diff options
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-core.c | 26 | ||||
| -rw-r--r-- | block/blk-settings.c | 12 | ||||
| -rw-r--r-- | block/blk.h | 11 | ||||
| -rw-r--r-- | block/elevator.c | 5 |
4 files changed, 52 insertions, 2 deletions
diff --git a/block/blk-core.c b/block/blk-core.c index 570819b04..9f671cd6c 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -312,7 +312,14 @@ inline void __blk_run_queue_uncond(struct request_queue *q) * can wait until all these request_fn calls have finished. */ q->request_fn_active++; - q->request_fn(q); + if (!q->notified_urgent && + q->elevator->type->ops.elevator_is_urgent_fn && + q->urgent_request_fn && + q->elevator->type->ops.elevator_is_urgent_fn(q)) { + q->notified_urgent = true; + q->urgent_request_fn(q); + } else + q->request_fn(q); q->request_fn_active--; } @@ -323,6 +330,12 @@ inline void __blk_run_queue_uncond(struct request_queue *q) * Description: * See @blk_run_queue. This variant must be called with the queue lock * held and interrupts disabled. + * Device driver will be notified of an urgent request + * pending under the following conditions: + * 1. The driver and the current scheduler support urgent reques handling + * 2. There is an urgent request pending in the scheduler + * 3. There isn't already an urgent request in flight, meaning previously + * notified urgent request completed (!q->notified_urgent) */ void __blk_run_queue(struct request_queue *q) { @@ -2351,8 +2364,17 @@ struct request *blk_fetch_request(struct request_queue *q) struct request *rq; rq = blk_peek_request(q); - if (rq) + if (rq) { + /* + * Assumption: the next request fetched from scheduler after we + * notified "urgent request pending" - will be the urgent one + */ + if (q->notified_urgent && !q->dispatched_urgent) { + q->dispatched_urgent = true; + (void)blk_mark_rq_urgent(rq); + } blk_start_request(rq); + } return rq; } EXPORT_SYMBOL(blk_fetch_request); diff --git a/block/blk-settings.c b/block/blk-settings.c index ec00a0f75..f19c2bce6 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -100,6 +100,18 @@ void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn) EXPORT_SYMBOL_GPL(blk_queue_lld_busy); /** + * blk_urgent_request() - Set an urgent_request handler function for queue + * @q: queue + * @fn: handler for urgent requests + * + */ +void blk_urgent_request(struct request_queue *q, request_fn_proc *fn) +{ + q->urgent_request_fn = fn; +} +EXPORT_SYMBOL(blk_urgent_request); + +/** * blk_set_default_limits - reset limits to default values * @lim: the queue_limits structure to reset * diff --git a/block/blk.h b/block/blk.h index b3bdeb36f..f1f44408b 100644 --- a/block/blk.h +++ b/block/blk.h @@ -42,6 +42,7 @@ void blk_add_timer(struct request *); */ enum rq_atomic_flags { REQ_ATOM_COMPLETE = 0, + REQ_ATOM_URGENT = 1, }; /* @@ -58,6 +59,16 @@ static inline void blk_clear_rq_complete(struct request *rq) clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags); } +static inline int blk_mark_rq_urgent(struct request *rq) +{ + return test_and_set_bit(REQ_ATOM_URGENT, &rq->atomic_flags); +} + +static inline void blk_clear_rq_urgent(struct request *rq) +{ + clear_bit(REQ_ATOM_URGENT, &rq->atomic_flags); +} + /* * Internal elevator interface */ diff --git a/block/elevator.c b/block/elevator.c index 3d1c3a729..3bfb00dbb 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -786,6 +786,11 @@ void elv_completed_request(struct request_queue *q, struct request *rq) { struct elevator_queue *e = q->elevator; + if (test_bit(REQ_ATOM_URGENT, &rq->atomic_flags)) { + q->notified_urgent = false; + q->dispatched_urgent = false; + blk_clear_rq_urgent(rq); + } /* * request is released from the driver, io must be done */ |