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3 years agoblock/mq-deadline: Remove a WARN_ON_ONCE() call
Bart Van Assche [Sun, 27 Jun 2021 21:11:12 +0000 (14:11 -0700)]
block/mq-deadline: Remove a WARN_ON_ONCE() call

The purpose of the WARN_ON_ONCE() statement in dd_insert_request() is to
verify that dd_prepare_request() cleared rq->elv.priv[0]. Since
dd_prepare_request() is called during request initialization but not if a
request is requeued, a warning is triggered if a request is requeued. Fix
this by removing the WARN_ON_ONCE() statement. This patch suppresses the
following kernel warning:

WARNING: CPU: 28 PID: 432 at block/mq-deadline-main.c:740 dd_insert_request+0x4d4/0x5b0
Workqueue: kblockd blk_mq_requeue_work
Call Trace:
 dd_insert_requests+0xfa/0x130
 blk_mq_sched_insert_request+0x22c/0x240
 blk_mq_requeue_work+0x21c/0x2d0
 process_one_work+0x4c2/0xa70
 worker_thread+0x2e5/0x6d0
 kthread+0x21c/0x250
 ret_from_fork+0x1f/0x30

Reported-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
Fixes: 08a9ad8bf607 ("block/mq-deadline: Add cgroup support")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20210627211112.12720-1-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblk-mq: update hctx->dispatch_busy in case of real scheduler
Ming Lei [Fri, 25 Jun 2021 02:02:48 +0000 (10:02 +0800)]
blk-mq: update hctx->dispatch_busy in case of real scheduler

Commit 6e6fcbc27e77 ("blk-mq: support batching dispatch in case of io")
starts to support io batching submission by using hctx->dispatch_busy.

However, blk_mq_update_dispatch_busy() isn't changed to update hctx->dispatch_busy
in that commit, so fix the issue by updating hctx->dispatch_busy in case
of real scheduler.

Reported-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jan Kara <jack@suse.cz>
Fixes: 6e6fcbc27e77 ("blk-mq: support batching dispatch in case of io")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20210625020248.1630497-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblk: Fix lock inversion between ioc lock and bfqd lock
Jan Kara [Wed, 23 Jun 2021 09:36:34 +0000 (11:36 +0200)]
blk: Fix lock inversion between ioc lock and bfqd lock

Lockdep complains about lock inversion between ioc->lock and bfqd->lock:

bfqd -> ioc:
 put_io_context+0x33/0x90 -> ioc->lock grabbed
 blk_mq_free_request+0x51/0x140
 blk_put_request+0xe/0x10
 blk_attempt_req_merge+0x1d/0x30
 elv_attempt_insert_merge+0x56/0xa0
 blk_mq_sched_try_insert_merge+0x4b/0x60
 bfq_insert_requests+0x9e/0x18c0 -> bfqd->lock grabbed
 blk_mq_sched_insert_requests+0xd6/0x2b0
 blk_mq_flush_plug_list+0x154/0x280
 blk_finish_plug+0x40/0x60
 ext4_writepages+0x696/0x1320
 do_writepages+0x1c/0x80
 __filemap_fdatawrite_range+0xd7/0x120
 sync_file_range+0xac/0xf0

ioc->bfqd:
 bfq_exit_icq+0xa3/0xe0 -> bfqd->lock grabbed
 put_io_context_active+0x78/0xb0 -> ioc->lock grabbed
 exit_io_context+0x48/0x50
 do_exit+0x7e9/0xdd0
 do_group_exit+0x54/0xc0

To avoid this inversion we change blk_mq_sched_try_insert_merge() to not
free the merged request but rather leave that upto the caller similarly
to blk_mq_sched_try_merge(). And in bfq_insert_requests() we make sure
to free all the merged requests after dropping bfqd->lock.

Fixes: aee69d78dec0 ("block, bfq: introduce the BFQ-v0 I/O scheduler as an extra scheduler")
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Acked-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20210623093634.27879-3-jack@suse.cz
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agobfq: Remove merged request already in bfq_requests_merged()
Jan Kara [Wed, 23 Jun 2021 09:36:33 +0000 (11:36 +0200)]
bfq: Remove merged request already in bfq_requests_merged()

Currently, bfq does very little in bfq_requests_merged() and handles all
the request cleanup in bfq_finish_requeue_request() called from
blk_mq_free_request(). That is currently safe only because
blk_mq_free_request() is called shortly after bfq_requests_merged()
while bfqd->lock is still held. However to fix a lock inversion between
bfqd->lock and ioc->lock, we need to call blk_mq_free_request() after
dropping bfqd->lock. That would mean that already merged request could
be seen by other processes inside bfq queues and possibly dispatched to
the device which is wrong. So move cleanup of the request from
bfq_finish_requeue_request() to bfq_requests_merged().

Acked-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20210623093634.27879-2-jack@suse.cz
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock: pass a gendisk to bdev_disk_changed
Christoph Hellwig [Thu, 24 Jun 2021 12:32:40 +0000 (14:32 +0200)]
block: pass a gendisk to bdev_disk_changed

bdev_disk_changed can only operate on whole devices.  Make that clear
by passing a gendisk instead of the struct block_device.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210624123240.441814-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock: move bdev_disk_changed
Christoph Hellwig [Thu, 24 Jun 2021 12:32:39 +0000 (14:32 +0200)]
block: move bdev_disk_changed

Move bdev_disk_changed to block/partitions/core.c, together with the
rest of the partition scanning code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210624123240.441814-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock: add the events* attributes to disk_attrs
Christoph Hellwig [Thu, 24 Jun 2021 07:38:43 +0000 (09:38 +0200)]
block: add the events* attributes to disk_attrs

Add the events attributes to the disk_attrs array, which ensures they are
added by the driver core when the device is created rather than adding
them after the device has been added, which is racy versus uevents and
requires more boilerplate code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20210624073843.251178-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock: move the disk events code to a separate file
Christoph Hellwig [Thu, 24 Jun 2021 07:38:42 +0000 (09:38 +0200)]
block: move the disk events code to a separate file

Move the code for handling disk events from genhd.c into a new file
as it isn't very related to the rest of the file while at the same
time requiring lots of forward declarations.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20210624073843.251178-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock: fix trace completion for chained bio
Edward Hsieh [Thu, 24 Jun 2021 12:30:30 +0000 (20:30 +0800)]
block: fix trace completion for chained bio

For chained bio, trace_block_bio_complete in bio_endio is currently called
only by the parent bio once upon all chained bio completed.
However, the sector and size for the parent bio are modified in bio_split.
Therefore, the size and sector of the complete events might not match the
queue events in blktrace.

The original fix of bio completion trace <fbbaf700e7b1> ("block: trace
completion of all bios.") wants multiple complete events to correspond
to one queue event but missed this.

The issue can be reproduced by md/raid5 read with bio cross chunks.

To fix, move trace completion into the loop for every chained bio to call.

Fixes: fbbaf700e7b1 ("block: trace completion of all bios.")
Reviewed-by: Wade Liang <wadel@synology.com>
Reviewed-by: BingJing Chang <bingjingc@synology.com>
Signed-off-by: Edward Hsieh <edwardh@synology.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210624123030.27014-1-edwardh@synology.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock/partitions/msdos: Fix typo inidicator -> indicator
Thomas Bracht Laumann Jespersen [Sat, 19 Jun 2021 19:51:31 +0000 (21:51 +0200)]
block/partitions/msdos: Fix typo inidicator -> indicator

Just a fix for a small typo in msdos_partition().

