History log of /openbmc/linux/drivers/block/loop.c (Results 151 – 175 of 2452)
Revision (<<< Hide revision tags) (Show revision tags >>>) Date Author Comments
# 6f8191fd 19-Jun-2022 Christoph Hellwig <hch@lst.de>

block: simplify disk shutdown

Set the queue dying flag and call blk_mq_exit_queue from del_gendisk for
all disks that do not have separately allocated queues, and thus remove
the need to call blk_cl

block: simplify disk shutdown

Set the queue dying flag and call blk_mq_exit_queue from del_gendisk for
all disks that do not have separately allocated queues, and thus remove
the need to call blk_cleanup_queue for them.

Rename blk_cleanup_disk to blk_mq_destroy_queue to make it clear that
this function is intended only for separately allocated blk-mq queues.

This saves an extra queue freeze for devices without a separately
allocated queue.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20220619060552.1850436-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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# 2b1333b8 20-Jun-2022 Thomas Zimmermann <tzimmermann@suse.de>

Merge drm/drm-next into drm-misc-next

Backmerging to get new regmap APIs of v5.19-rc1.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>


Revision tags: v5.15.48
# f777316e 15-Jun-2022 Takashi Iwai <tiwai@suse.de>

Merge branch 'topic/ctl-enhancements' into for-next

Pull ALSA control enhancement patches.
One is the faster lookup of control elements, and another is to
introduce the input data validation.

Signe

Merge branch 'topic/ctl-enhancements' into for-next

Pull ALSA control enhancement patches.
One is the faster lookup of control elements, and another is to
introduce the input data validation.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

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Revision tags: v5.15.47
# a98a62e4 09-Jun-2022 Jakub Kicinski <kuba@kernel.org>

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

No conflicts.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>


# 66da6500 09-Jun-2022 Paolo Bonzini <pbonzini@redhat.com>

Merge tag 'kvm-riscv-fixes-5.19-1' of https://github.com/kvm-riscv/linux into HEAD

KVM/riscv fixes for 5.19, take #1

- Typo fix in arch/riscv/kvm/vmid.c

- Remove broken reference pattern from MAIN

Merge tag 'kvm-riscv-fixes-5.19-1' of https://github.com/kvm-riscv/linux into HEAD

KVM/riscv fixes for 5.19, take #1

- Typo fix in arch/riscv/kvm/vmid.c

- Remove broken reference pattern from MAINTAINERS entry

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Revision tags: v5.15.46
# 6e2b347d 08-Jun-2022 Maxime Ripard <maxime@cerno.tech>

Merge v5.19-rc1 into drm-misc-fixes

Let's kick-off the start of the 5.19 fix cycle

Signed-off-by: Maxime Ripard <maxime@cerno.tech>


# 073350da 07-Jun-2022 Mark Brown <broonie@kernel.org>

Merge tag 'v5.19-rc1' into asoc-5.19

Linux 5.19-rc1


Revision tags: v5.15.45
# 78c6499c 03-Jun-2022 Linus Torvalds <torvalds@linux-foundation.org>

Merge tag 'for-5.19/drivers-2022-06-02' of git://git.kernel.dk/linux-block

Pull more block driver updates from Jens Axboe:
"A collection of stragglers that were late on sending in their changes
a

Merge tag 'for-5.19/drivers-2022-06-02' of git://git.kernel.dk/linux-block

Pull more block driver updates from Jens Axboe:
"A collection of stragglers that were late on sending in their changes
and just followup fixes.

- NVMe fixes pull request via Christoph:
- set controller enable bit in a separate write (Niklas Cassel)
- disable namespace identifiers for the MAXIO MAP1001 (Christoph)
- fix a comment typo (Julia Lawall)"

- MD fixes pull request via Song:
- Remove uses of bdevname (Christoph Hellwig)
- Bug fixes (Guoqing Jiang, and Xiao Ni)

- bcache fixes series (Coly)

- null_blk zoned write fix (Damien)

- nbd fixes (Yu, Zhang)

- Fix for loop partition scanning (Christoph)"

