Linux kernel ============ The Linux kernel is the core of any Linux operating system. It manages hardware, system resources, and provides the fundamental services for all other software. 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bio_alloc_bioset tries non-waiting slab allocations first for the bio and
bvec array, but does so in a somewhat convoluted way.
Restructure the function so that it first open codes these slab
allocations, and then falls back to the mempools with the original
gfp mask.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> -ck
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://patch.msgid.link/20260316161144.1607877-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Only used in bio.c these days.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> -ck
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://patch.msgid.link/20260316161144.1607877-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The ublk driver doesn't access request integrity buffers directly, it
only copies them to/from the ublk server in ublk_copy_user_integrity().
ublk_copy_user_integrity() uses bio_for_each_integrity_vec() to walk all
the integrity segments. ublk devices are therefore capable of handling
requests with integrity intervals split across segments. Set
BLK_SPLIT_INTERVAL_CAPABLE in the struct blk_integrity flags for ublk
devices to opt out of the integrity-interval dma_alignment limit.
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Link: https://patch.msgid.link/20260313144701.1221652-3-kbusch@meta.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
A bio segment may have partial interval block data with the rest
continuing into the next segments because direct-io data payloads only
need to align in memory to the device's DMA limits.
At the same time, the protection information may also be split in
multiple segments. The most likely way that may happen is if two
requests merge, or if we're directly using the io_uring user metadata.
The generate/verify, however, only ever accessed the first bip_vec.
Further, it may be possible to unalign the protection fields from the
user space buffer, or if there are odd additional opaque bytes in front
or in back of the protection information metadata region.
Change up the iteration to allow spanning multiple segments. This patch
is mostly a re-write of the protection information handling to allow any
arbitrary alignments, so it's probably easier to review the end result
rather than the diff.
Many controllers are not able to handle interval data composed of
multiple segments when PI is used, so this patch introduces a new
integrity limit that a low level driver can set to notify that it is
capable, default to false. The nvme driver is the first one to enable it
in this patch. Everyone else will force DMA alignment to the logical
block size as before to ensure interval data is always aligned within a
single segment.
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Link: https://patch.msgid.link/20260313144701.1221652-2-kbusch@meta.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When a queue is shared across disk rebind (e.g., SCSI unbind/bind), the
previous disk's blkcg state is cleaned up asynchronously via
disk_release() -> blkcg_exit_disk(). If the new disk's blkcg_init_disk()
runs before that cleanup finishes, we may overwrite q->root_blkg while
the old one is still alive, and radix_tree_insert() in blkg_create()
fails with -EEXIST because the old blkg entries still occupy the same
queue id slot in blkcg->blkg_tree. This causes the sd probe to fail
with -ENOMEM.
Fix it by waiting in blkcg_init_disk() for root_blkg to become NULL,
which indicates the previous disk's blkcg cleanup has completed.
Fixes: 1059699f87eb ("block: move blkcg initialization/destroy into disk allocation/release handler")
Cc: Yi Zhang <yi.zhang@redhat.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20260311032837.2368714-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When a bio goes through the rq_qos infrastructure on a path's request
queue, it gets BIO_QOS_THROTTLED or BIO_QOS_MERGED flags set. These
flags indicate that rq_qos_done_bio() should be called on completion
to update rq_qos accounting.
During path failover in nvme_failover_req(), the bio's bi_bdev is
redirected from the failed path's disk to the multipath head's disk
via bio_set_dev(). However, the BIO_QOS flags are not cleared.
When the bio eventually completes (either successfully via a new path
or with an error via bio_io_error()), rq_qos_done_bio() checks for
these flags and calls __rq_qos_done_bio(q->rq_qos, bio) where q is
obtained from the bio's current bi_bdev - which is now the multipath
head's queue, not the original path's queue.
The multipath head's queue does not have rq_qos enabled (q->rq_qos is
NULL), but the code assumes that if BIO_QOS_* flags are set, q->rq_qos
must be valid.
This breaks when a bio is moved between queues during NVMe multipath
failover, leading to a NULL pointer dereference.
