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2023-07-03Merge tag 'block-6.5-2023-07-03' of git://git.kernel.dk/linuxLinus Torvalds
Pull more block updates from Jens Axboe: "Mostly items that came in a bit late for the initial pull request, wanted to make sure they had the appropriate amount of linux-next soak before going upstream. Outside of stragglers, just generic fixes for either merge window items, or longer standing bugs" * tag 'block-6.5-2023-07-03' of git://git.kernel.dk/linux: (25 commits) md/raid0: add discard support for the 'original' layout nvme: disable controller on reset state failure nvme: sync timeout work on failed reset nvme: ensure unquiesce on teardown cdrom/gdrom: Fix build error nvme: improved uring polling block: add request polling helper nvme-mpath: fix I/O failure with EAGAIN when failing over I/O nvme: host: fix command name spelling blk-sysfs: add a new attr_group for blk_mq blk-iocost: move wbt_enable/disable_default() out of spinlock blk-wbt: cleanup rwb_enabled() and wbt_disabled() blk-wbt: remove dead code to handle wbt enable/disable with io inflight blk-wbt: don't create wbt sysfs entry if CONFIG_BLK_WBT is disabled blk-mq: fix two misuses on RQF_USE_SCHED blk-throttle: Fix io statistics for cgroup v1 bcache: Fix bcache device claiming bcache: Alloc holder object before async registration raid10: avoid spin_lock from fastpath from raid10_unplug() md: fix 'delete_mutex' deadlock ...
2023-06-30Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsiLinus Torvalds
Pull SCSI updates from James Bottomley: "Updates to the usual drivers (ufs, pm80xx, libata-scsi, smartpqi, lpfc, qla2xxx). We have a couple of major core changes impacting other systems: - Command Duration Limits, which spills into block and ATA - block level Persistent Reservation Operations, which touches block, nvme, target and dm Both of these are added with merge commits containing a cover letter explaining what's going on" * tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (187 commits) scsi: core: Improve warning message in scsi_device_block() scsi: core: Replace scsi_target_block() with scsi_block_targets() scsi: core: Don't wait for quiesce in scsi_device_block() scsi: core: Don't wait for quiesce in scsi_stop_queue() scsi: core: Merge scsi_internal_device_block() and device_block() scsi: sg: Increase number of devices scsi: bsg: Increase number of devices scsi: qla2xxx: Remove unused nvme_ls_waitq wait queue scsi: ufs: ufs-pci: Add support for Intel Arrow Lake scsi: sd: sd_zbc: Use PAGE_SECTORS_SHIFT scsi: ufs: wb: Add explicit flush_threshold sysfs attribute scsi: ufs: ufs-qcom: Switch to the new ICE API scsi: ufs: dt-bindings: qcom: Add ICE phandle scsi: ufs: ufs-mediatek: Set UFSHCD_QUIRK_MCQ_BROKEN_RTC quirk scsi: ufs: ufs-mediatek: Set UFSHCD_QUIRK_MCQ_BROKEN_INTR quirk scsi: ufs: core: Add host quirk UFSHCD_QUIRK_MCQ_BROKEN_RTC scsi: ufs: core: Add host quirk UFSHCD_QUIRK_MCQ_BROKEN_INTR scsi: ufs: core: Remove dedicated hwq for dev command scsi: ufs: core: mcq: Fix the incorrect OCS value for the device command scsi: ufs: dt-bindings: samsung,exynos: Drop unneeded quotes ...