* tag 'for-5.19/drivers-2022-06-02' of git://git.kernel.dk/linux-block: (23 commits)
block: null_blk: Fix null_zone_write()
nvmet: fix typo in comment
nvme: set controller enable bit in a separate write
nvme-pci: disable namespace identifiers for the MAXIO MAP1001
bcache: avoid unnecessary soft lockup in kworker update_writeback_rate()
nbd: use pr_err to output error message
nbd: fix possible overflow on 'first_minor' in nbd_dev_add()
nbd: fix io hung while disconnecting device
nbd: don't clear 'NBD_CMD_INFLIGHT' flag if request is not completed
nbd: fix race between nbd_alloc_config() and module removal
nbd: call genl_unregister_family() first in nbd_cleanup()
md: bcache: check the return value of kzalloc() in detached_dev_do_request()
bcache: memset on stack variables in bch_btree_check() and bch_sectors_dirty_init()
block, loop: support partitions without scanning
bcache: avoid journal no-space deadlock by reserving 1 journal bucket
bcache: remove incremental dirty sector counting for bch_sectors_dirty_init()
bcache: improve multithreaded bch_sectors_dirty_init()
bcache: improve multithreaded bch_btree_check()
md: fix double free of io_acct_set bioset
md: Don't set mddev private to NULL in raid0 pers->free
...

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# 03ab8e62 31-May-2022 Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

Merge tag 'v5.18'

Linux 5.18


Revision tags: v5.15.44
# 690e1790 27-May-2022 Dmitry Torokhov <dmitry.torokhov@gmail.com>

Merge tag 'v5.18' into next

Sync up with mainline to get updates to OMAP4 keypad driver and other
upstream goodies.


# b9684a71 27-May-2022 Christoph Hellwig <hch@lst.de>

block, loop: support partitions without scanning

Historically we did distinguish between a flag that surpressed partition
scanning, and a combinations of the minors variable and another flag if
any

block, loop: support partitions without scanning

Historically we did distinguish between a flag that surpressed partition
scanning, and a combinations of the minors variable and another flag if
any partitions were supported. This was generally confusing and doesn't
make much sense, but some corner case uses of the loop driver actually
do want to support manually added partitions on a device that does not
actively scan for partitions. To make things worsee the loop driver
also wants to dynamically toggle the scanning for partitions on a live
gendisk, which makes the disk->flags updates non-atomic.

Introduce a new GD_SUPPRESS_PART_SCAN bit in disk->state that disables
just scanning for partitions, and toggle that instead of GENHD_FL_NO_PART
in the loop driver.

Fixes: 1ebe2e5f9d68 ("block: remove GENHD_FL_EXT_DEVT")
Reported-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20220527055806.1972352-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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# 98931dd9 26-May-2022 Linus Torvalds <torvalds@linux-foundation.org>

Merge tag 'mm-stable-2022-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:
"Almost all of MM here. A few things are still getting finished off,

Merge tag 'mm-stable-2022-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:
"Almost all of MM here. A few things are still getting finished off,
reviewed, etc.

- Yang Shi has improved the behaviour of khugepaged collapsing of
readonly file-backed transparent hugepages.

- Johannes Weiner has arranged for zswap memory use to be tracked and
managed on a per-cgroup basis.

- Munchun Song adds a /proc knob ("hugetlb_optimize_vmemmap") for
runtime enablement of the recent huge page vmemmap optimization
feature.

- Baolin Wang contributes a series to fix some issues around hugetlb
pagetable invalidation.

- Zhenwei Pi has fixed some interactions between hwpoisoned pages and
virtualization.

- Tong Tiangen has enabled the use of the presently x86-only
page_table_check debugging feature on arm64 and riscv.

- David Vernet has done some fixup work on the memcg selftests.

- Peter Xu has taught userfaultfd to handle write protection faults
against shmem- and hugetlbfs-backed files.

- More DAMON development from SeongJae Park - adding online tuning of
the feature and support for monitoring of fixed virtual address
ranges. Also easier discovery of which monitoring operations are
available.

- Nadav Amit has done some optimization of TLB flushing during
mprotect().

- Neil Brown continues to labor away at improving our swap-over-NFS
support.

- David Hildenbrand has some fixes to anon page COWing versus
get_user_pages().

- Peng Liu fixed some errors in the core hugetlb code.

- Joao Martins has reduced the amount of memory consumed by
device-dax's compound devmaps.

- Some cleanups of the arch-specific pagemap code from Anshuman
Khandual.

- Muchun Song has found and fixed some errors in the TLB flushing of
transparent hugepages.

- Roman Gushchin has done more work on the memcg selftests.

... and, of course, many smaller fixes and cleanups. Notably, the
customary million cleanup serieses from Miaohe Lin"

* tag 'mm-stable-2022-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (381 commits)
mm: kfence: use PAGE_ALIGNED helper
selftests: vm: add the "settings" file with timeout variable
selftests: vm: add "test_hmm.sh" to TEST_FILES
selftests: vm: check numa_available() before operating "merge_across_nodes" in ksm_tests
selftests: vm: add migration to the .gitignore
selftests/vm/pkeys: fix typo in comment
ksm: fix typo in comment
selftests: vm: add process_mrelease tests
Revert "mm/vmscan: never demote for memcg reclaim"
mm/kfence: print disabling or re-enabling message
include/trace/events/percpu.h: cleanup for "percpu: improve percpu_alloc_percpu event trace"
include/trace/events/mmflags.h: cleanup for "tracing: incorrect gfp_t conversion"
mm: fix a potential infinite loop in start_isolate_page_range()
MAINTAINERS: add Muchun as co-maintainer for HugeTLB
zram: fix Kconfig dependency warning
mm/shmem: fix shmem folio swapoff hang
cgroup: fix an error handling path in alloc_pagecache_max_30M()
mm: damon: use HPAGE_PMD_SIZE
tracing: incorrect isolate_mote_t cast in mm_vmscan_lru_isolate
nodemask.h: fix compilation error with GCC12
...

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Revision tags: v5.15.43, v5.15.42
# 5dc92186 23-May-2022 Linus Torvalds <torvalds@linux-foundation.org>

Merge tag 'for-5.19/drivers-2022-05-22' of git://git.kernel.dk/linux-block

Pull block driver updates from Jens Axboe:
"Here are the driver updates queued up for 5.19. This contains:

- NVMe pull

Merge tag 'for-5.19/drivers-2022-05-22' of git://git.kernel.dk/linux-block

Pull block driver updates from Jens Axboe:
"Here are the driver updates queued up for 5.19. This contains:

- NVMe pull requests via Christoph:
- tighten the PCI presence check (Stefan Roese)
- fix a potential NULL pointer dereference in an error path (Kyle
Miller Smith)
- fix interpretation of the DMRSL field (Tom Yan)
- relax the data transfer alignment (Keith Busch)
- verbose error logging improvements (Max Gurtovoy, Chaitanya
Kulkarni)
- misc cleanups (Chaitanya Kulkarni, Christoph)
- set non-mdts limits in nvme_scan_work (Chaitanya Kulkarni)
- add support for TP4084 - Time-to-Ready Enhancements (Christoph)

- MD pull request via Song:
- Improve annotation in raid5 code, by Logan Gunthorpe
- Support MD_BROKEN flag in raid-1/5/10, by Mariusz Tkaczyk
- Other small fixes/cleanups

- null_blk series making the configfs side much saner (Damien)

- Various minor drbd cleanups and fixes (Haowen, Uladzislau, Jiapeng,
Arnd, Cai)

- Avoid using the system workqueue (and hence flushing it) in rnbd
(Jack)

- Avoid using the system workqueue (and hence flushing it) in aoe
(Tetsuo)

- Series fixing discard_alignment issues in drivers (Christoph)

- Small series fixing drivers poking at disk->part0 for openers
information (Christoph)

- Series fixing deadlocks in loop (Christoph, Tetsuo)

- Remove loop.h and add SPDX headers (Christoph)

- Various fixes and cleanups (Julia, Xie, Yu)"

