The NVMe specification states that MAXCMD is mandatory
for NVMe-over-Fabrics implementations. However, some NVMe/TCP
and NVMe/FC arrays from major vendors have buggy firmware
that reports MAXCMD as zero in the Identify Controller data structure.
Currently, the implementation closes the connection in such cases,
completely preventing the host from connecting to the target.
Fix the issue by printing a clear error message about the firmware bug
and allowing the connection to proceed. It assumes that the
target supports a MAXCMD value of SQSIZE + 1. If any issues arise,
the user can manually adjust SQSIZE to mitigate them.
Fixes: 4999568184 ("nvme-fabrics: check max outstanding commands")
Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>
Reviewed-by: Laurence Oberman <loberman@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
The quirk was initially used as a signal to set the discard_zeroes_data
queue limit because there were some use cases that relied on that
behavior. The queue limit no longer exists as every user of it has been
converted to use the write zeroes operation instead.
The quirk now means to use a discard command as an alias to a write
zeroes request. Two of the devices previously using the quirk support
the write zeroes command directly, so these don't need or want to use
discard when the desired operation is to write zeroes.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Commit 63dfa10043 ("nvme: move NVME_QUIRK_DEALLOCATE_ZEROES out of
nvme_config_discard") started applying the NVME_QUIRK_DEALLOCATE_ZEROES
quirk even then the Dataset Management is not supported. It turns out
that there versions of these old Intel SSDs that have DSM support
disabled in the firmware, which will now lead to errors everytime
a Write Zeroes command is issued. Fix this by checking for DSM support
before applying the quirk.
Reported-by: Saeed Mirzamohammadi <saeed.mirzamohammadi@oracle.com>
Fixes: 63dfa10043 ("nvme: move NVME_QUIRK_DEALLOCATE_ZEROES out of nvme_config_discard")
Tested-by: Saeed Mirzamohammadi <saeed.mirzamohammadi@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Nitesh Shetty <nj.shetty@samsung.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
The nvme_execute_identify_ns_nvm function uses ZERO_PAGE for copying
SG list with all zeros. As ZERO_PAGE would not necessarily return the
virtual-address of the zero page, we need to first convert the page
address to kernel virtual-address and then use it as source address
for copying the data to SG list with all zeros. Using return address
of ZERO_PAGE(0) as source address for copying data to SG list would
fill the target buffer with random/garbage value and causes the
undesired side effect.
As other identify implemenations uses kzalloc for allocating a zero
filled buffer, we decided use kzalloc for allocating a zero filled
buffer in nvme_execute_identify_ns_nvm function and then use this
buffer for copying all zeros to SG list buffers. So esentially, we
now avoid using ZERO_PAGE.
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Fixes: 64a51080ea ("nvmet: implement id ns for nvm command set")
Link: https://lore.kernel.org/all/CAHj4cs8OVyxmn4XTvA=y4uQ3qWpdw-x3M3FSUYr-KpE-nhaFEA@mail.gmail.com/
Signed-off-by: Nilay Shroff <nilay@linux.ibm.com>
Tested-by: Yi Zhang <yi.zhang@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
- Use correct srcu list traversal (Breno)
- Scatter-gather support for metadata (Keith)
- Fabrics shutdown race condition fix (Nilay)
- Persistent reservations updates (Guixin)
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Merge tag 'nvme-6.13-2024-11-21' of git://git.infradead.org/nvme into for-6.13/block
Pull NVMe updates from Keith:
"nvme updates for Linux 6.13
- Use correct srcu list traversal (Breno)
- Scatter-gather support for metadata (Keith)
- Fabrics shutdown race condition fix (Nilay)
- Persistent reservations updates (Guixin)"
* tag 'nvme-6.13-2024-11-21' of git://git.infradead.org/nvme:
nvme: tuning pr code by using defined structs and macros
nvme: introduce change ptpl and iekey definition
nvme-fabrics: fix kernel crash while shutting down controller
Revert "nvme: make keep-alive synchronous operation"
nvme-pci: use sgls for all user requests if possible
nvme: define the remaining used sgls constants
nvme-pci: add support for sgl metadata
nvme/multipath: Fix RCU list traversal to use SRCU primitive
All the modifications are simply to make the code more readable,
and this patch does not include any functional changes.
