &= ~(RPC_CALL_MAJORSEEN|RPC_TASK_SENT);
 	rpc_init_task_statistics(task);
 }
 
@@ -768,11 +837,16 @@ rpc_reset_task_statistics(struct rpc_task *task)
  */
 void rpc_exit_task(struct rpc_task *task)
 {
+	trace_rpc_task_end(task, task->tk_action);
 	task->tk_action = NULL;
+	if (task->tk_ops->rpc_count_stats)
+		task->tk_ops->rpc_count_stats(task, task->tk_calldata);
+	else if (task->tk_client)
+		rpc_count_iostats(task, task->tk_client->cl_metrics);
 	if (task->tk_ops->rpc_call_done != NULL) {
+		trace_rpc_task_call_done(task, task->tk_ops->rpc_call_done);
 		task->tk_ops->rpc_call_done(task, task->tk_calldata);
 		if (task->tk_action != NULL) {
-			WARN_ON(RPC_ASSASSINATED(task));
 			/* Always release the RPC slot and buffer memory */
 			xprt_release(task);
 			rpc_reset_task_statistics(task);
@@ -780,12 +854,37 @@ void rpc_exit_task(struct rpc_task *task)
 	}
 }
 
+void rpc_signal_task(struct rpc_task *task)
+{
+	struct rpc_wait_queue *queue;
+
+	if (!RPC_IS_ACTIVATED(task))
+		return;
+
+	if (!rpc_task_set_rpc_status(task, -ERESTARTSYS))
+		return;
+	trace_rpc_task_signalled(task, task->tk_action);
+	queue = READ_ONCE(task->tk_waitqueue);
+	if (queue)
+		rpc_wake_up_queued_task(queue, task);
+}
+
+void rpc_task_try_cancel(struct rpc_task *task, int error)
+{
+	struct rpc_wait_queue *queue;
+
+	if (!rpc_task_set_rpc_status(task, error))
+		return;
+	queue = READ_ONCE(task->tk_waitqueue);
+	if (queue)
+		rpc_wake_up_queued_task(queue, task);
+}
+
 void rpc_exit(struct rpc_task *task, int status)
 {
 	task->tk_status = status;
 	task->tk_action = rpc_exit_task;
-	if (RPC_IS_QUEUED(task))
-		rpc_wake_up_queued_task(task->tk_waitqueue, task);
+	rpc_wake_up_queued_task(task->tk_waitqueue, task);
 }
 EXPORT_SYMBOL_GPL(rpc_exit);
 
@@ -795,6 +894,15 @@ void rpc_release_calldata(const struct rpc_call_ops *ops, void *calldata)
 		ops->rpc_release(calldata);
 }
 
+static bool xprt_needs_memalloc(struct rpc_xprt *xprt, struct rpc_task *tk)
+{
+	if (!xprt)
+		return false;
+	if (!atomic_read(&xprt->swapper))
+		return false;
+	return test_bit(XPRT_LOCKED, &xprt->state) && xprt->snd_task == tk;
+}
+
 /*
  * This is the RPC `scheduler' (or rather, the finite state machine).
  */
@@ -803,9 +911,7 @@ static void __rpc_execute(struct rpc_task *task)
 	struct rpc_wait_queue *queue;
 	int task_is_async = RPC_IS_ASYNC(task);
 	int status = 0;
-
-	dprintk("RPC: %5u __rpc_execute flags=0x%x\n",
-			task->tk_pid, task->tk_flags);
+	unsigned long pflags = current->flags;
 
