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-rw-r--r--net/sunrpc/sched.c101
1 files changed, 67 insertions, 34 deletions
diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index 6357fcb..bfa3171 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -98,6 +98,23 @@ __rpc_add_timer(struct rpc_wait_queue *queue, struct rpc_task *task)
list_add(&task->u.tk_wait.timer_list, &queue->timer_list.list);
}
+static void rpc_set_waitqueue_priority(struct rpc_wait_queue *queue, int priority)
+{
+ queue->priority = priority;
+}
+
+static void rpc_set_waitqueue_owner(struct rpc_wait_queue *queue, pid_t pid)
+{
+ queue->owner = pid;
+ queue->nr = RPC_BATCH_COUNT;
+}
+
+static void rpc_reset_waitqueue_priority(struct rpc_wait_queue *queue)
+{
+ rpc_set_waitqueue_priority(queue, queue->maxpriority);
+ rpc_set_waitqueue_owner(queue, 0);
+}
+
/*
* Add new request to a priority queue.
*/
@@ -109,9 +126,11 @@ static void __rpc_add_wait_queue_priority(struct rpc_wait_queue *queue,
struct rpc_task *t;
INIT_LIST_HEAD(&task->u.tk_wait.links);
- q = &queue->tasks[queue_priority];
if (unlikely(queue_priority > queue->maxpriority))
- q = &queue->tasks[queue->maxpriority];
+ queue_priority = queue->maxpriority;
+ if (queue_priority > queue->priority)
+ rpc_set_waitqueue_priority(queue, queue_priority);
+ q = &queue->tasks[queue_priority];
list_for_each_entry(t, q, u.tk_wait.list) {
if (t->tk_owner == task->tk_owner) {
list_add_tail(&task->u.tk_wait.list, &t->u.tk_wait.links);
@@ -133,7 +152,9 @@ static void __rpc_add_wait_queue(struct rpc_wait_queue *queue,
struct rpc_task *task,
unsigned char queue_priority)
{
- BUG_ON (RPC_IS_QUEUED(task));
+ WARN_ON_ONCE(RPC_IS_QUEUED(task));
+ if (RPC_IS_QUEUED(task))
+ return;
if (RPC_IS_PRIORITY(queue))
__rpc_add_wait_queue_priority(queue, task, queue_priority);
@@ -178,24 +199,6 @@ static void __rpc_remove_wait_queue(struct rpc_wait_queue *queue, struct rpc_tas
task->tk_pid, queue, rpc_qname(queue));
}
-static inline void rpc_set_waitqueue_priority(struct rpc_wait_queue *queue, int priority)
-{
- queue->priority = priority;
- queue->count = 1 << (priority * 2);
-}
-
-static inline void rpc_set_waitqueue_owner(struct rpc_wait_queue *queue, pid_t pid)
-{
- queue->owner = pid;
- queue->nr = RPC_BATCH_COUNT;
-}
-
-static inline void rpc_reset_waitqueue_priority(struct rpc_wait_queue *queue)
-{
- rpc_set_waitqueue_priority(queue, queue->maxpriority);
- rpc_set_waitqueue_owner(queue, 0);
-}
-
static void __rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const char *qname, unsigned char nr_queues)
{
int i;
@@ -334,7 +337,7 @@ static void __rpc_sleep_on_priority(struct rpc_wait_queue *q,
__rpc_add_wait_queue(q, task, queue_priority);
- BUG_ON(task->tk_callback != NULL);
+ WARN_ON_ONCE(task->tk_callback != NULL);
task->tk_callback = action;
__rpc_add_timer(q, task);
}
@@ -343,7 +346,12 @@ void rpc_sleep_on(struct rpc_wait_queue *q, struct rpc_task *task,
rpc_action action)
{
/* We shouldn't ever put an inactive task to sleep */
- BUG_ON(!RPC_IS_ACTIVATED(task));
+ WARN_ON_ONCE(!RPC_IS_ACTIVATED(task));
+ if (!RPC_IS_ACTIVATED(task)) {
+ task->tk_status = -EIO;
+ rpc_put_task_async(task);
+ return;
+ }
/*
* Protect the queue operations.
