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Commit c9254f2d authored by Bart Van Assche's avatar Bart Van Assche Committed by Jens Axboe
Browse files

block: Add the QUEUE_FLAG_PREEMPT_ONLY request queue flag 



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: default avatarBart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: default avatarHannes Reinecke <hare@suse.com>
Tested-by: default avatarMartin Steigerwald <martin@lichtvoll.de>
Tested-by: default avatarOleksandr Natalenko <oleksandr@natalenko.name>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 039c635f

block/blk-core.c

+30 −0
Original line number Diff line number Diff line
@@ -348,6 +348,36 @@ void blk_sync_queue(struct request_queue *q) 
}

EXPORT_SYMBOL(blk_sync_queue);



/**

 * blk_set_preempt_only - set QUEUE_FLAG_PREEMPT_ONLY

 * @q: request queue pointer

 *

 * Returns the previous value of the PREEMPT_ONLY flag - 0 if the flag was not

 * set and 1 if the flag was already set.

 */

int blk_set_preempt_only(struct request_queue *q)

{

	unsigned long flags;

	int res;



	spin_lock_irqsave(q->queue_lock, flags);

	res = queue_flag_test_and_set(QUEUE_FLAG_PREEMPT_ONLY, q);

	spin_unlock_irqrestore(q->queue_lock, flags);



	return res;

}

EXPORT_SYMBOL_GPL(blk_set_preempt_only);



void blk_clear_preempt_only(struct request_queue *q)

{

	unsigned long flags;



	spin_lock_irqsave(q->queue_lock, flags);

	queue_flag_clear(QUEUE_FLAG_PREEMPT_ONLY, q);

	spin_unlock_irqrestore(q->queue_lock, flags);

}

EXPORT_SYMBOL_GPL(blk_clear_preempt_only);



/**

 * __blk_run_queue_uncond - run a queue whether or not it has been stopped

 * @q:	The queue to run

block/blk-mq-debugfs.c

+1 −0
Original line number Diff line number Diff line
@@ -74,6 +74,7 @@ static const char *const blk_queue_flag_name[] = { 
	QUEUE_FLAG_NAME(REGISTERED),

	QUEUE_FLAG_NAME(SCSI_PASSTHROUGH),

	QUEUE_FLAG_NAME(QUIESCED),

	QUEUE_FLAG_NAME(PREEMPT_ONLY),

};

#undef QUEUE_FLAG_NAME

include/linux/blkdev.h

+6 −0
Original line number Diff line number Diff line
@@ -632,6 +632,7 @@ 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_SAME_COMP)	|	\
@@ -732,6 +733,11 @@ 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 int blk_set_preempt_only(struct request_queue *q);

extern void blk_clear_preempt_only(struct request_queue *q);



static inline bool blk_account_rq(struct request *rq)

{