Commit 20bd1d02 ("scsi: sd: Keep disk read-only when re-reading
partition") addressed a long-standing problem with user read-only
policy being overridden as a result of a device-initiated revalidate.
The commit has since been reverted due to a regression that left some
USB devices read-only indefinitely.

To fix the underlying problems with revalidate we need to keep track
of hardware state and user policy separately.

The gendisk has been updated to reflect the current hardware state set
by the device driver. This is done to allow returning the device to
the hardware state once the user clears the BLKROSET flag.

The resulting semantics are as follows:

 - If BLKROSET sets a given partition read-only, that partition will
   remain read-only even if the underlying storage stack initiates a
   revalidate. However, the BLKRRPART ioctl will cause the partition
   table to be dropped and any user policy on partitions will be lost.

 - If BLKROSET has not been set, both the whole disk device and any
   partitions will reflect the current write-protect state of the
   underlying device.

Based on a patch from Martin K. Petersen <martin.petersen@oracle.com>.
Reported-by: NOleksii Kurochko <olkuroch@cisco.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=201221Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMing Lei <ming.lei@redhat.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Only a single caller can end up in bdev_read_only, so move the check
there.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMing Lei <ming.lei@redhat.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Showing the hctx flags for when BLK_MQ_F_TAG_HCTX_SHARED is set gives
something like:

root@debian:/home/john# more /sys/kernel/debug/block/sda/hctx0/flags
alloc_policy=FIFO SHOULD_MERGE|TAG_QUEUE_SHARED|3

Add the decoding for that flag.

Fixes: 32bc15af ("blk-mq: Facilitate a shared sbitmap per tagset")
Signed-off-by: NJohn Garry <john.garry@huawei.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Make sure that bdgrab() is done on the 'block_device' instance before
referring to it for avoiding use-after-free.

Cc: <stable@vger.kernel.org>
Reported-by: syzbot+825f0f9657d4e528046e@syzkaller.appspotmail.com
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

BFQ computes number of tags it allows to be allocated for each request type
based on tag bitmap. However it uses 1 << bitmap.shift as number of
available tags which is wrong. 'shift' is just an internal bitmap value
containing logarithm of how many bits bitmap uses in each bitmap word.
Thus number of tags allowed for some request types can be far to low.
Use proper bitmap.depth which has the number of tags instead.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

When initializing iocost for a queue, its rqos should be registered before
the blkcg policy is activated to allow policy data initiailization to lookup
the associated ioc. This unfortunately means that the rqos methods can be
called on bios before iocgs are attached to all existing blkgs.

While the race is theoretically possible on ioc_rqos_throttle(), it mostly
happened in ioc_rqos_merge() due to the difference in how they lookup ioc.
The former determines it from the passed in @rqos and then bails before
dereferencing iocg if the looked up ioc is disabled, which most likely is
the case if initialization is still in progress. The latter looked up ioc by
dereferencing the possibly NULL iocg making it a lot more prone to actually
triggering the bug.

* Make ioc_rqos_merge() use the same method as ioc_rqos_throttle() to look
  up ioc for consistency.

* Make ioc_rqos_throttle() and ioc_rqos_merge() test for NULL iocg before
  dereferencing it.

* Explain the danger of NULL iocgs in blk_iocost_init().
Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-by: NJonathan Lemon <bsd@fb.com>
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: NJens Axboe <axboe@kernel.dk>

This was missed in 021a2446. Leads to the numeric value of
QUEUE_FLAG_NOWAIT (i.e. 29) showing up in
/sys/kernel/debug/block/*/state.

Fixes: 021a2446
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: NAndres Freund <andres@anarazel.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Update copyrights for files that have gotten some major rewrites lately.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

With force threaded interrupts enabled, raising softirq from an SMP
function call will always result in waking the ksoftirqd thread. This is
not optimal given that the thread runs at SCHED_OTHER priority.

Completing the request in hard IRQ-context on PREEMPT_RT (which enforces
the force threaded mode) is bad because the completion handler may
acquire sleeping locks which violate the locking context.

Disable request completing on a remote CPU in force threaded mode.
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDaniel Wagner <dwagner@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

It will be helpful to trace the iocg's whole state, including active and
idle state. And we can easily expand the original iocost_iocg_activate
trace event to support a state trace class, including active and idle
state tracing.
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NBaolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

It's guaranteed that no request is in flight when a hctx is going
offline. This warning is only triggered when the wq's CPU is hot
plugged and the blk-mq is not synced up yet.

As this state is temporary and the request is still processed
correctly, better remove the warning as this is the fast path.
Suggested-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NDaniel Wagner <dwagner@suse.de>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Delay to wait for queue running is milli second unit which is passed to
delayed work via msecs_to_jiffies() which is to convert milliseconds to
jiffies.
Signed-off-by: NMinwoo Im <minwoo.im.dev@gmail.com>
Reviewed-by: NJohn Garry <john.garry@huawei.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Update mis-named argument description of blk_mq_map_queue().  This patch
also updates description that argument to software queue percpu context.
Signed-off-by: NMinwoo Im <minwoo.im.dev@gmail.com>
Reviewed-by: NJohn Garry <john.garry@huawei.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

tagset->set is allocated from blk_mq_alloc_tag_set() rather than being
reallocated.  This patch added a helper to make its meaning explicitly
which is to allocate rather than to reallocate.
Signed-off-by: NMinwoo Im <minwoo.im.dev@gmail.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

blk_queue_enter() accepts BLK_MQ_REQ_PM requests independent of the runtime
power management state. Now that SCSI domain validation no longer depends
on this behavior, modify the behavior of blk_queue_enter() as follows:

   - Do not accept any requests while suspended.

   - Only process power management requests while suspending or resuming.

Submitting BLK_MQ_REQ_PM requests to a device that is runtime suspended
causes runtime-suspended devices not to resume as they should. The request
which should cause a runtime resume instead gets issued directly, without
resuming the device first. Of course the device can't handle it properly,
the I/O fails, and the device remains suspended.

The problem is fixed by checking that the queue's runtime-PM status isn't
RPM_SUSPENDED before allowing a request to be issued, and queuing a
runtime-resume request if it is.  In particular, the inline
blk_pm_request_resume() routine is renamed blk_pm_resume_queue() and the
code is unified by merging the surrounding checks into the routine.  If the
queue isn't set up for runtime PM, or there currently is no restriction on
allowed requests, the request is allowed.  Likewise if the BLK_MQ_REQ_PM
flag is set and the status isn't RPM_SUSPENDED.  Otherwise a runtime resume
is queued and the request is blocked until conditions are more suitable.

[ bvanassche: modified commit message and removed Cc: stable because
  without the previous patches from this series this patch would break
  parallel SCSI domain validation + introduced queue_rpm_status() ]

Link: https://lore.kernel.org/r/20201209052951.16136-9-bvanassche@acm.org
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Can Guo <cang@codeaurora.org>
Cc: Stanley Chu <stanley.chu@mediatek.com>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reported-and-tested-by: NMartin Kepplinger <martin.kepplinger@puri.sm>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NCan Guo <cang@codeaurora.org>
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Remove flag RQF_PREEMPT and BLK_MQ_REQ_PREEMPT since these are no longer
used by any kernel code.

Link: https://lore.kernel.org/r/20201209052951.16136-8-bvanassche@acm.org
Cc: Can Guo <cang@codeaurora.org>
Cc: Stanley Chu <stanley.chu@mediatek.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Martin Kepplinger <martin.kepplinger@puri.sm>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NJens Axboe <axboe@kernel.dk>
Reviewed-by: NCan Guo <cang@codeaurora.org>
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Introduce the BLK_MQ_REQ_PM flag. This flag makes the request allocation
functions set RQF_PM. This is the first step towards removing
BLK_MQ_REQ_PREEMPT.

Link: https://lore.kernel.org/r/20201209052951.16136-3-bvanassche@acm.org
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Stanley Chu <stanley.chu@mediatek.com>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Can Guo <cang@codeaurora.org>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NJens Axboe <axboe@kernel.dk>
Reviewed-by: NCan Guo <cang@codeaurora.org>
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

With the current implementation the following race can happen:

 * blk_pre_runtime_suspend() calls blk_freeze_queue_start() and
   blk_mq_unfreeze_queue().

 * blk_queue_enter() calls blk_queue_pm_only() and that function returns
   true.

 * blk_queue_enter() calls blk_pm_request_resume() and that function does
   not call pm_request_resume() because the queue runtime status is
   RPM_ACTIVE.

 * blk_pre_runtime_suspend() changes the queue status into RPM_SUSPENDING.

Fix this race by changing the queue runtime status into RPM_SUSPENDING
before switching q_usage_counter to atomic mode.

Link: https://lore.kernel.org/r/20201209052951.16136-2-bvanassche@acm.org
Fixes: 986d413b ("blk-mq: Enable support for runtime power management")
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: stable <stable@vger.kernel.org>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NJens Axboe <axboe@kernel.dk>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Acked-by: NStanley Chu <stanley.chu@mediatek.com>
Co-developed-by: NCan Guo <cang@codeaurora.org>
Signed-off-by: NCan Guo <cang@codeaurora.org>
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

This reverts commit b3c6a599.

