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<title>kernel/include/linux/blk-mq.h, branch linux-5.11.y</title>
<subtitle>Hosts the 0x221E linux distro kernel.</subtitle>
<id>https://universe.0xinfinity.dev/distro/kernel/atom?h=linux-5.11.y</id>
<link rel='self' href='https://universe.0xinfinity.dev/distro/kernel/atom?h=linux-5.11.y'/>
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<updated>2021-01-01T20:58:07Z</updated>
<entry>
<title>Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi</title>
<updated>2021-01-01T20:58:07Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-01-01T20:58:07Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=eda809aef53426d044b519405d25d9da55319b76'/>
<id>urn:sha1:eda809aef53426d044b519405d25d9da55319b76</id>
<content type='text'>
Pull SCSI fixes from James Bottomley:
 "This is a load of driver fixes (12 ufs, 1 mpt3sas, 1 cxgbi).

  The big core two fixes are for power management ("block: Do not accept
  any requests while suspended" and "block: Fix a race in the runtime
  power management code") which finally sorts out the resume problems
  we've occasionally been having.

  To make the resume fix, there are seven necessary precursors which
  effectively renames REQ_PREEMPT to REQ_PM, so every "special" request
  in block is automatically a power management exempt one.

  All of the non-PM preempt cases are removed except for the one in the
  SCSI Parallel Interface (spi) domain validation which is a genuine
  case where we have to run requests at high priority to validate the
  bus so this becomes an autopm get/put protected request"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (22 commits)
  scsi: cxgb4i: Fix TLS dependency
  scsi: ufs: Un-inline ufshcd_vops_device_reset function
  scsi: ufs: Re-enable WriteBooster after device reset
  scsi: ufs-mediatek: Use correct path to fix compile error
  scsi: mpt3sas: Signedness bug in _base_get_diag_triggers()
  scsi: block: Do not accept any requests while suspended
  scsi: block: Remove RQF_PREEMPT and BLK_MQ_REQ_PREEMPT
  scsi: core: Only process PM requests if rpm_status != RPM_ACTIVE
  scsi: scsi_transport_spi: Set RQF_PM for domain validation commands
  scsi: ide: Mark power management requests with RQF_PM instead of RQF_PREEMPT
  scsi: ide: Do not set the RQF_PREEMPT flag for sense requests
  scsi: block: Introduce BLK_MQ_REQ_PM
  scsi: block: Fix a race in the runtime power management code
  scsi: ufs-pci: Enable UFSHCD_CAP_RPM_AUTOSUSPEND for Intel controllers
  scsi: ufs-pci: Fix recovery from hibernate exit errors for Intel controllers
  scsi: ufs-pci: Ensure UFS device is in PowerDown mode for suspend-to-disk -&gt;poweroff()
  scsi: ufs-pci: Fix restore from S4 for Intel controllers
  scsi: ufs-mediatek: Keep VCC always-on for specific devices
  scsi: ufs: Allow regulators being always-on
  scsi: ufs: Clear UAC for RPMB after ufshcd resets
  ...
</content>
</entry>
<entry>
<title>Merge tag 'for-5.11/drivers-2020-12-14' of git://git.kernel.dk/linux-block</title>
<updated>2020-12-16T21:09:32Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2020-12-16T21:09:32Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=69f637c33560b02ae7313e0c142d847361cc723a'/>
<id>urn:sha1:69f637c33560b02ae7313e0c142d847361cc723a</id>
<content type='text'>
Pull block driver updates from Jens Axboe:
 "Nothing major in here:

   - NVMe pull request from Christoph:
        - nvmet passthrough improvements (Chaitanya Kulkarni)
        - fcloop error injection support (James Smart)
        - read-only support for zoned namespaces without Zone Append
          (Javier González)
        - improve some error message (Minwoo Im)
        - reject I/O to offline fabrics namespaces (Victor Gladkov)
        - PCI queue allocation cleanups (Niklas Schnelle)
        - remove an unused allocation in nvmet (Amit Engel)
        - a Kconfig spelling fix (Colin Ian King)
        - nvme_req_qid simplication (Baolin Wang)

   - MD pull request from Song:
        - Fix race condition in md_ioctl() (Dae R. Jeong)
        - Initialize read_slot properly for raid10 (Kevin Vigor)
        - Code cleanup (Pankaj Gupta)
        - md-cluster resync/reshape fix (Zhao Heming)

   - Move null_blk into its own directory (Damien Le Moal)

   - null_blk zone and discard improvements (Damien Le Moal)

   - bcache race fix (Dongsheng Yang)

   - Set of rnbd fixes/improvements (Gioh Kim, Guoqing Jiang, Jack Wang,
     Lutz Pogrell, Md Haris Iqbal)

   - lightnvm NULL pointer deref fix (tangzhenhao)

   - sr in_interrupt() removal (Sebastian Andrzej Siewior)

   - FC endpoint security support for s390/dasd (Jan Höppner, Sebastian
     Ott, Vineeth Vijayan). From the s390 arch guys, arch bits included
     as it made it easier for them to funnel the feature through the
     block driver tree.