2023-06-28block: add request polling helperKeith Busch
Provide a direct request polling will for drivers. The interface does not require a bio, and can skip the overhead associated with polling those. The biggest gain from skipping the relatively expensive xarray lookup unnecessary when you already have the request. With this, the simple rq/qc conversion functions have only one caller each, so open code this and remove the helpers. Signed-off-by: Keith Busch <kbusch@kernel.org> Reviewed-by: Kanchan Joshi <joshi.k@samsung.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230612190343.2087040-2-kbusch@meta.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-28Merge branch 'for-6.5/block-late' into block-6.5Jens Axboe
* for-6.5/block-late: blk-sysfs: add a new attr_group for blk_mq blk-iocost: move wbt_enable/disable_default() out of spinlock blk-wbt: cleanup rwb_enabled() and wbt_disabled() blk-wbt: remove dead code to handle wbt enable/disable with io inflight blk-wbt: don't create wbt sysfs entry if CONFIG_BLK_WBT is disabled blk-mq: fix two misuses on RQF_USE_SCHED blk-throttle: Fix io statistics for cgroup v1 bcache: Fix bcache device claiming bcache: Alloc holder object before async registration raid10: avoid spin_lock from fastpath from raid10_unplug() md: fix 'delete_mutex' deadlock md: use mddev->external to select holder in export_rdev() md/raid1-10: fix casting from randomized structure in raid1_submit_write() md/raid10: fix the condition to call bio_end_io_acct()
2023-06-28Merge tag 'mm-stable-2023-06-24-19-15' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull mm updates from Andrew Morton: - Yosry Ahmed brought back some cgroup v1 stats in OOM logs - Yosry has also eliminated cgroup's atomic rstat flushing - Nhat Pham adds the new cachestat() syscall. It provides userspace with the ability to query pagecache status - a similar concept to mincore() but more powerful and with improved usability - Mel Gorman provides more optimizations for compaction, reducing the prevalence of page rescanning - Lorenzo Stoakes has done some maintanance work on the get_user_pages() interface - Liam Howlett continues with cleanups and maintenance work to the maple tree code. Peng Zhang also does some work on maple tree - Johannes Weiner has done some cleanup work on the compaction code - David Hildenbrand has contributed additional selftests for get_user_pages() - Thomas Gleixner has contributed some maintenance and optimization work for the vmalloc code - Baolin Wang has provided some compaction cleanups, - SeongJae Park continues maintenance work on the DAMON code - Huang Ying has done some maintenance on the swap code's usage of device refcounting - Christoph Hellwig has some cleanups for the filemap/directio code - Ryan Roberts provides two patch series which yield some rationalization of the kernel's access to pte entries - use the provided APIs rather than open-coding accesses - Lorenzo Stoakes has some fixes to the interaction between pagecache and directio access to file mappings - John Hubbard has a series of fixes to the MM selftesting code - ZhangPeng continues the folio conversion campaign - Hugh Dickins has been working on the pagetable handling code, mainly with a view to reducing the load on the mmap_lock - Catalin Marinas has reduced the arm64 kmalloc() minimum alignment from 128 to 8 - Domenico Cerasuolo has improved the zswap reclaim mechanism by reorganizing the LRU management - Matthew Wilcox provides some fixups to make gfs2 work better with the buffer_head code - Vishal Moola also has done some folio conversion work - Matthew Wilcox has removed the remnants of the pagevec code - their functionality is migrated over to struct folio_batch * tag 'mm-stable-2023-06-24-19-15' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (380 commits) mm/hugetlb: remove hugetlb_set_page_subpool() mm: nommu: correct the range of mmap_sem_read_lock in task_mem() hugetlb: revert use of page_cache_next_miss() Revert "page cache: fix page_cache_next/prev_miss off by one" mm/vmscan: fix root proactive reclaim unthrottling unbalanced node mm: memcg: rename and document global_reclaim() mm: kill [add|del]_page_to_lru_list() mm: compaction: convert to use a folio in isolate_migratepages_block() mm: zswap: fix double invalidate with exclusive loads mm: remove unnecessary pagevec includes mm: remove references to pagevec mm: rename invalidate_mapping_pagevec to mapping_try_invalidate mm: remove struct pagevec net: convert sunrpc from pagevec to folio_batch i915: convert i915_gpu_error to use a folio_batch pagevec: rename fbatch_count() mm: remove check_move_unevictable_pages() drm: convert drm_gem_put_pages() to use a folio_batch i915: convert shmem_sg_free_table() to use a folio_batch scatterlist: add sg_set_folio() ...
