When blk_mq_delay_run_hw_queues sets an hctx to run in the future, it can
reset the delay length for an already pending delayed work run_work. This
creates a scenario where multiple hctx may have their queues set to run,
but if one runs first and finds nothing to do, it can reset the delay of
another hctx and stall the other hctx's ability to run requests.
To avoid this I/O stall when an hctx's run_work is already pending,
leave it untouched to run at its current designated time rather than
extending its delay. The work will still run which keeps closed the race
calling blk_mq_delay_run_hw_queues is needed for while also avoiding the
I/O stall.
Signed-off-by: David Jeffery <djeffery@redhat.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20220131203337.GA17666@redhat
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk_crypto_bio_prep() is called for both bio based and blk-mq drivers,
so move it out of blk-mq.c, then we can unify this kind of handling.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220216044514.2903784-3-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The request must be submitted to the queue it was allocated for, so
remove the extra request_queue argument.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220215100540.3892965-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Fold blk_cloned_rq_check_limits into its only caller.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220215100540.3892965-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The code to stack blk-mq drivers is only used by dm-multipath, and
will preferably stay that way. Make it optional and only selected
by device mapper, so that the buildbots more easily catch abuses
like the one that slipped in in the ufs driver in the last merged
window. Another positive side effects is that kernel builds without
device mapper shrink a little bit as well.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220215100540.3892965-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Currently, rasdaemon uses the existing tracepoint block_rq_complete
and filters out non-error cases in order to capture block disk errors.
But there are a few problems with this approach:
1. Even kernel trace filter could do the filtering work, there is
still some overhead after we enable this tracepoint.
2. The filter is merely based on errno, which does not align with kernel
logic to check the errors for print_req_error().
3. block_rq_complete only provides dev major and minor to identify
the block device, it is not convenient to use in user-space.
So introduce a new tracepoint block_rq_error just for the error case.
With this patch, rasdaemon could switch to block_rq_error.
Since the new tracepoint has the similar implementation with
block_rq_complete, so move the existing code from TRACE_EVENT
block_rq_complete() into new event class block_rq_completion(). Then add
event for block_rq_complete and block_rq_err respectively from the newly
created event class per the suggestion from Chaitanya Kulkarni.
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@infradead.org>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220210225222.260069-1-shy828301@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Zone append command needs special handling to update the bi_sector
field in the bio struct with the actual position of the data in the
device. It is stored in __sector field of the request struct.
Fixes: 5581a5ddfe ("block: add completion handler for fast path")
Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Adam Manzanares <a.manzanares@samsung.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20220211093425.43262-2-p.raghav@samsung.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pass a block_device to bio_clone_fast and __bio_clone_fast and give
the functions more suitable names.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220202160109.108149-14-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If blk_mq_request_issue_directly() failed from
blk_insert_cloned_request(), the request will be accounted start.
Currently, blk_insert_cloned_request() is only called by dm, and such
request won't be accounted done by dm.
In normal path, io will be accounted start from blk_mq_bio_to_request(),
when the request is allocated, and such io will be accounted done from
__blk_mq_end_request_acct() whether it succeeded or failed. Thus add
blk_account_io_done() to fix the problem.
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220126012132.3111551-1-yukuai3@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'bitmap-5.17-rc1' of git://github.com/norov/linux
Pull bitmap updates from Yury Norov:
- introduce for_each_set_bitrange()
- use find_first_*_bit() instead of find_next_*_bit() where possible
- unify for_each_bit() macros
* tag 'bitmap-5.17-rc1' of git://github.com/norov/linux:
vsprintf: rework bitmap_list_string
lib: bitmap: add performance test for bitmap_print_to_pagebuf
bitmap: unify find_bit operations
mm/percpu: micro-optimize pcpu_is_populated()
Replace for_each_*_bit_from() with for_each_*_bit() where appropriate
find: micro-optimize for_each_{set,clear}_bit()
include/linux: move for_each_bit() macros from bitops.h to find.h
cpumask: replace cpumask_next_* with cpumask_first_* where appropriate
tools: sync tools/bitmap with mother linux
all: replace find_next{,_zero}_bit with find_first{,_zero}_bit where appropriate
cpumask: use find_first_and_bit()
lib: add find_first_and_bit()
arch: remove GENERIC_FIND_FIRST_BIT entirely
include: move find.h from asm_generic to linux
bitops: move find_bit_*_le functions from le.h to find.h
bitops: protect find_first_{,zero}_bit properly
bio_clone_fast() sets the cloned bio to have the same ->bi_bdev as the
source bio. This means that when request-based dm called setup_clone(),
the cloned bio had its ->bi_bdev pointing to the dm device. After Commit
0b6e522cdc ("blk-mq: use ->bi_bdev for I/O accounting")
__blk_account_io_start() started using the request's ->bio->bi_bdev for
I/O accounting, if it was set. This caused IO going to the underlying
devices to use the dm device for their I/O accounting.
Set up the proper ->bi_bdev in blk_rq_prep_clone based on the whole
device bdev for the queue the request is cloned onto.
Fixes: 0b6e522cdc ("blk-mq: use ->bi_bdev for I/O accounting")
Reported-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
[hch: the commit message is mostly from a different patch from Benjamin]
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Benjamin Marzinski <bmarzins@redhat.com>
Link: https://lore.kernel.org/r/20220118070444.1241739-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
cpumask_first() is a more effective analogue of 'next' version if n == -1
(which means start == 0). This patch replaces 'next' with 'first' where
things look trivial.
There's no cpumask_first_zero() function, so create it.
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Commit cc9c884dd7 ("block: call submit_bio_checks under q_usage_counter")
uses q_usage_counter to protect submit_bio_checks for avoiding IO after
disk is deleted by del_gendisk().
Turns out the protection isn't necessary, because once
blk_mq_freeze_queue_wait() in del_gendisk() returns:
1) all in-flight IO has been done
2) all new IO will be failed in __bio_queue_enter() because
q_usage_counter is dead, and GD_DEAD is set
3) both disk and request queue instance are safe since caller of
submit_bio() guarantees that the disk can't be closed.
Once submit_bio_checks() needn't the protection of q_usage_counter, we can
move submit_bio_checks before calling blk_mq_submit_bio() and
->submit_bio(). With this change, we needn't to throttle queue with
holding one allocated request, then precise driver tag or request won't be
wasted in throttling. Meantime we can unify the bio check for both bio
based and request based driver.
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20220104134223.590803-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The low level drivers don't expect to see new requests after a
successful quiesce completes. Check the queue quiesce state within the
rcu protected area prior to calling the driver's queue_rqs().
Fixes: 3c67d44de7 ("block: add mq_ops->queue_rqs hook")
Signed-off-by: Keith Busch <kbusch@kernel.org>
Link: https://lore.kernel.org/r/20211220205919.180191-1-kbusch@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we have a list of requests in our plug list, send it to the driver in
one go, if possible. The driver must set mq_ops->queue_rqs() to support
this, if not the usual one-by-one path is used.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The batched completions only deal with non-partial requests anyway,
and it doesn't deal with any requests that have errors. Add a completion
handler that assumes it's a full request and that it's all being ended
successfully.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The only user of blk_mq_hw_ctx blk_mq_hw_ctx argument is
blk_mq_rq_inflight().
Function blk_mq_rq_inflight() uses the hctx to find the associated request
queue to match against the request. However this same check is already
done in caller bt_iter(), so drop this check.
With that change there are no more users of busy_iter_fn blk_mq_hw_ctx
argument, so drop the argument.
Reviewed-by Hannes Reinecke <hare@suse.de>
Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Tested-by: Kashyap Desai <kashyap.desai@broadcom.com>
Link: https://lore.kernel.org/r/1638794990-137490-2-git-send-email-john.garry@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk_mq_run_dispatch_ops() is defined as one macro, and plug->mq_list
will be changed when running 'dispatch_ops', so add one local variable
for holding request queue.
Reported-and-tested-by: Yi Zhang <yi.zhang@redhat.com>
Fixes: 4cafe86c92 ("blk-mq: run dispatch lock once in case of issuing from list")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The operation protected via blk_mq_run_dispatch_ops() in blk_mq_run_hw_queue
won't sleep, so don't run might_sleep() for it.
Reported-and-tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
It isn't necessary to call blk_mq_run_dispatch_ops() once for issuing
single request directly, and enough to do it one time when issuing from
whole list.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211203131534.3668411-5-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We have switched to allocate srcu into request queue, so it is fine
to pass request queue to blk_mq_run_dispatch_ops().
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211203131534.3668411-4-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In case of BLK_MQ_F_BLOCKING, per-hctx srcu is used to protect dispatch
critical area. However, this srcu instance stays at the end of hctx, and
it often takes standalone cacheline, often cold.
Inside srcu_read_lock() and srcu_read_unlock(), WRITE is always done on
the indirect percpu variable which is allocated from heap instead of
being embedded, srcu->srcu_idx is read only in srcu_read_lock(). It
doesn't matter if srcu structure stays in hctx or request queue.
So switch to per-request-queue srcu for protecting dispatch, and this
way simplifies quiesce a lot, not mention quiesce is always done on the
request queue wide.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211203131534.3668411-3-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Remove hctx_lock and hctx_unlock, and add one helper of
blk_mq_run_dispatch_ops() to run code block defined in dispatch_ops
with rcu/srcu read held.
Compared with hctx_lock()/hctx_unlock():
1) remove 2 branch to 1, so we just need to check
(hctx->flags & BLK_MQ_F_BLOCKING) once when running one dispatch_ops
2) srcu_idx needn't to be touched in case of non-blocking
3) might_sleep_if() can be moved to the blocking branch
Also put the added blk_mq_run_dispatch_ops() in private header, so that
the following patch can use it out of blk-mq.c.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211203131534.3668411-2-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
refcount_t is not as expensive as it used to be, but it's still more
expensive than the io_uring method of using atomic_t and just checking
for potential over/underflow.
This borrows that same implementation, which in turn is based on the
mm implementation from Linus.
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When we attempt to merge off the cached request path, we return NULL
if successful. This makes the caller believe that it's should allocate
a new request, and hence we end up with the bio both merged and associated
with a new request. This, predictably, leads to all sorts of crashes.
Pass in a pointer to the bio pointer, and clear it for the merge case.
Then the caller knows that the bio is already queued, and no new requests
need to get allocated.
Fixes: 5b13bc8a3f ("blk-mq: cleanup request allocation")
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Expected case is returning a request, just check for success and return
the request rather than having an error label.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Remove the gendisk aregument to blk_execute_rq and blk_execute_rq_nowait
given that it is unused now. Also convert the boolean at_head parameter
to actually use the bool type while touching the prototype.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20211126121802.2090656-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Just use the disk attached to the request_queue instead.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20211126121802.2090656-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
After the prepare side has been moved to the only I/O scheduler that
cares, do the same for the cleanup and the NULL initialization.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211126115817.2087431-9-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
bio->bi_opf isn't finalized before checking the bio, so use it after
submit_bio_checks() returns.
Fixes: 5b13bc8a3f ("blk-mq: cleanup request allocation")
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Refactor the request alloction so that blk_mq_get_cached_request tries
to find a cached request first, and the entirely separate and now
self contained blk_mq_get_new_requests allocates one or more requests
if that is not possible.
There is a small change in behavior as submit_bio_checks is called
twice now if a cached request is present but can't be used, but that
is a small price to pay for unwinding this code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211124062856.1444266-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The only user of the io_context for IO is BFQ, yet we put the checking
and logic of it into the normal IO path.
Put the creation into blk_mq_sched_assign_ioc(), and have BFQ use that
helper.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This is essentially never used, yet it's about 1/3rd of the total
queue size. Allocate it when needed, and don't embed it in the queue.
Kill the queue flag for this while at it, since we can just check the
assigned pointer now.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk_mq_submit_bio has two different plug cases, one that uses full
plugging and a limited plugging one.
The limited plugging case is only used for a corner case that does
not matter in real life:
- no ->commit_rqs (so not NVMe)
- no shared tags (so not SCSI)
- not rotational (so no old disk or floppy driver)
- must have multiple queues (so no eMMC)
Remove the limited merging case and all the related junk to simplify
blk_mq_submit_bio and the functions called from it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211123160443.1315598-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This function is only used by the request completion path. Factor out
a blk_status_to_str to keep blk_errors private in blk-core.c.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20211117061404.331732-11-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk_dump_rq_flags deals with a request, so move it to blk-mq.c.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20211117061404.331732-10-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
These are only used for request based I/O, so move them where they are
used.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20211117061404.331732-9-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Keep all the request based code together.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20211117061404.331732-8-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk_rq_init deals with a request structure, so move it to blk-mq.c
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20211117061404.331732-7-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Keep all the request based code together.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20211117061404.331732-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Move blk_mq_flush_plug_list and blk_mq_plug_issue_direct down in blk-mq.c
to prepare for marking blk_mq_request_issue_directly static without the
need of a forward declaration.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20211117061404.331732-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
All this code is tightly coupled to the blk-mq core, so move it
there.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20211117061404.331732-4-hch@lst.de
[axboe: remove doc generation for blk-exec.c]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We need to call rq_qos_done() regardless of whether or not we're freeing
the request or not, as the reference count doesn't cover the IO completion
tracking.
Fixes: f794f3351f ("block: add support for blk_mq_end_request_batch()")
Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Reported-by: Kenneth R. Crudup <kenny@panix.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We never insert flush request into scheduler queue before.
Recently commit d92ca9d834 ("blk-mq: don't handle non-flush requests in
blk_insert_flush") tries to handle FUA data request as normal request.
This way has caused warning[1] in mq-deadline dd_exit_sched() or io hang in
case of kyber since RQF_ELVPRIV isn't set for flush request, then
->finish_request won't be called.
Fix the issue by inserting FUA data request with blk_mq_request_bypass_insert()
when the device supports FUA, just like what we did before.
[1] https://lore.kernel.org/linux-block/CAHj4cs-_vkTW=dAzbZYGxpEWSpzpcmaNeY1R=vH311+9vMUSdg@mail.gmail.com/
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Fixes: d92ca9d834 ("blk-mq: don't handle non-flush requests in blk_insert_flush")
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20211118153041.2163228-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we fail the submission queue checks, we don't put the queue afterwards.
This can cause various issues like stalls on scheduler switch or failure
to remove the device, or like in the original bug report, timeout waiting
for the device on reboot/restart.
While in there, fix a few whitespace discrepancies in the surrounding
code.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215039
Fixes: b637108a40 ("blk-mq: fix filesystem I/O request allocation")
Reported-and-tested-by: Stephen Smith <stephenmsmith@blueyonder.co.uk>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
submit_bio_checks() may update bio->bi_opf, so we have to initialize
blk_mq_alloc_data.cmd_flags with bio->bi_opf after submit_bio_checks()
returns when allocating new request.
In case of using cached request, fallback to allocate new request if
cached rq isn't compatible with the incoming bio, otherwise change
rq->cmd_flags with incoming bio->bi_opf.
Fixes: 900e080752 ("block: move queue enter logic into blk_mq_submit_bio()")
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
It is very annoying to have two block layer functions which share same
name, so rename blk_attempt_bio_merge in blk-mq.c as
blk_mq_attempt_bio_merge.
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211111085134.345235-3-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'for-5.16/block-2021-11-09' of git://git.kernel.dk/linux-block
Pull block fixes from Jens Axboe:
- Set of fixes for the batched tag allocation (Ming, me)
- add_disk() error handling fix (Luis)
- Nested queue quiesce fixes (Ming)
- Shared tags init error handling fix (Ye)
- Misc cleanups (Jean, Ming, me)
* tag 'for-5.16/block-2021-11-09' of git://git.kernel.dk/linux-block:
nvme: wait until quiesce is done
scsi: make sure that request queue queiesce and unquiesce balanced
scsi: avoid to quiesce sdev->request_queue two times
blk-mq: add one API for waiting until quiesce is done
blk-mq: don't free tags if the tag_set is used by other device in queue initialztion
block: fix device_add_disk() kobject_create_and_add() error handling
block: ensure cached plug request matches the current queue
block: move queue enter logic into blk_mq_submit_bio()
block: make bio_queue_enter() fast-path available inline
block: split request allocation components into helpers
block: have plug stored requests hold references to the queue
blk-mq: update hctx->nr_active in blk_mq_end_request_batch()
blk-mq: add RQF_ELV debug entry
blk-mq: only try to run plug merge if request has same queue with incoming bio
block: move RQF_ELV setting into allocators
dm: don't stop request queue after the dm device is suspended
block: replace always false argument with 'false'
block: assign correct tag before doing prefetch of request
blk-mq: fix redundant check of !e expression
Some drivers(NVMe, SCSI) need to call quiesce and unquiesce in pair, but it
is hard to switch to this style, so these drivers need one atomic flag for
helping to balance quiesce and unquiesce.
When quiesce is in-progress, the driver still needs to wait until
the quiesce is done, so add API of blk_mq_wait_quiesce_done() for
these drivers.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20211109071144.181581-2-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We got UAF report on v5.10 as follows:
[ 1446.674930] ==================================================================
[ 1446.675970] BUG: KASAN: use-after-free in blk_mq_get_driver_tag+0x9a4/0xa90
[ 1446.676902] Read of size 8 at addr ffff8880185afd10 by task kworker/1:2/12348
[ 1446.677851]
[ 1446.678073] CPU: 1 PID: 12348 Comm: kworker/1:2 Not tainted 5.10.0-10177-gc9c81b1e346a #2
[ 1446.679168] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
[ 1446.680692] Workqueue: kthrotld blk_throtl_dispatch_work_fn
[ 1446.681448] Call Trace:
[ 1446.681800] dump_stack+0x9b/0xce
[ 1446.682916] print_address_description.constprop.6+0x3e/0x60
[ 1446.685999] kasan_report.cold.9+0x22/0x3a
[ 1446.687186] blk_mq_get_driver_tag+0x9a4/0xa90
[ 1446.687785] blk_mq_dispatch_rq_list+0x21a/0x1d40
[ 1446.692576] __blk_mq_do_dispatch_sched+0x394/0x830
[ 1446.695758] __blk_mq_sched_dispatch_requests+0x398/0x4f0
[ 1446.698279] blk_mq_sched_dispatch_requests+0xdf/0x140
[ 1446.698967] __blk_mq_run_hw_queue+0xc0/0x270
[ 1446.699561] __blk_mq_delay_run_hw_queue+0x4cc/0x550
[ 1446.701407] blk_mq_run_hw_queue+0x13b/0x2b0
[ 1446.702593] blk_mq_sched_insert_requests+0x1de/0x390
[ 1446.703309] blk_mq_flush_plug_list+0x4b4/0x760
[ 1446.705408] blk_flush_plug_list+0x2c5/0x480
[ 1446.708471] blk_finish_plug+0x55/0xa0
[ 1446.708980] blk_throtl_dispatch_work_fn+0x23b/0x2e0
[ 1446.711236] process_one_work+0x6d4/0xfe0
[ 1446.711778] worker_thread+0x91/0xc80
[ 1446.713400] kthread+0x32d/0x3f0
[ 1446.714362] ret_from_fork+0x1f/0x30
[ 1446.714846]
[ 1446.715062] Allocated by task 1:
[ 1446.715509] kasan_save_stack+0x19/0x40
[ 1446.716026] __kasan_kmalloc.constprop.1+0xc1/0xd0
[ 1446.716673] blk_mq_init_tags+0x6d/0x330
[ 1446.717207] blk_mq_alloc_rq_map+0x50/0x1c0
[ 1446.717769] __blk_mq_alloc_map_and_request+0xe5/0x320
[ 1446.718459] blk_mq_alloc_tag_set+0x679/0xdc0
[ 1446.719050] scsi_add_host_with_dma.cold.3+0xa0/0x5db
[ 1446.719736] virtscsi_probe+0x7bf/0xbd0
[ 1446.720265] virtio_dev_probe+0x402/0x6c0
[ 1446.720808] really_probe+0x276/0xde0
[ 1446.721320] driver_probe_device+0x267/0x3d0
[ 1446.721892] device_driver_attach+0xfe/0x140
[ 1446.722491] __driver_attach+0x13a/0x2c0
[ 1446.723037] bus_for_each_dev+0x146/0x1c0
[ 1446.723603] bus_add_driver+0x3fc/0x680
[ 1446.724145] driver_register+0x1c0/0x400
[ 1446.724693] init+0xa2/0xe8
[ 1446.725091] do_one_initcall+0x9e/0x310
[ 1446.725626] kernel_init_freeable+0xc56/0xcb9
[ 1446.726231] kernel_init+0x11/0x198
[ 1446.726714] ret_from_fork+0x1f/0x30
[ 1446.727212]
[ 1446.727433] Freed by task 26992:
[ 1446.727882] kasan_save_stack+0x19/0x40
[ 1446.728420] kasan_set_track+0x1c/0x30
[ 1446.728943] kasan_set_free_info+0x1b/0x30
[ 1446.729517] __kasan_slab_free+0x111/0x160
[ 1446.730084] kfree+0xb8/0x520
[ 1446.730507] blk_mq_free_map_and_requests+0x10b/0x1b0
[ 1446.731206] blk_mq_realloc_hw_ctxs+0x8cb/0x15b0
[ 1446.731844] blk_mq_init_allocated_queue+0x374/0x1380
[ 1446.732540] blk_mq_init_queue_data+0x7f/0xd0
[ 1446.733155] scsi_mq_alloc_queue+0x45/0x170
[ 1446.733730] scsi_alloc_sdev+0x73c/0xb20
[ 1446.734281] scsi_probe_and_add_lun+0x9a6/0x2d90
[ 1446.734916] __scsi_scan_target+0x208/0xc50
[ 1446.735500] scsi_scan_channel.part.3+0x113/0x170
[ 1446.736149] scsi_scan_host_selected+0x25a/0x360
[ 1446.736783] store_scan+0x290/0x2d0
[ 1446.737275] dev_attr_store+0x55/0x80
[ 1446.737782] sysfs_kf_write+0x132/0x190
[ 1446.738313] kernfs_fop_write_iter+0x319/0x4b0
[ 1446.738921] new_sync_write+0x40e/0x5c0
[ 1446.739429] vfs_write+0x519/0x720
[ 1446.739877] ksys_write+0xf8/0x1f0
[ 1446.740332] do_syscall_64+0x2d/0x40
[ 1446.740802] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 1446.741462]
[ 1446.741670] The buggy address belongs to the object at ffff8880185afd00
[ 1446.741670] which belongs to the cache kmalloc-256 of size 256
[ 1446.743276] The buggy address is located 16 bytes inside of
[ 1446.743276] 256-byte region [ffff8880185afd00, ffff8880185afe00)
[ 1446.744765] The buggy address belongs to the page:
[ 1446.745416] page:ffffea0000616b00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x185ac
[ 1446.746694] head:ffffea0000616b00 order:2 compound_mapcount:0 compound_pincount:0
[ 1446.747719] flags: 0x1fffff80010200(slab|head)
[ 1446.748337] raw: 001fffff80010200 ffffea00006a3208 ffffea000061bf08 ffff88801004f240
[ 1446.749404] raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
[ 1446.750455] page dumped because: kasan: bad access detected
[ 1446.751227]
[ 1446.751445] Memory state around the buggy address:
[ 1446.752102] ffff8880185afc00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 1446.753090] ffff8880185afc80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 1446.754079] >ffff8880185afd00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 1446.755065] ^
[ 1446.755589] ffff8880185afd80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 1446.756574] ffff8880185afe00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 1446.757566] ==================================================================
Flag 'BLK_MQ_F_TAG_QUEUE_SHARED' will be set if the second device on the
same host initializes it's queue successfully. However, if the second
device failed to allocate memory in blk_mq_alloc_and_init_hctx() from
blk_mq_realloc_hw_ctxs() from blk_mq_init_allocated_queue(),
__blk_mq_free_map_and_rqs() will be called on error path, and if
'BLK_MQ_TAG_HCTX_SHARED' is not set, 'tag_set->tags' will be freed
while it's still used by the first device.