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 b3c6a599("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: NKashyap Desai <kashyap.desai@broadcom.com>
Reported-by: NQian Cai <cai@redhat.com>
Reviewed-by: NChristoph 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: NMing Lei <ming.lei@redhat.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJens 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 b3c6a599("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: NKashyap Desai <kashyap.desai@broadcom.com>
Reported-by: NQian 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: NMing Lei <ming.lei@redhat.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

iopoll is initially for small size, latency sensitive IO. It doesn't
work well for big IO, especially when it needs to be split to multiple
bios. In this case, the returned cookie of __submit_bio_noacct_mq() is
indeed the cookie of the last split bio. The completion of *this* last
split bio done by iopoll doesn't mean the whole original bio has
completed. Callers of iopoll still need to wait for completion of other
split bios.

Besides bio splitting may cause more trouble for iopoll which isn't
supposed to be used in case of big IO.

iopoll for split bio may cause potential race if CPU migration happens
during bio submission. Since the returned cookie is that of the last
split bio, polling on the corresponding hardware queue doesn't help
complete other split bios, if these split bios are enqueued into
different hardware queues. Since interrupts are disabled for polling
queues, the completion of these other split bios depends on timeout
mechanism, thus causing a potential hang.

iopoll for split bio may also cause hang for sync polling. Currently
both the blkdev and iomap-based fs (ext4/xfs, etc) support sync polling
in direct IO routine. These routines will submit bio without REQ_NOWAIT
flag set, and then start sync polling in current process context. The
process may hang in blk_mq_get_tag() if the submitted bio has to be
split into multiple bios and can rapidly exhaust the queue depth. The
process are waiting for the completion of the previously allocated
requests, which should be reaped by the following polling, and thus
causing a deadlock.

To avoid these subtle trouble described above, just disable iopoll for
split bio and return BLK_QC_T_NONE in this case. The side effect is that
non-HIPRI IO also returns BLK_QC_T_NONE now. It should be acceptable
since the returned cookie is never used for non-HIPRI IO.
Suggested-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJeffle Xu <jefflexu@linux.alibaba.com>
Reviewed-by: NMing Lei <ming.lei@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Block device drivers do not have to call blk_queue_max_hw_sectors() to
set a limit on request size if the default limit BLK_SAFE_MAX_SECTORS
is acceptable. However, this limit (255 sectors) may not be aligned
to the device logical block size which cannot be used as is for a
request maximum size. This is the case for the null_blk device driver.

Modify blk_queue_max_hw_sectors() to make sure that the request size
limits specified by the max_hw_sectors and max_sectors queue limits
are always aligned to the device logical block size. Additionally, to
avoid introducing a dependence on the execution order of this function
with blk_queue_logical_block_size(), also modify
blk_queue_logical_block_size() to perform the same alignment when the
logical block size is set after max_hw_sectors.
Signed-off-by: NDamien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Improves the checks on the zones of a zoned block device done in
blk_revalidate_disk_zones() by making sure that the device report_zones
method did report at least one zone and that the zones reported exactly
cover the entire disk capacity, that is, that there are no missing zones
at the end of the disk sector range.
Signed-off-by: NDamien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

If blk_poll() is not going to spin (i.e. @spin=false), it also must not
sleep in hybrid polling, otherwise it might be pretty suprising for
users trying to do a quick check and expecting no-wait behaviour.
Signed-off-by: NPavel Begunkov <asml.silence@gmail.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Factor out the base vrate change code into a separate function
to fimplify the ioc_timer_fn().

No functional change.
Signed-off-by: NBaolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Factor out the iocgs' state check into a separate function to
simplify the ioc_timer_fn().

No functional change.
Signed-off-by: NBaolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

We only use the hweight based usage ratio to calculate the new
hweight_inuse of the iocg to decide if this iocg can donate some
surplus vtime.

Thus move the usage ratio calculation to the correct place to
avoid unnecessary calculation for some vtime shortage iocgs.
Signed-off-by: NBaolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Remove unnecessary advance declaration of struct ioc_gq.
Signed-off-by: NBaolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Fix some typos in comments.
Signed-off-by: NBaolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Commit 882ec4e6 ("dm table: stack 'chunk_sectors' limit to account
for target-specific splitting") caused a couple regressions:
1) Using lcm_not_zero() when stacking chunk_sectors was a bug because
   chunk_sectors must reflect the most limited of all devices in the
   IO stack.
2) DM targets that set max_io_len but that do _not_ provide an
   .iterate_devices method no longer had there IO split properly.

And commit 5091cdec ("dm: change max_io_len() to use
blk_max_size_offset()") also caused a regression where DM no longer
supported varied (per target) IO splitting. The implication being the
potential for severely reduced performance for IO stacks that use a DM
target like dm-cache to hide performance limitations of a slower
device (e.g. one that requires 4K IO splitting).

Coming full circle: Fix all these issues by discontinuing stacking
chunk_sectors up using ti->max_io_len in dm_calculate_queue_limits(),
add optional chunk_sectors override argument to blk_max_size_offset()
and update DM's max_io_len() to pass ti->max_io_len to its
blk_max_size_offset() call.

Passing in an optional chunk_sectors override to blk_max_size_offset()
allows for code reuse of block's centralized calculation for max IO
size based on provided offset and split boundary.

Fixes: 882ec4e6 ("dm table: stack 'chunk_sectors' limit to account for target-specific splitting")
Fixes: 5091cdec ("dm: change max_io_len() to use blk_max_size_offset()")
Cc: stable@vger.kernel.org
Reported-by: NJohn Dorminy <jdorminy@redhat.com>
Reported-by: NBruce Johnston <bjohnsto@redhat.com>
Reported-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Reviewed-by: NJohn Dorminy <jdorminy@redhat.com>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>
Reviewed-by: NJens Axboe <axboe@kernel.dk>

The request_queue can trivially be derived from the request.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDamien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The request_queue can trivially be derived from the bio.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDamien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The request_queue can trivially be derived from the bio.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDamien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The block_bio_merge tracepoint class can be reused for most bio-based
tracepoints.  For that it just needs to lose the superfluous q and rq
parameters.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDamien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

blk-throttle: don't check whether or not lower limit is valid if CONFIG_BLK_DEV_THROTTLING_LOW is off

blk_throtl_update_limit_valid() will search for descendants to see if
'LIMIT_LOW' of bps/iops and READ/WRITE is nonzero. However, they're always
zero if CONFIG_BLK_DEV_THROTTLING_LOW is not set, furthermore, a lot of
time will be wasted to iterate descendants.

Thus do nothing in blk_throtl_update_limit_valid() in such situation.
Signed-off-by: NYu Kuai <yukuai3@huawei.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The inflight of partition 0 doesn't include inflight IOs to all
sub-partitions, since currently mq calculates inflight of specific
partition by simply camparing the value of the partition pointer.

Thus the following case is possible:

$ cat /sys/block/vda/inflight
       0        0
$ cat /sys/block/vda/vda1/inflight
       0      128

While single queue device (on a previous version, e.g. v3.10) has no
this issue:

$cat /sys/block/sda/sda3/inflight
       0       33
$cat /sys/block/sda/inflight
       0       33

Partition 0 should be specially handled since it represents the whole
disk. This issue is introduced since commit bf0ddaba ("blk-mq: fix
sysfs inflight counter").

Besides, this patch can also fix the inflight statistics of part 0 in
/proc/diskstats. Before this patch, the inflight statistics of part 0
doesn't include that of sub partitions. (I have marked the 'inflight'
field with asterisk.)

$cat /proc/diskstats
 259       0 nvme0n1 45974469 0 367814768 6445794 1 0 1 0 *0* 111062 6445794 0 0 0 0 0 0
 259       2 nvme0n1p1 45974058 0 367797952 6445727 0 0 0 0 *33* 111001 6445727 0 0 0 0 0 0

This is introduced since commit f299b7c7 ("blk-mq: provide internal
in-flight variant").

Fixes: bf0ddaba ("blk-mq: fix sysfs inflight counter")
Fixes: f299b7c7 ("blk-mq: provide internal in-flight variant")
Signed-off-by: NJeffle Xu <jefflexu@linux.alibaba.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
[axboe: adapt for 5.11 partition change]
Signed-off-by: NJens Axboe <axboe@kernel.dk>

__bio_for_each_bvec(), __bio_for_each_segment() and bio_copy_data_iter()
fall under conditions of bvec_iter_advance_single(), which is a faster
and slimmer version of bvec_iter_advance(). Add
bio_advance_iter_single() and convert them.
Signed-off-by: NPavel Begunkov <asml.silence@gmail.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

We can just dereference the point in struct gendisk instead.  Also
remove the now unused export.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJan Kara <jack@suse.cz>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Instead of having two structures that represent each block device with
different life time rules, merge them into a single one.  This also
greatly simplifies the reference counting rules, as we can use the inode
reference count as the main reference count for the new struct
block_device, with the device model reference front ending it for device
model interaction.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJan Kara <jack@suse.cz>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Switch the partition iter infrastructure to iterate over block_device
references instead of hd_struct ones mostly used to get at the
block_device.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJan Kara <jack@suse.cz>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>