2023-06-26Merge tag 'for-6.5/block-2023-06-23' of git://git.kernel.dk/linuxLinus Torvalds
Pull block updates from Jens Axboe: - NVMe pull request via Keith: - Various cleanups all around (Irvin, Chaitanya, Christophe) - Better struct packing (Christophe JAILLET) - Reduce controller error logs for optional commands (Keith) - Support for >=64KiB block sizes (Daniel Gomez) - Fabrics fixes and code organization (Max, Chaitanya, Daniel Wagner) - bcache updates via Coly: - Fix a race at init time (Mingzhe Zou) - Misc fixes and cleanups (Andrea, Thomas, Zheng, Ye) - use page pinning in the block layer for dio (David) - convert old block dio code to page pinning (David, Christoph) - cleanups for pktcdvd (Andy) - cleanups for rnbd (Guoqing) - use the unchecked __bio_add_page() for the initial single page additions (Johannes) - fix overflows in the Amiga partition handling code (Michael) - improve mq-deadline zoned device support (Bart) - keep passthrough requests out of the IO schedulers (Christoph, Ming) - improve support for flush requests, making them less special to deal with (Christoph) - add bdev holder ops and shutdown methods (Christoph) - fix the name_to_dev_t() situation and use cases (Christoph) - decouple the block open flags from fmode_t (Christoph) - ublk updates and cleanups, including adding user copy support (Ming) - BFQ sanity checking (Bart) - convert brd from radix to xarray (Pankaj) - constify various structures (Thomas, Ivan) - more fine grained persistent reservation ioctl capability checks (Jingbo) - misc fixes and cleanups (Arnd, Azeem, Demi, Ed, Hengqi, Hou, Jan, Jordy, Li, Min, Yu, Zhong, Waiman) * tag 'for-6.5/block-2023-06-23' of git://git.kernel.dk/linux: (266 commits) scsi/sg: don't grab scsi host module reference ext4: Fix warning in blkdev_put() block: don't return -EINVAL for not found names in devt_from_devname cdrom: Fix spectre-v1 gadget block: Improve kernel-doc headers blk-mq: don't insert passthrough request into sw queue bsg: make bsg_class a static const structure ublk: make ublk_chr_class a static const structure aoe: make aoe_class a static const structure block/rnbd: make all 'class' structures const block: fix the exclusive open mask in disk_scan_partitions block: add overflow checks for Amiga partition support block: change all __u32 annotations to __be32 in affs_hardblocks.h block: fix signed int overflow in Amiga partition support block: add capacity validation in bdev_add_partition() block: fine-granular CAP_SYS_ADMIN for Persistent Reservation block: disallow Persistent Reservation on partitions reiserfs: fix blkdev_put() warning from release_journal_dev() block: fix wrong mode for blkdev_get_by_dev() from disk_scan_partitions() block: document the holder argument to blkdev_get_by_path ...
2023-06-26Merge tag 'for-6.5/io_uring-2023-06-23' of git://git.kernel.dk/linuxLinus Torvalds
Pull io_uring updates from Jens Axboe: "Nothing major in this release, just a bunch of cleanups and some optimizations around networking mostly. - clean up file request flags handling (Christoph) - clean up request freeing and CQ locking (Pavel) - support for using pre-registering the io_uring fd at setup time (Josh) - Add support for user allocated ring memory, rather than having the kernel allocate it. Mostly for packing rings into a huge page (me) - avoid an unnecessary double retry on receive (me) - maintain ordering for task_work, which also improves performance (me) - misc cleanups/fixes (Pavel, me)" * tag 'for-6.5/io_uring-2023-06-23' of git://git.kernel.dk/linux: (39 commits) io_uring: merge conditional unlock flush helpers io_uring: make io_cq_unlock_post static io_uring: inline __io_cq_unlock io_uring: fix acquire/release annotations io_uring: kill io_cq_unlock() io_uring: remove IOU_F_TWQ_FORCE_NORMAL io_uring: don't batch task put on reqs free io_uring: move io_clean_op() io_uring: inline io_dismantle_req() io_uring: remove io_free_req_tw io_uring: open code io_put_req_find_next io_uring: add helpers to decode the fixed file file_ptr io_uring: use io_file_from_index in io_msg_grab_file io_uring: use io_file_from_index in __io_sync_cancel io_uring: return REQ_F_ flags from io_file_get_flags io_uring: remove io_req_ffs_set io_uring: remove a confusing comment above io_file_get_flags io_uring: remove the mode variable in io_file_get_flags io_uring: remove __io_file_supports_nowait io_uring: wait interruptibly for request completions on exit ...