Signed-off-by: Thomas Bracht Laumann Jespersen <t@laumann.xyz>
Link: https://lore.kernel.org/r/20210619195130.19348-1-t@laumann.xyz
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock, bfq: reset waker pointer with shared queues
Paolo Valente [Sat, 19 Jun 2021 14:09:48 +0000 (16:09 +0200)]
block, bfq: reset waker pointer with shared queues

Commit 85686d0dc194 ("block, bfq: keep shared queues out of the waker
mechanism") leaves shared bfq_queues out of the waker-detection
mechanism. It attains this goal by not updating the pointer
last_completed_rq_bfqq, if the last request completed belongs to a
shared bfq_queue (so that the pointer will not point to the shared
bfq_queue).

Yet this has a side effect: the pointer last_completed_rq_bfqq keeps
pointing, deceptively, to a bfq_queue that actually is not the last
one to have had a request completed. As a consequence, such a
bfq_queue may deceptively be considered as a waker of some bfq_queue,
even of some shared bfq_queue.

To address this issue, reset last_completed_rq_bfqq if the last
request completed belongs to a shared queue.

Fixes: 85686d0dc194 ("block, bfq: keep shared queues out of the waker mechanism")
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Link: https://lore.kernel.org/r/20210619140948.98712-8-paolo.valente@linaro.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock, bfq: check waker only for queues with no in-flight I/O
Paolo Valente [Sat, 19 Jun 2021 14:09:47 +0000 (16:09 +0200)]
block, bfq: check waker only for queues with no in-flight I/O

Consider two bfq_queues, say Q1 and Q2, with Q2 empty. If a request of
Q1 gets completed shortly before a new request arrives for Q2, then
BFQ flags Q1 as a candidate waker for Q2. Yet, the arrival of this new
request may have a different cause, in the following case. If also Q2
has requests in flight while waiting for the arrival of a new request,
then the completion of its own requests may be the actual cause of the
awakening of the process that sends I/O to Q2. So Q1 may be flagged
wrongly as a candidate waker.

This commit avoids this deceptive flagging, by disabling
candidate-waker flagging for Q2, if Q2 has in-flight I/O.

Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Link: https://lore.kernel.org/r/20210619140948.98712-7-paolo.valente@linaro.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock, bfq: avoid delayed merge of async queues
Paolo Valente [Sat, 19 Jun 2021 14:09:46 +0000 (16:09 +0200)]
block, bfq: avoid delayed merge of async queues

Since commit 430a67f9d616 ("block, bfq: merge bursts of newly-created
queues"), BFQ may schedule a merge between a newly created sync
bfq_queue, say Q2, and the last sync bfq_queue created, say Q1. To this
goal, BFQ stores the address of Q1 in the field bic->stable_merge_bfqq
of the bic associated with Q2. So, when the time for the possible merge
arrives, BFQ knows which bfq_queue to merge Q2 with. In particular,
BFQ checks for possible merges on request arrivals.

Yet the same bic may also be associated with an async bfq_queue, say
Q3. So, if a request for Q3 arrives, then the above check may happen
to be executed while the bfq_queue at hand is Q3, instead of Q2. In
this case, Q1 happens to be merged with an async bfq_queue. This is
not only a conceptual mistake, because async queues are to be kept out
of queue merging, but also a bug that leads to inconsistent states.

This commits simply filters async queues out of delayed merges.

Fixes: 430a67f9d616 ("block, bfq: merge bursts of newly-created queues")
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Link: https://lore.kernel.org/r/20210619140948.98712-6-paolo.valente@linaro.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock, bfq: boost throughput by extending queue-merging times
Pietro Pedroni [Sat, 19 Jun 2021 14:09:45 +0000 (16:09 +0200)]
block, bfq: boost throughput by extending queue-merging times

One of the methods with which bfq boosts throughput is by merging queues.
One of the merging variants in bfq is the stable merge.
This mechanism is activated between two queues only if they are created
within a certain maximum time T1 from each other.
Merging can happen soon or be delayed. In the second case, before
merging, bfq needs to evaluate a throughput-boost parameter that
indicates whether the queue generates a high throughput is served alone.
Merging occurs when this throughput-boost is not high enough.
In particular, this parameter is evaluated and late merging may occur
only after at least a time T2 from the creation of the queue.

Currently T1 and T2 are set to 180ms and 200ms, respectively.
In this way the merging mechanism rarely occurs because time is not
enough. This results in a noticeable lowering of the overall throughput
with some workloads (see the example below).

This commit introduces two constants bfq_activation_stable_merging and
bfq_late_stable_merging in order to increase the duration of T1 and T2.
Both the stable merging activation time and the late merging
time are set to 600ms. This value has been experimentally evaluated
using sqlite benchmark in the Phoronix Test Suite on a HDD.
The duration of the benchmark before this fix was 111.02s, while now
it has reached 97.02s, a better result than that of all the other
schedulers.

Signed-off-by: Pietro Pedroni <pedroni.pietro.96@gmail.com>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Link: https://lore.kernel.org/r/20210619140948.98712-5-paolo.valente@linaro.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock, bfq: consider also creation time in delayed stable merge
Paolo Valente [Sat, 19 Jun 2021 14:09:44 +0000 (16:09 +0200)]
block, bfq: consider also creation time in delayed stable merge

Since commit 430a67f9d616 ("block, bfq: merge bursts of newly-created
queues"), BFQ may schedule a merge between a newly created sync
bfq_queue and the last sync bfq_queue created. Such a merging is not
performed immediately, because BFQ needs first to find out whether the
newly created queue actually reaches a higher throughput if not merged
at all (and in that case BFQ will not perform any stable merging). To
check that, a little time must be waited after the creation of the new
queue, so that some I/O can flow in the queue, and statistics on such
I/O can be computed.

Yet, to evaluate the above waiting time, the last split time is
considered as start time, instead of the creation time of the
queue. This is a mistake, because considering the split time is
correct only in the following scenario.

The queue undergoes a non-stable merges on the arrival of its very
first I/O request, due to close I/O with some other queue. While the
queue is merged for close I/O, stable merging is not considered. Yet
the queue may then happen to be split, if the close I/O finishes (or
happens to be a false positive). From this time on, the queue can
again be considered for stable merging. But, again, a little time must
elapse, to let some new I/O flow in the queue and to get updated
statistics. To wait for this time, the split time is to be taken into
account.

Yet, if the queue does not undergo a non-stable merge on the arrival
of its very first request, then BFQ immediately checks whether the
stable merge is to be performed. It happens because the split time for
a queue is initialized to minus infinity when the queue is created.

This commit fixes this mistake by adding the missing condition. Now
the check for delayed stable-merge is performed after a little time is
elapsed not only from the last queue split time, but also from the
creation time of the queue.

Fixes: 430a67f9d616 ("block, bfq: merge bursts of newly-created queues")
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Link: https://lore.kernel.org/r/20210619140948.98712-4-paolo.valente@linaro.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock, bfq: fix delayed stable merge check
Luca Mariotti [Sat, 19 Jun 2021 14:09:43 +0000 (16:09 +0200)]
block, bfq: fix delayed stable merge check

When attempting to schedule a merge of a given bfq_queue with the currently
in-service bfq_queue or with a cooperating bfq_queue among the scheduled
bfq_queues, delayed stable merge is checked for rotational or non-queueing
devs. For this stable merge to be performed, some conditions must be met.
If the current bfq_queue underwent some split from some merged bfq_queue,
one of these conditions is that two hundred milliseconds must elapse from
split, otherwise this condition is always met.