   - Follow up fixes (Colin Ian King)"

* tag 'for-5.11/drivers-2020-12-14' of git://git.kernel.dk/linux-block: (64 commits)
  block: drop dead assignments in loop_init()
  sr: Remove in_interrupt() usage in sr_init_command().
  sr: Switch the sector size back to 2048 if sr_read_sector() changed it.
  cdrom: Reset sector_size back it is not 2048.
  drivers/lightnvm: fix a null-ptr-deref bug in pblk-core.c
  null_blk: Move driver into its own directory
  null_blk: Allow controlling max_hw_sectors limit
  null_blk: discard zones on reset
  null_blk: cleanup discard handling
  null_blk: Improve implicit zone close
  null_blk: improve zone locking
  block: Align max_hw_sectors to logical blocksize
  null_blk: Fail zone append to conventional zones
  null_blk: Fix zone size initialization
  bcache: fix race between setting bdev state to none and new write request direct to backing
  block/rnbd: fix a null pointer dereference on dev-&gt;blk_symlink_name
  block/rnbd-clt: Dynamically alloc buffer for pathname &amp; blk_symlink_name
  block/rnbd: call kobject_put in the failure path
  Documentation/ABI/rnbd-srv: add document for force_close
  block/rnbd-srv: close a mapped device from server side.
  ...
</content>
</entry>
<entry>
<title>scsi: block: Remove RQF_PREEMPT and BLK_MQ_REQ_PREEMPT</title>
<updated>2020-12-09T16:41:42Z</updated>
<author>
<name>Bart Van Assche</name>
<email>bvanassche@acm.org</email>
</author>
<published>2020-12-09T05:29:50Z</published>
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<id>urn:sha1:a4d34da715e3cb7e0741fe603dcd511bed067e00</id>
<content type='text'>
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 &lt;cang@codeaurora.org&gt;
Cc: Stanley Chu &lt;stanley.chu@mediatek.com&gt;
Cc: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Cc: Ming Lei &lt;ming.lei@redhat.com&gt;
Cc: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Cc: Martin Kepplinger &lt;martin.kepplinger@puri.sm&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Hannes Reinecke &lt;hare@suse.de&gt;
Reviewed-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Reviewed-by: Can Guo &lt;cang@codeaurora.org&gt;
Signed-off-by: Bart Van Assche &lt;bvanassche@acm.org&gt;
Signed-off-by: Martin K. Petersen &lt;martin.petersen@oracle.com&gt;
</content>
</entry>
<entry>
<title>scsi: block: Introduce BLK_MQ_REQ_PM</title>
<updated>2020-12-09T16:41:41Z</updated>
<author>
<name>Bart Van Assche</name>
<email>bvanassche@acm.org</email>
</author>
<published>2020-12-09T05:29:45Z</published>
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<id>urn:sha1:0854bcdcdec26aecdc92c303816f349ee1fba2bc</id>
<content type='text'>
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 &lt;stern@rowland.harvard.edu&gt;
Cc: Stanley Chu &lt;stanley.chu@mediatek.com&gt;
Cc: Ming Lei &lt;ming.lei@redhat.com&gt;
Cc: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Cc: Can Guo &lt;cang@codeaurora.org&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Hannes Reinecke &lt;hare@suse.de&gt;
Reviewed-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Reviewed-by: Can Guo &lt;cang@codeaurora.org&gt;
Signed-off-by: Bart Van Assche &lt;bvanassche@acm.org&gt;
Signed-off-by: Martin K. Petersen &lt;martin.petersen@oracle.com&gt;
</content>
</entry>
<entry>
<title>blk-mq: add new API of blk_mq_hctx_set_fq_lock_class</title>
<updated>2020-12-08T03:30:19Z</updated>
<author>
<name>Ming Lei</name>
<email>ming.lei@redhat.com</email>
</author>
<published>2020-12-03T01:26:36Z</published>
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<id>urn:sha1:fb01a2932e81a1fb2273f87ff92dc8172b8880ee</id>
<content type='text'>
flush_end_io() may be called recursively from some driver, such as
nvme-loop, so lockdep may complain 'possible recursive locking'.
Commit b3c6a5997541("block: Fix a lockdep complaint triggered by
request queue flushing") tried to address this issue by assigning
dynamically allocated per-flush-queue lock class. This solution
adds synchronize_rcu() for each hctx's release handler, and causes
horrible SCSI MQ probe delay(more than half an hour on megaraid sas).