Execution Context timeline :-
* =====> dd process context
[USER] dd process
[SYSCALL] write() - dd process context
submit_bio()
nvme_ns_head_submit_bio() - path selection
blk_mq_submit_bio() #### QOS FLAGS SET HERE
[USER] dd waits or returns
==== I/O in flight on NVMe hardware =====
===== End of submission path ====
------------------------------------------------------
* dd ====> Interrupt context;
[IRQ] NVMe completion interrupt
nvme_irq()
nvme_complete_rq()
nvme_failover_req() ### BIO MOVED TO HEAD
spin_lock_irqsave (atomic section)
bio_set_dev() changes bi_bdev
### BUG: QOS flags NOT cleared
kblockd_schedule_work()
* Interrupt context =====> kblockd workqueue
[WQ] kblockd workqueue - kworker process
nvme_requeue_work()
submit_bio_noacct()
nvme_ns_head_submit_bio()
nvme_find_path() returns NULL
bio_io_error()
bio_endio()
rq_qos_done_bio() ### CRASH ###
KERNEL PANIC / OOPS
Crash from blktests nvme/058 (rapid namespace remapping):
[ 1339.636033] BUG: kernel NULL pointer dereference, address: 0000000000000000
[ 1339.641025] nvme nvme4: rescanning namespaces.
[ 1339.642064] #PF: supervisor read access in kernel mode
[ 1339.642067] #PF: error_code(0x0000) - not-present page
[ 1339.642070] PGD 0 P4D 0
[ 1339.642073] Oops: Oops: 0000 [#1] SMP NOPTI
[ 1339.642078] CPU: 35 UID: 0 PID: 4579 Comm: kworker/35:2H
Tainted: G O N 6.17.0-rc3nvme+ #5 PREEMPT(voluntary)
[ 1339.642084] Tainted: [O]=OOT_MODULE, [N]=TEST
[ 1339.673446] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[ 1339.682359] Workqueue: kblockd nvme_requeue_work [nvme_core]
[ 1339.686613] RIP: 0010:__rq_qos_done_bio+0xd/0x40
[ 1339.690161] Code: 75 dd 5b 5d 41 5c c3 cc cc cc cc 66 90 90 90 90 90 90 90
90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 55 48 89 f5
53 48 89 fb <48> 8b 03 48 8b 40 30 48 85 c0 74 0b 48 89 ee
48 89 df ff d0 0f 1f
[ 1339.703691] RSP: 0018:ffffc900066f3c90 EFLAGS: 00010202
[ 1339.706844] RAX: ffff888148b9ef00 RBX: 0000000000000000 RCX: 0000000000000000
[ 1339.711136] RDX: 00000000000001c0 RSI: ffff8882aaab8a80 RDI: 0000000000000000
[ 1339.715691] RBP: ffff8882aaab8a80 R08: 0000000000000000 R09: 0000000000000000
[ 1339.720472] R10: 0000000000000000 R11: fefefefefefefeff R12: ffff8882aa3b6010
[ 1339.724650] R13: 0000000000000000 R14: ffff8882338bcef0 R15: ffff8882aa3b6020
[ 1339.729029] FS: 0000000000000000(0000) GS:ffff88985c0cf000(0000) knlGS:0000000000000000
[ 1339.734525] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1339.738563] CR2: 0000000000000000 CR3: 0000000111045000 CR4: 0000000000350ef0
[ 1339.742750] DR0: ffffffff845ccbec DR1: ffffffff845ccbed DR2: ffffffff845ccbee
[ 1339.745630] DR3: ffffffff845ccbef DR6: 00000000ffff0ff0 DR7: 0000000000000600
[ 1339.748488] Call Trace:
[ 1339.749512] <TASK>
[ 1339.750449] bio_endio+0x71/0x2e0
[ 1339.751833] nvme_ns_head_submit_bio+0x290/0x320 [nvme_core]
[ 1339.754073] __submit_bio+0x222/0x5e0
[ 1339.755623] ? rcu_is_watching+0xd/0x40
[ 1339.757201] ? submit_bio_noacct_nocheck+0x131/0x370
[ 1339.759210] submit_bio_noacct_nocheck+0x131/0x370
[ 1339.761189] ? submit_bio_noacct+0x20/0x620
[ 1339.762849] nvme_requeue_work+0x4b/0x60 [nvme_core]
[ 1339.764828] process_one_work+0x20e/0x630
[ 1339.766528] worker_thread+0x184/0x330
[ 1339.768129] ? __pfx_worker_thread+0x10/0x10
[ 1339.769942] kthread+0x10a/0x250
[ 1339.771263] ? __pfx_kthread+0x10/0x10
[ 1339.772776] ? __pfx_kthread+0x10/0x10
[ 1339.774381] ret_from_fork+0x273/0x2e0
[ 1339.775948] ? __pfx_kthread+0x10/0x10
[ 1339.777504] ret_from_fork_asm+0x1a/0x30
[ 1339.779163] </TASK>
Fix this by clearing both BIO_QOS_THROTTLED and BIO_QOS_MERGED flags
when bios are redirected to the multipath head in nvme_failover_req().
This is consistent with the existing code that clears REQ_POLLED and
REQ_NOWAIT flags when the bio changes queues.
Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20260226031243.87200-3-kch@nvidia.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk_steal_bios() transfers bios from a request to a bio_list when the
request is requeued to a different queue. The NVMe multipath failover
path (nvme_failover_req) currently open-codes clearing of REQ_POLLED,
bi_cookie, and REQ_NOWAIT on each bio before calling blk_steal_bios().
Move these fixups into blk_steal_bios() itself so that any caller
automatically gets correct flag state when bios cross queue boundaries.
Simplify nvme_failover_req() accordingly.
Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20260226031243.87200-2-kch@nvidia.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Merge in integrity changes which are also landing in the VFS tree as
dependencies for fs related changes.
* for-7.1/block-integrity:
block: pass a maxlen argument to bio_iov_iter_bounce
block: add fs_bio_integrity helpers
block: make max_integrity_io_size public
block: prepare generation / verification helpers for fs usage
block: add a bdev_has_integrity_csum helper
block: factor out a bio_integrity_setup_default helper
block: factor out a bio_integrity_action helper
bdev_nonrot() is simply the negative return value of bdev_rot().
So replace all call sites of bdev_nonrot() with calls to bdev_rot()
and remove bdev_nonrot().
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Allow the file system to limit the size processed in a single
bounce operation. This is needed when generating integrity data
so that the size of a single integrity segment can't overflow.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Anuj Gupta <anuj20.g@samsung.com>
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Tested-by: Anuj Gupta <anuj20.g@samsung.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Correct the comments that the cloned bio must be freed before the memory
pointed to by @bio_src->bi_io_vecs (is freed).
Christoph Hellwig contributed most the of the update wording.
Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a set of helpers for file system initiated integrity information.
These include mempool backed allocations and verifying based on a passed
in sector and size which is often available from file system completion
routines.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Anuj Gupta <anuj20.g@samsung.com>
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Tested-by: Anuj Gupta <anuj20.g@samsung.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Update the documentation file Documentation/ABI/stable/sysfs-block to
describe the zoned_qd1_writes sysfs queue attribute file.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
File systems that generate integrity will need this, so move it out
of the block private or blk-mq specific headers.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Anuj Gupta <anuj20.g@samsung.com>
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Tested-by: Anuj Gupta <anuj20.g@samsung.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
For blk-mq rotational zoned block devices (e.g. SMR HDDs), default to
having zone write plugging limit write operations to a maximum queue
depth of 1 for all zones. This significantly reduce write seek overhead
and improves SMR HDD write throughput.
For remotely connected disks with a very high network latency this
features might not be useful. However, remotely connected zoned devices
are rare at the moment, and we cannot know the round trip latency to
pick a good default for network attached devices. System administrators
can however disable this feature in that case.
For BIO based (non blk-mq) rotational zoned block devices, the device
driver (e.g. a DM target driver) can directly set an appropriate
default.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Return the status from verify instead of directly stashing it in the bio,
and rename the helpers to use the usual bio_ prefix for things operating
on a bio.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Anuj Gupta <anuj20.g@samsung.com>
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Tested-by: Anuj Gupta <anuj20.g@samsung.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>