Unfortunately, by mistake, time_is_after_jiffies() was written instead of
time_is_before_jiffies() for this check, verifying that less than two
hundred milliseconds have elapsed instead of verifying that at least two
hundred milliseconds have elapsed.

Fix this issue by replacing time_is_after_jiffies() with
time_is_before_jiffies().

Signed-off-by: Luca Mariotti <mariottiluca1@hotmail.it>
Signed-off-by: Paolo Valente <paolo.valente@unimore.it>
Signed-off-by: Pietro Pedroni <pedroni.pietro.96@gmail.com>
Link: https://lore.kernel.org/r/20210619140948.98712-3-paolo.valente@linaro.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock, bfq: let also stably merged queues enjoy weight raising
Paolo Valente [Sat, 19 Jun 2021 14:09:42 +0000 (16:09 +0200)]
block, bfq: let also stably merged queues enjoy weight raising

Merged bfq_queues are kept out of weight-raising (low-latency)
mechanisms. The reason is that these queues are usually created for
non-interactive and non-soft-real-time tasks. Yet this is not the case
for stably-merged queues. These queues are merged just because they
are created shortly after each other. So they may easily serve the I/O
of an interactive or soft-real time application, if the application
happens to spawn multiple processes.

To address this issue, this commits lets also stably-merged queued
enjoy weight raising.

Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Link: https://lore.kernel.org/r/20210619140948.98712-2-paolo.valente@linaro.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblk-wbt: make sure throttle is enabled properly
Zhang Yi [Sat, 19 Jun 2021 09:37:00 +0000 (17:37 +0800)]
blk-wbt: make sure throttle is enabled properly

After commit a79050434b45 ("blk-rq-qos: refactor out common elements of
blk-wbt"), if throttle was disabled by wbt_disable_default(), we could
not enable again, fix this by set enable_state back to
WBT_STATE_ON_DEFAULT.

Fixes: a79050434b45 ("blk-rq-qos: refactor out common elements of blk-wbt")
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://lore.kernel.org/r/20210619093700.920393-3-yi.zhang@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblk-wbt: introduce a new disable state to prevent false positive by rwb_enabled()
Zhang Yi [Sat, 19 Jun 2021 09:36:59 +0000 (17:36 +0800)]
blk-wbt: introduce a new disable state to prevent false positive by rwb_enabled()

Now that we disable wbt by simply zero out rwb->wb_normal in
wbt_disable_default() when switch elevator to bfq, but it's not safe
because it will become false positive if we change queue depth. If it
become false positive between wbt_wait() and wbt_track() when submit
write request, it will lead to drop rqw->inflight to -1 in wbt_done(),
which will end up trigger IO hung. Fix this issue by introduce a new
state which mean the wbt was disabled.

Fixes: a79050434b45 ("blk-rq-qos: refactor out common elements of blk-wbt")
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://lore.kernel.org/r/20210619093700.920393-2-yi.zhang@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock/mq-deadline: Prioritize high-priority requests
Bart Van Assche [Fri, 18 Jun 2021 00:44:56 +0000 (17:44 -0700)]
block/mq-deadline: Prioritize high-priority requests

While one or more requests with a certain I/O priority are pending, do not
dispatch lower priority requests. Dispatch lower priority requests anyway
after the "aging" time has expired.

This patch has been tested as follows:

modprobe scsi_debug ndelay=1000000 max_queue=16 &&
sd='' &&
while [ -z "$sd" ]; do
  sd=/dev/$(basename /sys/bus/pseudo/drivers/scsi_debug/adapter*/host*/target*/*/block/*)
done &&
echo $((100*1000)) > /sys/block/$sd/queue/iosched/aging_expire &&
cd /sys/fs/cgroup/blkio/ &&
echo $$ >cgroup.procs &&
echo restrict-to-be >blkio.prio.class &&
mkdir -p hipri &&
cd hipri &&
echo none-to-rt >blkio.prio.class &&
{ max-iops -a1 -d32 -j1 -e mq-deadline $sd >& ~/low-pri.txt & } &&
echo $$ >cgroup.procs &&
max-iops -a1 -d32 -j1 -e mq-deadline $sd >& ~/hi-pri.txt

Result:
* 11000 IOPS for the high-priority job
*    40 IOPS for the low-priority job

If the aging expiry time is changed from 100s into 0, the IOPS results change
into 6712 and 6796 IOPS.

The max-iops script is a script that runs fio with the following arguments:
--bs=4K --gtod_reduce=1 --ioengine=libaio --ioscheduler=${arg_e} --runtime=60
--norandommap --rw=read --thread --buffered=0 --numjobs=${arg_j}
--iodepth=${arg_d} --iodepth_batch_submit=${arg_a}
--iodepth_batch_complete=$((arg_d / 2)) --name=${positional_argument_1}
--filename=${positional_argument_1}

Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20210618004456.7280-17-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock/mq-deadline: Add cgroup support
Bart Van Assche [Fri, 18 Jun 2021 00:44:55 +0000 (17:44 -0700)]
block/mq-deadline: Add cgroup support

Maintain statistics per cgroup and export these to user space. These
statistics are essential for verifying whether the proper I/O priorities
have been assigned to requests. An example of the statistics data with
this patch applied:

$ cat /sys/fs/cgroup/io.stat
11:2 rbytes=0 wbytes=0 rios=3 wios=0 dbytes=0 dios=0 [NONE] dispatched=0 inserted=0 merged=171 [RT] dispatched=0 inserted=0 merged=0 [BE] dispatched=0 inserted=0 merged=0 [IDLE] dispatched=0 inserted=0 merged=0
8:32 rbytes=2142720 wbytes=0 rios=105 wios=0 dbytes=0 dios=0 [NONE] dispatched=0 inserted=0 merged=171 [RT] dispatched=0 inserted=0 merged=0 [BE] dispatched=0 inserted=0 merged=0 [IDLE] dispatched=0 inserted=0 merged=0

Cc: Damien Le Moal <damien.lemoal@wdc.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20210618004456.7280-16-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock/mq-deadline: Track I/O statistics
Bart Van Assche [Fri, 18 Jun 2021 00:44:54 +0000 (17:44 -0700)]
block/mq-deadline: Track I/O statistics

Track I/O statistics per I/O priority and export these statistics to
debugfs. These statistics help developers of the deadline scheduler.

Cc: Damien Le Moal <damien.lemoal@wdc.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20210618004456.7280-15-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock/mq-deadline: Add I/O priority support
Bart Van Assche [Fri, 18 Jun 2021 00:44:53 +0000 (17:44 -0700)]
block/mq-deadline: Add I/O priority support

Maintain one dispatch list and one FIFO list per I/O priority class: RT, BE
and IDLE. Maintain statistics for each priority level. Split the debugfs
attributes per priority level as follows:

$ ls /sys/kernel/debug/block/.../sched/
async_depth  dispatch2        read_next_rq      write2_fifo_list
batching     read0_fifo_list  starved           write_next_rq
dispatch0    read1_fifo_list  write0_fifo_list
dispatch1    read2_fifo_list  write1_fifo_list

Cc: Damien Le Moal <damien.lemoal@wdc.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20210618004456.7280-14-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock/mq-deadline: Micro-optimize the batching algorithm
Bart Van Assche [Fri, 18 Jun 2021 00:44:52 +0000 (17:44 -0700)]
block/mq-deadline: Micro-optimize the batching algorithm

When dispatching the first request of a batch, the deadline_move_request()
call clears .next_rq[] for the opposite data direction. .next_rq[] is not
restored when changing data direction. Fix this by not clearing .next_rq[]
and by keeping track of the data direction of a batch in a variable instead.