2023-06-26Merge tag 'for-6.5/splice-2023-06-23' of git://git.kernel.dk/linuxLinus Torvalds
Pull splice updates from Jens Axboe: "This kills off ITER_PIPE to avoid a race between truncate, iov_iter_revert() on the pipe and an as-yet incomplete DMA to a bio with unpinned/unref'ed pages from an O_DIRECT splice read. This causes memory corruption. Instead, we either use (a) filemap_splice_read(), which invokes the buffered file reading code and splices from the pagecache into the pipe; (b) copy_splice_read(), which bulk-allocates a buffer, reads into it and then pushes the filled pages into the pipe; or (c) handle it in filesystem-specific code. Summary: - Rename direct_splice_read() to copy_splice_read() - Simplify the calculations for the number of pages to be reclaimed in copy_splice_read() - Turn do_splice_to() into a helper, vfs_splice_read(), so that it can be used by overlayfs and coda to perform the checks on the lower fs - Make vfs_splice_read() jump to copy_splice_read() to handle direct-I/O and DAX - Provide shmem with its own splice_read to handle non-existent pages in the pagecache. We don't want a ->read_folio() as we don't want to populate holes, but filemap_get_pages() requires it - Provide overlayfs with its own splice_read to call down to a lower layer as overlayfs doesn't provide ->read_folio() - Provide coda with its own splice_read to call down to a lower layer as coda doesn't provide ->read_folio() - Direct ->splice_read to copy_splice_read() in tty, procfs, kernfs and random files as they just copy to the output buffer and don't splice pages - Provide wrappers for afs, ceph, ecryptfs, ext4, f2fs, nfs, ntfs3, ocfs2, orangefs, xfs and zonefs to do locking and/or revalidation - Make cifs use filemap_splice_read() - Replace pointers to generic_file_splice_read() with pointers to filemap_splice_read() as DIO and DAX are handled in the caller; filesystems can still provide their own alternate ->splice_read() op - Remove generic_file_splice_read() - Remove ITER_PIPE and its paraphernalia as generic_file_splice_read was the only user" * tag 'for-6.5/splice-2023-06-23' of git://git.kernel.dk/linux: (31 commits) splice: kdoc for filemap_splice_read() and copy_splice_read() iov_iter: Kill ITER_PIPE splice: Remove generic_file_splice_read() splice: Use filemap_splice_read() instead of generic_file_splice_read() cifs: Use filemap_splice_read() trace: Convert trace/seq to use copy_splice_read() zonefs: Provide a splice-read wrapper xfs: Provide a splice-read wrapper orangefs: Provide a splice-read wrapper ocfs2: Provide a splice-read wrapper ntfs3: Provide a splice-read wrapper nfs: Provide a splice-read wrapper f2fs: Provide a splice-read wrapper ext4: Provide a splice-read wrapper ecryptfs: Provide a splice-read wrapper ceph: Provide a splice-read wrapper afs: Provide a splice-read wrapper 9p: Add splice_read wrapper net: Make sock_splice_read() use copy_splice_read() by default tty, proc, kernfs, random: Use copy_splice_read() ...
2023-06-26blk-sysfs: add a new attr_group for blk_mqYu Kuai
Currently wbt sysfs entry is created for bio based device, and wbt can be enabled for such device through sysfs while it doesn't make sense because wbt can only work for rq based device. In the meantime, there are other similar sysfs entries. Fix this by adding a new attr_group for blk_mq, and sysfs entries will only be created when the device is rq based. Suggested-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230527010644.647900-6-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-26blk-iocost: move wbt_enable/disable_default() out of spinlockYu Kuai
There are following smatch warning: block/blk-wbt.c:843 wbt_init() warn: sleeping in atomic context ioc_qos_write() <- disables preempt -> wbt_enable_default() -> wbt_init() wbt_init() will be called from wbt_enable_default() if wbt is not initialized, currently this is only possible in blk_register_queue(), hence wbt_init() will never be called from iocost and this warning is false positive. However, we might support rq_qos destruction dynamically in the future, and it's better to prevent that, hence move wbt_enable_default() outside 'ioc->lock'. This is safe because queue is still freezed. Reported-by: Dan Carpenter <error27@gmail.com> Link: https://lore.kernel.org/lkml/Y+Ja5SRs886CEz7a@kadam/ Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230527010644.647900-5-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-26blk-wbt: cleanup rwb_enabled() and wbt_disabled()Yu Kuai
'wb_normal' will set to 0 if 'min_lat_nsec' is 0, and 'min_lat_nsec' can only be set to 0 through sysfs configuration where 'WBT_STATE_OFF_MANUAL' is set together, in the meantime, they can only be cleared together through sysfs afterwards. Hence 'wb_normal != 0' is the same as 'rwb->enable_state != WBT_STATE_OFF_MANUAL'. The code is redundan, hence replace the checking of 'wb_normal' to 'enable_state' in rwb_enabled() and reuse rwb_enabled() for wbt_disabled(). Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230527010644.647900-4-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-26blk-wbt: remove dead code to handle wbt enable/disable with io inflightYu Kuai