 	WARN_ON_ONCE(RPC_IS_QUEUED(task));
 	if (RPC_IS_QUEUED(task))
@@ -818,24 +924,36 @@ static void __rpc_execute(struct rpc_task *task)
 		 * Perform the next FSM step or a pending callback.
 		 *
 		 * tk_action may be NULL if the task has been killed.
-		 * In particular, note that rpc_killall_tasks may
-		 * do this at any time, so beware when dereferencing.
 		 */
 		do_action = task->tk_action;
+		/* Tasks with an RPC error status should exit */
+		if (do_action && do_action != rpc_exit_task &&
+		    (status = READ_ONCE(task->tk_rpc_status)) != 0) {
+			task->tk_status = status;
+			do_action = rpc_exit_task;
+		}
+		/* Callbacks override all actions */
 		if (task->tk_callback) {
 			do_action = task->tk_callback;
 			task->tk_callback = NULL;
 		}
 		if (!do_action)
 			break;
+		if (RPC_IS_SWAPPER(task) ||
+		    xprt_needs_memalloc(task->tk_xprt, task))
+			current->flags |= PF_MEMALLOC;
+
 		trace_rpc_task_run_action(task, do_action);
 		do_action(task);
 
 		/*
 		 * Lockless check for whether task is sleeping or not.
 		 */
-		if (!RPC_IS_QUEUED(task))
+		if (!RPC_IS_QUEUED(task)) {
+			cond_resched();
 			continue;
+		}
+
 		/*
 		 * The queue->lock protects against races with
 		 * rpc_make_runnable().
@@ -846,39 +964,43 @@ static void __rpc_execute(struct rpc_task *task)
 		 * rpc_task pointer may still be dereferenced.
 		 */
 		queue = task->tk_waitqueue;
-		spin_lock_bh(&queue->lock);
+		spin_lock(&queue->lock);
 		if (!RPC_IS_QUEUED(task)) {
-			spin_unlock_bh(&queue->lock);
+			spin_unlock(&queue->lock);
+			continue;
+		}
+		/* Wake up any task that has an exit status */
+		if (READ_ONCE(task->tk_rpc_status) != 0) {
+			rpc_wake_up_task_queue_locked(queue, task);
+			spin_unlock(&queue->lock);
 			continue;
 		}
 		rpc_clear_running(task);
-		spin_unlock_bh(&queue->lock);
+		spin_unlock(&queue->lock);
 		if (task_is_async)
-			return;
+			goto out;
 
 		/* sync task: sleep here */
-		dprintk("RPC: %5u sync task going to sleep\n", task->tk_pid);
+		trace_rpc_task_sync_sleep(task, task->tk_action);
 		status = out_of_line_wait_on_bit(&task->tk_runstate,
 				RPC_TASK_QUEUED, rpc_wait_bit_killable,
-				TASK_KILLABLE);
-		if (status == -ERESTARTSYS) {
+				TASK_KILLABLE|TASK_FREEZABLE);
+		if (status < 0) {
 			/*
 			 * When a sync task receives a signal, it exits with
 			 * -ERESTARTSYS. In order to catch any callbacks that
 			 * clean up after sleeping on some queue, we don't
 			 * break the loop here, but go around once more.
 			 */
-			dprintk("RPC: %5u got signal\n", task->tk_pid);
-			task->tk_flags |= RPC_TASK_KILLED;
-			rpc_exit(task, -ERESTARTSYS);
+			rpc_signal_task(task);
 		}
-		dprintk("RPC: %5u sync task resuming\n", task->tk_pid);
+		trace_rpc_task_sync_wake(task, task->tk_action);
 	}
 
-	dprintk("RPC: %5u return %d, status %d\n", task->tk_pid, status,
-			task->tk_status);
 	/* Release all resources associated with the task */
 	rpc_release_task(task);
+out:
+	current_restore_flags(pflags, PF_MEMALLOC);
 }
 
 /*
@@ -896,13 +1018,19 @@ void rpc_execute(struct rpc_task *task)
 
 	rpc_set_active(task);
 	rpc_make_runnable(rpciod_workqueue, task);
-	if (!is_async)
+	if (!is_async) {
+		unsigned int pflags = memalloc_nofs_save();
 		__rpc_execute(task);
+		memalloc_nofs_restore(pflags);
+	}
 }
 
 static void rpc_async_schedule(struct work_struct *work)
 {
+	unsigned int pflags = memalloc_nofs_save();
+
 	__rpc_execute(container_of(work, struct rpc_task, u.tk_work));
+	memalloc_nofs_restore(pflags);
 }
 
 /**
@@ -921,37 +1049,31 @@ static void rpc_async_schedule(struct work_struct *work)
  * Most requests are 'small' (under 2KiB) and can be serviced from a
  * mempool, ensuring that NFS reads and writes can always proceed,
  * and that there is good locality of reference for these buffers.
- *
- * In order to avoid memory starvation triggering more writebacks of
- * NFS requests, we avoid using GFP_KERNEL.
  */
 int rpc_malloc(struct rpc_task *task)
 {
 	struct rpc_rqst *rqst = task->tk_rqstp;
 	size_t size = rqst->rq_callsize + rqst->rq_rcvsize;
 	struct rpc_buffer *buf;
-	gfp_t gfp = GFP_NOIO | __GFP_NOWARN;
-
-	if (RPC_IS_SWAPPER(task))
-		gfp = __GFP_MEMALLOC | GFP_NOWAIT | __GFP_NOWARN;
+	gfp_t gfp = rpc_task_gfp_mask();
 
 	size += sizeof(struct rpc_buffer);
-	if (size <= RPC_BUFFER_MAXSIZE)
-		buf = mempool_alloc(rpc_buffer_mempool, gfp);
-	else
+	if (size <= RPC_BUFFER_MAXSIZE) {
+		buf = kmem_cache_alloc(rpc_buffer_slabp, gfp);
+		/* Reach for the mempool if dynamic allocation fails */
+		if (!buf && RPC_IS_ASYNC(task))
+			buf = mempool_alloc(rpc_buffer_mempool, GFP_NOWAIT);
+	} else
 		buf = kmalloc(size, gfp);
 
 	if (!buf)
 		return -ENOMEM;
 
 	buf->len = size;
-	dprintk("RPC: %5u allocated buffer of size %zu at %p\n",
-			task->tk_pid, size, buf);
 	rqst->rq_buffer = buf->data;
 	rqst->rq_rbuffer = (char *)rqst->rq_buffer + rqst->rq_callsize;
 	return 0;
 }
-EXPORT_SYMBOL_GPL(rpc_malloc);
 
 /**
  * rpc_free - free RPC buffer resources allocated via rpc_malloc
@@ -967,15 +1089,11 @@ void rpc_free(struct rpc_task *task)
 	buf = container_of(buffer, struct rpc_buffer, data);
 	size = buf->len;
 
-	dprintk("RPC:       freeing buffer of size %zu at %p\n",
-			size, buf);
-
 	if (size <= RPC_BUFFER_MAXSIZE)
 		mempool_free(buf, rpc_buffer_mempool);
 	else
 		kfree(buf);
 }
-EXPORT_SYMBOL_GPL(rpc_free);
 
 /*
  * Creation and deletion of RPC task structures
@@ -995,7 +1113,8 @@ static void rpc_init_task(struct rpc_task *task, const struct rpc_task_setup *ta
 	/* Initialize workqueue for async tasks */
 	task->tk_workqueue = task_setup_data->workqueue;
 
-	task->tk_xprt = xprt_get(task_setup_data->rpc_xprt);
+	task->tk_xprt = rpc_task_get_xprt(task_setup_data->rpc_client,
+			xprt_get(task_setup_data->rpc_xprt));
 
 	task->tk_op_cred = get_rpccred(task_setup_data->rpc_op_cred);
 
@@ -1003,15 +1122,16 @@ static void rpc_init_task(struct rpc_task *task, const struct rpc_task_setup *ta
 		task->tk_action = rpc_prepare_task;
 
 	rpc_init_task_statistics(task);
-
-	dprintk("RPC:       new task initialized, procpid %u\n",
-				task_pid_nr(current));
 }
 