Signed-off-by: Guixin Liu <kanie@linux.alibaba.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
This is for the next tuning pr code more readble patch, make
linux/nvme.h's changes separately.
Signed-off-by: Guixin Liu <kanie@linux.alibaba.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
get_disk_ro and bdev_read_only return boolean conditions,
don't masquerade them as int.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20241119160932.1327864-7-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
bdev_read_only is already defined as an inline function in blkdev.h.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20241119160932.1327864-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk_rq_aligned returns a boolean condition, don't mascquerade it as int.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20241119160932.1327864-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The underlying limits are defined as unsigned int, so return that from
blk_lim_dma_alignment_and_pad as well.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20241119160932.1327864-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The underlying limit is defined as an unsigned int, so return that from
queue_dma_alignment as well.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20241119160932.1327864-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The underlying limit is defined as an unsigned int, so return that from
bdev_io_opt as well.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20241119160932.1327864-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
As smatch, which is a lot smarter than me noticed. So remove the checks
for it, and condense these checks a bit including the comments stating
the obvious.
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20241119161157.1328171-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Because it already is encoded in the opcode.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20241119161157.1328171-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Fix an issue detected by the `smatch` tool:
block/blk-mq.c:3314 blk_rq_prep_clone() error: uninitialized
symbol 'bio'.
This patch refactors `blk_rq_prep_clone()` to improve code
readability and ensure safety by addressing potential misuse of
the `bio` variable:
- Move the bio_put(bio); call to the bio_ctr error handling block,
which is the only place where it can be triggered.
- Move the bio variable into the __rq_for_each_bio loop scope.
This change removes the need to set bio to NULL at the loop's
end.
discussion on why bio remains uninitialized:
https://lore.kernel.org/lkml/20241004141037.43277-1-surajsonawane0215@gmail.com
Summary of above discussion:
- I pointed out that `bio` can remain uninitialized if the
allocation with `bio_alloc_clone` fails.
- Keith Busch explained that `bio` is initialized to `NULL` when
`bio_alloc_clone()` fails, preventing uninitialized usage.
- John Garry questioned whether `rq_src->bio` being `NULL` could
leave `bio` uninitialized. Keith clarified that in such cases,
`bio` is not referenced, so it does not need initialization.
- Christoph Hellwig recommended code improvements:
- move the bio_put to the bio_ctr error handling, which is the only
case where it can happen
- move the bio variable into the __rq_for_each_bio scope, which
also removed the need to zero it at the end of the loop
These changes enhance code clarity, address static analysis tool
warnings, and make the function more maintainable.
thread of previous version patch discussion:
https://lore.kernel.org/lkml/20241004100842.9052-1-surajsonawane0215@gmail.com
Signed-off-by: Suraj Sonawane <surajsonawane0215@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20241119164412.37609-1-surajsonawane0215@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Set BLK_FEAT_ATOMIC_WRITES_STACKED to enable atomic writes.
For an attempt to atomic write to a region which has bad blocks, error
the write as we just cannot do this. It is unlikely to find devices which
support atomic writes and bad blocks.
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20241118105018.1870052-6-john.g.garry@oracle.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Set BLK_FEAT_ATOMIC_WRITES_STACKED to enable atomic writes.
For an attempt to atomic write to a region which has bad blocks, error
the write as we just cannot do this. It is unlikely to find devices which
support atomic writes and bad blocks.
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20241118105018.1870052-5-john.g.garry@oracle.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Set BLK_FEAT_ATOMIC_WRITES_STACKED to enable atomic writes. All other
stacked device request queue limits should automatically be set properly.
With regards to atomic write max bytes limit, this will be set at
hw_max_sectors and this is limited by the stripe width, which we want.
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20241118105018.1870052-4-john.g.garry@oracle.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Allow stacked devices to support atomic writes by aggregating the minimum
capability of all bottom devices.
Flag BLK_FEAT_ATOMIC_WRITES_STACKED is set for stacked devices which
have been enabled to support atomic writes.
Some things to note on the implementation:
- For simplicity, all bottom devices must have same atomic write boundary
value (if any)
- The atomic write boundary must be a power-of-2 already, but this
restriction could be relaxed. Furthermore, it is now required that the
chunk sectors for a top device must be aligned with this boundary.
