diff options
| -rw-r--r-- | block/blk-core.c | 39 | ||||
| -rw-r--r-- | block/blk.h | 6 | ||||
| -rw-r--r-- | block/elevator.c | 25 | ||||
| -rw-r--r-- | include/linux/blkdev.h | 5 |
4 files changed, 46 insertions, 29 deletions
diff --git a/block/blk-core.c b/block/blk-core.c index fccb2502112..98ddef43009 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -410,6 +410,42 @@ void blk_drain_queue(struct request_queue *q, bool drain_all) } /** + * blk_queue_bypass_start - enter queue bypass mode + * @q: queue of interest + * + * In bypass mode, only the dispatch FIFO queue of @q is used. This + * function makes @q enter bypass mode and drains all requests which were + * issued before. On return, it's guaranteed that no request has ELVPRIV + * set. + */ +void blk_queue_bypass_start(struct request_queue *q) +{ + spin_lock_irq(q->queue_lock); + q->bypass_depth++; + queue_flag_set(QUEUE_FLAG_BYPASS, q); + spin_unlock_irq(q->queue_lock); + + blk_drain_queue(q, false); +} +EXPORT_SYMBOL_GPL(blk_queue_bypass_start); + +/** + * blk_queue_bypass_end - leave queue bypass mode + * @q: queue of interest + * + * Leave bypass mode and restore the normal queueing behavior. + */ +void blk_queue_bypass_end(struct request_queue *q) +{ + spin_lock_irq(q->queue_lock); + if (!--q->bypass_depth) + queue_flag_clear(QUEUE_FLAG_BYPASS, q); + WARN_ON_ONCE(q->bypass_depth < 0); + spin_unlock_irq(q->queue_lock); +} +EXPORT_SYMBOL_GPL(blk_queue_bypass_end); + +/** * blk_cleanup_queue - shutdown a request queue * @q: request queue to shutdown * @@ -862,8 +898,7 @@ retry: * Also, lookup icq while holding queue_lock. If it doesn't exist, * it will be created after releasing queue_lock. */ - if (blk_rq_should_init_elevator(bio) && - !test_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags)) { + if (blk_rq_should_init_elevator(bio) && !blk_queue_bypass(q)) { rw_flags |= REQ_ELVPRIV; rl->elvpriv++; if (et->icq_cache && ioc) diff --git a/block/blk.h b/block/blk.h index 9c12f80882b..7422f3133c5 100644 --- a/block/blk.h +++ b/block/blk.h @@ -23,7 +23,8 @@ void blk_rq_bio_prep(struct request_queue *q, struct request *rq, struct bio *bio); int blk_rq_append_bio(struct request_queue *q, struct request *rq, struct bio *bio); -void blk_drain_queue(struct request_queue *q, bool drain_all); +void blk_queue_bypass_start(struct request_queue *q); +void blk_queue_bypass_end(struct request_queue *q); void blk_dequeue_request(struct request *rq); void __blk_queue_free_tags(struct request_queue *q); bool __blk_end_bidi_request(struct request *rq, int error, @@ -144,9 +145,6 @@ void blk_queue_congestion_threshold(struct request_queue *q); int blk_dev_init(void); -void elv_quiesce_start(struct request_queue *q); -void elv_quiesce_end(struct request_queue *q); - /* * Return the threshold (number of used requests) at which the queue is diff --git a/block/elevator.c b/block/elevator.c index f81c061dad1..0bdea0ed03a 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -553,25 +553,6 @@ void elv_drain_elevator(struct request_queue *q) } } -void elv_quiesce_start(struct request_queue *q) -{ - if (!q->elevator) - return; - - spin_lock_irq(q->queue_lock); - queue_flag_set(QUEUE_FLAG_ELVSWITCH, q); - spin_unlock_irq(q->queue_lock); - - blk_drain_queue(q, false); -} - -void elv_quiesce_end(struct request_queue *q) -{ - spin_lock_irq(q->queue_lock); - queue_flag_clear(QUEUE_FLAG_ELVSWITCH, q); - spin_unlock_irq(q->queue_lock); -} - void __elv_add_request(struct request_queue *q, struct request *rq, int where) { trace_block_rq_insert(q, rq); @@ -903,7 +884,7 @@ static int elevator_switch(struct request_queue *q, struct elevator_type *new_e) * using INSERT_BACK. All requests have SOFTBARRIER set and no * merge happens either. */ - elv_quiesce_start(q); + blk_queue_bypass_start(q); /* unregister and clear all auxiliary data of the old elevator */ if (registered) @@ -933,7 +914,7 @@ static int elevator_switch(struct request_queue *q, struct elevator_type *new_e) /* done, kill the old one and finish */ elevator_exit(old); - elv_quiesce_end(q); + blk_queue_bypass_end(q); blk_add_trace_msg(q, "elv switch: %s", new_e->elevator_name); @@ -945,7 +926,7 @@ fail_init: /* switch failed, restore and re-register old elevator */ q->elevator = old; elv_register_queue(q); - elv_quiesce_end(q); + blk_queue_bypass_end(q); return err; } diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 606cf339bb5..315db1d91bc 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -389,6 +389,8 @@ struct request_queue { struct mutex sysfs_lock; + int bypass_depth; + #if defined(CONFIG_BLK_DEV_BSG) bsg_job_fn *bsg_job_fn; int bsg_job_size; @@ -406,7 +408,7 @@ struct request_queue { #define QUEUE_FLAG_SYNCFULL 3 /* read queue has been filled */ #define QUEUE_FLAG_ASYNCFULL 4 /* write queue has been filled */ #define QUEUE_FLAG_DEAD 5 /* queue being torn down */ -#define QUEUE_FLAG_ELVSWITCH 6 /* don't use elevator, just do FIFO */ +#define QUEUE_FLAG_BYPASS 6 /* act as dumb FIFO queue */ #define QUEUE_FLAG_BIDI 7 /* queue supports bidi requests */ #define QUEUE_FLAG_NOMERGES 8 /* disable merge attempts */ #define QUEUE_FLAG_SAME_COMP 9 /* complete on same CPU-group */ @@ -494,6 +496,7 @@ static inline void queue_flag_clear(unsigned int flag, struct request_queue *q) #define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags) #define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags) #define blk_queue_dead(q) test_bit(QUEUE_FLAG_DEAD, &(q)->queue_flags) +#define blk_queue_bypass(q) test_bit(QUEUE_FLAG_BYPASS, &(q)->queue_flags) #define blk_queue_nomerges(q) test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags) #define blk_queue_noxmerges(q) \ test_bit(QUEUE_FLAG_NOXMERGES, &(q)->queue_flags) |