-static struct rpc_task *
-rpc_alloc_task(void)
+static struct rpc_task *rpc_alloc_task(void)
 {
-	return (struct rpc_task *)mempool_alloc(rpc_task_mempool, GFP_NOIO);
+	struct rpc_task *task;
+
+	task = kmem_cache_alloc(rpc_task_slabp, rpc_task_gfp_mask());
+	if (task)
+		return task;
+	return mempool_alloc(rpc_task_mempool, GFP_NOWAIT);
 }
 
 /*
@@ -1024,12 +1144,16 @@ struct rpc_task *rpc_new_task(const struct rpc_task_setup *setup_data)
 
 	if (task == NULL) {
 		task = rpc_alloc_task();
+		if (task == NULL) {
+			rpc_release_calldata(setup_data->callback_ops,
+					     setup_data->callback_data);
+			return ERR_PTR(-ENOMEM);
+		}
 		flags = RPC_TASK_DYNAMIC;
 	}
 
 	rpc_init_task(task, setup_data);
 	task->tk_flags |= flags;
-	dprintk("RPC:       allocated task %p\n", task);
 	return task;
 }
 
@@ -1059,22 +1183,24 @@ static void rpc_free_task(struct rpc_task *task)
 	put_rpccred(task->tk_op_cred);
 	rpc_release_calldata(task->tk_ops, task->tk_calldata);
 
-	if (tk_flags & RPC_TASK_DYNAMIC) {
-		dprintk("RPC: %5u freeing task\n", task->tk_pid);
+	if (tk_flags & RPC_TASK_DYNAMIC)
 		mempool_free(task, rpc_task_mempool);
-	}
 }
 
 static void rpc_async_release(struct work_struct *work)
 {
+	unsigned int pflags = memalloc_nofs_save();
+
 	rpc_free_task(container_of(work, struct rpc_task, u.tk_work));
+	memalloc_nofs_restore(pflags);
 }
 
 static void rpc_release_resources_task(struct rpc_task *task)
 {
 	xprt_release(task);
 	if (task->tk_msg.rpc_cred) {
-		put_cred(task->tk_msg.rpc_cred);
+		if (!(task->tk_flags & RPC_TASK_CRED_NOREF))
+			put_cred(task->tk_msg.rpc_cred);
 		task->tk_msg.rpc_cred = NULL;
 	}
 	rpc_task_release_client(task);
@@ -1112,8 +1238,6 @@ EXPORT_SYMBOL_GPL(rpc_put_task_async);
 
 static void rpc_release_task(struct rpc_task *task)
 {
-	dprintk("RPC: %5u release task\n", task->tk_pid);
-
 	WARN_ON_ONCE(RPC_IS_QUEUED(task));
 
 	rpc_release_resources_task(task);
@@ -1154,13 +1278,11 @@ static int rpciod_start(void)
 	/*
 	 * Create the rpciod thread and wait for it to start.
 	 */
-	dprintk("RPC:       creating workqueue rpciod\n");
 	wq = alloc_workqueue("rpciod", WQ_MEM_RECLAIM | WQ_UNBOUND, 0);
 	if (!wq)
 		goto out_failed;
 	rpciod_workqueue = wq;
-	/* Note: highpri because network receive is latency sensitive */
-	wq = alloc_workqueue("xprtiod", WQ_UNBOUND|WQ_MEM_RECLAIM|WQ_HIGHPRI, 0);
+	wq = alloc_workqueue("xprtiod", WQ_UNBOUND | WQ_MEM_RECLAIM, 0);
 	if (!wq)
 		goto free_rpciod;
 	xprtiod_workqueue = wq;
@@ -1179,7 +1301,6 @@ static void rpciod_stop(void)
 
 	if (rpciod_workqueue == NULL)
 		return;
-	dprintk("RPC:       destroying workqueue rpciod\n");
 
 	wq = rpciod_workqueue;
 	rpciod_workqueue = NULL;