Callers may use this counter to optimize flushes
Signed-off-by: Dmitry Monakhov <dmonak...@openvz.org>
---
block/blk-core.c | 1 +
block/blk-flush.c | 3 ++-
include/linux/blkdev.h | 1 +
3 files changed, 4 insertions(+), 1 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index 074b758..afb5a4b 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -537,6 +537,7 @@ void blk_cleanup_queue(struct request_queue *q)
spin_unlock_irq(lock);
mutex_unlock(&q->sysfs_lock);
+ atomic_set(&q->flush_tag, 0);
/*
* Drain all requests queued before DYING marking. Set DEAD flag to
* prevent that q->request_fn() gets invoked after draining finished.
diff --git a/block/blk-flush.c b/block/blk-flush.c
index cc2b827..b1adc75 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -203,7 +203,7 @@ static void flush_end_io(struct request *flush_rq, int
error)
/* account completion of the flush request */
q->flush_running_idx ^= 1;
elv_completed_request(q, flush_rq);
-
+ atomic_inc(&q->flush_tag);
/* and push the waiting requests to the next stage */
list_for_each_entry_safe(rq, n, running, flush.list) {
unsigned int seq = blk_flush_cur_seq(rq);
@@ -268,6 +268,7 @@ static bool blk_kick_flush(struct request_queue *q)
q->flush_rq.end_io = flush_end_io;
q->flush_pending_idx ^= 1;
+ atomic_inc(&q->flush_tag);
list_add_tail(&q->flush_rq.queuelist, &q->queue_head);
return true;
}
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 78feda9..e079fbd 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -416,6 +416,7 @@ struct request_queue {
unsigned int flush_queue_delayed:1;
unsigned int flush_pending_idx:1;
unsigned int flush_running_idx:1;
+ atomic_t flush_tag;
unsigned long flush_pending_since;
struct list_head flush_queue[2];
struct list_head flush_data_in_flight;
--
1.7.1
--
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