enable or disable wbt is always called with queue freezed, so that wbt can never be enabled or disabled while io is still inflight, and this behaviour should always hold to avoid io hang(There have been reported several times). Therefor, the code to handle wbt enable/diskble with io inflight is not and never will be used, hence remove such dead code. Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230527010644.647900-3-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-26blk-wbt: don't create wbt sysfs entry if CONFIG_BLK_WBT is disabledYu Kuai
sysfs entry /sys/block/[device]/queue/wbt_lat_usec will be created even if CONFIG_BLK_WBT is disabled, while read and write will always fail. It doesn't make sense to create a sysfs entry that can't be accessed, so don't create such entry. Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230527010644.647900-2-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-25blk-mq: fix two misuses on RQF_USE_SCHEDMing Lei
Request allocated from sched tags can't be issued via ->queue_rqs() directly, since driver tag isn't allocated yet. This is the 1st misuse of RQF_USE_SCHED for figuring out plug->has_elevator. Request allocated from sched tags can't be ended by blk_mq_end_request_batch() too, fix the 2nd RQF_USE_SCHED misuse in blk_mq_add_to_batch(). Without this patch, NVMe uring cmd passthrough IO workload can run into hang easily with real io scheduler. Fixes: dd6216bb16e8 ("blk-mq: make sure elevator callbacks aren't called for passthrough request") Reported-by: Guangwu Zhang <guazhang@redhat.com> Closes: https://lore.kernel.org/linux-block/CAGS2=YrBjpLPOKa-gzcKuuOG60AGth5794PNCDwatdnnscB9ug@mail.gmail.com/ Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20230624130105.1443879-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-25blk-throttle: Fix io statistics for cgroup v1Jinke Han
After commit f382fb0bcef4 ("block: remove legacy IO schedulers"), blkio.throttle.io_serviced and blkio.throttle.io_service_bytes become the only stable io stats interface of cgroup v1, and these statistics are done in the blk-throttle code. But the current code only counts the bios that are actually throttled. When the user does not add the throttle limit, the io stats for cgroup v1 has nothing. I fix it according to the statistical method of v2, and made it count all ios accurately. Fixes: a7b36ee6ba29 ("block: move blk-throtl fast path inline") Tested-by: Andrea Righi <andrea.righi@canonical.com> Signed-off-by: Jinke Han <hanjinke.666@bytedance.com> Acked-by: Muchun Song <songmuchun@bytedance.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20230507170631.89607-1-hanjinke.666@bytedance.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-22block: don't return -EINVAL for not found names in devt_from_devnameChristoph Hellwig
When we didn't find a device and didn't guess it might be a partition, it might still show up later, so don't disable rootwait for it by returning -EINVAL. Fixes: 079caa35f786 ("init: clear root_wait on all invalid root= strings") Reported-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230622150644.600327-1-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-22block: make sure local irq is disabled when calling __blkcg_rstat_flushMing Lei
When __blkcg_rstat_flush() is called from cgroup_rstat_flush*() code path, interrupt is always disabled. When we start to flush blkcg per-cpu stats list in __blkg_release() for avoiding to leak blkcg_gq's reference in commit 20cb1c2fb756 ("blk-cgroup: Flush stats before releasing blkcg_gq"), local irq isn't disabled yet, then lockdep warning may be triggered because the dependent cgroup locks may be acquired from irq(soft irq) handler. Fix the issue by disabling local irq always. Fixes: 20cb1c2fb756 ("blk-cgroup: Flush stats before releasing blkcg_gq") Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com> Closes: https://lore.kernel.org/linux-block/pz2wzwnmn5tk3pwpskmjhli6g3qly7eoknilb26of376c7kwxy@qydzpvt6zpis/T/#u Cc: stable@vger.kernel.org Cc: Jay Shin <jaeshin@redhat.com> Cc: Tejun Heo <tj@kernel.org> Cc: Waiman Long <longman@redhat.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Waiman Long <longman@redhat.com> Link: https://lore.kernel.org/r/20230622084249.1208005-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-21block: Improve kernel-doc headersBart Van Assche
Fix the documentation of the devt_from_partuuid() return value. Fix the following two recently introduced kernel-doc warnings: block/bdev.c:570: warning: Function parameter or member 'hops' not described in 'bd_finish_claiming' block/early-lookup.c:46: warning: Function parameter or member 'devt' not described in 'devt_from_partuuid' Cc: Christoph Hellwig <hch@lst.de> Fixes: 0718afd47f70 ("block: introduce holder ops") Fixes: cf056a431215 ("init: improve the name_to_dev_t interface") Signed-off-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20230621165054.743815-1-bvanassche@acm.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-21blk-mq: don't insert passthrough request into sw queueMing Lei
In case of real io scheduler, q->elevator is set, so blk_mq_run_hw_queue() may just check if scheduler queue has request to dispatch, see __blk_mq_sched_dispatch_requests(). Then IO hang may be caused because all passthorugh requests may stay in sw queue. And any passthrough request should have been inserted to hctx->dispatch always. Reported-by: Guangwu Zhang <guazhang@redhat.com> Fixes: d97217e7f024 ("blk-mq: don't queue plugged passthrough requests into scheduler") Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20230621132208.1142318-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-21bsg: make bsg_class a static const structureIvan Orlov
Now that the driver core allows for struct class to be in read-only memory, move the bsg_class structure to be declared at build time placing it into read-only memory, instead of having to be dynamically allocated at boot time. Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Jens Axboe <axboe@kernel.dk> Cc: linux-scsi@vger.kernel.org Cc: linux-block@vger.kernel.org Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: https://lore.kernel.org/r/20230620180129.645646-8-gregkh@linuxfoundation.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-21block: fix the exclusive open mask in disk_scan_partitionsChristoph Hellwig
FMODE_EXEC has nothing to do with exclusive opens, and even is of the wrong type. We need to check for BLK_OPEN_EXCL here. Fixes: 985958b8584c ("block: fix wrong mode for blkdev_get_by_dev() from disk_scan_partitions()") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230621124914.185992-1-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-20block: add overflow checks for Amiga partition supportMichael Schmitz
The Amiga partition parser module uses signed int for partition sector address and count, which will overflow for disks larger than 1 TB. Use u64 as type for sector address and size to allow using disks up to 2 TB without LBD support, and disks larger than 2 TB with LBD. The RBD format allows to specify disk sizes up to 2^128 bytes (though native OS limitations reduce this somewhat, to max 2^68 bytes), so check for u64 overflow carefully to protect against overflowing sector_t. Bail out if sector addresses overflow 32 bits on kernels without LBD support. This bug was reported originally in 2012, and the fix was created by the RDB author, Joanne Dow <jdow@earthlink.net>. A patch had been discussed and reviewed on linux-m68k at that time but never officially submitted (now resubmitted as patch 1 in this series). This patch adds additional error checking and warning messages. Reported-by: Martin Steigerwald <Martin@lichtvoll.de> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=43511 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Message-ID: <201206192146.09327.Martin@lichtvoll.de> Cc: <stable@vger.kernel.org> # 5.2 Signed-off-by: Michael Schmitz <schmitzmic@gmail.com> Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org> Reviewed-by: Christoph Hellwig <hch@infradead.org> Link: https://lore.kernel.org/r/20230620201725.7020-4-schmitzmic@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-20block: fix signed int overflow in Amiga partition supportMichael Schmitz
The Amiga partition parser module uses signed int for partition sector address and count, which will overflow for disks larger than 1 TB. Use sector_t as type for sector address and size to allow using disks up to 2 TB without LBD support, and disks larger than 2 TB with LBD. This bug was reported originally in 2012, and the fix was created by the RDB author, Joanne Dow <jdow@earthlink.net>. A patch had been discussed and reviewed on linux-m68k at that time but never officially submitted. This patch differs from Joanne's patch only in its use of sector_t instead of unsigned int. No checking for overflows is done (see patch 3 of this series for that). Reported-by: Martin Steigerwald <Martin@lichtvoll.de> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=43511 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Message-ID: <201206192146.09327.Martin@lichtvoll.de> Cc: <stable@vger.kernel.org> # 5.2 Signed-off-by: Michael Schmitz <schmitzmic@gmail.com> Tested-by: Martin Steigerwald <Martin@lichtvoll.de> Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230620201725.7020-2-schmitzmic@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-20block: add capacity validation in bdev_add_partition()Min Li
In the function bdev_add_partition(),there is no check that the start and end sectors exceed the size of the disk before calling add_partition. When we call the block's ioctl interface directly to add a partition, and the capacity of the disk is set to 0 by driver,the command will continue to execute. Signed-off-by: Min Li <min15.li@samsung.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Link: https://lore.kernel.org/r/20230619091214.31615-1-min15.li@samsung.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-20block: fine-granular CAP_SYS_ADMIN for Persistent ReservationJingbo Xu
