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author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-02-24 14:13:34 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-02-24 14:13:34 -0800 |
commit | 1802979ab1ee8ec5a72987ad518f5a91bf41cd89 (patch) | |
tree | 4b1bfc68a180040d713e8b1f106ca12f2461b8ec /block/blk-mq.c | |
parent | f1ef09fde17f9b77ca1435a5b53a28b203afb81c (diff) | |
parent | 61febef40bfe8ab68259d8545257686e8a0d91d1 (diff) | |
download | linux-stable-1802979ab1ee8ec5a72987ad518f5a91bf41cd89.tar.gz linux-stable-1802979ab1ee8ec5a72987ad518f5a91bf41cd89.tar.bz2 linux-stable-1802979ab1ee8ec5a72987ad518f5a91bf41cd89.zip |
Merge branch 'for-linus' of git://git.kernel.dk/linux-block
Pull block updates and fixes from Jens Axboe:
- NVMe updates and fixes that missed the first pull request. This
includes bug fixes, and support for autonomous power management.
- Fix from Christoph for missing clear of the request payload, causing
a problem with (at least) the storvsc driver.
- Further fixes for the queue/bdi life time issues from Jan.
- The Kconfig mq scheduler update from me.
- Fixing a use-after-free in dm-rq, spotted by Bart, introduced in this
merge window.
- Three fixes for nbd from Josef.
- Bug fix from Omar, fixing a bug in sas transport code that oopses
when bsg ioctls were used. From Omar.
- Improvements to the queue restart and tag wait from from Omar.
- Set of fixes for the sed/opal code from Scott.
- Three trivial patches to cciss from Tobin
* 'for-linus' of git://git.kernel.dk/linux-block: (41 commits)
dm-rq: don't dereference request payload after ending request
blk-mq-sched: separate mark hctx and queue restart operations
blk-mq: use sbq wait queues instead of restart for driver tags
block/sed-opal: Propagate original error message to userland.
nvme/pci: re-check security protocol support after reset
block/sed-opal: Introduce free_opal_dev to free the structure and clean up state
nvme: detect NVMe controller in recent MacBooks
nvme-rdma: add support for host_traddr
nvmet-rdma: Fix error handling
nvmet-rdma: use nvme cm status helper
nvme-rdma: move nvme cm status helper to .h file
nvme-fc: don't bother to validate ioccsz and iorcsz
nvme/pci: No special case for queue busy on IO
nvme/core: Fix race kicking freed request_queue
nvme/pci: Disable on removal when disconnected
nvme: Enable autonomous power state transitions
nvme: Add a quirk mechanism that uses identify_ctrl
nvme: make nvmf_register_transport require a create_ctrl callback
nvme: Use CNS as 8-bit field and avoid endianness conversion
nvme: add semicolon in nvme_command setting
...
Diffstat (limited to 'block/blk-mq.c')
-rw-r--r-- | block/blk-mq.c | 64 |
1 files changed, 55 insertions, 9 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c index b29e7dc7b309..9e6b064e5339 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -904,6 +904,44 @@ static bool reorder_tags_to_front(struct list_head *list) return first != NULL; } +static int blk_mq_dispatch_wake(wait_queue_t *wait, unsigned mode, int flags, + void *key) +{ + struct blk_mq_hw_ctx *hctx; + + hctx = container_of(wait, struct blk_mq_hw_ctx, dispatch_wait); + + list_del(&wait->task_list); + clear_bit_unlock(BLK_MQ_S_TAG_WAITING, &hctx->state); + blk_mq_run_hw_queue(hctx, true); + return 1; +} + +static bool blk_mq_dispatch_wait_add(struct blk_mq_hw_ctx *hctx) +{ + struct sbq_wait_state *ws; + + /* + * The TAG_WAITING bit serves as a lock protecting hctx->dispatch_wait. + * The thread which wins the race to grab this bit adds the hardware + * queue to the wait queue. + */ + if (test_bit(BLK_MQ_S_TAG_WAITING, &hctx->state) || + test_and_set_bit_lock(BLK_MQ_S_TAG_WAITING, &hctx->state)) + return false; + + init_waitqueue_func_entry(&hctx->dispatch_wait, blk_mq_dispatch_wake); + ws = bt_wait_ptr(&hctx->tags->bitmap_tags, hctx); + + /* + * As soon as this returns, it's no longer safe to fiddle with + * hctx->dispatch_wait, since a completion can wake up the wait queue + * and unlock the bit. + */ + add_wait_queue(&ws->wait, &hctx->dispatch_wait); + return true; +} + bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list) { struct request_queue *q = hctx->queue; @@ -931,15 +969,22 @@ bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list) continue; /* - * We failed getting a driver tag. Mark the queue(s) - * as needing a restart. Retry getting a tag again, - * in case the needed IO completed right before we - * marked the queue as needing a restart. + * The initial allocation attempt failed, so we need to + * rerun the hardware queue when a tag is freed. */ - blk_mq_sched_mark_restart(hctx); - if (!blk_mq_get_driver_tag(rq, &hctx, false)) + if (blk_mq_dispatch_wait_add(hctx)) { + /* + * It's possible that a tag was freed in the + * window between the allocation failure and + * adding the hardware queue to the wait queue. + */ + if (!blk_mq_get_driver_tag(rq, &hctx, false)) + break; + } else { break; + } } + list_del_init(&rq->queuelist); bd.rq = rq; @@ -995,10 +1040,11 @@ bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list) * * blk_mq_run_hw_queue() already checks the STOPPED bit * - * If RESTART is set, then let completion restart the queue - * instead of potentially looping here. + * If RESTART or TAG_WAITING is set, then let completion restart + * the queue instead of potentially looping here. */ - if (!blk_mq_sched_needs_restart(hctx)) + if (!blk_mq_sched_needs_restart(hctx) && + !test_bit(BLK_MQ_S_TAG_WAITING, &hctx->state)) blk_mq_run_hw_queue(hctx, true); } |