This patch is a micro-optimization because:
- The number of deadline_next_request() calls for the read direction is
  halved.
- The number of times that deadline_next_request() returns NULL is reduced.

Cc: Damien Le Moal <damien.lemoal@wdc.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20210618004456.7280-13-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock/mq-deadline: Reserve 25% of scheduler tags for synchronous requests
Bart Van Assche [Fri, 18 Jun 2021 00:44:51 +0000 (17:44 -0700)]
block/mq-deadline: Reserve 25% of scheduler tags for synchronous requests

For interactive workloads it is important that synchronous requests are
not delayed. Hence reserve 25% of scheduler tags for synchronous requests.
This patch still allows asynchronous requests to fill the hardware queues
since blk_mq_init_sched() makes sure that the number of scheduler requests
is the double of the hardware queue depth. From blk_mq_init_sched():

q->nr_requests = 2 * min_t(unsigned int, q->tag_set->queue_depth,
   BLKDEV_MAX_RQ);

Cc: Damien Le Moal <damien.lemoal@wdc.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20210618004456.7280-12-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock/mq-deadline: Improve the sysfs show and store macros
Bart Van Assche [Fri, 18 Jun 2021 00:44:50 +0000 (17:44 -0700)]
block/mq-deadline: Improve the sysfs show and store macros

Define separate macros for integers and jiffies to improve readability.
Use sysfs_emit() and kstrtoint() instead of sprintf() and simple_strtol().
The former functions are the recommended functions.

Cc: Damien Le Moal <damien.lemoal@wdc.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20210618004456.7280-11-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock/mq-deadline: Improve compile-time argument checking
Bart Van Assche [Fri, 18 Jun 2021 00:44:49 +0000 (17:44 -0700)]
block/mq-deadline: Improve compile-time argument checking

Modern compilers complain if an out-of-range value is passed to a function
argument that has an enumeration type. Let the compiler detect out-of-range
data direction arguments instead of verifying the data_dir argument at
runtime.

Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Cc: Damien Le Moal <damien.lemoal@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20210618004456.7280-10-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock/mq-deadline: Rename dd_init_queue() and dd_exit_queue()
Bart Van Assche [Fri, 18 Jun 2021 00:44:48 +0000 (17:44 -0700)]
block/mq-deadline: Rename dd_init_queue() and dd_exit_queue()

Change "queue" into "sched" to make the function names reflect better the
purpose of these functions.

Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Cc: Damien Le Moal <damien.lemoal@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20210618004456.7280-9-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock/mq-deadline: Remove two local variables
Bart Van Assche [Fri, 18 Jun 2021 00:44:47 +0000 (17:44 -0700)]
block/mq-deadline: Remove two local variables

Make __dd_dispatch_request() easier to read by removing two local
variables.

Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Cc: Damien Le Moal <damien.lemoal@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20210618004456.7280-8-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock/mq-deadline: Add two lockdep_assert_held() statements
Bart Van Assche [Fri, 18 Jun 2021 00:44:46 +0000 (17:44 -0700)]
block/mq-deadline: Add two lockdep_assert_held() statements

Document the locking strategy by adding two lockdep_assert_held()
statements.

Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Cc: Damien Le Moal <damien.lemoal@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20210618004456.7280-7-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock/mq-deadline: Add several comments
Bart Van Assche [Fri, 18 Jun 2021 00:44:45 +0000 (17:44 -0700)]
block/mq-deadline: Add several comments

Make the code easier to read by adding more comments.

Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20210618004456.7280-6-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock: Introduce the ioprio rq-qos policy
Bart Van Assche [Fri, 18 Jun 2021 00:44:44 +0000 (17:44 -0700)]
block: Introduce the ioprio rq-qos policy

Introduce an rq-qos policy that assigns an I/O priority to requests based
on blk-cgroup configuration settings. This policy has the following
advantages over the ioprio_set() system call:
- This policy is cgroup based so it has all the advantages of cgroups.
- While ioprio_set() does not affect page cache writeback I/O, this rq-qos
  controller affects page cache writeback I/O for filesystems that support
  assiociating a cgroup with writeback I/O. See also
  Documentation/admin-guide/cgroup-v2.rst.

Cc: Damien Le Moal <damien.lemoal@wdc.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20210618004456.7280-5-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock/blk-rq-qos: Move a function from a header file into a C file
Bart Van Assche [Fri, 18 Jun 2021 00:44:43 +0000 (17:44 -0700)]
block/blk-rq-qos: Move a function from a header file into a C file

rq_qos_id_to_name() is only used in blk-mq-debugfs.c so move that function
into in blk-mq-debugfs.c.

Cc: Damien Le Moal <damien.lemoal@wdc.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Link: https://lore.kernel.org/r/20210618004456.7280-4-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock/blk-cgroup: Swap the blk_throtl_init() and blk_iolatency_init() calls
Bart Van Assche [Fri, 18 Jun 2021 00:44:42 +0000 (17:44 -0700)]
block/blk-cgroup: Swap the blk_throtl_init() and blk_iolatency_init() calls

Before adding more calls in this function, simplify the error path.

Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20210618004456.7280-3-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock/Kconfig: Make the BLK_WBT and BLK_WBT_MQ entries consecutive
Bart Van Assche [Fri, 18 Jun 2021 00:44:41 +0000 (17:44 -0700)]
block/Kconfig: Make the BLK_WBT and BLK_WBT_MQ entries consecutive

These entries were consecutive at the time of their introduction but are no
longer consecutive. Make these again consecutive. Additionally, modify the
help text since it refers to blk-mq and since the legacy block layer has
been removed.

Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Link: https://lore.kernel.org/r/20210618004456.7280-2-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblk-wbt: remove outdated comment
lijiazi [Fri, 18 Jun 2021 03:17:20 +0000 (11:17 +0800)]
blk-wbt: remove outdated comment

Now wbt_wait() returns void, so remove now outdated comment.

Signed-off-by: lijiazi <lijiazi@xiaomi.com>
Link: https://lore.kernel.org/r/1623986240-13878-1-git-send-email-lijiazi@xiaomi.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblk-mq: fix an IS_ERR() vs NULL bug
Dan Carpenter [Fri, 18 Jun 2021 13:45:22 +0000 (16:45 +0300)]
blk-mq: fix an IS_ERR() vs NULL bug

The __blk_mq_alloc_disk() function doesn't return NULLs it returns
error pointers.

Fixes: b461dfc49eb6 ("blk-mq: add the blk_mq_alloc_disk APIs")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/YMyjci35WBqrtqG+@mwanda
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock: Remove unnecessary elevator operation checks
Damien Le Moal [Fri, 18 Jun 2021 01:59:22 +0000 (10:59 +0900)]
block: Remove unnecessary elevator operation checks

The insert_requests and dispatch_request elevator operations are
mandatory for the correct execution of an elevator, and all implemented
elevators (bfq, kyber and mq-deadline) implement them. As a result,
there is no need to check for these operations before calling them when
a queue has an elevator set. This simplifies the code in
__blk_mq_sched_dispatch_requests() and blk_mq_sched_insert_request().

To avoid out-of-tree elevators to crash the kernel in case of bad
implementation, add a check in elv_register() to verify that these
operations are implemented.

A small, probably not significant, IOPS improvement of 0.1% is observed
with this patch applied (4.117 MIOPS to 4.123 MIOPS, average of 20 fio
runs doing 4K random direct reads with psync and 32 jobs).

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20210618015922.713999-1-damien.lemoal@wdc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblk-mq: fix use-after-free in blk_mq_exit_sched
Ming Lei [Wed, 9 Jun 2021 06:30:46 +0000 (14:30 +0800)]
blk-mq: fix use-after-free in blk_mq_exit_sched

tagset can't be used after blk_cleanup_queue() is returned because
freeing tagset usually follows blk_clenup_queue(). Commit d97e594c5166
("blk-mq: Use request queue-wide tags for tagset-wide sbitmap") adds
check on q->tag_set->flags in blk_mq_exit_sched(), and causes
use-after-free.

Fixes it by using hctx->flags.

Reported-by: syzbot+77ba3d171a25c56756ea@syzkaller.appspotmail.com
Fixes: d97e594c5166 ("blk-mq: Use request queue-wide tags for tagset-wide sbitmap")
Cc: John Garry <john.garry@huawei.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Tested-by: John Garry <john.garry@huawei.com>
Reviewed-by: John Garry <john.garry@huawei.com>
Link: https://lore.kernel.org/r/20210609063046.122843-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agodocs/cgroup-v1/blkio: update for 5.x kernels
Kir Kolyshkin [Fri, 11 Jun 2021 03:07:37 +0000 (20:07 -0700)]
docs/cgroup-v1/blkio: update for 5.x kernels

Commit bf382fb0bcef4 ("block: remove legacy IO schedulers", Oct 12 2018)
removes the CFQ scheduler, together with blkio.weight and
blkio.weight_device described in cgroup v1 documentation. Users are
supposed to use the BFQ scheduler, which cgroup file for setting weight
is blkio.bfq.weight, but there is no way to set per-device weight.

Later, commit 795fe54c2a8 per-device weights for BFQ, meaning that
blkio.bfq.weight and blkio.bfq.weight_device can be used in a way
similar to the old CFQ cgroup interface.

Yet, the cgroup v1 docs were never updated. Fix this:
 - use the new file names;
 - fix the range for weight (used to be 10..1000, now 1..1000);
 - link to BFQ scheduler docs.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agodocs/cgroup-v1/blkio: stop abusing itemized list
Kir Kolyshkin [Fri, 11 Jun 2021 03:07:36 +0000 (20:07 -0700)]
docs/cgroup-v1/blkio: stop abusing itemized list

Fix many formatting issues by stop (ab)using itemized lists for
everything (mostly replaced by definition lists).

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agodocs: block/bfq: describe per-device weight
Kir Kolyshkin [Mon, 14 Jun 2021 21:41:09 +0000 (14:41 -0700)]
docs: block/bfq: describe per-device weight

The functionality of setting per-device weight for BFQ was added
in v5.4 (commit 795fe54c2a828099), but the documentation was never
updated.

While at it, improve formatting a bit.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Link: https://lore.kernel.org/r/20210614214109.207430-1-kolyshkin@gmail.com
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock: mark queue init done at the end of blk_register_queue
Ming Lei [Wed, 9 Jun 2021 01:58:22 +0000 (09:58 +0800)]
block: mark queue init done at the end of blk_register_queue

Mark queue init done when everything is done well in blk_register_queue(),
so that wbt_enable_default() can be run quickly without any RCU period
involved since adding rq qos requires to freeze queue.

Also no any side effect by delaying to mark queue init done.

Reported-by: Yi Zhang <yi.zhang@redhat.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Yi Zhang <yi.zhang@redhat.com>
Link: https://lore.kernel.org/r/20210609015822.103433-3-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock: fix race between adding/removing rq qos and normal IO
Ming Lei [Wed, 9 Jun 2021 01:58:21 +0000 (09:58 +0800)]
block: fix race between adding/removing rq qos and normal IO

Yi reported several kernel panics on:

[16687.001777] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008
...
[16687.163549] pc : __rq_qos_track+0x38/0x60

or

[  997.690455] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000020
...
[  997.850347] pc : __rq_qos_done+0x2c/0x50

Turns out it is caused by race between adding rq qos(wbt) and normal IO
because rq_qos_add can be run when IO is being submitted, fix this issue
by freezing queue before adding/deleting rq qos to queue.

rq_qos_exit() needn't to freeze queue because it is called after queue
has been frozen.

iolatency calls rq_qos_add() during allocating queue, so freezing won't
add delay because queue usage refcount works at atomic mode at that
time.

iocost calls rq_qos_add() when writing cgroup attribute file, that is
fine to freeze queue at that time since we usually freeze queue when
storing to queue sysfs attribute, meantime iocost only exists on the
root cgroup.

wbt_init calls it in blk_register_queue() and queue sysfs attribute
store(queue_wb_lat_store() when write it 1st time in case of !BLK_WBT_MQ),
the following patch will speedup the queue freezing in wbt_init.

Reported-by: Yi Zhang <yi.zhang@redhat.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Yi Zhang <yi.zhang@redhat.com>
Link: https://lore.kernel.org/r/20210609015822.103433-2-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoloop: fix order of cleaning up the queue and freeing the tagset
Christoph Hellwig [Wed, 16 Jun 2021 07:15:47 +0000 (09:15 +0200)]
loop: fix order of cleaning up the queue and freeing the tagset

We must release the queue before freeing the tagset.

Fixes: 1c99502fae35 ("loop: use blk_mq_alloc_disk and blk_cleanup_disk")
Reported-by: Bruno Goncalves <bgoncalv@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agomtd_blkdevs: initialze new->rq in add_mtd_blktrans_dev
Christoph Hellwig [Wed, 16 Jun 2021 07:15:46 +0000 (09:15 +0200)]
mtd_blkdevs: initialze new->rq in add_mtd_blktrans_dev

Various places expect the request_queue in ->rq.  Initialize it to
avoid NULL pointer derefences.

Fixes: 6966bb921def ("mtd_blkdevs: use blk_mq_alloc_disk")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoz2ram: use blk_mq_alloc_disk and blk_cleanup_disk
Christoph Hellwig [Wed, 2 Jun 2021 06:53:45 +0000 (09:53 +0300)]
z2ram: use blk_mq_alloc_disk and blk_cleanup_disk

Use blk_mq_alloc_disk and blk_cleanup_disk to simplify the gendisk and
request_queue allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-31-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoataflop: use blk_mq_alloc_disk and blk_cleanup_disk
Christoph Hellwig [Wed, 2 Jun 2021 06:53:44 +0000 (09:53 +0300)]
ataflop: use blk_mq_alloc_disk and blk_cleanup_disk

Use blk_mq_alloc_disk and blk_cleanup_disk to simplify the gendisk and
request_queue allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-30-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoamiflop: use blk_mq_alloc_disk and blk_cleanup_disk
Christoph Hellwig [Wed, 2 Jun 2021 06:53:43 +0000 (09:53 +0300)]
amiflop: use blk_mq_alloc_disk and blk_cleanup_disk

Use blk_mq_alloc_disk and blk_cleanup_disk to simplify the gendisk and
request_queue allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-29-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoscm_blk: use blk_mq_alloc_disk and blk_cleanup_disk
Christoph Hellwig [Wed, 2 Jun 2021 06:53:42 +0000 (09:53 +0300)]
scm_blk: use blk_mq_alloc_disk and blk_cleanup_disk

Use blk_mq_alloc_disk and blk_cleanup_disk to simplify the gendisk and
request_queue allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Niklas Schnelle <schnelle@linux.ibm.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-28-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoubi: use blk_mq_alloc_disk and blk_cleanup_disk
Christoph Hellwig [Wed, 2 Jun 2021 06:53:41 +0000 (09:53 +0300)]
ubi: use blk_mq_alloc_disk and blk_cleanup_disk

Use blk_mq_alloc_disk and blk_cleanup_disk to simplify the gendisk and
request_queue allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-27-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoxen-blkfront: use blk_mq_alloc_disk and blk_cleanup_disk
Christoph Hellwig [Wed, 2 Jun 2021 06:53:40 +0000 (09:53 +0300)]
xen-blkfront: use blk_mq_alloc_disk and blk_cleanup_disk

Use blk_mq_alloc_disk and blk_cleanup_disk to simplify the gendisk and
request_queue allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-26-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agosx8: use blk_mq_alloc_disk and blk_cleanup_disk
Christoph Hellwig [Wed, 2 Jun 2021 06:53:39 +0000 (09:53 +0300)]
sx8: use blk_mq_alloc_disk and blk_cleanup_disk

Use blk_mq_alloc_disk and blk_cleanup_disk to simplify the gendisk and
request_queue allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-25-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agornbd: use blk_mq_alloc_disk and blk_cleanup_disk
Christoph Hellwig [Wed, 2 Jun 2021 06:53:38 +0000 (09:53 +0300)]
rnbd: use blk_mq_alloc_disk and blk_cleanup_disk

Use blk_mq_alloc_disk and blk_cleanup_disk to simplify the gendisk and
request_queue allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jack Wang <jinpu.wang@ionos.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-24-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agorbd: use blk_mq_alloc_disk and blk_cleanup_disk
Christoph Hellwig [Wed, 2 Jun 2021 06:53:37 +0000 (09:53 +0300)]
rbd: use blk_mq_alloc_disk and blk_cleanup_disk

Use blk_mq_alloc_disk and blk_cleanup_disk to simplify the gendisk and
request_queue allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-23-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agopd: use blk_mq_alloc_disk and blk_cleanup_disk
Christoph Hellwig [Wed, 2 Jun 2021 06:53:36 +0000 (09:53 +0300)]
pd: use blk_mq_alloc_disk and blk_cleanup_disk

Use blk_mq_alloc_disk and blk_cleanup_disk to simplify the gendisk and
request_queue allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-22-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agonullb: use blk_mq_alloc_disk
Christoph Hellwig [Wed, 2 Jun 2021 06:53:35 +0000 (09:53 +0300)]
nullb: use blk_mq_alloc_disk

Use blk_mq_alloc_disk and blk_cleanup_disk to simplify the gendisk and
request_queue allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-21-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agonbd: use blk_mq_alloc_disk and blk_cleanup_disk
Christoph Hellwig [Wed, 2 Jun 2021 06:53:34 +0000 (09:53 +0300)]
nbd: use blk_mq_alloc_disk and blk_cleanup_disk

Use blk_mq_alloc_disk and blk_cleanup_disk to simplify the gendisk and
request_queue allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-20-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoloop: use blk_mq_alloc_disk and blk_cleanup_disk
Christoph Hellwig [Wed, 2 Jun 2021 06:53:33 +0000 (09:53 +0300)]
loop: use blk_mq_alloc_disk and blk_cleanup_disk

Use blk_mq_alloc_disk and blk_cleanup_disk to simplify the gendisk and
request_queue allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-19-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agofloppy: use blk_mq_alloc_disk and blk_cleanup_disk
Christoph Hellwig [Wed, 2 Jun 2021 06:53:32 +0000 (09:53 +0300)]
floppy: use blk_mq_alloc_disk and blk_cleanup_disk

Use blk_mq_alloc_disk and blk_cleanup_disk to simplify the gendisk and
request_queue allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-18-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoaoe: use blk_mq_alloc_disk and blk_cleanup_disk
Christoph Hellwig [Wed, 2 Jun 2021 06:53:31 +0000 (09:53 +0300)]
aoe: use blk_mq_alloc_disk and blk_cleanup_disk

Use blk_mq_alloc_disk and blk_cleanup_disk to simplify the gendisk and
request_queue allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-17-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblk-mq: remove blk_mq_init_sq_queue
Christoph Hellwig [Wed, 2 Jun 2021 06:53:30 +0000 (09:53 +0300)]
blk-mq: remove blk_mq_init_sq_queue

All users are gone now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-16-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agogdrom: use blk_mq_alloc_disk
Christoph Hellwig [Wed, 2 Jun 2021 06:53:29 +0000 (09:53 +0300)]
gdrom: use blk_mq_alloc_disk

Use the blk_mq_alloc_disk API to simplify the gendisk and request_queue
allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-15-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agosunvdc: use blk_mq_alloc_disk
Christoph Hellwig [Wed, 2 Jun 2021 06:53:28 +0000 (09:53 +0300)]
sunvdc: use blk_mq_alloc_disk

Use the blk_mq_alloc_disk API to simplify the gendisk and request_queue
allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-14-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoswim: use blk_mq_alloc_disk
Christoph Hellwig [Wed, 2 Jun 2021 06:53:27 +0000 (09:53 +0300)]
swim: use blk_mq_alloc_disk

Use the blk_mq_alloc_disk API to simplify the gendisk and request_queue
allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-13-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoswim3: use blk_mq_alloc_disk
Christoph Hellwig [Wed, 2 Jun 2021 06:53:26 +0000 (09:53 +0300)]
swim3: use blk_mq_alloc_disk

Use the blk_mq_alloc_disk API to simplify the gendisk and request_queue
allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-12-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agops3disk: use blk_mq_alloc_disk
Christoph Hellwig [Wed, 2 Jun 2021 06:53:25 +0000 (09:53 +0300)]
ps3disk: use blk_mq_alloc_disk

Use the blk_mq_alloc_disk API to simplify the gendisk and request_queue
allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Geoff Levand <geoff@infradead.org>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-11-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agomtd_blkdevs: use blk_mq_alloc_disk
Christoph Hellwig [Wed, 2 Jun 2021 06:53:24 +0000 (09:53 +0300)]
mtd_blkdevs: use blk_mq_alloc_disk

Use the blk_mq_alloc_disk API to simplify the gendisk and request_queue
allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-10-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agomspro: use blk_mq_alloc_disk
Christoph Hellwig [Wed, 2 Jun 2021 06:53:23 +0000 (09:53 +0300)]
mspro: use blk_mq_alloc_disk

Use the blk_mq_alloc_disk API to simplify the gendisk and request_queue
allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-9-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoms_block: use blk_mq_alloc_disk
Christoph Hellwig [Wed, 2 Jun 2021 06:53:22 +0000 (09:53 +0300)]
ms_block: use blk_mq_alloc_disk

Use the blk_mq_alloc_disk API to simplify the gendisk and request_queue
allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-8-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agopf: use blk_mq_alloc_disk
Christoph Hellwig [Wed, 2 Jun 2021 06:53:21 +0000 (09:53 +0300)]
pf: use blk_mq_alloc_disk

Use the blk_mq_alloc_disk API to simplify the gendisk and request_queue
allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-7-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agopcd: use blk_mq_alloc_disk
Christoph Hellwig [Wed, 2 Jun 2021 06:53:20 +0000 (09:53 +0300)]
pcd: use blk_mq_alloc_disk

Use the blk_mq_alloc_disk API to simplify the gendisk and request_queue
allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agovirtio-blk: use blk_mq_alloc_disk
Christoph Hellwig [Wed, 2 Jun 2021 06:53:19 +0000 (09:53 +0300)]
virtio-blk: use blk_mq_alloc_disk

Use the blk_mq_alloc_disk API to simplify the gendisk and request_queue
allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblk-mq: add the blk_mq_alloc_disk APIs
Christoph Hellwig [Wed, 2 Jun 2021 06:53:18 +0000 (09:53 +0300)]
blk-mq: add the blk_mq_alloc_disk APIs