Add new API of blk_mq_hctx_set_fq_lock_class() for these drivers, so
we just need to use driver specific lock class for avoiding the
lockdep warning of 'possible recursive locking'.

Tested-by: Kashyap Desai &lt;kashyap.desai@broadcom.com&gt;
Reported-by: Qian Cai &lt;cai@redhat.com&gt;
Cc: Sumit Saxena &lt;sumit.saxena@broadcom.com&gt;
Cc: John Garry &lt;john.garry@huawei.com&gt;
Cc: Kashyap Desai &lt;kashyap.desai@broadcom.com&gt;
Cc: Bart Van Assche &lt;bvanassche@acm.org&gt;
Cc: Hannes Reinecke &lt;hare@suse.de&gt;
Signed-off-by: Ming Lei &lt;ming.lei@redhat.com&gt;
Reviewed-by: Hannes Reinecke &lt;hare@suse.de&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
</content>
</entry>
<entry>
<title>block: move blk_rq_bio_prep() to linux/blk-mq.h</title>
<updated>2020-12-01T19:36:35Z</updated>
<author>
<name>Chaitanya Kulkarni</name>
<email>chaitanya.kulkarni@wdc.com</email>
</author>
<published>2020-11-10T02:24:03Z</published>
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<id>urn:sha1:53ffabfd4ddb3a24c5603ae82eefb5537ecb5c20</id>
<content type='text'>
This is a preparation patch to have minimal block layer request bio
append functionality in the context of the NVMeOF Passthru driver which
falls in the fast path and doesn't need calls from blk_rq_append_bio().

Signed-off-by: Chaitanya Kulkarni &lt;chaitanya.kulkarni@wdc.com&gt;
Reviewed-by: Logan Gunthorpe &lt;logang@deltatee.com&gt;
Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
</content>
</entry>
<entry>
<title>blk-mq: docs: add kernel-doc description for a new struct member</title>
<updated>2020-10-28T17:26:10Z</updated>
<author>
<name>Mauro Carvalho Chehab</name>
<email>mchehab+huawei@kernel.org</email>
</author>
<published>2020-10-27T09:51:13Z</published>
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<id>urn:sha1:6a6223ec7779dfdabb9c2567bb42079bc300cf27</id>
<content type='text'>
As reported by kernel-doc:
	./include/linux/blk-mq.h:267: warning: Function parameter or member 'active_queues_shared_sbitmap' not described in 'blk_mq_tag_set'

There is now a new member for struct blk_mq_tag_set. Add a
description for it, based on the commit that introduced it.

Fixes: f1b49fdc1c64 ("blk-mq: Record active_queues_shared_sbitmap per tag_set for when using shared sbitmap")
Signed-off-by: Mauro Carvalho Chehab &lt;mchehab+huawei@kernel.org&gt;
Reviewed-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Reviewed-by: John Garry &lt;john.garry@huawei.com&gt;
Link: https://lore.kernel.org/r/8e513153b83eefc05e358f51f2632b592c3f6772.1603791716.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet &lt;corbet@lwn.net&gt;
</content>
</entry>
<entry>
<title>blk-mq, elevator: Count requests per hctx to improve performance</title>
<updated>2020-09-03T21:20:47Z</updated>
<author>
<name>Kashyap Desai</name>
<email>kashyap.desai@broadcom.com</email>
</author>
<published>2020-08-19T15:20:28Z</published>
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<id>urn:sha1:b445547ec1bbd3e7bf4b1c142550942f70527d95</id>
<content type='text'>
High CPU utilization on "native_queued_spin_lock_slowpath" due to lock
contention is possible for mq-deadline and bfq IO schedulers
when nr_hw_queues is more than one.

It is because kblockd work queue can submit IO from all online CPUs
(through blk_mq_run_hw_queues()) even though only one hctx has pending
commands.

The elevator callback .has_work for mq-deadline and bfq scheduler considers
pending work if there are any IOs on request queue but it does not account
hctx context.

Add a per-hctx 'elevator_queued' count to the hctx to avoid triggering
the elevator even though there are no requests queued.