* tag 'for-5.19/drivers-2022-05-22' of git://git.kernel.dk/linux-block: (72 commits)
mtip32xx: fix typo in comment
nvme: set non-mdts limits in nvme_scan_work
nvme: add support for TP4084 - Time-to-Ready Enhancements
nvme: split the enum used for various register constants
nbd: Fix hung on disconnect request if socket is closed before
nvme-fabrics: add a request timeout helper
nvme-pci: harden drive presence detect in nvme_dev_disable()
nvme-pci: fix a NULL pointer dereference in nvme_alloc_admin_tags
nvme: mark internal passthru request RQF_QUIET
nvme: remove unneeded include from constants file
nvme: add missing status values to verbose logging
nvme: set dma alignment to dword
nvme: fix interpretation of DMRSL
loop: remove most the top-of-file boilerplate comment from the UAPI header
loop: remove most the top-of-file boilerplate comment
loop: add a SPDX header
loop: remove loop.h
block: null_blk: Improve device creation with configfs
block: null_blk: Cleanup messages
block: null_blk: Cleanup device creation and deletion
...

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# 115cd471 23-May-2022 Linus Torvalds <torvalds@linux-foundation.org>

Merge tag 'for-5.19/block-2022-05-22' of git://git.kernel.dk/linux-block

Pull block updates from Jens Axboe:
"Here are the core block changes for 5.19. This contains:

- blk-throttle accounting

Merge tag 'for-5.19/block-2022-05-22' of git://git.kernel.dk/linux-block

Pull block updates from Jens Axboe:
"Here are the core block changes for 5.19. This contains:

- blk-throttle accounting fix (Laibin)

- Series removing redundant assignments (Michal)

- Expose bio cache via the bio_set, so that DM can use it (Mike)

- Finish off the bio allocation interface cleanups by dealing with
the weirdest member of the family. bio_kmalloc combines a kmalloc
for the bio and bio_vecs with a hidden bio_init call and magic
cleanup semantics (Christoph)

- Clean up the block layer API so that APIs consumed by file systems
are (almost) only struct block_device based, so that file systems
don't have to poke into block layer internals like the
request_queue (Christoph)

- Clean up the blk_execute_rq* API (Christoph)

- Clean up various lose end in the blk-cgroup code to make it easier
to follow in preparation of reworking the blkcg assignment for bios
(Christoph)

- Fix use-after-free issues in BFQ when processes with merged queues
get moved to different cgroups (Jan)

- BFQ fixes (Jan)

- Various fixes and cleanups (Bart, Chengming, Fanjun, Julia, Ming,
Wolfgang, me)"

* tag 'for-5.19/block-2022-05-22' of git://git.kernel.dk/linux-block: (83 commits)
blk-mq: fix typo in comment
bfq: Remove bfq_requeue_request_body()
bfq: Remove superfluous conversion from RQ_BIC()
bfq: Allow current waker to defend against a tentative one
bfq: Relax waker detection for shared queues
blk-cgroup: delete rcu_read_lock_held() WARN_ON_ONCE()
blk-throttle: Set BIO_THROTTLED when bio has been throttled
blk-cgroup: Remove unnecessary rcu_read_lock/unlock()
blk-cgroup: always terminate io.stat lines
block, bfq: make bfq_has_work() more accurate
block, bfq: protect 'bfqd->queued' by 'bfqd->lock'
block: cleanup the VM accounting in submit_bio
block: Fix the bio.bi_opf comment
block: reorder the REQ_ flags
blk-iocost: combine local_stat and desc_stat to stat
block: improve the error message from bio_check_eod
block: allow passing a NULL bdev to bio_alloc_clone/bio_init_clone
block: remove superfluous calls to blkcg_bio_issue_init
kthread: unexport kthread_blkcg
blk-cgroup: cleanup blkcg_maybe_throttle_current
...

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Revision tags: v5.18, v5.15.41, v5.15.40, v5.15.39, v5.15.38, v5.15.37, v5.15.36, v5.15.35
# eb04bb15 19-Apr-2022 Christoph Hellwig <hch@lst.de>

loop: remove most the top-of-file boilerplate comment

Remove the irrelevant changelogs and todo notes and just leave the SPDX
marker and the copyright notice.

Signed-off-by: Christoph Hellwig <hch@

loop: remove most the top-of-file boilerplate comment

Remove the irrelevant changelogs and todo notes and just leave the SPDX
marker and the copyright notice.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220419063303.583106-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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# f21e6e18 19-Apr-2022 Christoph Hellwig <hch@lst.de>

loop: add a SPDX header

The copyright statement says:

"Redistribution of this file is permitted under the GNU General Public
License." and was added by Ted in 1993, at which point GPLv2 only
was

loop: add a SPDX header

The copyright statement says:

"Redistribution of this file is permitted under the GNU General Public
License." and was added by Ted in 1993, at which point GPLv2 only
was the default Linux license.

