talos-op-linux/include/linux/blk-mq.h, branch v4.8.5

blk-mq: Introduce blk_mq_reinit_tagset

2016-07-08T14:38:49+00:00

The new nvme-rdma driver will need to reinitialize all the tags as part of the error recovery procedure (realloc the tag memory region). Add a helper in blk-mq for it that can iterate over all requests in a tagset to make this easier. Signed-off-by: Sagi Grimberg Tested-by: Ming Lin Reviewed-by: Stephen Bates Signed-off-by: Christoph Hellwig Reviewed-by: Steve Wise Tested-by: Steve Wise Signed-off-by: Jens Axboe

blk-mq: add blk_mq_alloc_request_hctx

2016-07-05T17:28:07+00:00

For some protocols like NVMe over Fabrics we need to be able to send initialization commands to a specific queue. Based on an earlier patch from Christoph Hellwig . Signed-off-by: Ming Lin [hch: disallow sleeping allocation, req_op fixes] Signed-off-by: Christoph Hellwig Reviewed-by: Keith Busch Signed-off-by: Jens Axboe

blk-mq: Make blk_mq_all_tag_busy_iter static

2016-04-12T21:07:36+00:00

No caller outside the blk-mq code so we can settle with it static. Signed-off-by: Sagi Grimberg Reviewed-by: Christoph Hellwig Reviewed-by: Johannes Thumshirn Signed-off-by: Jens Axboe

blk-mq: Export tagset iter function

2016-04-12T19:43:53+00:00

Its useful to iterate on all the active tags in cases where we will need to fail all the queues IO. Signed-off-by: Sagi Grimberg [hch: carefully check for valid tagsets] Reviewed-by: Christoph Hellwig Reviewed-by: Johannes Thumshirn Signed-off-by: Jens Axboe

blk-mq: Use proper cpumask iterator

2016-03-20T15:34:02+00:00

queue_for_each_ctx() iterates over per_cpu variables under the assumption that the possible cpu mask cannot have holes. That's wrong as all cpumasks can have holes. In case there are holes the iteration ends up accessing uninitialized memory and crashing as a result. Replace the macro by a proper for_each_possible_cpu() loop and drop the unused macro blk_ctx_sum() which references queue_for_each_ctx(). Reported-by: Xiong Zhou Signed-off-by: Thomas Gleixner Signed-off-by: Jens Axboe

blk-mq: dynamic h/w context count

2016-02-09T19:42:17+00:00

The hardware's provided queue count may change at runtime with resource provisioning. This patch allows a block driver to alter the number of h/w queues available when its resource count changes. The main part is a new blk-mq API to request a new number of h/w queues for a given live tag set. The new API freezes all queues using that set, then adjusts the allocated count prior to remapping these to CPUs. The bulk of the rest just shifts where h/w contexts and all their artifacts are allocated and freed. The number of max h/w contexts is capped to the number of possible cpus since there is no use for more than that. As such, all pre-allocated memory for pointers need to account for the max possible rather than the initial number of queues. A side effect of this is that the blk-mq will proceed successfully as long as it can allocate at least one h/w context. Previously it would fail request queue initialization if less than the requested number was allocated. Signed-off-by: Keith Busch Reviewed-by: Christoph Hellwig Tested-by: Jon Derrick Signed-off-by: Jens Axboe

blk-mq: add a flags parameter to blk_mq_alloc_request

2015-12-01T17:53:59+00:00

We already have the reserved flag, and a nowait flag awkwardly encoded as a gfp_t. Add a real flags argument to make the scheme more extensible and allow for a nicer calling convention. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe

block: add block polling support

2015-11-07T17:40:47+00:00

Add basic support for polling for specific IO to complete. This uses the cookie that blk-mq passes back, which enables the block layer to pass this cookie to the driver to spin for a specific request. This will be combined with request latency tracking, so we can make qualified decisions about when to poll and when not to. For now, for benchmark purposes, we add a sysfs file that controls whether polling is enabled or not. Signed-off-by: Jens Axboe Acked-by: Christoph Hellwig Acked-by: Keith Busch

block: generic request_queue reference counting

2015-10-21T20:43:41+00:00

Allow pmem, and other synchronous/bio-based block drivers, to fallback on a per-cpu reference count managed by the core for tracking queue live/dead state. The existing per-cpu reference count for the blk_mq case is promoted to be used in all block i/o scenarios. This involves initializing it by default, waiting for it to drop to zero at exit, and holding a live reference over the invocation of q->make_request_fn() in generic_make_request(). The blk_mq code continues to take its own reference per blk_mq request and retains the ability to freeze the queue, but the check that the queue is frozen is moved to generic_make_request(). This fixes crash signatures like the following: BUG: unable to handle kernel paging request at ffff880140000000 [..] Call Trace: [] ? copy_user_handle_tail+0x5f/0x70 [] pmem_do_bvec.isra.11+0x70/0xf0 [nd_pmem] [] pmem_make_request+0xd1/0x200 [nd_pmem] [] ? mempool_alloc+0x72/0x1a0 [] generic_make_request+0xd6/0x110 [] submit_bio+0x76/0x170 [] submit_bh_wbc+0x12f/0x160 [] submit_bh+0x12/0x20 [] jbd2_write_superblock+0x8d/0x170 [] jbd2_mark_journal_empty+0x5d/0x90 [] jbd2_journal_destroy+0x24b/0x270 [] ? put_pwq_unlocked+0x2a/0x30 [] ? destroy_workqueue+0x225/0x250 [] ext4_put_super+0x64/0x360 [] generic_shutdown_super+0x6a/0xf0 Cc: Jens Axboe Cc: Keith Busch Cc: Ross Zwisler Suggested-by: Christoph Hellwig Reviewed-by: Christoph Hellwig Tested-by: Ross Zwisler Signed-off-by: Dan Williams Signed-off-by: Jens Axboe

blk-mq: factor out a helper to iterate all tags for a request_queue

2015-10-01T08:10:57+00:00

And replace the blk_mq_tag_busy_iter with it - the driver use has been replaced with a new helper a while ago, and internal to the block we only need the new version. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe