Convert any user of ktime_get_ns() to use blk_time_get_ns(), and
ktime_get() to blk_time_get(), so we have a unified API for querying the
current time in nanoseconds or as ktime.
No functional changes intended, this patch just wraps ktime_get_ns()
and ktime_get() with a block helper.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Since the previous patch change to only account active requests when
we really allocate the driver tag, the RQF_MQ_INFLIGHT can be removed
and no double account problem.
1. none elevator: flush request will use the first pending request's
driver tag, won't double account.
2. other elevator: flush request will be accounted when allocate driver
tag when issue, and will be unaccounted when it put the driver tag.
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230913151616.3164338-3-chengming.zhou@linux.dev
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Since we don't need to maintain inflight flush_data requests list
anymore, we can reuse rq->queuelist for flush pending list.
Note in mq_flush_data_end_io(), we need to re-initialize rq->queuelist
before reusing it in the state machine when end, since the rq->rq_next
also reuse it, may have corrupted rq->queuelist by the driver.
This patch decrease the size of struct request by 16 bytes.
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230717040058.3993930-5-chengming.zhou@linux.dev
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The flush state machine use a double list to link all inflight
flush_data requests, to avoid issuing separate post-flushes for
these flush_data requests which shared PREFLUSH.
So we can't reuse rq->queuelist, this is why we need rq->flush.list
In preparation of the next patch that reuse rq->queuelist for flush
state machine, we change the double linked list to unsigned long
counter, which count all inflight flush_data requests.
This is ok since we only need to know if there is any inflight
flush_data request, so unsigned long counter is good.
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230717040058.3993930-4-chengming.zhou@linux.dev
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If the policy == (REQ_FSEQ_DATA | REQ_FSEQ_POSTFLUSH), it means that the
data sequence and post-flush sequence need to be done for this request.
The rq->flush.seq should record what sequences have been done (or don't
need to be done). So in this case, pre-flush doesn't need to be done,
we should init rq->flush.seq to REQ_FSEQ_PREFLUSH not REQ_FSEQ_POSTFLUSH.
Fixes: 615939a2ae ("blk-mq: defer to the normal submission path for post-flush requests")
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230717040058.3993930-3-chengming.zhou@linux.dev
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We used to insert the data commands following a pre-flush to the head
of the queue until commit 1e82fadfc6 ("blk-mq: do not do head insertions
post-pre-flush commands"). Not doing this seems to cause hangs of
such commands on NFS workloads when exported from file systems with
SATA SSDs. I have no idea why this would starve these workloads,
but doing a semantic revert of this patch (which looks quite different
due to various other changes) fixes the hangs.
Fixes: 1e82fadfc6 ("blk-mq: do not do head insertions post-pre-flush commands")
Reported-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://lore.kernel.org/r/20230714143014.11879-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Currently both requeues of commands that were already sent to the driver
and flush commands submitted from the flush state machine share the same
requeue_list struct request_queue, despite requeues doing head
insertions and flushes not. Switch to using two separate lists instead.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20230519044050.107790-8-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk_flush_complete_seq currently queues requests that write data after
a pre-flush from the flush state machine at the head of the queue.
This doesn't really make sense, as the original request bypassed all
queue lists by directly diverting to blk_insert_flush from
blk_mq_submit_bio.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20230519044050.107790-7-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Requests with the FUA bit on hardware without FUA support need a post
flush before returning to the caller, but they can still be sent using
the normal I/O path after initializing the flush-related fields and
end I/O handler.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20230519044050.107790-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If blk_insert_flush decides that a command does not need to use the
flush state machine, return false and let blk_mq_submit_bio handle
it the normal way (including using an I/O scheduler) instead of doing
a bypass insert.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20230519044050.107790-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Use a switch statement to decide on the disposition of a flush request
instead of multiple if statements, out of which one does checks that are
more complex than required. Also warn on a malformed request early
on instead of doing a BUG_ON later.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20230519044050.107790-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Factor out a helper from blk_insert_flush that initializes the flush
machine related fields in struct request, and don't bother with the
full memset as there's just a few fields to initialize, and all but
one already have explicit initializers.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20230519044050.107790-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Commit b12e5c6c75 accidentally changes blk_kick_flush to do a head
insert into the requeue list, fix this up.
Fixes: b12e5c6c75 ("blk-mq: pass a flags argument to blk_mq_add_to_requeue_list")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230416073553.966161-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Replace the boolean at_head argument with the same flags that are already
passed to blk_mq_insert_request.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20230413064057.707578-21-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Replace the boolean at_head argument with the same flags that are already
passed to blk_mq_insert_request.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20230413064057.707578-19-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk_mq_add_to_requeue_list takes a bool parameter to control how to kick
the requeue list at the end of the function. Move the call to
blk_mq_kick_requeue_list to the callers that want it instead.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20230413064057.707578-17-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk_mq_request_bypass_insert takes a bool parameter to control how to run
the queue at the end of the function. Move the blk_mq_run_hw_queue call
to the callers that want it instead.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20230413064057.707578-16-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Just call blk_mq_add_to_requeue_list directly from the two callers.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20230413064057.707578-10-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
block/blk-mq.h needs various definitions from <linux/blk-mq.h>,
include it there instead of relying on the source files to include
both.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20230413064057.707578-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk-mq-tag.h is always included by blk-mq.h, and causes recursive
inclusion hell with further changes. Just merge it into blk-mq.h
instead.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20230413064057.707578-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Everything is just converted to returning RQ_END_IO_NONE, and there
should be no functional changes with this patch.
In preparation for allowing the end_io handler to pass ownership back
to the block layer, rather than retain ownership of the request.
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We've never had any useful reports from this BUG_ON(), and in fact a
number of the BUG_ON()'s in the flush handling need to be turned into
more graceful handling.
In preparation for allowing batched completions of the end_io handling,
where we can enter the flush completion with queuelist having been reused
for the batch, get rid of this BUG_ON().
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Use the new blk_opf_t type for arguments and variables that represent
request flags or a bitwise combination of a request operation and
request flags. Rename the function arguments and also a structure member
that hold a request operation and flags from 'rw' into 'opf'.
This patch does not change any functionality.
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Damien Le Moal <damien.lemoal@wdc.com>
Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20220714180729.1065367-7-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pass the block_device that we plan to use this bio for and the
operation to bio_init to optimize the assignment. A NULL block_device
can be passed, both for the passthrough case on a raw request_queue and
to temporarily avoid refactoring some nasty code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220124091107.642561-19-hch@lst.de
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>
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>
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>
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>
is_flush_rq() is called from bt_iter()/bt_tags_iter(), and runs the
following check:
hctx->fq->flush_rq == req
but the passed hctx from bt_iter()/bt_tags_iter() may be NULL because:
1) memory re-order in blk_mq_rq_ctx_init():
rq->mq_hctx = data->hctx;
...
refcount_set(&rq->ref, 1);
OR
2) tag re-use and ->rqs[] isn't updated with new request.
Fix the issue by re-writing is_flush_rq() as:
return rq->end_io == flush_end_io;
which turns out simpler to follow and immune to data race since we have
ordered WRITE rq->end_io and refcount_set(&rq->ref, 1).
Fixes: 2e315dc07d ("blk-mq: grab rq->refcount before calling ->fn in blk_mq_tagset_busy_iter")
Cc: "Blank-Burian, Markus, Dr." <blankburian@uni-muenster.de>
Cc: Yufen Yu <yuyufen@huawei.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20210818010925.607383-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
For fixing use-after-free during iterating over requests, we grabbed
request's refcount before calling ->fn in commit 2e315dc07d ("blk-mq:
grab rq->refcount before calling ->fn in blk_mq_tagset_busy_iter").
Turns out this way may cause kernel panic when iterating over one flush
request:
1) old flush request's tag is just released, and this tag is reused by
one new request, but ->rqs[] isn't updated yet
2) the flush request can be re-used for submitting one new flush command,
so blk_rq_init() is called at the same time
3) meantime blk_mq_queue_tag_busy_iter() is called, and old flush request
is retrieved from ->rqs[tag]; when blk_mq_put_rq_ref() is called,
flush_rq->end_io may not be updated yet, so NULL pointer dereference
is triggered in blk_mq_put_rq_ref().
Fix the issue by calling refcount_set(&flush_rq->ref, 1) after
flush_rq->end_io is set. So far the only other caller of blk_rq_init() is
scsi_ioctl_reset() in which the request doesn't enter block IO stack and
the request reference count isn't used, so the change is safe.
Fixes: 2e315dc07d ("blk-mq: grab rq->refcount before calling ->fn in blk_mq_tagset_busy_iter")
Reported-by: "Blank-Burian, Markus, Dr." <blankburian@uni-muenster.de>
Tested-by: "Blank-Burian, Markus, Dr." <blankburian@uni-muenster.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Garry <john.garry@huawei.com>
Link: https://lore.kernel.org/r/20210811142624.618598-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
For flush request, rq->end_io() may be called two times, one is from
timeout handling(blk_mq_check_expired()), another is from normal
completion(__blk_mq_end_request()).
Move blk_account_io_flush() after flush_rq->ref drops to zero, so
io accounting can be done just once for flush request.
Fixes: b686631865 ("block: add iostat counters for flush requests")
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: John Garry <john.garry@huawei.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20210511152236.763464-2-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There is no point in allocating memory for a synchronous flush.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Acked-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
-----BEGIN PGP SIGNATURE-----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=zo4w
-----END PGP SIGNATURE-----
Merge tag 'for-5.11/block-2020-12-14' of git://git.kernel.dk/linux-block
Pull block updates from Jens Axboe:
"Another series of killing more code than what is being added, again
thanks to Christoph's relentless cleanups and tech debt tackling.
This contains:
- blk-iocost improvements (Baolin Wang)
- part0 iostat fix (Jeffle Xu)
- Disable iopoll for split bios (Jeffle Xu)
- block tracepoint cleanups (Christoph Hellwig)
- Merging of struct block_device and hd_struct (Christoph Hellwig)
- Rework/cleanup of how block device sizes are updated (Christoph
Hellwig)
- Simplification of gendisk lookup and removal of block device
aliasing (Christoph Hellwig)
- Block device ioctl cleanups (Christoph Hellwig)
- Removal of bdget()/blkdev_get() as exported API (Christoph Hellwig)
- Disk change rework, avoid ->revalidate_disk() (Christoph Hellwig)
- sbitmap improvements (Pavel Begunkov)
- Hybrid polling fix (Pavel Begunkov)
- bvec iteration improvements (Pavel Begunkov)
- Zone revalidation fixes (Damien Le Moal)
- blk-throttle limit fix (Yu Kuai)
- Various little fixes"
* tag 'for-5.11/block-2020-12-14' of git://git.kernel.dk/linux-block: (126 commits)
blk-mq: fix msec comment from micro to milli seconds
blk-mq: update arg in comment of blk_mq_map_queue
blk-mq: add helper allocating tagset->tags
Revert "block: Fix a lockdep complaint triggered by request queue flushing"
nvme-loop: use blk_mq_hctx_set_fq_lock_class to set loop's lock class
blk-mq: add new API of blk_mq_hctx_set_fq_lock_class
block: disable iopoll for split bio
block: Improve blk_revalidate_disk_zones() checks
sbitmap: simplify wrap check
sbitmap: replace CAS with atomic and
sbitmap: remove swap_lock
sbitmap: optimise sbitmap_deferred_clear()
blk-mq: skip hybrid polling if iopoll doesn't spin
blk-iocost: Factor out the base vrate change into a separate function
blk-iocost: Factor out the active iocgs' state check into a separate function
blk-iocost: Move the usage ratio calculation to the correct place
blk-iocost: Remove unnecessary advance declaration
blk-iocost: Fix some typos in comments
blktrace: fix up a kerneldoc comment
block: remove the request_queue to argument request based tracepoints
...
This reverts commit b3c6a59975.
Now we can avoid nvme-loop lockdep warning of 'lockdep possible recursive locking'
by nvme-loop's lock class, no need to apply dynamically allocated lock class key,
so revert commit b3c6a5997541("block: Fix a lockdep complaint triggered by request
queue flushing").
This way fixes horrible SCSI probe delay issue on megaraid_sas, and it is reported
the whole probe may take more than half an hour.
Tested-by: Kashyap Desai <kashyap.desai@broadcom.com>
Reported-by: Qian Cai <cai@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Sumit Saxena <sumit.saxena@broadcom.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Kashyap Desai <kashyap.desai@broadcom.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Hannes Reinecke <hare@suse.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
flush_end_io() may be called recursively from some driver, such as
nvme-loop, so lockdep may complain 'possible recursive locking'.
Commit b3c6a5997541("block: Fix a lockdep complaint triggered by
request queue flushing") tried to address this issue by assigning
dynamically allocated per-flush-queue lock class. This solution
adds synchronize_rcu() for each hctx's release handler, and causes
horrible SCSI MQ probe delay(more than half an hour on megaraid sas).
Add new API of blk_mq_hctx_set_fq_lock_class() for these drivers, so
we just need to use driver specific lock class for avoiding the
lockdep warning of 'possible recursive locking'.
Tested-by: Kashyap Desai <kashyap.desai@broadcom.com>
Reported-by: Qian Cai <cai@redhat.com>
Cc: Sumit Saxena <sumit.saxena@broadcom.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Kashyap Desai <kashyap.desai@broadcom.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Hannes Reinecke <hare@suse.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Use struct block_device to lookup partitions on a disk. This removes
all usage of struct hd_struct from the I/O path.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Coly Li <colyli@suse.de> [bcache]
Acked-by: Chao Yu <yuchao0@huawei.com> [f2fs]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Allocate hd_struct together with struct block_device to pre-load
the lifetime rule changes in preparation of merging the two structures.
Note that part0 was previously embedded into struct gendisk, but is
a separate allocation now, and already points to the block_device instead
of the hd_struct. The lifetime of struct gendisk is still controlled by
the struct device embedded in the part0 hd_struct.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
For avoiding use-after-free on flush request, we call its .end_io() from
both timeout code path and __blk_mq_end_request().
When flush request's ref doesn't drop to zero, it is still used, we
can't mark it as IDLE, so fix it by marking IDLE when its refcount drops
to zero really.
Fixes: 65ff5cd045 ("blk-mq: mark flush request as IDLE in flush_end_io()")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Cc: Yi Zhang <yi.zhang@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Mark flush request as IDLE in its .end_io(), aligning it with how normal
requests behave. The flush request stays in in-flight tags if we're not
using an IO scheduler, so we need to change its state into IDLE.
Otherwise, we will hang in blk_mq_tagset_wait_completed_request() during
error recovery because flush the request state is kept as COMPLETED.
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Tested-by: Yi Zhang <yi.zhang@redhat.com>
Cc: Chao Leng <lengchao@huawei.com>
Cc: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In case of none scheduler, we share data request's driver tag for
flush request, so have to mark the flush request as INFLIGHT for
avoiding double account of this driver tag.
Fixes: 568f270065 ("blk-mq: centralise related handling into blk_mq_get_driver_tag")
Reported-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Tested-by: Matthew Wilcox <willy@infradead.org>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Commit 7520872c0c ("block: don't defer flushes on blk-mq + scheduling")
tried to fix deadlock for cycled wait between flush requests and data
request into flush_data_in_flight. The former holded all driver tags
and wait for data request completion, but the latter can not complete
for waiting free driver tags.
After commit 923218f616 ("blk-mq: don't allocate driver tag upfront
for flush rq"), flush requests will not get driver tag before queuing
into flush queue.
* With elevator, flush request just get sched_tags before inserting
flush queue. It will not get driver tag until issue them to driver.
data request on list fq->flush_data_in_flight will complete in
the end.
* Without elevator, each flush request will get a driver tag when
allocate request. Then data request on fq->flush_data_in_flight
don't worry about lacking driver tag.
In both of these cases, cycled wait cannot be true. So we may allow
to defer flush request.
Signed-off-by: Yufen Yu <yuyufen@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Move .nr_active update and request assignment into blk_mq_get_driver_tag(),
all are good to do during getting driver tag.
Meantime blk-flush related code is simplified and flush request needn't
to update the request table manually any more.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Move .nr_active update and request assignment into blk_mq_get_driver_tag(),
all are good to do during getting driver tag.
Meantime blk-flush related code is simplified and flush request needn't
to update the request table manually any more.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
It is natural to release driver tag when this request is completed by
LLD or device since its purpose is for LLD use.
One big benefit is that the released tag can be re-used quicker since
bio_endio() may take too long.
Meantime we don't need to release driver tag for flush request.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The argument isn't used by any caller, and drivers don't fill out
bi_sector for flush requests either.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