Replace it with the usual GPLv2 only SPDX header.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220419063303.583106-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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# 754d9679 19-Apr-2022 Christoph Hellwig <hch@lst.de>

loop: remove loop.h

Merge loop.h into loop.c as all the content is only used there.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore

loop: remove loop.h

Merge loop.h into loop.c as all the content is only used there.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220419063303.583106-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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# a2ad63da 09-May-2022 NeilBrown <neilb@suse.de>

VFS: add FMODE_CAN_ODIRECT file flag

Currently various places test if direct IO is possible on a file by
checking for the existence of the direct_IO address space operation.
This is a poor choice, a

VFS: add FMODE_CAN_ODIRECT file flag

Currently various places test if direct IO is possible on a file by
checking for the existence of the direct_IO address space operation.
This is a poor choice, as the direct_IO operation may not be used - it is
only used if the generic_file_*_iter functions are called for direct IO
and some filesystems - particularly NFS - don't do this.

Instead, introduce a new f_mode flag: FMODE_CAN_ODIRECT and change the
various places to check this (avoiding pointer dereferences).
do_dentry_open() will set this flag if ->direct_IO is present, so
filesystems do not need to be changed.

NFS *is* changed, to set the flag explicitly and discard the direct_IO
entry in the address_space_operations for files.

Other filesystems which currently use noop_direct_IO could usefully be
changed to set this flag instead.

Link: https://lkml.kernel.org/r/164859778128.29473.15189737957277399416.stgit@noble.brown
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: NeilBrown <neilb@suse.de>
Tested-by: David Howells <dhowells@redhat.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

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# 4418bfd8 17-Apr-2022 Christoph Hellwig <hch@lst.de>

loop: remove a spurious clear of discard_alignment

The loop driver never sets a discard_alignment, so it also doens't need
to clear it to zero.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewe

loop: remove a spurious clear of discard_alignment

The loop driver never sets a discard_alignment, so it also doens't need
to clear it to zero.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20220418045314.360785-9-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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# bbb1ebe7 19-Apr-2022 Christoph Hellwig <hch@lst.de>

blk-cgroup: replace bio_blkcg with bio_blkcg_css

All callers of bio_blkcg actually want the CSS, so replace it with an
interface that does return the CSS. This now allows to move
struct blkcg_gq to

blk-cgroup: replace bio_blkcg with bio_blkcg_css

All callers of bio_blkcg actually want the CSS, so replace it with an
interface that does return the CSS. This now allows to move
struct blkcg_gq to block/blk-cgroup.h instead of exposing it in a
public header.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220420042723.1010598-10-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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Revision tags: v5.15.34, v5.15.33
# d292dc80 30-Mar-2022 Christoph Hellwig <hch@lst.de>

loop: don't destroy lo->workqueue in __loop_clr_fd

There is no need to destroy the workqueue when clearing unbinding
a loop device from a backing file. Not doing so on the other hand
avoid creating

loop: don't destroy lo->workqueue in __loop_clr_fd

There is no need to destroy the workqueue when clearing unbinding
a loop device from a backing file. Not doing so on the other hand
avoid creating a complex lock dependency chain involving the global
system_transition_mutex.

Based on a patch from Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>.

Reported-by: syzbot+6479585dfd4dedd3f7e1@syzkaller.appspotmail.com
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Tested-by: syzbot+6479585dfd4dedd3f7e1@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/20220330052917.2566582-16-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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# a0e286b6 30-Mar-2022 Christoph Hellwig <hch@lst.de>

loop: remove lo_refcount and avoid lo_mutex in ->open / ->release

lo_refcount counts how many openers a loop device has, but that count
is already provided by the block layer in the bd_openers field

loop: remove lo_refcount and avoid lo_mutex in ->open / ->release

lo_refcount counts how many openers a loop device has, but that count
is already provided by the block layer in the bd_openers field of the
whole-disk block_device. Remove lo_refcount and allow opens to
succeed even on devices beeing deleted - now that ->free_disk is
implemented we can handle that race gracefull and all I/O on it will
just fail. Similarly there is a small race window now where
loop_control_remove does not synchronize the delete vs the remove
due do bd_openers not being under lo_mutex protection, but we can
handle that just as gracefully.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220330052917.2566582-15-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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# 158eaeba 30-Mar-2022 Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>

loop: avoid loop_validate_mutex/lo_mutex in ->release

Since ->release is called with disk->open_mutex held, and __loop_clr_fd()
from lo_release() is called via ->release when disk_openers() == 0, w

loop: avoid loop_validate_mutex/lo_mutex in ->release

Since ->release is called with disk->open_mutex held, and __loop_clr_fd()
from lo_release() is called via ->release when disk_openers() == 0, we are
guaranteed that "struct file" which will be passed to loop_validate_file()
via fget() cannot be the loop device __loop_clr_fd(lo, true) will clear.
Thus, there is no need to hold loop_validate_mutex from __loop_clr_fd()
if release == true.

When I made commit 3ce6e1f662a91097 ("loop: reintroduce global lock for
safe loop_validate_file() traversal"), I wrote "It is acceptable for
loop_validate_file() to succeed, for actual clear operation has not started
yet.". But now I came to feel why it is acceptable to succeed.

It seems that the loop driver was added in Linux 1.3.68, and

if (lo->lo_refcnt > 1)
return -EBUSY;

check in loop_clr_fd() was there from the beginning. The intent of this
check was unclear. But now I think that current

disk_openers(lo->lo_disk) > 1

form is there for three reasons.

(1) Avoid I/O errors when some process which opens and reads from this
loop device in response to uevent notification (e.g. systemd-udevd),
as described in commit a1ecac3b0656a682 ("loop: Make explicit loop
device destruction lazy"). This opener is short-lived because it is
likely that the file descriptor used by that process is closed soon.

(2) Avoid I/O errors caused by underlying layer of stacked loop devices
(i.e. ioctl(some_loop_fd, LOOP_SET_FD, other_loop_fd)) being suddenly
disappeared. This opener is long-lived because this reference is
associated with not a file descriptor but lo->lo_backing_file.

(3) Avoid I/O errors caused by underlying layer of mounted loop device
(i.e. mount(some_loop_device, some_mount_point)) being suddenly
disappeared. This opener is long-lived because this reference is
associated with not a file descriptor but mount.

While race in (1) might be acceptable, (2) and (3) should be checked
racelessly. That is, make sure that __loop_clr_fd() will not run if
loop_validate_file() succeeds, by doing refcount check with global lock
held when explicit loop device destruction is requested.

As a result of no longer waiting for lo->lo_mutex after setting Lo_rundown,
we can remove pointless BUG_ON(lo->lo_state != Lo_rundown) check.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220330052917.2566582-14-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

show more ...


# 498ef5c7 30-Mar-2022 Christoph Hellwig <hch@lst.de>

loop: suppress uevents while reconfiguring the device

Currently, udev change event is generated for a loop device before the
device is ready for IO. Due to serialization on lo->lo_mutex in
lo_open()

loop: suppress uevents while reconfiguring the device

Currently, udev change event is generated for a loop device before the
device is ready for IO. Due to serialization on lo->lo_mutex in
lo_open() this does not matter because anybody is able to open the
device and do IO only after the configuration is finished. However this
synchronization in lo_open() is going away so make sure userspace
reacting to the change event will see the new device state by generating
the event only when the device is setup.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220330052917.2566582-13-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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# d2c7f56f 30-Mar-2022 Christoph Hellwig <hch@lst.de>

loop: implement ->free_disk

Ensure that the lo_device which is stored in the gendisk private
data is valid until the gendisk is freed. Currently the loop driver
uses a lot of effort to make sure a

loop: implement ->free_disk

Ensure that the lo_device which is stored in the gendisk private
data is valid until the gendisk is freed. Currently the loop driver
uses a lot of effort to make sure a device is not freed when it is
still in use, but to to fix a potential deadlock this will be relaxed
a bit soon.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220330052917.2566582-12-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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