[jpg: Relocated atomic_dec() in dd_dispatch_request(), update commit message per Kashyap]

Signed-off-by: Kashyap Desai &lt;kashyap.desai@broadcom.com&gt;
Signed-off-by: Hannes Reinecke &lt;hare@suse.de&gt;
Signed-off-by: John Garry &lt;john.garry@huawei.com&gt;
Tested-by: Douglas Gilbert &lt;dgilbert@interlog.com&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
</content>
</entry>
<entry>
<title>blk-mq: Record active_queues_shared_sbitmap per tag_set for when using shared sbitmap</title>
<updated>2020-09-03T21:20:47Z</updated>
<author>
<name>John Garry</name>
<email>john.garry@huawei.com</email>
</author>
<published>2020-08-19T15:20:27Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=f1b49fdc1c64db110aa1315831e5fe0f8599fa56'/>
<id>urn:sha1:f1b49fdc1c64db110aa1315831e5fe0f8599fa56</id>
<content type='text'>
For when using a shared sbitmap, no longer should the number of active
request queues per hctx be relied on for when judging how to share the tag
bitmap.

Instead maintain the number of active request queues per tag_set, and make
the judgement based on that.

Originally-from: Kashyap Desai &lt;kashyap.desai@broadcom.com&gt;
Signed-off-by: John Garry &lt;john.garry@huawei.com&gt;
Tested-by: Don Brace&lt;don.brace@microsemi.com&gt; #SCSI resv cmds patches used
Tested-by: Douglas Gilbert &lt;dgilbert@interlog.com&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
</content>
</entry>
<entry>
<title>blk-mq: Facilitate a shared sbitmap per tagset</title>
<updated>2020-09-03T21:20:47Z</updated>
<author>
<name>John Garry</name>
<email>john.garry@huawei.com</email>
</author>
<published>2020-08-19T15:20:24Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=32bc15afed04bd73e29d713d8db47818d6aa89af'/>
<id>urn:sha1:32bc15afed04bd73e29d713d8db47818d6aa89af</id>
<content type='text'>
Some SCSI HBAs (such as HPSA, megaraid, mpt3sas, hisi_sas_v3 ..) support
multiple reply queues with single hostwide tags.

In addition, these drivers want to use interrupt assignment in
pci_alloc_irq_vectors(PCI_IRQ_AFFINITY). However, as discussed in [0],
CPU hotplug may cause in-flight IO completion to not be serviced when an
interrupt is shutdown. That problem is solved in commit bf0beec0607d
("blk-mq: drain I/O when all CPUs in a hctx are offline").

However, to take advantage of that blk-mq feature, the HBA HW queuess are
required to be mapped to that of the blk-mq hctx's; to do that, the HBA HW
queues need to be exposed to the upper layer.

In making that transition, the per-SCSI command request tags are no
longer unique per Scsi host - they are just unique per hctx. As such, the
HBA LLDD would have to generate this tag internally, which has a certain
performance overhead.

However another problem is that blk-mq assumes the host may accept
(Scsi_host.can_queue * #hw queue) commands. In commit 6eb045e092ef ("scsi:
 core: avoid host-wide host_busy counter for scsi_mq"), the Scsi host busy
counter was removed, which would stop the LLDD being sent more than
.can_queue commands; however, it should still be ensured that the block
layer does not issue more than .can_queue commands to the Scsi host.

To solve this problem, introduce a shared sbitmap per blk_mq_tag_set,
which may be requested at init time.

New flag BLK_MQ_F_TAG_HCTX_SHARED should be set when requesting the
tagset to indicate whether the shared sbitmap should be used.

Even when BLK_MQ_F_TAG_HCTX_SHARED is set, a full set of tags and requests
are still allocated per hctx; the reason for this is that if tags and
requests were only allocated for a single hctx - like hctx0 - it may break
block drivers which expect a request be associated with a specific hctx,
i.e. not always hctx0. This will introduce extra memory usage.

This change is based on work originally from Ming Lei in [1] and from
Bart's suggestion in [2].

[0] https://lore.kernel.org/linux-block/alpine.DEB.2.21.1904051331270.1802@nanos.tec.linutronix.de/
[1] https://lore.kernel.org/linux-block/20190531022801.10003-1-ming.lei@redhat.com/
[2] https://lore.kernel.org/linux-block/ff77beff-5fd9-9f05-12b6-826922bace1f@huawei.com/T/#m3db0a602f095cbcbff27e9c884d6b4ae826144be

Signed-off-by: John Garry &lt;john.garry@huawei.com&gt;
Tested-by: Don Brace&lt;don.brace@microsemi.com&gt; #SCSI resv cmds patches used
Tested-by: Douglas Gilbert &lt;dgilbert@interlog.com&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
</content>
</entry>
</feed>
