diff options
| -rw-r--r-- | block/blk-core.c | 74 |
1 files changed, 35 insertions, 39 deletions
diff --git a/block/blk-core.c b/block/blk-core.c index 64f9a8668253..080204a10fcf 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -837,7 +837,7 @@ static struct io_context *rq_ioc(struct bio *bio) } /** - * get_request - get a free request + * __get_request - get a free request * @q: request_queue to allocate request from * @rw_flags: RW and SYNC flags * @bio: bio to allocate request for (can be %NULL) @@ -850,8 +850,8 @@ static struct io_context *rq_ioc(struct bio *bio) * Returns %NULL on failure, with @q->queue_lock held. * Returns !%NULL on success, with @q->queue_lock *not held*. */ -static struct request *get_request(struct request_queue *q, int rw_flags, - struct bio *bio, gfp_t gfp_mask) +static struct request *__get_request(struct request_queue *q, int rw_flags, + struct bio *bio, gfp_t gfp_mask) { struct request *rq; struct request_list *rl = &q->rq; @@ -1029,56 +1029,55 @@ rq_starved: } /** - * get_request_wait - get a free request with retry + * get_request - get a free request * @q: request_queue to allocate request from * @rw_flags: RW and SYNC flags * @bio: bio to allocate request for (can be %NULL) + * @gfp_mask: allocation mask * - * Get a free request from @q. This function keeps retrying under memory - * pressure and fails iff @q is dead. + * Get a free request from @q. If %__GFP_WAIT is set in @gfp_mask, this + * function keeps retrying under memory pressure and fails iff @q is dead. * * Must be callled with @q->queue_lock held and, * Returns %NULL on failure, with @q->queue_lock held. * Returns !%NULL on success, with @q->queue_lock *not held*. */ -static struct request *get_request_wait(struct request_queue *q, int rw_flags, - struct bio *bio) +static struct request *get_request(struct request_queue *q, int rw_flags, + struct bio *bio, gfp_t gfp_mask) { const bool is_sync = rw_is_sync(rw_flags) != 0; + DEFINE_WAIT(wait); + struct request_list *rl = &q->rq; struct request *rq; +retry: + rq = __get_request(q, rw_flags, bio, gfp_mask); + if (rq) + return rq; - rq = get_request(q, rw_flags, bio, GFP_NOIO); - while (!rq) { - DEFINE_WAIT(wait); - struct request_list *rl = &q->rq; - - if (unlikely(blk_queue_dead(q))) - return NULL; - - prepare_to_wait_exclusive(&rl->wait[is_sync], &wait, - TASK_UNINTERRUPTIBLE); + if (!(gfp_mask & __GFP_WAIT) || unlikely(blk_queue_dead(q))) + return NULL; - trace_block_sleeprq(q, bio, rw_flags & 1); + /* wait on @rl and retry */ + prepare_to_wait_exclusive(&rl->wait[is_sync], &wait, + TASK_UNINTERRUPTIBLE); - spin_unlock_irq(q->queue_lock); - io_schedule(); + trace_block_sleeprq(q, bio, rw_flags & 1); - /* - * After sleeping, we become a "batching" process and - * will be able to allocate at least one request, and - * up to a big batch of them for a small period time. - * See ioc_batching, ioc_set_batching - */ - create_io_context(GFP_NOIO, q->node); - ioc_set_batching(q, current->io_context); + spin_unlock_irq(q->queue_lock); + io_schedule(); - spin_lock_irq(q->queue_lock); - finish_wait(&rl->wait[is_sync], &wait); + /* + * After sleeping, we become a "batching" process and will be able + * to allocate at least one request, and up to a big batch of them + * for a small period time. See ioc_batching, ioc_set_batching + */ + create_io_context(GFP_NOIO, q->node); + ioc_set_batching(q, current->io_context); - rq = get_request(q, rw_flags, bio, GFP_NOIO); - }; + spin_lock_irq(q->queue_lock); + finish_wait(&rl->wait[is_sync], &wait); - return rq; + goto retry; } struct request *blk_get_request(struct request_queue *q, int rw, gfp_t gfp_mask) @@ -1088,10 +1087,7 @@ struct request *blk_get_request(struct request_queue *q, int rw, gfp_t gfp_mask) BUG_ON(rw != READ && rw != WRITE); spin_lock_irq(q->queue_lock); - if (gfp_mask & __GFP_WAIT) - rq = get_request_wait(q, rw, NULL); - else - rq = get_request(q, rw, NULL, gfp_mask); + rq = get_request(q, rw, NULL, gfp_mask); if (!rq) spin_unlock_irq(q->queue_lock); /* q->queue_lock is unlocked at this point */ @@ -1481,7 +1477,7 @@ get_rq: * Grab a free request. This is might sleep but can not fail. * Returns with the queue unlocked. */ - req = get_request_wait(q, rw_flags, bio); + req = get_request(q, rw_flags, bio, GFP_NOIO); if (unlikely(!req)) { bio_endio(bio, -ENODEV); /* @q is dead */ goto out_unlock; |