Add a new API to allocate a gendisk including the request_queue for use
with blk-mq based drivers.  This is to avoid boilerplate code in drivers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblk-mq: improve the blk_mq_init_allocated_queue interface
Christoph Hellwig [Wed, 2 Jun 2021 06:53:17 +0000 (09:53 +0300)]
blk-mq: improve the blk_mq_init_allocated_queue interface

Don't return the passed in request_queue but a normal error code, and
drop the elevator_init argument in favor of just calling elevator_init_mq
directly from dm-rq.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblk-mq: factor out a blk_mq_alloc_sq_tag_set helper
Christoph Hellwig [Wed, 2 Jun 2021 06:53:16 +0000 (09:53 +0300)]
blk-mq: factor out a blk_mq_alloc_sq_tag_set helper

Factour out a helper to initialize a simple single hw queue tag_set from
blk_mq_init_sq_queue.  This will allow to phase out blk_mq_init_sq_queue
in favor of a more symmetric and general API.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agolibnvdimm/pmem: Fix blk_cleanup_disk() usage
Dan Williams [Mon, 7 Jun 2021 23:52:43 +0000 (16:52 -0700)]
libnvdimm/pmem: Fix blk_cleanup_disk() usage

The queue_to_disk() helper can not be used after del_gendisk()
communicate @disk via the pgmap->owner.

Otherwise, queue_to_disk() returns NULL resulting in the splat below.

 Kernel attempted to read user page (330) - exploit attempt? (uid: 0)
 BUG: Kernel NULL pointer dereference on read at 0x00000330
 Faulting instruction address: 0xc000000000906344
 Oops: Kernel access of bad area, sig: 11 [#1]
 [..]
 NIP [c000000000906344] pmem_pagemap_cleanup+0x24/0x40
 LR [c0000000004701d4] memunmap_pages+0x1b4/0x4b0
 Call Trace:
 [c000000022cbb9c0] [c0000000009063c8] pmem_pagemap_kill+0x28/0x40 (unreliable)
 [c000000022cbb9e0] [c0000000004701d4] memunmap_pages+0x1b4/0x4b0
 [c000000022cbba90] [c0000000008b28a0] devm_action_release+0x30/0x50
 [c000000022cbbab0] [c0000000008b39c8] release_nodes+0x2f8/0x3e0
 [c000000022cbbb60] [c0000000008ac440] device_release_driver_internal+0x190/0x2b0
 [c000000022cbbba0] [c0000000008a8450] unbind_store+0x130/0x170

Reported-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
Fixes: 87eb73b2ca7c ("nvdimm-pmem: convert to blk_alloc_disk/blk_cleanup_disk")
Link: http://lore.kernel.org/r/DFB75BA8-603F-4A35-880B-C5B23EF8FA7D@linux.vnet.ibm.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
Link: https://lore.kernel.org/r/162310994435.1571616.334551212901820961.stgit@dwillia2-desk3.amr.corp.intel.com
[axboe: fold in compile warning fix]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agorq-qos: fix missed wake-ups in rq_qos_throttle try two
Jan Kara [Mon, 7 Jun 2021 11:26:13 +0000 (13:26 +0200)]
rq-qos: fix missed wake-ups in rq_qos_throttle try two

Commit 545fbd0775ba ("rq-qos: fix missed wake-ups in rq_qos_throttle")
tried to fix a problem that a process could be sleeping in rq_qos_wait()
without anyone to wake it up. However the fix is not complete and the
following can still happen:

CPU1 (waiter1) CPU2 (waiter2) CPU3 (waker)
rq_qos_wait() rq_qos_wait()
  acquire_inflight_cb() -> fails
  acquire_inflight_cb() -> fails

completes IOs, inflight
  decreased
  prepare_to_wait_exclusive()
  prepare_to_wait_exclusive()
  has_sleeper = !wq_has_single_sleeper() -> true as there are two sleepers
  has_sleeper = !wq_has_single_sleeper() -> true
  io_schedule()   io_schedule()

Deadlock as now there's nobody to wakeup the two waiters. The logic
automatically blocking when there are already sleepers is really subtle
and the only way to make it work reliably is that we check whether there
are some waiters in the queue when adding ourselves there. That way, we
are guaranteed that at least the first process to enter the wait queue
will recheck the waiting condition before going to sleep and thus
guarantee forward progress.

Fixes: 545fbd0775ba ("rq-qos: fix missed wake-ups in rq_qos_throttle")
CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20210607112613.25344-1-jack@suse.cz
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock: return the correct bvec when checking for gaps
Long Li [Mon, 7 Jun 2021 19:34:05 +0000 (12:34 -0700)]
block: return the correct bvec when checking for gaps

After commit 07173c3ec276 ("block: enable multipage bvecs"), a bvec can
have multiple pages. But bio_will_gap() still assumes one page bvec while
checking for merging. If the pages in the bvec go across the
seg_boundary_mask, this check for merging can potentially succeed if only
the 1st page is tested, and can fail if all the pages are tested.

Later, when SCSI builds the SG list the same check for merging is done in
__blk_segment_map_sg_merge() with all the pages in the bvec tested. This
time the check may fail if the pages in bvec go across the
seg_boundary_mask (but tested okay in bio_will_gap() earlier, so those
BIOs were merged). If this check fails, we end up with a broken SG list
for drivers assuming the SG list not having offsets in intermediate pages.
This results in incorrect pages written to the disk.

Fix this by returning the multi-page bvec when testing gaps for merging.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: Pavel Begunkov <asml.silence@gmail.com>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org
Fixes: 07173c3ec276 ("block: enable multipage bvecs")
Signed-off-by: Long Li <longli@microsoft.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/1623094445-22332-1-git-send-email-longli@linuxonhyperv.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock: Update blk_update_request() documentation
Bart Van Assche [Wed, 19 May 2021 17:52:26 +0000 (10:52 -0700)]
block: Update blk_update_request() documentation

Although the original intent was to use blk_update_request() in stacking
block drivers only, it is used much more widely today. Reflect this in the
documentation block above this function. See also:
* commit 32fab448e5e8 ("block: add request update interface").
* commit 2e60e02297cf ("block: clean up request completion API").
* commit ed6565e73424 ("block: handle partial completions for special
  payload requests").

Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.de>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20210519175226.8853-1-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock: Do not pull requests from the scheduler when we cannot dispatch them
Jan Kara [Thu, 3 Jun 2021 10:47:21 +0000 (12:47 +0200)]
block: Do not pull requests from the scheduler when we cannot dispatch them

Provided the device driver does not implement dispatch budget accounting
(which only SCSI does) the loop in __blk_mq_do_dispatch_sched() pulls
requests from the IO scheduler as long as it is willing to give out any.
That defeats scheduling heuristics inside the scheduler by creating
false impression that the device can take more IO when it in fact
cannot.

For example with BFQ IO scheduler on top of virtio-blk device setting
blkio cgroup weight has barely any impact on observed throughput of
async IO because __blk_mq_do_dispatch_sched() always sucks out all the
IO queued in BFQ. BFQ first submits IO from higher weight cgroups but
when that is all dispatched, it will give out IO of lower weight cgroups
as well. And then we have to wait for all this IO to be dispatched to
the disk (which means lot of it actually has to complete) before the
IO scheduler is queried again for dispatching more requests. This
completely destroys any service differentiation.

So grab request tag for a request pulled out of the IO scheduler already
in __blk_mq_do_dispatch_sched() and do not pull any more requests if we
cannot get it because we are unlikely to be able to dispatch it. That
way only single request is going to wait in the dispatch list for some
tag to free.

Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20210603104721.6309-1-jack@suse.cz
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agonull_blk: Fix null pointer dereference on nullb->disk on blk_cleanup_disk call
Colin Ian King [Wed, 2 Jun 2021 10:06:59 +0000 (11:06 +0100)]
null_blk: Fix null pointer dereference on nullb->disk on blk_cleanup_disk call

The error handling on a nullb->disk allocation currently jumps to
out_cleanup_disk that calls blk_cleanup_disk with a null pointer causing
a null pointer dereference issue. Fix this by jumping to out_cleanup_tags
instead.

Addresses-Coverity: ("Dereference after null check")
Fixes: 132226b301b5 ("null_blk: convert to blk_alloc_disk/blk_cleanup_disk")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210602100659.11058-1-colin.king@canonical.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock: remove bdget_disk
Christoph Hellwig [Tue, 25 May 2021 06:13:01 +0000 (08:13 +0200)]
block: remove bdget_disk

Just opencode the xa_load in the callers, as none of them actually
needs a reference to the bdev.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20210525061301.2242282-9-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock: factor out a part_devt helper
Christoph Hellwig [Tue, 25 May 2021 06:13:00 +0000 (08:13 +0200)]
block: factor out a part_devt helper

Add a helper to find the dev_t for a disk + partno tuple.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20210525061301.2242282-8-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock: move bd_part_count to struct gendisk
Christoph Hellwig [Tue, 25 May 2021 06:12:59 +0000 (08:12 +0200)]
block: move bd_part_count to struct gendisk

The bd_part_count value only makes sense for whole devices, so move it
to struct gendisk and give it a more descriptive name.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20210525061301.2242282-7-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock: split __blkdev_put
Christoph Hellwig [Tue, 25 May 2021 06:12:58 +0000 (08:12 +0200)]
block: split __blkdev_put

Split __blkdev_put into one helper for the whole device, and one for
partitions as well as another shared helper for flushing the block
device inode mapping.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20210525061301.2242282-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock: move adjusting bd_part_count out of __blkdev_get
Christoph Hellwig [Tue, 25 May 2021 06:12:57 +0000 (08:12 +0200)]
block: move adjusting bd_part_count out of __blkdev_get

Keep in the callers and thus remove the for_part argument.  This mirrors
what is done on the blkdev_get side and slightly simplifies
blkdev_get_part as well.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@rehat.com>
Link: https://lore.kernel.org/r/20210525061301.2242282-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock: move bd_mutex to struct gendisk
Christoph Hellwig [Tue, 25 May 2021 06:12:56 +0000 (08:12 +0200)]
block: move bd_mutex to struct gendisk

Replace the per-block device bd_mutex with a per-gendisk open_mutex,
thus simplifying locking wherever we deal with partitions.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Link: https://lore.kernel.org/r/20210525061301.2242282-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock: move sync_blockdev from __blkdev_put to blkdev_put
Christoph Hellwig [Tue, 25 May 2021 06:12:55 +0000 (08:12 +0200)]
block: move sync_blockdev from __blkdev_put to blkdev_put

Do the early unlocked syncing even earlier to move more code out of
the recursive path.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20210525061301.2242282-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock: split __blkdev_get
Christoph Hellwig [Tue, 25 May 2021 06:12:54 +0000 (08:12 +0200)]
block: split __blkdev_get

Split __blkdev_get into one helper for the whole device, and one for
opening partitions.  This removes the (bounded) recursion when opening
a partition.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20210525061301.2242282-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoblock: unexport blk_alloc_queue
Christoph Hellwig [Fri, 21 May 2021 05:51:16 +0000 (07:51 +0200)]
block: unexport blk_alloc_queue

blk_alloc_queue is just an internal helper now, unexport it and remove
it from the public header.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20210521055116.1053587-27-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agonull_blk: convert to blk_alloc_disk/blk_cleanup_disk
Christoph Hellwig [Fri, 21 May 2021 05:51:15 +0000 (07:51 +0200)]
null_blk: convert to blk_alloc_disk/blk_cleanup_disk

Convert the null_blk driver to use the blk_alloc_disk and blk_cleanup_disk
helpers to simplify gendisk and request_queue allocation.  Note that the
blk-mq mode is left with its own allocations scheme, to be handled later.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20210521055116.1053587-26-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agoxpram: convert to blk_alloc_disk/blk_cleanup_disk
Christoph Hellwig [Fri, 21 May 2021 05:51:14 +0000 (07:51 +0200)]
xpram: convert to blk_alloc_disk/blk_cleanup_disk

Convert the xpram driver to use the blk_alloc_disk and blk_cleanup_disk
helpers to simplify gendisk and request_queue allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20210521055116.1053587-25-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agodcssblk: convert to blk_alloc_disk/blk_cleanup_disk
Christoph Hellwig [Fri, 21 May 2021 05:51:13 +0000 (07:51 +0200)]
dcssblk: convert to blk_alloc_disk/blk_cleanup_disk

Convert the dcssblk driver to use the blk_alloc_disk and blk_cleanup_disk
helpers to simplify gendisk and request_queue allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20210521055116.1053587-24-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agops3vram: convert to blk_alloc_disk/blk_cleanup_disk
Christoph Hellwig [Fri, 21 May 2021 05:51:12 +0000 (07:51 +0200)]
ps3vram: convert to blk_alloc_disk/blk_cleanup_disk

Convert the ps3vram driver to use the blk_alloc_disk and blk_cleanup_disk
helpers to simplify gendisk and request_queue allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20210521055116.1053587-23-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agon64cart: convert to blk_alloc_disk
Christoph Hellwig [Fri, 21 May 2021 05:51:11 +0000 (07:51 +0200)]
n64cart: convert to blk_alloc_disk

Convert the n64cart driver to use the blk_alloc_disk helper to simplify
gendisk and request_queue allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20210521055116.1053587-22-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agosimdisk: convert to blk_alloc_disk/blk_cleanup_disk
Christoph Hellwig [Fri, 21 May 2021 05:51:10 +0000 (07:51 +0200)]
simdisk: convert to blk_alloc_disk/blk_cleanup_disk

Convert the simdisk driver to use the blk_alloc_disk and blk_cleanup_disk
helpers to simplify gendisk and request_queue allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20210521055116.1053587-21-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agonfblock: convert to blk_alloc_disk/blk_cleanup_disk
Christoph Hellwig [Fri, 21 May 2021 05:51:09 +0000 (07:51 +0200)]
nfblock: convert to blk_alloc_disk/blk_cleanup_disk

Convert the nfblock driver to use the blk_alloc_disk and blk_cleanup_disk
helpers to simplify gendisk and request_queue allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20210521055116.1053587-20-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agonvme-multipath: convert to blk_alloc_disk/blk_cleanup_disk
Christoph Hellwig [Fri, 21 May 2021 05:51:08 +0000 (07:51 +0200)]
nvme-multipath: convert to blk_alloc_disk/blk_cleanup_disk

Convert the nvme-multipath driver to use the blk_alloc_disk and
blk_cleanup_disk helpers to simplify gendisk and request_queue
allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20210521055116.1053587-19-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
3 years agonvdimm-pmem: convert to blk_alloc_disk/blk_cleanup_disk
Christoph Hellwig [Fri, 21 May 2021 05:51:07 +0000 (07:51 +0200)]
nvdimm-pmem: convert to blk_alloc_disk/blk_cleanup_disk

Convert the nvdimm-pmem driver to use the blk_alloc_disk and
blk_cleanup_disk helpers to simplify gendisk and request_queue
allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20210521055116.1053587-18-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>