- If a bottom device atomic write unit min/max are not aligned with the
top device chunk sectors, the top device atomic write unit min/max are
reduced to a value which works for the chunk sectors.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20241118105018.1870052-3-john.g.garry@oracle.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
It is so far expected that the limits passed are valid.
In future atomic writes will be supported for stacked block devices, and
calculating the limits there will be complicated, so add extra sanity
checks to ensure that the values are always valid.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20241118105018.1870052-2-john.g.garry@oracle.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
lim->discard_granularity is always at least SECTOR_SIZE, so drop the
pointless check for granularity less than SECTOR_SIZE.
Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20241112092144.4059847-1-john.g.garry@oracle.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The nvme keep-alive operation, which executes at a periodic interval,
could potentially sneak in while shutting down a fabric controller.
This may lead to a race between the fabric controller admin queue
destroy code path (invoked while shutting down controller) and hw/hctx
queue dispatcher called from the nvme keep-alive async request queuing
operation. This race could lead to the kernel crash shown below:
Call Trace:
autoremove_wake_function+0x0/0xbc (unreliable)
__blk_mq_sched_dispatch_requests+0x114/0x24c
blk_mq_sched_dispatch_requests+0x44/0x84
blk_mq_run_hw_queue+0x140/0x220
nvme_keep_alive_work+0xc8/0x19c [nvme_core]
process_one_work+0x200/0x4e0
worker_thread+0x340/0x504
kthread+0x138/0x140
start_kernel_thread+0x14/0x18
While shutting down fabric controller, if nvme keep-alive request sneaks
in then it would be flushed off. The nvme_keep_alive_end_io function is
then invoked to handle the end of the keep-alive operation which
decrements the admin->q_usage_counter and assuming this is the last/only
request in the admin queue then the admin->q_usage_counter becomes zero.
If that happens then blk-mq destroy queue operation (blk_mq_destroy_
queue()) which could be potentially running simultaneously on another
cpu (as this is the controller shutdown code path) would forward
progress and deletes the admin queue. So, now from this point onward
we are not supposed to access the admin queue resources. However the
issue here's that the nvme keep-alive thread running hw/hctx queue
dispatch operation hasn't yet finished its work and so it could still
potentially access the admin queue resource while the admin queue had
been already deleted and that causes the above crash.
The above kernel crash is regression caused due to changes implemented
in commit a54a93d0e3 ("nvme: move stopping keep-alive into
nvme_uninit_ctrl()"). Ideally we should stop keep-alive before destroyin
g the admin queue and freeing the admin tagset so that it wouldn't sneak
in during the shutdown operation. However we removed the keep alive stop
operation from the beginning of the controller shutdown code path in commit
a54a93d0e3 ("nvme: move stopping keep-alive into nvme_uninit_ctrl()")
and added it under nvme_uninit_ctrl() which executes very late in the
shutdown code path after the admin queue is destroyed and its tagset is
removed. So this change created the possibility of keep-alive sneaking in
and interfering with the shutdown operation and causing observed kernel
crash.
To fix the observed crash, we decided to move nvme_stop_keep_alive() from
nvme_uninit_ctrl() to nvme_remove_admin_tag_set(). This change would ensure
that we don't forward progress and delete the admin queue until the keep-
alive operation is finished (if it's in-flight) or cancelled and that would
help contain the race condition explained above and hence avoid the crash.
Moving nvme_stop_keep_alive() to nvme_remove_admin_tag_set() instead of
adding nvme_stop_keep_alive() to the beginning of the controller shutdown
code path in nvme_stop_ctrl(), as was the case earlier before commit
a54a93d0e3 ("nvme: move stopping keep-alive into nvme_uninit_ctrl()"),
would help save one callsite of nvme_stop_keep_alive().
Fixes: a54a93d0e3 ("nvme: move stopping keep-alive into nvme_uninit_ctrl()")
Link: https://lore.kernel.org/all/1a21f37b-0f2a-4745-8c56-4dc8628d3983@linux.ibm.com/
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
This reverts commit d06923670b.
It was realized that the fix implemented to contain the race condition
among the keep alive task and the fabric shutdown code path in the commit
d06923670b5ia ("nvme: make keep-alive synchronous operation") is not
optimal. The reason being keep-alive runs under the workqueue and making
it synchronous would waste a workqueue context.