To fix this issue we move release newly allocated hardware context from
blk_mq_realloc_hw_ctxs to __blk_mq_update_nr_hw_queues. As there is needn't to
release hardware context in blk_mq_init_allocated_queue.
Fixes: 868f2f0b72 ("blk-mq: dynamic h/w context count")
Signed-off-by: Ye Bin <yebin10@huawei.com>
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211108074019.1058843-1-yebin10@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we're driving multiple devices, we could have pre-populated the cache
for a different device. Ensure that the empty request matches the current
queue.
Fixes: 47c122e35d ("block: pre-allocate requests if plug is started and is a batch")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Retain the old logic for the fops based submit, but for our internal
blk_mq_submit_bio(), move the queue entering logic into the core
function itself.
We need to be a bit careful if going into the scheduler, as a scheduler
or queue mappings can arbitrarily change before we have entered the queue.
Have the bio scheduler mapping do that separately, it's a very cheap
operation compared to actually doing merging locking and lookups.
Reviewed-by: Christoph Hellwig <hch@lst.de>
[axboe: update to check merge post submit_bio_checks() doing remap...]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This is in preparation for a fix, but serves as a cleanup as well moving
the cached vs regular alloc logic out of blk_mq_submit_bio().
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Requests that were stored in the cache deliberately didn't hold an enter
reference to the queue, instead we grabbed one every time we pulled a
request out of there. That made for awkward logic on freeing the remainder
of the cached list, if needed, where we had to artificially raise the
queue usage count before each free.
Grab references up front for cached plug requests. That's safer, and also
more efficient.
Fixes: 47c122e35d ("block: pre-allocate requests if plug is started and is a batch")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In case of shared tags and none io sched, batched completion still may
be run into, and hctx->nr_active is accounted when getting driver tag,
so it has to be updated in blk_mq_end_request_batch().
Otherwise, hctx->nr_active may become same with queue depth, then
hctx_may_queue() always return false, then io hang is caused.
Fixes the issue by updating the counter in batched way.
Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Fixes: f794f3351f ("block: add support for blk_mq_end_request_batch()")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211102153619.3627505-4-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
It's not safe to do this before blk_queue_enter(), as the scheduler state
could have changed in between. Hence move the RQF_ELV setting into the
allocators, where we know the queue is already entered.
Suggested-by: Ming Lei <ming.lei@redhat.com>
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Reported-by: Steffen Maier <maier@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
A previous commit fixed up the condition for doing direct issue, but that
left the 'from_schedule' argument dead inside the branch. Replace it with
'false'.
Fixes: ff1552232b ("blk-mq: don't issue request directly in case that current is to be blocked")
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Ensure that current tag is correctly assigned before attempting
to prefetch the first cacheline of the request.
Fixes: 92aff191cc ("block: prefetch request to be initialized")
Reported-and-tested-by: syzbot+cd20829ac44b92bf6ed0@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'for-5.16/block-2021-10-29' of git://git.kernel.dk/linux-block
Pull block updates from Jens Axboe:
- mq-deadline accounting improvements (Bart)
- blk-wbt timer fix (Andrea)
- Untangle the block layer includes (Christoph)
- Rework the poll support to be bio based, which will enable adding
support for polling for bio based drivers (Christoph)
- Block layer core support for multi-actuator drives (Damien)
- blk-crypto improvements (Eric)
- Batched tag allocation support (me)
- Request completion batching support (me)
- Plugging improvements (me)
- Shared tag set improvements (John)
- Concurrent queue quiesce support (Ming)
- Cache bdev in ->private_data for block devices (Pavel)
- bdev dio improvements (Pavel)
- Block device invalidation and block size improvements (Xie)
- Various cleanups, fixes, and improvements (Christoph, Jackie,
Masahira, Tejun, Yu, Pavel, Zheng, me)
* tag 'for-5.16/block-2021-10-29' of git://git.kernel.dk/linux-block: (174 commits)
blk-mq-debugfs: Show active requests per queue for shared tags
block: improve readability of blk_mq_end_request_batch()
virtio-blk: Use blk_validate_block_size() to validate block size
loop: Use blk_validate_block_size() to validate block size
nbd: Use blk_validate_block_size() to validate block size
block: Add a helper to validate the block size
block: re-flow blk_mq_rq_ctx_init()
block: prefetch request to be initialized
block: pass in blk_mq_tags to blk_mq_rq_ctx_init()
block: add rq_flags to struct blk_mq_alloc_data
block: add async version of bio_set_polled
block: kill DIO_MULTI_BIO
block: kill unused polling bits in __blkdev_direct_IO()
block: avoid extra iter advance with async iocb
block: Add independent access ranges support
blk-mq: don't issue request directly in case that current is to be blocked
sbitmap: silence data race warning
blk-cgroup: synchronize blkg creation against policy deactivation
block: refactor bio_iov_bvec_set()
block: add single bio async direct IO helper
...