@@ -358,7 +366,12 @@ void rpc_sleep_on_priority(struct rpc_wait_queue *q, struct rpc_task *task,
rpc_action action, int priority)
{
/* We shouldn't ever put an inactive task to sleep */
- BUG_ON(!RPC_IS_ACTIVATED(task));
+ WARN_ON_ONCE(!RPC_IS_ACTIVATED(task));
+ if (!RPC_IS_ACTIVATED(task)) {
+ task->tk_status = -EIO;
+ rpc_put_task_async(task);
+ return;
+ }
/*
* Protect the queue operations.
@@ -367,6 +380,7 @@ void rpc_sleep_on_priority(struct rpc_wait_queue *q, struct rpc_task *task,
__rpc_sleep_on_priority(q, task, action, priority - RPC_PRIORITY_LOW);
spin_unlock_bh(&q->lock);
}
+EXPORT_SYMBOL_GPL(rpc_sleep_on_priority);
/**
* __rpc_do_wake_up_task - wake up a single rpc_task
@@ -451,8 +465,7 @@ static struct rpc_task *__rpc_find_next_queued_priority(struct rpc_wait_queue *q
/*
* Check if we need to switch queues.
*/
- if (--queue->count)
- goto new_owner;
+ goto new_owner;
}
/*
@@ -697,7 +710,9 @@ static void __rpc_execute(struct rpc_task *task)
dprintk("RPC: %5u __rpc_execute flags=0x%x\n",
task->tk_pid, task->tk_flags);
- BUG_ON(RPC_IS_QUEUED(task));
+ WARN_ON_ONCE(RPC_IS_QUEUED(task));
+ if (RPC_IS_QUEUED(task))
+ return;
for (;;) {
void (*do_action)(struct rpc_task *);
@@ -919,16 +934,35 @@ struct rpc_task *rpc_new_task(const struct rpc_task_setup *setup_data)
return task;
}
+/*
+ * rpc_free_task - release rpc task and perform cleanups
+ *
+ * Note that we free up the rpc_task _after_ rpc_release_calldata()
+ * in order to work around a workqueue dependency issue.
+ *
+ * Tejun Heo states:
+ * "Workqueue currently considers two work items to be the same if they're
+ * on the same address and won't execute them concurrently - ie. it
+ * makes a work item which is queued again while being executed wait
+ * for the previous execution to complete.
+ *
+ * If a work function frees the work item, and then waits for an event
+ * which should be performed by another work item and *that* work item
+ * recycles the freed work item, it can create a false dependency loop.
+ * There really is no reliable way to detect this short of verifying
+ * every memory free."
+ *
+ */
static void rpc_free_task(struct rpc_task *task)
{
- const struct rpc_call_ops *tk_ops = task->tk_ops;
- void *calldata = task->tk_calldata;
+ unsigned short tk_flags = task->tk_flags;
+
+ rpc_release_calldata(task->tk_ops, task->tk_calldata);
- if (task->tk_flags & RPC_TASK_DYNAMIC) {
+ if (tk_flags & RPC_TASK_DYNAMIC) {
dprintk("RPC: %5u freeing task\n", task->tk_pid);
mempool_free(task, rpc_task_mempool);
}
- rpc_release_calldata(tk_ops, calldata);
}
static void rpc_async_release(struct work_struct *work)
@@ -938,8 +972,7 @@ static void rpc_async_release(struct work_struct *work)
static void rpc_release_resources_task(struct rpc_task *task)
{
- if (task->tk_rqstp)
- xprt_release(task);
+ xprt_release(task);
if (task->tk_msg.rpc_cred) {
put_rpccred(task->tk_msg.rpc_cred);
task->tk_msg.rpc_cred = NULL;
@@ -981,7 +1014,7 @@ static void rpc_release_task(struct rpc_task *task)
{
dprintk("RPC: %5u release task\n", task->tk_pid);
- BUG_ON (RPC_IS_QUEUED(task));
+ WARN_ON_ONCE(RPC_IS_QUEUED(task));
rpc_release_resources_task(task);
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