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-rw-r--r--block/blk-core.c83
-rw-r--r--block/blk-exec.c2
-rw-r--r--block/blk-flush.c4
-rw-r--r--block/blk-settings.c16
-rw-r--r--block/blk.h1
-rw-r--r--block/cfq-iosched.c6
-rw-r--r--block/elevator.c4
7 files changed, 74 insertions, 42 deletions
diff --git a/block/blk-core.c b/block/blk-core.c
index 78b7b0cb721..5fa3dd2705c 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -204,7 +204,7 @@ static void blk_delay_work(struct work_struct *work)
q = container_of(work, struct request_queue, delay_work.work);
spin_lock_irq(q->queue_lock);
- __blk_run_queue(q, false);
+ __blk_run_queue(q);
spin_unlock_irq(q->queue_lock);
}
@@ -220,7 +220,8 @@ static void blk_delay_work(struct work_struct *work)
*/
void blk_delay_queue(struct request_queue *q, unsigned long msecs)
{
- schedule_delayed_work(&q->delay_work, msecs_to_jiffies(msecs));
+ queue_delayed_work(kblockd_workqueue, &q->delay_work,
+ msecs_to_jiffies(msecs));
}
EXPORT_SYMBOL(blk_delay_queue);
@@ -238,7 +239,7 @@ void blk_start_queue(struct request_queue *q)
WARN_ON(!irqs_disabled());
queue_flag_clear(QUEUE_FLAG_STOPPED, q);
- __blk_run_queue(q, false);
+ __blk_run_queue(q);
}
EXPORT_SYMBOL(blk_start_queue);
@@ -296,9 +297,8 @@ EXPORT_SYMBOL(blk_sync_queue);
* Description:
* See @blk_run_queue. This variant must be called with the queue lock
* held and interrupts disabled.
- *
*/
-void __blk_run_queue(struct request_queue *q, bool force_kblockd)
+void __blk_run_queue(struct request_queue *q)
{
if (unlikely(blk_queue_stopped(q)))
return;
@@ -307,7 +307,7 @@ void __blk_run_queue(struct request_queue *q, bool force_kblockd)
* Only recurse once to avoid overrunning the stack, let the unplug
* handling reinvoke the handler shortly if we already got there.
*/
- if (!force_kblockd && !queue_flag_test_and_set(QUEUE_FLAG_REENTER, q)) {
+ if (!queue_flag_test_and_set(QUEUE_FLAG_REENTER, q)) {
q->request_fn(q);
queue_flag_clear(QUEUE_FLAG_REENTER, q);
} else
@@ -316,6 +316,20 @@ void __blk_run_queue(struct request_queue *q, bool force_kblockd)
EXPORT_SYMBOL(__blk_run_queue);
/**
+ * blk_run_queue_async - run a single device queue in workqueue context
+ * @q: The queue to run
+ *
+ * Description:
+ * Tells kblockd to perform the equivalent of @blk_run_queue on behalf
+ * of us.
+ */
+void blk_run_queue_async(struct request_queue *q)
+{
+ if (likely(!blk_queue_stopped(q)))
+ queue_delayed_work(kblockd_workqueue, &q->delay_work, 0);
+}
+
+/**
* blk_run_queue - run a single device queue
* @q: The queue to run
*
@@ -328,7 +342,7 @@ void blk_run_queue(struct request_queue *q)
unsigned long flags;
spin_lock_irqsave(q->queue_lock, flags);
- __blk_run_queue(q, false);
+ __blk_run_queue(q);
spin_unlock_irqrestore(q->queue_lock, flags);
}
EXPORT_SYMBOL(blk_run_queue);
@@ -977,7 +991,7 @@ void blk_insert_request(struct request_queue *q, struct request *rq,
blk_queue_end_tag(q, rq);
add_acct_request(q, rq, where);
- __blk_run_queue(q, false);
+ __blk_run_queue(q);
spin_unlock_irqrestore(q->queue_lock, flags);
}
EXPORT_SYMBOL(blk_insert_request);
@@ -1321,7 +1335,7 @@ get_rq:
} else {
spin_lock_irq(q->queue_lock);
add_acct_request(q, req, where);
- __blk_run_queue(q, false);
+ __blk_run_queue(q);
out_unlock:
spin_unlock_irq(q->queue_lock);
}
@@ -2638,6 +2652,7 @@ void blk_start_plug(struct blk_plug *plug)
plug->magic = PLUG_MAGIC;
INIT_LIST_HEAD(&plug->list);
+ INIT_LIST_HEAD(&plug->cb_list);
plug->should_sort = 0;
/*
@@ -2670,12 +2685,41 @@ static int plug_rq_cmp(void *priv, struct list_head *a, struct list_head *b)
*/
static void queue_unplugged(struct request_queue *q, unsigned int depth,
bool from_schedule)
+ __releases(q->queue_lock)
{
trace_block_unplug(q, depth, !from_schedule);
- __blk_run_queue(q, from_schedule);
- if (q->unplugged_fn)
- q->unplugged_fn(q);
+ /*
+ * 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);
+ blk_run_queue_async(q);
+ } else {
+ __blk_run_queue(q);
+ spin_unlock(q->queue_lock);
+ }
+
+}
+
+static void flush_plug_callbacks(struct blk_plug *plug)
+{
+ LIST_HEAD(callbacks);
+
+ if (list_empty(&plug->cb_list))
+ return;
+
+ list_splice_init(&plug->cb_list, &callbacks);
+
+ while (!list_empty(&callbacks)) {
+ struct blk_plug_cb *cb = list_first_entry(&callbacks,
+ struct blk_plug_cb,
+ list);
+ list_del(&cb->list);
+ cb->callback(cb);
+ }
}
void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
@@ -2688,6 +2732,7 @@ void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
BUG_ON(plug->magic != PLUG_MAGIC);
+ flush_plug_callbacks(plug);