It's faster and easier to read if we tolerate cur_hctx being NULL in
the "when to flush" condition. Rename last_hctx to cur_hctx while at it,
as it better describes the role of that variable.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Now that we have flags passed in, we can do a final re-arrange of the
flow of blk_mq_rq_ctx_init() so we're always writing request in the
order in which it is laid out.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/20211019153300.623322-5-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Now we have the tags available in __blk_mq_alloc_requests_batch(), we
can start fetching the first request cacheline before calling into the
request initialization.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/20211019153300.623322-4-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Instead of getting this from data for every invocation of request
initialization, pass it in as an argument instead.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/20211019153300.623322-3-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There's a hole here we can use, and it's faster to set this earlier
rather than need to check q->elevator multiple times.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/20211019153300.623322-2-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When dispatching a zone append write request to a SCSI zoned block device,
if the target zone of the request is already locked, the device driver will
return BLK_STS_ZONE_RESOURCE and the request will be pushed back to the
hctx dipatch queue. The queue will be marked as RESTART in
dd_finish_request() and restarted in __blk_mq_free_request(). However, this
restart applies to the hctx of the completed request. If the requeued
request is on a different hctx, dispatch will no be retried until another
request is submitted or the next periodic queue run triggers, leading to up
to 30 seconds latency for the requeued request.
Fix this problem by scheduling a queue restart similarly to the
BLK_STS_RESOURCE case or when we cannot get the budget.
Also, consolidate the checks into the "need_resource" variable to simplify
the condition.
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Niklas Cassel <Niklas.Cassel@wdc.com>
Link: https://lore.kernel.org/r/20211026165127.4151055-1-naohiro.aota@wdc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When flushing plug list in case that current will be blocked, we can't
issue request directly because ->queue_rq() may sleep, otherwise scheduler
may complain.
Fixes: dc5fc361d8 ("block: attempt direct issue of plug list")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211026082257.2889890-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Shinichiro Kawasaki reports that there is a bug in a recent
req_bio_endio() patch causing problems with zonefs. As Shinichiro
suggested, inverse the condition in zone append path to resemble how it
was before: fail when it's not fully completed.
Fixes: 478eb72b81 ("block: optimise req_bio_endio()")
Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/344ea4e334aace9148b41af5f2426da38c8aa65a.1634914228.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Replace the call to blk_flush_plug_list in blk_mq_submit_bio with a
direct call to blk_mq_flush_plug_list. This means we do not flush
plug callback from stackable devices, which doesn't really help with
the accumulated requests anyway, and it also means the cached requests
aren't freed here as they can still be used later on.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211020144119.142582-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This check is meant to catch cases where a requeue is attempted on a
request that is still inserted. It's never really been useful to catch any
misuse, and now it's actively wrong. Outside of that, this should not be a
BUG_ON() to begin with.
Remove the check as it's now causing active harm, as requeue off the plug
path will trigger it even though the request state is just fine.
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Link: https://lore.kernel.org/linux-block/CAHj4cs80zAUc2grnCZ015-2Rvd-=gXRfB_dFKy=RTm+wRo09HQ@mail.gmail.com/
Signed-off-by: Jens Axboe <axboe@kernel.dk>
First, get rid of an extra branch and chain error checks. Also reshuffle
it with bio_advance(), so it goes closer to the final check, with that
the compiler loads rq->rq_flags only once, and also doesn't reload
bio->bi_iter.bi_size if bio_advance() didn't actually advanced the iter.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we don't use an IO scheduler or have shared tags, then we don't need
to call into this external function at all. This saves ~2% for such
a setup.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Return to the normal blk_mq_submit_bio flow if the bio did not end up
actually being a flush because the device didn't support it. Note that
this is basically impossible to hit without special instrumentation given
that submit_bio_checks already clears these flags usually, so we'd need a
tight race to actually hit this code path.
With this the call to blk_mq_run_hw_queue for the flush requests can be
removed given that the actual flush requests are always issued via the
requeue workqueue which runs the queue unconditionally.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211019122553.2467817-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we have just one queue type in the plug list, then we can extend our
direct issue to cover a full plug list as well. This allows sending a
batch of requests for direct issue, which is more efficient than doing
one-at-a-time kind of issue.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Use a singly linked list for the blk_plug. This saves 8 bytes in the
blk_plug struct, and makes for faster list manipulations than doubly
linked lists. As we don't use the doubly linked lists for anything,
singly linked is just fine.
This yields a bump in default (merging enabled) performance from 7.0
to 7.1M IOPS, and ~7.5M IOPS with merging disabled.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This is in the fast path of driver issue or completion, and it's a single
array index operation. Move it inline to avoid a function call for it.
This does mean making struct blk_mq_tags block layer public, but there's
not really much in there.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Even if we have multiple queues in the plug list, chances that they
are very interspersed is minimal. Don't bother spending CPU cycles
sorting the list.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Instead of returning the same queue request through a request pointer,
use a boolean to accomplish the same.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We only need to call it to resolve the blk_status_t -> errno mapping for
tracing, so move the conversion into the tracepoints that are not called
at all when tracing isn't enabled.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We added RQF_ELV to tell whether there's an IO scheduler attached, and
RQF_ELVPRIV tells us whether there's an IO scheduler with private data
attached. Don't check RQF_ELV in blk_mq_free_request(), what we care
about here is just if we have scheduler private data attached.
This fixes a boot crash
Fixes: 2ff0682da6 ("block: store elevator state in request")
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Reported-by: syzbot+eb8104072aeab6cc1195@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Instead of calling blk_mq_end_request() on a single request, add a helper
that takes the new struct io_comp_batch and completes any request stored
in there.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
struct io_comp_batch contains a list head and a completion handler, which
will allow completions to more effciently completed batches of IO.
For now, no functional changes in this patch, we just define the
io_comp_batch structure and add the argument to the file_operations iopoll
handler.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Instead of open-coding the list additions, traversal, and removal,
provide a basic set of helpers.
Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Just like the blk_mq_ctx counterparts, we've got a bunch of counters
in here that are only for debugfs and are of questionnable value. They
are:
- dispatched, index of how many requests were dispatched in one go
- poll_{considered,invoked,success}, which track poll sucess rates. We're
confident in the iopoll implementation at this point, don't bother
tracking these.
As a bonus, this shrinks each hardware queue from 576 bytes to 512 bytes,
dropping a whole cacheline.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
These were added as part of early days debugging for blk-mq, and they
are not really useful anymore. Rather than spend cycles updating them,
just get rid of them.
As a bonus, this shrinks the per-cpu software queue size from 256b
to 192b. That's a whole cacheline less.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a local variable for rq_flags, it helps to compile out some of
rq_flags reloads.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We should have enough of registers in blk_mq_rq_ctx_init(), store them
in local vars, so we don't keep reloading them.
note: keeping q->elevator may look unnecessary, but it's also used
inside inlined blk_mq_tags_from_data().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Don't init rq->hash and rq->rb_node in blk_mq_rq_ctx_init() if there is
no elevator. Also, move some other initialisers that imply barriers to
the end, so the compiler is free to rearrange and optimise other the
rest of them.
note: fold in a change from Jens leaving queue_list unconditional, as
it might lead to problems otherwise.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add an rq private RQF_ELV flag, which tells the block layer that this
request was initialized on a queue that has an IO scheduler attached.
This allows for faster checking in the fast path, rather than having to
deference rq->q later on.
Elevator switching does full quiesce of the queue before detaching an
IO scheduler, so it's safe to cache this in the request itself.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
For some reason we still have them in blk-core, with the rest of the
request completion being in blk-mq. That causes and out-of-line call
for each completion.
Move them into blk-mq.c instead, where they belong.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The fast path is no splitting needed. Separate the handling into a
check part we can inline, and an out-of-line handling path if we do
need to split.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Replace the blk_poll interface that requires the caller to keep a queue
and cookie from the submissions with polling based on the bio.
Polling for the bio itself leads to a few advantages:
- the cookie construction can made entirely private in blk-mq.c
- the caller does not need to remember the request_queue and cookie
separately and thus sidesteps their lifetime issues
- keeping the device and the cookie inside the bio allows to trivially
support polling BIOs remapping by stacking drivers
- a lot of code to propagate the cookie back up the submission path can
be removed entirely.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Mark Wunderlich <mark.wunderlich@intel.com>
Link: https://lore.kernel.org/r/20211012111226.760968-15-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Unlike the RWF_HIPRI userspace ABI which is intentionally kept vague,
the bio flag is specific to the polling implementation, so rename and
document it properly.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Tested-by: Mark Wunderlich <mark.wunderlich@intel.com>
Link: https://lore.kernel.org/r/20211012111226.760968-12-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There is no point in sleeping for the expected I/O completion timeout
in the io_uring async polling model as we never poll for a specific
I/O.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Mark Wunderlich <mark.wunderlich@intel.com>
Link: https://lore.kernel.org/r/20211012111226.760968-11-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
David Jeffery