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Diffstat (limited to 'block/blk-core.c')
-rw-r--r--block/blk-core.c127
1 files changed, 76 insertions, 51 deletions
diff --git a/block/blk-core.c b/block/blk-core.c
index 3c95c4d6e31..c973249d68c 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -40,6 +40,7 @@
EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap);
EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete);
+EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug);
DEFINE_IDA(blk_queue_ida);
@@ -219,12 +220,13 @@ static void blk_delay_work(struct work_struct *work)
* Description:
* Sometimes queueing needs to be postponed for a little while, to allow
* resources to come back. This function will make sure that queueing is
- * restarted around the specified time.
+ * restarted around the specified time. Queue lock must be held.
*/
void blk_delay_queue(struct request_queue *q, unsigned long msecs)
{
- queue_delayed_work(kblockd_workqueue, &q->delay_work,
- msecs_to_jiffies(msecs));
+ if (likely(!blk_queue_dead(q)))
+ queue_delayed_work(kblockd_workqueue, &q->delay_work,
+ msecs_to_jiffies(msecs));
}
EXPORT_SYMBOL(blk_delay_queue);
@@ -293,6 +295,34 @@ void blk_sync_queue(struct request_queue *q)
EXPORT_SYMBOL(blk_sync_queue);
/**
+ * __blk_run_queue_uncond - run a queue whether or not it has been stopped
+ * @q: The queue to run
+ *
+ * Description:
+ * Invoke request handling on a queue if there are any pending requests.
+ * May be used to restart request handling after a request has completed.
+ * This variant runs the queue whether or not the queue has been
+ * stopped. Must be called with the queue lock held and interrupts
+ * disabled. See also @blk_run_queue.
+ */
+inline void __blk_run_queue_uncond(struct request_queue *q)
+{
+ if (unlikely(blk_queue_dead(q)))
+ return;
+
+ /*
+ * Some request_fn implementations, e.g. scsi_request_fn(), unlock
+ * the queue lock internally. As a result multiple threads may be
+ * running such a request function concurrently. Keep track of the
+ * number of active request_fn invocations such that blk_drain_queue()
+ * can wait until all these request_fn calls have finished.
+ */
+ q->request_fn_active++;
+ q->request_fn(q);
+ q->request_fn_active--;
+}
+
+/**
* __blk_run_queue - run a single device queue
* @q: The queue to run
*
@@ -305,7 +335,7 @@ void __blk_run_queue(struct request_queue *q)
if (unlikely(blk_queue_stopped(q)))
return;
- q->request_fn(q);
+ __blk_run_queue_uncond(q);
}
EXPORT_SYMBOL(__blk_run_queue);
@@ -315,11 +345,11 @@ EXPORT_SYMBOL(__blk_run_queue);
*
* Description:
* Tells kblockd to perform the equivalent of @blk_run_queue on behalf
- * of us.
+ * of us. The caller must hold the queue lock.
*/
void blk_run_queue_async(struct request_queue *q)
{
- if (likely(!blk_queue_stopped(q)))
+ if (likely(!blk_queue_stopped(q) && !blk_queue_dead(q)))
mod_delayed_work(kblockd_workqueue, &q->delay_work, 0);
}
EXPORT_SYMBOL(blk_run_queue_async);
@@ -349,7 +379,7 @@ void blk_put_queue(struct request_queue *q)
EXPORT_SYMBOL(blk_put_queue);
/**
- * blk_drain_queue - drain requests from request_queue
+ * __blk_drain_queue - drain requests from request_queue
* @q: queue to drain
* @drain_all: whether to drain all requests or only the ones w/ ELVPRIV
*
@@ -357,15 +387,17 @@ EXPORT_SYMBOL(blk_put_queue);
* If not, only ELVPRIV requests are drained. The caller is responsible
* for ensuring that no new requests which need to be drained are queued.
*/
-void blk_drain_queue(struct request_queue *q, bool drain_all)
+static void __blk_drain_queue(struct request_queue *q, bool drain_all)
+ __releases(q->queue_lock)
+ __acquires(q->queue_lock)
{
int i;
+ lockdep_assert_held(q->queue_lock);
+
while (true) {
bool drain = false;
- spin_lock_irq(q->queue_lock);
-
/*
* The caller might be trying to drain @q before its
* elevator is initialized.
@@ -386,6 +418,7 @@ void blk_drain_queue(struct request_queue *q, bool drain_all)
__blk_run_queue(q);
drain |= q->nr_rqs_elvpriv;
+ drain |= q->request_fn_active;
/*
* Unfortunately, requests are queued at and tracked from
@@ -401,11 +434,14 @@ void blk_drain_queue(struct request_queue *q, bool drain_all)
}
}
- spin_unlock_irq(q->queue_lock);
-
if (!drain)
break;
+
+ spin_unlock_irq(q->queue_lock);
+
msleep(10);
+
+ spin_lock_irq(q->queue_lock);
}
/*
@@ -416,13 +452,9 @@ void blk_drain_queue(struct request_queue *q, bool drain_all)
if (q->request_fn) {
struct request_list *rl;
- spin_lock_irq(q->queue_lock);
-
blk_queue_for_each_rl(rl, q)
for (i = 0; i < ARRAY_SIZE(rl->wait); i++)
wake_up_all(&rl->wait[i]);
-
- spin_unlock_irq(q->queue_lock);
}
}
@@ -446,7 +478,10 @@ void blk_queue_bypass_start(struct request_queue *q)
spin_unlock_irq(q->queue_lock);
if (drain) {
- blk_drain_queue(q, false);
+ spin_lock_irq(q->queue_lock);
+ __blk_drain_queue(q, false);
+ spin_unlock_irq(q->queue_lock);
+
/* ensure blk_queue_bypass() is %true inside RCU read lock */
synchronize_rcu();
}
@@ -473,20 +508,20 @@ EXPORT_SYMBOL_GPL(blk_queue_bypass_end);
* blk_cleanup_queue - shutdown a request queue
* @q: request queue to shutdown
*
- * Mark @q DEAD, drain all pending requests, destroy and put it. All
- * future requests will be failed immediately with -ENODEV.
+ * Mark @q DYING, drain all pending requests, mark @q DEAD, destroy and
+ * put it. All future requests will be failed immediately with -ENODEV.
*/
void blk_cleanup_queue(struct request_queue *q)
{
spinlock_t *lock = q->queue_lock;
- /* mark @q DEAD, no new request or merges will be allowed afterwards */
+ /* mark @q DYING, no new request or merges will be allowed afterwards */
mutex_lock(&q->sysfs_lock);
- queue_flag_set_unlocked(QUEUE_FLAG_DEAD, q);
+ queue_flag_set_unlocked(QUEUE_FLAG_DYING, q);
spin_lock_irq(lock);
/*
- * Dead queue is permanently in bypass mode till released. Note
+ * A dying queue is permanently in bypass mode till released. Note
* that, unlike blk_queue_bypass_start(), we aren't performing
* synchronize_rcu() after entering bypass mode to avoid the delay
* as some drivers create and destroy a lot of queues while
@@ -499,12 +534,18 @@ void blk_cleanup_queue(struct request_queue *q)
queue_flag_set(QUEUE_FLAG_NOMERGES, q);
queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
- queue_flag_set(QUEUE_FLAG_DEAD, q);
+ queue_flag_set(QUEUE_FLAG_DYING, q);
spin_unlock_irq(lock);
mutex_unlock(&q->sysfs_lock);
- /* drain all requests queued before DEAD marking */
- blk_drain_queue(q, true);
+ /*
+ * Drain all requests queued before DYING marking. Set DEAD flag to
+ * prevent that q->request_fn() gets invoked after draining finished.
+ */
+ spin_lock_irq(lock);
+ __blk_drain_queue(q, true);
+ queue_flag_set(QUEUE_FLAG_DEAD, q);
+ spin_unlock_irq(lock);
/* @q won't process any more request, flush async actions */
del_timer_sync(&q->backing_dev_info.laptop_mode_wb_timer);
@@ -549,7 +590,7 @@ void blk_exit_rl(struct request_list *rl)
struct request_queue *blk_alloc_queue(gfp_t gfp_mask)
{
- return blk_alloc_queue_node(gfp_mask, -1);
+ return blk_alloc_queue_node(gfp_mask, NUMA_NO_NODE);
}
EXPORT_SYMBOL(blk_alloc_queue);
@@ -660,7 +701,7 @@ EXPORT_SYMBOL(blk_alloc_queue_node);
struct request_queue *blk_init_queue(request_fn_proc *rfn, spinlock_t *lock)
{
- return blk_init_queue_node(rfn, lock, -1);
+ return blk_init_queue_node(rfn, lock, NUMA_NO_NODE);
}
EXPORT_SYMBOL(blk_init_queue);
@@ -716,7 +757,7 @@ EXPORT_SYMBOL(blk_init_allocated_queue);
bool blk_get_queue(struct request_queue *q)
{
- if (likely(!blk_queue_dead(q))) {
+ if (likely(!blk_queue_dying(q))) {
__blk_get_queue(q);
return true;
}
@@ -870,7 +911,7 @@ static struct request *__get_request(struct request_list *rl, int rw_flags,
const bool is_sync = rw_is_sync(rw_flags) != 0;
int may_queue;
- if (unlikely(blk_queue_dead(q)))
+ if (unlikely(blk_queue_dying(q)))
return NULL;
may_queue = elv_may_queue(q, rw_flags);
@@ -1050,7 +1091,7 @@ retry:
if (rq)
return rq;
- if (!(gfp_mask & __GFP_WAIT) || unlikely(blk_queue_dead(q))) {
+ if (!(gfp_mask & __GFP_WAIT) || unlikely(blk_queue_dying(q))) {
blk_put_rl(rl);
return NULL;
}
@@ -1910,7 +1951,7 @@ int blk_insert_cloned_request(struct request_queue *q, struct request *rq)
return -EIO;
spin_lock_irqsave(q->queue_lock, flags);
- if (unlikely(blk_queue_dead(q))) {
+ if (unlikely(blk_queue_dying(q))) {
spin_unlock_irqrestore(q->queue_lock, flags);
return -ENODEV;
}
@@ -2884,27 +2925,11 @@ static void queue_unplugged(struct request_queue *q, unsigned int depth,
{
trace_block_unplug(q, depth, !from_schedule);
- /*
- * Don't mess with dead queue.
- */
- if (unlikely(blk_queue_dead(q))) {
- spin_unlock(q->queue_lock);
- return;
- }
-
- /*
- * If we are punting this to kblockd, then we can safely drop
- * the queue_lock before waking kblockd (which needs to take
- * this lock).
- */
- if (from_schedule) {
- spin_unlock(q->queue_lock);
+ if (from_schedule)
blk_run_queue_async(q);
- } else {
+ else
__blk_run_queue(q);
- spin_unlock(q->queue_lock);
- }
-
+ spin_unlock(q->queue_lock);
}
static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule)
@@ -2996,7 +3021,7 @@ void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
/*
* Short-circuit if @q is dead
*/
- if (unlikely(blk_queue_dead(q))) {
+ if (unlikely(blk_queue_dying(q))) {
__blk_end_request_all(rq, -ENODEV);
continue;
}