linux-toradex.git/block, branch toradex_5.3.y

blk-rq-qos: fix first node deletion of rq_qos_del()

2019-10-29T08:22:47+00:00

commit 307f4065b9d7c1e887e8bdfb2487e4638559fea1 upstream.

rq_qos_del() incorrectly assigns the node being deleted to the head if
it was the first on the list in the !prev path.  Fix it by iterating
with ** instead.

Signed-off-by: Tejun Heo 
Cc: Josef Bacik 
Fixes: a79050434b45 ("blk-rq-qos: refactor out common elements of blk-wbt")
Cc: stable@vger.kernel.org # v4.19+
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

blk-mq: honor IO scheduler for multiqueue devices

2019-10-29T08:21:32+00:00

[ Upstream commit a12de1d42d74ef3c80e9fb9a2da94daaef747869 ]

If a device is using multiple queues, the IO scheduler may be bypassed.
This may hurt performance for some slow MQ devices, and it also breaks
zoned devices which depend on mq-deadline for respecting the write order
in one zone.

Don't bypass io scheduler if we have one setup.

This patch can double sequential write performance basically on MQ
scsi_debug when mq-deadline is applied.

Cc: Bart Van Assche 
Cc: Hannes Reinecke 
Cc: Dave Chinner 
Reviewed-by: Javier González 
Reviewed-by: Damien Le Moal 
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

blk-wbt: fix performance regression in wbt scale_up/scale_down

2019-10-17T20:47:13+00:00

commit b84477d3ebb96294f87dc3161e53fa8fe22d9bfd upstream.

scale_up wakes up waiters after scaling up. But after scaling max, it
should not wake up more waiters as waiters will not have anything to
do. This patch fixes this by making scale_up (and also scale_down)
return when threshold is reached.

This bug causes increased fdatasync latency when fdatasync and dd
conv=sync are performed in parallel on 4.19 compared to 4.14. This
bug was introduced during refactoring of blk-wbt code.

Fixes: a79050434b45 ("blk-rq-qos: refactor out common elements of blk-wbt")
Cc: stable@vger.kernel.org
Cc: Josef Bacik 
Signed-off-by: Harshad Shirwadkar 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

blk-mq: move lockdep_assert_held() into elevator_exit

2019-10-11T16:36:47+00:00

[ Upstream commit 284b94be1925dbe035ce5218d8b5c197321262c7 ]

Commit c48dac137a62 ("block: don't hold q->sysfs_lock in elevator_init_mq")
removes q->sysfs_lock from elevator_init_mq(), but forgot to deal with
lockdep_assert_held() called in blk_mq_sched_free_requests() which is
run in failure path of elevator_init_mq().

blk_mq_sched_free_requests() is called in the following 3 functions:

	elevator_init_mq()
	elevator_exit()
	blk_cleanup_queue()

In blk_cleanup_queue(), blk_mq_sched_free_requests() is followed exactly
by 'mutex_lock(&q->sysfs_lock)'.

So moving the lockdep_assert_held() from blk_mq_sched_free_requests()
into elevator_exit() for fixing the report by syzbot.

Reported-by: syzbot+da3b7677bb913dc1b737@syzkaller.appspotmail.com
Fixed: c48dac137a62 ("block: don't hold q->sysfs_lock in elevator_init_mq")
Reviewed-by: Bart Van Assche 
Reviewed-by: Damien Le Moal 
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

block, bfq: push up injection only after setting service time

2019-10-07T17:01:40+00:00

[ Upstream commit 58494c980f40274c465ebfdece02d401def088bf ]

If equal to 0, the injection limit for a bfq_queue is pushed to 1
after a first sample of the total service time of the I/O requests of
the queue is computed (to allow injection to start). Yet, because of a
mistake in the branch that performs this action, the push may happen
also in some other case. This commit fixes this issue.

Tested-by: Oleksandr Natalenko 
Signed-off-by: Paolo Valente 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

block: fix null pointer dereference in blk_mq_rq_timed_out()

2019-10-05T13:12:29+00:00

commit 8d6996630c03d7ceeabe2611378fea5ca1c3f1b3 upstream.

We got a null pointer deference BUG_ON in blk_mq_rq_timed_out()
as following:

[  108.825472] BUG: kernel NULL pointer dereference, address: 0000000000000040
[  108.827059] PGD 0 P4D 0
[  108.827313] Oops: 0000 [#1] SMP PTI
[  108.827657] CPU: 6 PID: 198 Comm: kworker/6:1H Not tainted 5.3.0-rc8+ #431
[  108.829503] Workqueue: kblockd blk_mq_timeout_work
[  108.829913] RIP: 0010:blk_mq_check_expired+0x258/0x330
[  108.838191] Call Trace:
[  108.838406]  bt_iter+0x74/0x80
[  108.838665]  blk_mq_queue_tag_busy_iter+0x204/0x450
[  108.839074]  ? __switch_to_asm+0x34/0x70
[  108.839405]  ? blk_mq_stop_hw_queue+0x40/0x40
[  108.839823]  ? blk_mq_stop_hw_queue+0x40/0x40
[  108.840273]  ? syscall_return_via_sysret+0xf/0x7f
[  108.840732]  blk_mq_timeout_work+0x74/0x200
[  108.841151]  process_one_work+0x297/0x680
[  108.841550]  worker_thread+0x29c/0x6f0
[  108.841926]  ? rescuer_thread+0x580/0x580
[  108.842344]  kthread+0x16a/0x1a0
[  108.842666]  ? kthread_flush_work+0x170/0x170
[  108.843100]  ret_from_fork+0x35/0x40

The bug is caused by the race between timeout handle and completion for
flush request.

When timeout handle function blk_mq_rq_timed_out() try to read
'req->q->mq_ops', the 'req' have completed and reinitiated by next
flush request, which would call blk_rq_init() to clear 'req' as 0.

After commit 12f5b93145 ("blk-mq: Remove generation seqeunce"),
normal requests lifetime are protected by refcount. Until 'rq->ref'
drop to zero, the request can really be free. Thus, these requests
cannot been reused before timeout handle finish.

However, flush request has defined .end_io and rq->end_io() is still
called even if 'rq->ref' doesn't drop to zero. After that, the 'flush_rq'
can be reused by the next flush request handle, resulting in null
pointer deference BUG ON.

We fix this problem by covering flush request with 'rq->ref'.
If the refcount is not zero, flush_end_io() return and wait the
last holder recall it. To record the request status, we add a new
entry 'rq_status', which will be used in flush_end_io().

Cc: Christoph Hellwig 
Cc: Keith Busch 
Cc: Bart Van Assche 
Cc: stable@vger.kernel.org # v4.18+
Reviewed-by: Ming Lei 
Reviewed-by: Bob Liu 
Signed-off-by: Yufen Yu 
Signed-off-by: Greg Kroah-Hartman 

-------
v2:
 - move rq_status from struct request to struct blk_flush_queue
v3:
 - remove unnecessary '{}' pair.
v4:
 - let spinlock to protect 'fq->rq_status'
v5:
 - move rq_status after flush_running_idx member of struct blk_flush_queue
Signed-off-by: Jens Axboe

block: mq-deadline: Fix queue restart handling

2019-10-05T13:12:29+00:00

commit cb8acabbe33b110157955a7425ee876fb81e6bbc upstream.

Commit 7211aef86f79 ("block: mq-deadline: Fix write completion
handling") added a call to blk_mq_sched_mark_restart_hctx() in
dd_dispatch_request() to make sure that write request dispatching does
not stall when all target zones are locked. This fix left a subtle race
when a write completion happens during a dispatch execution on another
CPU:

CPU 0: Dispatch			CPU1: write completion

dd_dispatch_request()
    lock(&dd->lock);
    ...
    lock(&dd->zone_lock);	dd_finish_request()
    rq = find request		lock(&dd->zone_lock);
    unlock(&dd->zone_lock);
    				zone write unlock
				unlock(&dd->zone_lock);
				...
				__blk_mq_free_request
                                      check restart flag (not set)
				      -> queue not run
    ...
    if (!rq && have writes)
        blk_mq_sched_mark_restart_hctx()
    unlock(&dd->lock)

Since the dispatch context finishes after the write request completion
handling, marking the queue as needing a restart is not seen from
__blk_mq_free_request() and blk_mq_sched_restart() not executed leading
to the dispatch stall under 100% write workloads.

Fix this by moving the call to blk_mq_sched_mark_restart_hctx() from
dd_dispatch_request() into dd_finish_request() under the zone lock to
ensure full mutual exclusion between write request dispatch selection
and zone unlock on write request completion.

Fixes: 7211aef86f79 ("block: mq-deadline: Fix write completion handling")
Cc: stable@vger.kernel.org
Reported-by: Hans Holmberg 
Reviewed-by: Hans Holmberg 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Damien Le Moal 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

block: make rq sector size accessible for block stats

2019-10-05T13:12:06+00:00

[ Upstream commit 3d24430694077313c75c6b89f618db09943621e4 ]

Currently rq->data_len will be decreased by partial completion or
zeroed by completion, so when blk_stat_add() is invoked, data_len
will be zero and there will never be samples in poll_cb because
blk_mq_poll_stats_bkt() will return -1 if data_len is zero.

We could move blk_stat_add() back to __blk_mq_complete_request(),
but that would make the effort of trying to call ktime_get_ns()
once in vain. Instead we can reuse throtl_size field, and use
it for both block stats and block throttle, and adjust the
logic in blk_mq_poll_stats_bkt() accordingly.

Fixes: 4bc6339a583c ("block: move blk_stat_add() to __blk_mq_end_request()")
Tested-by: Pavel Begunkov 
Signed-off-by: Hou Tao 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

blk-mq: Fix memory leak in blk_mq_init_allocated_queue error handling

2019-10-05T13:11:39+00:00

[ Upstream commit 73d9c8d4c0017e21e1ff519474ceb1450484dc9a ]

If blk_mq_init_allocated_queue->elevator_init_mq fails, need to release
the previously requested resources.

Fixes: d34849913819 ("blk-mq-sched: allow setting of default IO scheduler")
Signed-off-by: zhengbin 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

block: remove REQ_NOWAIT_INLINE

2019-08-15T17:09:16+00:00

We had a few issues with this code, and there's still a problem around
how we deal with error handling for chained/split bios. For now, just
revert the code and we'll try again with a thoroug solution. This
reverts commits:

e15c2ffa1091 ("block: fix O_DIRECT error handling for bio fragments")
0eb6ddfb865c ("block: Fix __blkdev_direct_IO() for bio fragments")
6a43074e2f46 ("block: properly handle IOCB_NOWAIT for async O_DIRECT IO")
893a1c97205a ("blk-mq: allow REQ_NOWAIT to return an error inline")

Signed-off-by: Jens Axboe