Furthermore, we later found that the above race condition is a regression
caused due to the changes implemented in commit a54a93d0e3 ("nvme: move
stopping keep-alive into nvme_uninit_ctrl()"). So we decided to revert the
commit d06923670b ("nvme: make keep-alive synchronous operation") and
then fix the regression.
Link: https://lore.kernel.org/all/196f4013-3bbf-43ff-98b4-9cb2a96c20c2@grimberg.me/
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Current loop calls vfs_statfs() while holding the q->limits_lock. If
FS takes some locking in vfs_statfs callback, this may lead to ABBA
locking bug (at least, FAT fs has this issue actually).
So this patch calls vfs_statfs() outside q->limits_locks instead,
because looks like no reason to hold q->limits_locks while getting
discord configs.
Chain exists of:
&sbi->fat_lock --> &q->q_usage_counter(io)#17 --> &q->limits_lock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&q->limits_lock);
lock(&q->q_usage_counter(io)#17);
lock(&q->limits_lock);
lock(&sbi->fat_lock);
*** DEADLOCK ***
Reported-by: syzbot+a5d8c609c02f508672cc@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=a5d8c609c02f508672cc
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The underlying limit is defined as an unsigned int, so return that from
bdev_io_min as well.
Fixes: ac481c20ef ("block: Topology ioctls")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Link: https://lore.kernel.org/r/20241119072602.1059488-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There was a bug report [1] where the user got a warning alignment
inconsistency. The user has optimal I/O 16776704 (0xFFFE00) and physical
block size 4096. Note that the optimal I/O size may be set by the DMA
engines or SCSI controllers and they have no knowledge about the disks
attached to them, so the situation with optimal I/O not aligned to
physical block size may happen.
This commit makes blk_validate_limits round down optimal I/O size to the
physical block size of the block device.
Closes: https://lore.kernel.org/dm-devel/1426ad71-79b4-4062-b2bf-84278be66a5d@redhat.com/T/ [1]
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Fixes: a23634644a ("block: take io_opt and io_min into account for max_sectors")
Cc: stable@vger.kernel.org # v6.11+
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/3dc0014b-9690-dc38-81c9-4a316a2d4fb2@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If the device supports SGLs, use these for all user requests. This
format encodes the expected transfer length so it can catch short buffer
errors in a user command, whether it occurred accidently or maliciously.
For controllers that support SGL data mode, this is a viable mitigation
to CVE-2023-6238. For controllers that don't support SGLs, log a warning
in the passthrough path since not having the capability can corrupt
data if the interface is not used correctly.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
This provides a little more context when reading the code than hardcoded
magic numbers.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Supporting this mode allows creating and merging multi-segment metadata
requests that wouldn't be possible otherwise. It also allows directly
using user space requests that straddle physically discontiguous pages.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
The code currently uses list_for_each_entry_rcu() while holding an SRCU
lock, triggering false positive warnings with CONFIG_PROVE_RCU=y
enabled:
drivers/nvme/host/multipath.c:168 RCU-list traversed in non-reader section!!
drivers/nvme/host/multipath.c:227 RCU-list traversed in non-reader section!!
drivers/nvme/host/multipath.c:260 RCU-list traversed in non-reader section!!
While the list is properly protected by SRCU lock, the code uses the
wrong list traversal primitive. Replace list_for_each_entry_rcu() with
list_for_each_entry_srcu() to correctly indicate SRCU-based protection
and eliminate the false warning.
Signed-off-by: Breno Leitao <leitao@debian.org>
Fixes: be647e2c76 ("nvme: use srcu for iterating namespace list")
Signed-off-by: Keith Busch <kbusch@kernel.org>
Pull MD fixes from Song:
"This set contains a fix for a W=1 warning, by John Garry, and a
MAINTAINERS update."
* tag 'md-6.13-20241115' of https://git.kernel.org/pub/scm/linux/kernel/git/mdraid/linux:
MAINTAINERS: Update git tree for mdraid subsystem
md/raid5: Increase r5conf.cache_name size
A previous commit changed how requests are linked in the plug structure,
but unlike the previous method, it uses a new type for it rather than
struct request. The latter is available even for !CONFIG_BLOCK, while
struct rq_list is now. Move it outside CONFIG_BLOCK.
Reported-by: Nathan Chancellor <nathan@kernel.org>
Fixes: a3396b9999 ("block: add a rq_list type")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
seq_printf is costly. For each block device, 19 decimal values are
yielded in /proc/diskstats via seq_printf. On a system with 16 logical
block devices, profiling for open/read/close sequences shows seq_printf
took ~75% samples of diskstats_show:
diskstats_show(92.626% 2269372/2450040)
seq_printf(76.026% 1725313/2269372)
vsnprintf(99.163% 1710866/1725313)
format_decode(26.597% 455040/1710866)
number(19.554% 334542/1710866)
memcpy_orig(4.183% 71570/1710866)
...
srso_return_thunk(0.009% 148/1725313)
part_stat_read_all(8.030% 182236/2269372)
One million rounds of open/read/close /proc/diskstats takes:
real 0m37.687s
user 0m0.264s
sys 0m32.911s
On average, each sequence tooks ~0.032ms
With this patch, most decimal values are yield via seq_put_decimal_ull,
performance is significantly improved:
real 0m20.792s
user 0m0.316s
sys 0m20.463s
On average, each sequence tooks ~0.020ms, a ~37.5% improvement.
Signed-off-by: David Wang <00107082@163.com>
Link: https://lore.kernel.org/r/20241108054500.4251-1-00107082@163.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
LIFO ordering for batched completions is a bit unexpected and also
defeats some merging optimizations in e.g. the XFS buffered write
code. Now that we can easily add the request to the tail of the list
do that.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20241113152050.157179-7-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add requests to the tail of the list instead of the front so that they
are queued up in submission order.
Remove the re-reordering in blk_mq_dispatch_plug_list, virtio_queue_rqs
and nvme_queue_rqs now that the list is ordered as expected.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20241113152050.157179-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Replace the semi-open coded request list helpers with a proper rq_list
type that mirrors the bio_list and has head and tail pointers. Besides
better type safety this actually allows to insert at the tail of the
list, which will be useful soon.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20241113152050.157179-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk_mq_flush_plug_list submits requests in the reverse order that they
were submitted, which leads to a rather suboptimal I/O pattern
especially in rotational devices. Fix this by rewriting virtio_queue_rqs
so that it always pops the requests from the passed in request list, and
then adds them to the head of a local submit list. This actually
simplifies the code a bit as it removes the complicated list splicing,
at the cost of extra updates of the rq_next pointer. As that should be
cache hot anyway it should be an easy price to pay.
Fixes: 0e9911fa76 ("virtio-blk: support mq_ops->queue_rqs()")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20241113152050.157179-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk_mq_flush_plug_list submits requests in the reverse order that they
were submitted, which leads to a rather suboptimal I/O pattern especially
in rotational devices. Fix this by rewriting nvme_queue_rqs so that it
always pops the requests from the passed in request list, and then adds
them to the head of a local submit list. This actually simplifies the
code a bit as it removes the complicated list splicing, at the cost of
extra updates of the rq_next pointer. As that should be cache hot
anyway it should be an easy price to pay.
Fixes: d62cbcf62f ("nvme: add support for mq_ops->queue_rqs()")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20241113152050.157179-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Call blk_validate_limits on the queue limits used for zone append
splitting so that calculated values get filled in and any stacking
conflicts get cought.
Without this there isn't a max_zone_append_sectors limits as of commit
559218d43e ("block: pre-calculate max_zone_append_sectors").
Fixes: 559218d43e ("block: pre-calculate max_zone_append_sectors")
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20241113084541.34315-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
While block drivers do the validation as part of committing them to the
queue, users that use the limit outside of a block device context have
to validate the limits and fill in the calculated values as well.
So far btrfs is the only user of queue limits without a block device,
and it has gotten away with that more or less by accident. But with
commit 559218d43e ("block: pre-calculate max_zone_append_sectors")
this became fatal for setups that have small max zone append size,
as it won't be limited now.
Export blk_validate_limits so that it can be called directly from btrfs.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20241113084541.34315-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add tracing of reservation commands, including register, acquire,
release and report, and also parse the action and rtype to string
to make the trace log more human-readable.
Signed-off-by: Guixin Liu <kanie@linux.alibaba.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Parse reservation commands's action(including rrega, racqa and rrela)
and rtype to string to make the trace log more human-readable.
Signed-off-by: Guixin Liu <kanie@linux.alibaba.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