if (list_empty(&plug->list))
return;
@@ -2712,10 +2757,11 @@ void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
BUG_ON(!(rq->cmd_flags & REQ_ON_PLUG));
BUG_ON(!rq->q);
if (rq->q != q) {
- if (q) {
+ /*
+ * This drops the queue lock
+ */
+ if (q)
queue_unplugged(q, depth, from_schedule);
- spin_unlock(q->queue_lock);
- }
q = rq->q;
depth = 0;
spin_lock(q->queue_lock);
@@ -2733,10 +2779,11 @@ void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
depth++;
}
- if (q) {
+ /*
+ * This drops the queue lock
+ */
+ if (q)
queue_unplugged(q, depth, from_schedule);
- spin_unlock(q->queue_lock);
- }
local_irq_restore(flags);
}
diff --git a/block/blk-exec.c b/block/blk-exec.c
index 7482b7fa863..81e31819a59 100644
--- a/block/blk-exec.c
+++ b/block/blk-exec.c
@@ -55,7 +55,7 @@ void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk,
WARN_ON(irqs_disabled());
spin_lock_irq(q->queue_lock);
__elv_add_request(q, rq, where);
- __blk_run_queue(q, false);
+ __blk_run_queue(q);
/* the queue is stopped so it won't be plugged+unplugged */
if (rq->cmd_type == REQ_TYPE_PM_RESUME)
q->request_fn(q);
diff --git a/block/blk-flush.c b/block/blk-flush.c
index eba4a2790c6..6c9b5e189e6 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -218,7 +218,7 @@ static void flush_end_io(struct request *flush_rq, int error)
* request_fn may confuse the driver. Always use kblockd.
*/
if (queued)
- __blk_run_queue(q, true);
+ blk_run_queue_async(q);
}
/**
@@ -274,7 +274,7 @@ static void flush_data_end_io(struct request *rq, int error)
* the comment in flush_end_io().
*/
if (blk_flush_complete_seq(rq, REQ_FSEQ_DATA, error))
- __blk_run_queue(q, true);
+ blk_run_queue_async(q);
}
/**
diff --git a/block/blk-settings.c b/block/blk-settings.c
index eb949045bb1..1fa76929359 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -790,22 +790,6 @@ void blk_queue_flush(struct request_queue *q, unsigned int flush)
}
EXPORT_SYMBOL_GPL(blk_queue_flush);
-/**
- * blk_queue_unplugged - register a callback for an unplug event
- * @q: the request queue for the device
- * @fn: the function to call
- *
- * Some stacked drivers may need to know when IO is dispatched on an
- * unplug event. By registrering a callback here, they will be notified
- * when someone flushes their on-stack queue plug. The function will be
- * called with the queue lock held.
- */
-void blk_queue_unplugged(struct request_queue *q, unplugged_fn *fn)
-{
- q->unplugged_fn = fn;
-}
-EXPORT_SYMBOL(blk_queue_unplugged);
-
static int __init blk_settings_init(void)
{
blk_max_low_pfn = max_low_pfn - 1;
diff --git a/block/blk.h b/block/blk.h
index 61263463e38..c9df8fc3c99 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -22,6 +22,7 @@ void blk_rq_timed_out_timer(unsigned long data);
void blk_delete_timer(struct request *);
void blk_add_timer(struct request *);
void __generic_unplug_device(struct request_queue *);
+void blk_run_queue_async(struct request_queue *q);
/*
* Internal atomic flags for request handling
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 3be881ec95a..46b0a1d1d92 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -3368,7 +3368,7 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
cfqd->busy_queues > 1) {
cfq_del_timer(cfqd, cfqq);
cfq_clear_cfqq_wait_request(cfqq);
- __blk_run_queue(cfqd->queue, false);
+ __blk_run_queue(cfqd->queue);
} else {
cfq_blkiocg_update_idle_time_stats(
&cfqq->cfqg->blkg);
@@ -3383,7 +3383,7 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
* this new queue is RT and the current one is BE
*/
cfq_preempt_queue(cfqd, cfqq);
- __blk_run_queue(cfqd->queue, false);
+ __blk_run_queue(cfqd->queue);
}
}
@@ -3743,7 +3743,7 @@ static void cfq_kick_queue(struct work_struct *work)
struct request_queue *q = cfqd->queue;
spin_lock_irq(q->queue_lock);
- __blk_run_queue(cfqd->queue, false);
+ __blk_run_queue(cfqd->queue);
spin_unlock_irq(q->queue_lock);
}
diff --git a/block/elevator.c b/block/elevator.c
index 0cdb4e7ebab..6f6abc08bb5 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -642,7 +642,7 @@ void elv_quiesce_start(struct request_queue *q)
*/
elv_drain_elevator(q);
while (q->rq.elvpriv) {
- __blk_run_queue(q, false);
+ __blk_run_queue(q);
spin_unlock_irq(q->queue_lock);
msleep(10);
spin_lock_irq(q->queue_lock);
@@ -695,7 +695,7 @@ void __elv_add_request(struct request_queue *q, struct request *rq, int where)
* with anything. There's no point in delaying queue
* processing.
*/
- __blk_run_queue(q, false);
+ __blk_run_queue(q);
break;
case ELEVATOR_INSERT_SORT_MERGE: