<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/block, branch v5.15.97</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>block, bfq: fix uaf for bfqq in bic_set_bfqq()</title>
<updated>2023-02-09T10:26:36+00:00</updated>
<author>
<name>Yu Kuai</name>
<email>yukuai3@huawei.com</email>
</author>
<published>2023-01-30T01:41:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=511c922c5bf6c8a166bea826e702336bc2424140'/>
<id>511c922c5bf6c8a166bea826e702336bc2424140</id>
<content type='text'>
[ Upstream commit b600de2d7d3a16f9007fad1bdae82a3951a26af2 ]

After commit 64dc8c732f5c ("block, bfq: fix possible uaf for 'bfqq-&gt;bic'"),
bic-&gt;bfqq will be accessed in bic_set_bfqq(), however, in some context
bic-&gt;bfqq will be freed, and bic_set_bfqq() is called with the freed
bic-&gt;bfqq.

Fix the problem by always freeing bfqq after bic_set_bfqq().

Fixes: 64dc8c732f5c ("block, bfq: fix possible uaf for 'bfqq-&gt;bic'")
Reported-and-tested-by: Shinichiro Kawasaki &lt;shinichiro.kawasaki@wdc.com&gt;
Signed-off-by: Yu Kuai &lt;yukuai3@huawei.com&gt;
Reviewed-by: Jan Kara &lt;jack@suse.cz&gt;
Link: https://lore.kernel.org/r/20230130014136.591038-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit b600de2d7d3a16f9007fad1bdae82a3951a26af2 ]

After commit 64dc8c732f5c ("block, bfq: fix possible uaf for 'bfqq-&gt;bic'"),
bic-&gt;bfqq will be accessed in bic_set_bfqq(), however, in some context
bic-&gt;bfqq will be freed, and bic_set_bfqq() is called with the freed
bic-&gt;bfqq.

Fix the problem by always freeing bfqq after bic_set_bfqq().

Fixes: 64dc8c732f5c ("block, bfq: fix possible uaf for 'bfqq-&gt;bic'")
Reported-and-tested-by: Shinichiro Kawasaki &lt;shinichiro.kawasaki@wdc.com&gt;
Signed-off-by: Yu Kuai &lt;yukuai3@huawei.com&gt;
Reviewed-by: Jan Kara &lt;jack@suse.cz&gt;
Link: https://lore.kernel.org/r/20230130014136.591038-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>block, bfq: replace 0/1 with false/true in bic apis</title>
<updated>2023-02-09T10:26:36+00:00</updated>
<author>
<name>Yu Kuai</name>
<email>yukuai3@huawei.com</email>
</author>
<published>2022-12-14T03:31:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a62c129dcbfab0df020a7acb9538716304c180de'/>
<id>a62c129dcbfab0df020a7acb9538716304c180de</id>
<content type='text'>
[ Upstream commit 337366e02b370d2800110fbc99940f6ddddcbdfa ]

Just to make the code a litter cleaner, there are no functional changes.

Signed-off-by: Yu Kuai &lt;yukuai3@huawei.com&gt;
Reviewed-by: Jan Kara &lt;jack@suse.cz&gt;
Link: https://lore.kernel.org/r/20221214033155.3455754-3-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Stable-dep-of: b600de2d7d3a ("block, bfq: fix uaf for bfqq in bic_set_bfqq()")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 337366e02b370d2800110fbc99940f6ddddcbdfa ]

Just to make the code a litter cleaner, there are no functional changes.

Signed-off-by: Yu Kuai &lt;yukuai3@huawei.com&gt;
Reviewed-by: Jan Kara &lt;jack@suse.cz&gt;
Link: https://lore.kernel.org/r/20221214033155.3455754-3-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Stable-dep-of: b600de2d7d3a ("block, bfq: fix uaf for bfqq in bic_set_bfqq()")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>block/bfq-iosched.c: use "false" rather than "BLK_RW_ASYNC"</title>
<updated>2023-02-09T10:26:36+00:00</updated>
<author>
<name>NeilBrown</name>
<email>neilb@suse.de</email>
</author>
<published>2022-03-22T21:39:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=37a744a068c99903c52f959907ea5135f8ce4ad6'/>
<id>37a744a068c99903c52f959907ea5135f8ce4ad6</id>
<content type='text'>
[ Upstream commit f6bad159f5d5e5b33531aba3d9b860ad8618afe0 ]

bfq_get_queue() expects a "bool" for the third arg, so pass "false"
rather than "BLK_RW_ASYNC" which will soon be removed.

Link: https://lkml.kernel.org/r/164549983746.9187.7949730109246767909.stgit@noble.brown
Signed-off-by: NeilBrown &lt;neilb@suse.de&gt;
Acked-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Cc: Anna Schumaker &lt;Anna.Schumaker@Netapp.com&gt;
Cc: Chao Yu &lt;chao@kernel.org&gt;
Cc: Darrick J. Wong &lt;djwong@kernel.org&gt;
Cc: Ilya Dryomov &lt;idryomov@gmail.com&gt;
Cc: Jaegeuk Kim &lt;jaegeuk@kernel.org&gt;
Cc: Jan Kara &lt;jack@suse.cz&gt;
Cc: Jeff Layton &lt;jlayton@kernel.org&gt;
Cc: Lars Ellenberg &lt;lars.ellenberg@linbit.com&gt;
Cc: Miklos Szeredi &lt;miklos@szeredi.hu&gt;
Cc: Paolo Valente &lt;paolo.valente@linaro.org&gt;
Cc: Philipp Reisner &lt;philipp.reisner@linbit.com&gt;
Cc: Ryusuke Konishi &lt;konishi.ryusuke@gmail.com&gt;
Cc: Trond Myklebust &lt;trond.myklebust@hammerspace.com&gt;
Cc: Wu Fengguang &lt;fengguang.wu@intel.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Stable-dep-of: b600de2d7d3a ("block, bfq: fix uaf for bfqq in bic_set_bfqq()")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit f6bad159f5d5e5b33531aba3d9b860ad8618afe0 ]

bfq_get_queue() expects a "bool" for the third arg, so pass "false"
rather than "BLK_RW_ASYNC" which will soon be removed.

Link: https://lkml.kernel.org/r/164549983746.9187.7949730109246767909.stgit@noble.brown
Signed-off-by: NeilBrown &lt;neilb@suse.de&gt;
Acked-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Cc: Anna Schumaker &lt;Anna.Schumaker@Netapp.com&gt;
Cc: Chao Yu &lt;chao@kernel.org&gt;
Cc: Darrick J. Wong &lt;djwong@kernel.org&gt;
Cc: Ilya Dryomov &lt;idryomov@gmail.com&gt;
Cc: Jaegeuk Kim &lt;jaegeuk@kernel.org&gt;
Cc: Jan Kara &lt;jack@suse.cz&gt;
Cc: Jeff Layton &lt;jlayton@kernel.org&gt;
Cc: Lars Ellenberg &lt;lars.ellenberg@linbit.com&gt;
Cc: Miklos Szeredi &lt;miklos@szeredi.hu&gt;
Cc: Paolo Valente &lt;paolo.valente@linaro.org&gt;
Cc: Philipp Reisner &lt;philipp.reisner@linbit.com&gt;
Cc: Ryusuke Konishi &lt;konishi.ryusuke@gmail.com&gt;
Cc: Trond Myklebust &lt;trond.myklebust@hammerspace.com&gt;
Cc: Wu Fengguang &lt;fengguang.wu@intel.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Stable-dep-of: b600de2d7d3a ("block, bfq: fix uaf for bfqq in bic_set_bfqq()")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>blk-cgroup: fix missing pd_online_fn() while activating policy</title>
<updated>2023-02-06T06:59:00+00:00</updated>
<author>
<name>Yu Kuai</name>
<email>yukuai3@huawei.com</email>
</author>
<published>2023-01-03T11:28:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6d7686cc11b76019db57f9b2dc555f4023d097a1'/>
<id>6d7686cc11b76019db57f9b2dc555f4023d097a1</id>
<content type='text'>
[ Upstream commit e3ff8887e7db757360f97634e0d6f4b8e27a8c46 ]

If the policy defines pd_online_fn(), it should be called after
pd_init_fn(), like blkg_create().

Signed-off-by: Yu Kuai &lt;yukuai3@huawei.com&gt;
Acked-by: Tejun Heo &lt;tj@kernel.org&gt;
Link: https://lore.kernel.org/r/20230103112833.2013432-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit e3ff8887e7db757360f97634e0d6f4b8e27a8c46 ]

If the policy defines pd_online_fn(), it should be called after
pd_init_fn(), like blkg_create().

Signed-off-by: Yu Kuai &lt;yukuai3@huawei.com&gt;
Acked-by: Tejun Heo &lt;tj@kernel.org&gt;
Link: https://lore.kernel.org/r/20230103112833.2013432-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>block: fix and cleanup bio_check_ro</title>
<updated>2023-02-01T07:27:30+00:00</updated>
<author>
<name>Christoph Hellwig</name>
<email>hch@lst.de</email>
</author>
<published>2022-03-04T18:00:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b57740036792332821de6b4ef4acd9a2bab9f06d'/>
<id>b57740036792332821de6b4ef4acd9a2bab9f06d</id>
<content type='text'>
commit 57e95e4670d1126c103305bcf34a9442f49f6d6a upstream.

Don't use a WARN_ON when printing a potentially user triggered
condition.  Also don't print the partno when the block device name
already includes it, and use the %pg specifier to simplify printing
the block device name.

Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Chaitanya Kulkarni &lt;kch@nvidia.com&gt;
Reviewed-by: Johannes Thumshirn &lt;johannes.thumshirn@wdc.com&gt;
Link: https://lore.kernel.org/r/20220304180105.409765-2-hch@lst.de
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Fedor Pchelkin &lt;pchelkin@ispras.ru&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 57e95e4670d1126c103305bcf34a9442f49f6d6a upstream.

Don't use a WARN_ON when printing a potentially user triggered
condition.  Also don't print the partno when the block device name
already includes it, and use the %pg specifier to simplify printing
the block device name.

Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Chaitanya Kulkarni &lt;kch@nvidia.com&gt;
Reviewed-by: Johannes Thumshirn &lt;johannes.thumshirn@wdc.com&gt;
Link: https://lore.kernel.org/r/20220304180105.409765-2-hch@lst.de
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Fedor Pchelkin &lt;pchelkin@ispras.ru&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>block: mq-deadline: Rename deadline_is_seq_writes()</title>
<updated>2023-01-24T06:22:49+00:00</updated>
<author>
<name>Damien Le Moal</name>
<email>damien.lemoal@opensource.wdc.com</email>
</author>
<published>2022-11-26T02:55:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=40a4797e08ec44514159625bc3fd67e93e8442cd'/>
<id>40a4797e08ec44514159625bc3fd67e93e8442cd</id>
<content type='text'>
commit 3692fec8bb476e8583e559ff5783a6adef306cf2 upstream.

Rename deadline_is_seq_writes() to deadline_is_seq_write() (remove the
"s" plural) to more correctly reflect the fact that this function tests
a single request, not multiple requests.

Fixes: 015d02f48537 ("block: mq-deadline: Do not break sequential write streams to zoned HDDs")
Signed-off-by: Damien Le Moal &lt;damien.lemoal@opensource.wdc.com&gt;
Link: https://lore.kernel.org/r/20221126025550.967914-2-damien.lemoal@opensource.wdc.com
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 3692fec8bb476e8583e559ff5783a6adef306cf2 upstream.

Rename deadline_is_seq_writes() to deadline_is_seq_write() (remove the
"s" plural) to more correctly reflect the fact that this function tests
a single request, not multiple requests.

Fixes: 015d02f48537 ("block: mq-deadline: Do not break sequential write streams to zoned HDDs")
Signed-off-by: Damien Le Moal &lt;damien.lemoal@opensource.wdc.com&gt;
Link: https://lore.kernel.org/r/20221126025550.967914-2-damien.lemoal@opensource.wdc.com
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>block: handle bio_split_to_limits() NULL return</title>
<updated>2023-01-18T10:48:58+00:00</updated>
<author>
<name>Jens Axboe</name>
<email>axboe@kernel.dk</email>
</author>
<published>2023-01-04T15:51:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=7ec9a45fc4ee7fc1054c2cabf8b09a6bc708472e'/>
<id>7ec9a45fc4ee7fc1054c2cabf8b09a6bc708472e</id>
<content type='text'>
commit 613b14884b8595e20b9fac4126bf627313827fbe upstream.

This can't happen right now, but in preparation for allowing
bio_split_to_limits() returning NULL if it ended the bio, check for it
in all the callers.

Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 613b14884b8595e20b9fac4126bf627313827fbe upstream.

This can't happen right now, but in preparation for allowing
bio_split_to_limits() returning NULL if it ended the bio, check for it
in all the callers.

Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>block: don't allow splitting of a REQ_NOWAIT bio</title>
<updated>2023-01-12T10:59:18+00:00</updated>
<author>
<name>Jens Axboe</name>
<email>axboe@kernel.dk</email>
</author>
<published>2023-01-04T15:52:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b7b9bc93055d69283fe259c38ea9c46a7a6c3421'/>
<id>b7b9bc93055d69283fe259c38ea9c46a7a6c3421</id>
<content type='text'>
commit 9cea62b2cbabff8ed46f2df17778b624ad9dd25a upstream.

