[PATCH v2 2/4] block: Add the QUEUE_PREEMPT_ONLY request queue flag
From: Bart Van Assche <hidden>
Date: 2017-09-21 21:22:53
Subsystem:
block layer, the rest · Maintainers:
Jens Axboe, Linus Torvalds
This flag will be used in the next patch to let the block layer core know whether or not a SCSI request queue has been quiesced. A quiesced SCSI queue namely only processes RQF_PREEMPT requests. Signed-off-by: Bart Van Assche <redacted> Cc: Ming Lei <redacted> Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.com> Cc: Johannes Thumshirn <redacted> --- block/blk-core.c | 13 +++++++++++++ include/linux/blkdev.h | 5 +++++ 2 files changed, 18 insertions(+)
diff --git a/block/blk-core.c b/block/blk-core.c
index d709c0e3a2ac..1ac337712bbd 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c@@ -346,6 +346,19 @@ void blk_sync_queue(struct request_queue *q) } EXPORT_SYMBOL(blk_sync_queue); +void blk_set_preempt_only(struct request_queue *q, bool preempt_only) +{ + unsigned long flags; + + spin_lock_irqsave(q->queue_lock, flags); + if (preempt_only) + queue_flag_set(QUEUE_FLAG_PREEMPT_ONLY, q); + else + queue_flag_clear(QUEUE_FLAG_PREEMPT_ONLY, q); + spin_unlock_irqrestore(q->queue_lock, flags); +} +EXPORT_SYMBOL(blk_set_preempt_only); + /** * __blk_run_queue_uncond - run a queue whether or not it has been stopped * @q: The queue to run
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index cd26901a6e25..5bd87599eed0 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h@@ -627,6 +627,7 @@ struct request_queue { #define QUEUE_FLAG_REGISTERED 26 /* queue has been registered to a disk */ #define QUEUE_FLAG_SCSI_PASSTHROUGH 27 /* queue supports SCSI commands */ #define QUEUE_FLAG_QUIESCED 28 /* queue has been quiesced */ +#define QUEUE_FLAG_PREEMPT_ONLY 29 /* only process REQ_PREEMPT requests */ #define QUEUE_FLAG_DEFAULT ((1 << QUEUE_FLAG_IO_STAT) | \ (1 << QUEUE_FLAG_STACKABLE) | \
@@ -731,6 +732,10 @@ static inline void queue_flag_clear(unsigned int flag, struct request_queue *q) ((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) +#define blk_queue_preempt_only(q) \ + test_bit(QUEUE_FLAG_PREEMPT_ONLY, &(q)->queue_flags) + +extern void blk_set_preempt_only(struct request_queue *q, bool preempt_only); static inline bool blk_account_rq(struct request *rq) {
--
2.14.1