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| author |   Ming Lei <ming.lei@redhat.com> | 2017-06-18 14:24:27 -0600 |
|---|---|---|
| committer |   Jens Axboe <axboe@kernel.dk> | 2017-06-18 14:24:27 -0600 |
| commit | f4560ffe8cec1361b1021d81aca6a4173f8e7c87 (patch) | |
| tree | 957cae770ed234d2e03fef8a6e458296f011369e /include/linux/blkdev.h | |
| parent | blk-mq: use the introduced blk_mq_unquiesce_queue() (diff) | |
| download | linux-dev-f4560ffe8cec1361b1021d81aca6a4173f8e7c87.tar.xz linux-dev-f4560ffe8cec1361b1021d81aca6a4173f8e7c87.zip | |
blk-mq: use QUEUE_FLAG_QUIESCED to quiesce queue
It is required that no dispatch can happen any more once
blk_mq_quiesce_queue() returns, and we don't have such requirement
on APIs of stopping queue.
But blk_mq_quiesce_queue() still may not block/drain dispatch in the
the case of BLK_MQ_S_START_ON_RUN, so use the new introduced flag of
QUEUE_FLAG_QUIESCED and evaluate it inside RCU read-side critical
sections for fixing this issue.
Also blk_mq_quiesce_queue() is implemented via stopping queue, which
limits its uses, and easy to cause race, because any queue restart in
other paths may break blk_mq_quiesce_queue(). With the introduced
flag of QUEUE_FLAG_QUIESCED, we don't need to depend on stopping queue
for quiescing any more.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Bart Van Assche <Bart.VanAssche@sandisk.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to '')
| -rw-r--r-- | include/linux/blkdev.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 8423f6baf818..22cfba64ce81 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -619,6 +619,7 @@ struct request_queue { #define QUEUE_FLAG_POLL_STATS 28 /* collecting stats for hybrid polling */ #define QUEUE_FLAG_REGISTERED 29 /* queue has been registered to a disk */ #define QUEUE_FLAG_SCSI_PASSTHROUGH 30 /* queue supports SCSI commands */ +#define QUEUE_FLAG_QUIESCED 31 /* queue has been quiesced */ #define QUEUE_FLAG_DEFAULT ((1 << QUEUE_FLAG_IO_STAT) | \ (1 << QUEUE_FLAG_STACKABLE) | \ @@ -715,6 +716,7 @@ static inline void queue_flag_clear(unsigned int flag, struct request_queue *q) #define blk_noretry_request(rq) \ ((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \ REQ_FAILFAST_DRIVER)) +#define blk_queue_quiesced(q) test_bit(QUEUE_FLAG_QUIESCED, &(q)->queue_flags) static inline bool blk_account_rq(struct request *rq) { |