If we split a bio marked with REQ_NOWAIT, then we can trigger spurious
EAGAIN if constituent parts of that split bio end up failing request
allocations. Parts will complete just fine, but just a single failure
in one of the chained bios will yield an EAGAIN final result for the
parent bio.

Return EAGAIN early if we end up needing to split such a bio, which
allows for saner recovery handling.

Cc: stable@vger.kernel.org # 5.15+
Link: https://github.com/axboe/liburing/issues/766
Reported-by: Michael Kelley &lt;mikelley@microsoft.com&gt;
Reviewed-by: Keith Busch &lt;kbusch@kernel.org&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 9cea62b2cbabff8ed46f2df17778b624ad9dd25a upstream.

If we split a bio marked with REQ_NOWAIT, then we can trigger spurious
EAGAIN if constituent parts of that split bio end up failing request
allocations. Parts will complete just fine, but just a single failure
in one of the chained bios will yield an EAGAIN final result for the
parent bio.

Return EAGAIN early if we end up needing to split such a bio, which
allows for saner recovery handling.

Cc: stable@vger.kernel.org # 5.15+
Link: https://github.com/axboe/liburing/issues/766
Reported-by: Michael Kelley &lt;mikelley@microsoft.com&gt;
Reviewed-by: Keith Busch &lt;kbusch@kernel.org&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>block: mq-deadline: Fix dd_finish_request() for zoned devices</title>
<updated>2023-01-12T10:59:03+00:00</updated>
<author>
<name>Damien Le Moal</name>
<email>damien.lemoal@opensource.wdc.com</email>
</author>
<published>2022-11-24T02:12:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=5234dd5d205b3b7ff4f636f705ec0b162749a0e0'/>
<id>5234dd5d205b3b7ff4f636f705ec0b162749a0e0</id>
<content type='text'>
commit 2820e5d0820ac4daedff1272616a53d9c7682fd2 upstream.

dd_finish_request() tests if the per prio fifo_list is not empty to
determine if request dispatching must be restarted for handling blocked
write requests to zoned devices with a call to
blk_mq_sched_mark_restart_hctx(). While simple, this implementation has
2 problems:

1) Only the priority level of the completed request is considered.
   However, writes to a zone may be blocked due to other writes to the
   same zone using a different priority level. While this is unlikely to
   happen in practice, as writing a zone with different IO priorirites
   does not make sense, nothing in the code prevents this from
   happening.
2) The use of list_empty() is dangerous as dd_finish_request() does not
   take dd-&gt;lock and may run concurrently with the insert and dispatch
   code.

Fix these 2 problems by testing the write fifo list of all priority
levels using the new helper dd_has_write_work(), and by testing each
fifo list using list_empty_careful().

Fixes: c807ab520fc3 ("block/mq-deadline: Add I/O priority support")
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Damien Le Moal &lt;damien.lemoal@opensource.wdc.com&gt;
Reviewed-by: Johannes Thumshirn &lt;johannes.thumshirn@wdc.com&gt;
Link: https://lore.kernel.org/r/20221124021208.242541-2-damien.lemoal@opensource.wdc.com
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 2820e5d0820ac4daedff1272616a53d9c7682fd2 upstream.

dd_finish_request() tests if the per prio fifo_list is not empty to
determine if request dispatching must be restarted for handling blocked
write requests to zoned devices with a call to
blk_mq_sched_mark_restart_hctx(). While simple, this implementation has
2 problems:

1) Only the priority level of the completed request is considered.
   However, writes to a zone may be blocked due to other writes to the
   same zone using a different priority level. While this is unlikely to
   happen in practice, as writing a zone with different IO priorirites
   does not make sense, nothing in the code prevents this from
   happening.
2) The use of list_empty() is dangerous as dd_finish_request() does not
   take dd-&gt;lock and may run concurrently with the insert and dispatch
   code.

Fix these 2 problems by testing the write fifo list of all priority
levels using the new helper dd_has_write_work(), and by testing each
fifo list using list_empty_careful().

Fixes: c807ab520fc3 ("block/mq-deadline: Add I/O priority support")
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Damien Le Moal &lt;damien.lemoal@opensource.wdc.com&gt;
Reviewed-by: Johannes Thumshirn &lt;johannes.thumshirn@wdc.com&gt;
Link: https://lore.kernel.org/r/20221124021208.242541-2-damien.lemoal@opensource.wdc.com
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>block: mq-deadline: Do not break sequential write streams to zoned HDDs</title>
<updated>2023-01-12T10:58:56+00:00</updated>
<author>
<name>Damien Le Moal</name>
<email>damien.lemoal@opensource.wdc.com</email>
</author>
<published>2022-11-24T02:12:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=94fe975d54ab8877d215a0b14543f4383f70c461'/>
<id>94fe975d54ab8877d215a0b14543f4383f70c461</id>
<content type='text'>
commit 015d02f48537cf2d1a65eeac50717566f9db6eec upstream.

mq-deadline ensures an in order dispatching of write requests to zoned
block devices using a per zone lock (a bit). This implies that for any
purely sequential write workload, the drive is exercised most of the
time at a maximum queue depth of one.

However, when such sequential write workload crosses a zone boundary
(when sequentially writing multiple contiguous zones), zone write
locking may prevent the last write to one zone to be issued (as the
previous write is still being executed) but allow the first write to the
following zone to be issued (as that zone is not yet being writen and
not locked). This result in an out of order delivery of the sequential
write commands to the device every time a zone boundary is crossed.

While such behavior does not break the sequential write constraint of
zoned block devices (and does not generate any write error), some zoned
hard-disks react badly to seeing these out of order writes, resulting in
lower write throughput.

This problem can be addressed by always dispatching the first request
of a stream of sequential write requests, regardless of the zones
targeted by these sequential writes. To do so, the function
deadline_skip_seq_writes() is introduced and used in
deadline_next_request() to select the next write command to issue if the
target device is an HDD (blk_queue_nonrot() being false).
deadline_fifo_request() is modified using the new
deadline_earlier_request() and deadline_is_seq_write() helpers to ignore
requests in the fifo list that have a preceding request in lba order
that is sequential.

With this fix, a sequential write workload executed with the following
fio command:

fio  --name=seq-write --filename=/dev/sda --zonemode=zbd --direct=1 \
     --size=68719476736  --ioengine=libaio --iodepth=32 --rw=write \
     --bs=65536

results in an increase from 225 MB/s to 250 MB/s of the write throughput
of an SMR HDD (11% increase).

Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Damien Le Moal &lt;damien.lemoal@opensource.wdc.com&gt;
Reviewed-by: Johannes Thumshirn &lt;johannes.thumshirn@wdc.com&gt;
Link: https://lore.kernel.org/r/20221124021208.242541-3-damien.lemoal@opensource.wdc.com
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 015d02f48537cf2d1a65eeac50717566f9db6eec upstream.

mq-deadline ensures an in order dispatching of write requests to zoned
block devices using a per zone lock (a bit). This implies that for any
purely sequential write workload, the drive is exercised most of the
time at a maximum queue depth of one.

However, when such sequential write workload crosses a zone boundary
(when sequentially writing multiple contiguous zones), zone write
locking may prevent the last write to one zone to be issued (as the
previous write is still being executed) but allow the first write to the
following zone to be issued (as that zone is not yet being writen and
not locked). This result in an out of order delivery of the sequential
write commands to the device every time a zone boundary is crossed.

While such behavior does not break the sequential write constraint of
zoned block devices (and does not generate any write error), some zoned
hard-disks react badly to seeing these out of order writes, resulting in
lower write throughput.

This problem can be addressed by always dispatching the first request
of a stream of sequential write requests, regardless of the zones
targeted by these sequential writes. To do so, the function
deadline_skip_seq_writes() is introduced and used in
deadline_next_request() to select the next write command to issue if the
target device is an HDD (blk_queue_nonrot() being false).
deadline_fifo_request() is modified using the new
deadline_earlier_request() and deadline_is_seq_write() helpers to ignore
requests in the fifo list that have a preceding request in lba order
that is sequential.

With this fix, a sequential write workload executed with the following
fio command:

fio  --name=seq-write --filename=/dev/sda --zonemode=zbd --direct=1 \
     --size=68719476736  --ioengine=libaio --iodepth=32 --rw=write \
     --bs=65536

results in an increase from 225 MB/s to 250 MB/s of the write throughput
of an SMR HDD (11% increase).

Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Damien Le Moal &lt;damien.lemoal@opensource.wdc.com&gt;
Reviewed-by: Johannes Thumshirn &lt;johannes.thumshirn@wdc.com&gt;
Link: https://lore.kernel.org/r/20221124021208.242541-3-damien.lemoal@opensource.wdc.com
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
