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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: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Tested-by: Martin Steigerwald <martin@lichtvoll.de>
Tested-by: Oleksandr 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: Jens Axboe <axboe@kernel.dk>
hifive-unleashed-5.1
Bart Van Assche 2017-11-09 10:49:57 -08:00 committed by Jens Axboe
parent 039c635f4e
commit c9254f2ddb
3 changed files with 37 additions and 0 deletions
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30
block/blk-core.c
View File

@ -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

1
block/blk-mq-debugfs.c
View File

@ -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

6
include/linux/blkdev.h
View File

@ -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)
{