Allow of unprivileged Persistent Reservation operations on devices if the write permission check on the device node has passed. brw-rw---- 1 root disk 259, 0 Jun 13 07:09 /dev/nvme0n1 In the example above, the "disk" group of nvme0n1 is also allowed to make reservations on the device even without CAP_SYS_ADMIN. Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230613084008.93795-3-jefflexu@linux.alibaba.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-20block: disallow Persistent Reservation on partitionsJingbo Xu
Refuse Persistent Reservation operations on partitions as reservation on partitions doesn't make sense. Besides, introduce blkdev_pr_allowed() helper, where more policies could be placed here later. Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230613084008.93795-2-jefflexu@linux.alibaba.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-20block: fix wrong mode for blkdev_get_by_dev() from disk_scan_partitions()Yu Kuai
After commit 2736e8eeb0cc ("block: use the holder as indication for exclusive opens"), blkdev_get_by_dev() will warn if holder is NULL and mode contains 'FMODE_EXCL'. holder from blkdev_get_by_dev() from disk_scan_partitions() is always NULL, hence it should not use 'FMODE_EXCL', which is broben by the commit. For consequence, WARN_ON_ONCE() will be triggered from blkdev_get_by_dev() if user scan partitions with device opened exclusively. Fix this problem by removing 'FMODE_EXCL' from disk_scan_partitions(), as it used to be. Reported-by: syzbot+00cd27751f78817f167b@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?extid=00cd27751f78817f167b Fixes: 2736e8eeb0cc ("block: use the holder as indication for exclusive opens") Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Christian Brauner <brauner@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230618140402.7556-1-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-20block: document the holder argument to blkdev_get_by_pathChristoph Hellwig
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230620043536.707249-1-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-20block: increment diskseq on all media change eventsDemi Marie Obenour
Currently, associating a loop device with a different file descriptor does not increment its diskseq. This allows the following race condition: 1. Program X opens a loop device 2. Program X gets the diskseq of the loop device. 3. Program X associates a file with the loop device. 4. Program X passes the loop device major, minor, and diskseq to something. 5. Program X exits. 6. Program Y detaches the file from the loop device. 7. Program Y attaches a different file to the loop device. 8. The opener finally gets around to opening the loop device and checks that the diskseq is what it expects it to be. Even though the diskseq is the expected value, the result is that the opener is accessing the wrong file. From discussions with Christoph Hellwig, it appears that disk_force_media_change() was supposed to call inc_diskseq(), but in fact it does not. Adding a Fixes: tag to indicate this. Christoph's Reported-by is because he stated that disk_force_media_change() calls inc_diskseq(), which is what led me to discover that it should but does not. Reported-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com> Fixes: e6138dc12de9 ("block: add a helper to raise a media changed event") Cc: stable@vger.kernel.org # 5.15+ Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230607170837.1559-1-demi@invisiblethingslab.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-16Merge patch series "scsi: fixes for targets with many LUNs, and ↵Martin K. Petersen
scsi_target_block rework" Martin Wilck <mwilck@suse.com> says: This patch series addresses some issues we saw in a test setup with a large number of SCSI LUNs. The first two patches simply increase the number of available sg and bsg devices. 3-5 fix a large delay we encountered between blocking a Fibre Channel remote port and the dev_loss_tmo. 6 renames scsi_target_block() to scsi_block_targets(), and makes additional changes to this API, as suggested in the review of the v2 series. 7 improves a warning message. Link: https://lore.kernel.org/r/20230614103616.31857-1-mwilck@suse.com Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2023-06-16scsi: bsg: Increase number of devicesHannes Reinecke
Larger setups may need to allocate more than 32k bsg devices, so increase the number of devices to the full range of minor device numbers. Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Martin Wilck <mwilck@suse.com> Link: https://lore.kernel.org/r/20230614103616.31857-2-mwilck@suse.com Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2023-06-16blk-mq: fix NULL dereference on q->elevator in blk_mq_elv_switch_noneMing Lei
After grabbing q->sysfs_lock, q->elevator may become NULL because of elevator switch. Fix the NULL dereference on q->elevator by checking it with lock. Reported-by: Guangwu Zhang <guazhang@redhat.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20230616132354.415109-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-16block: remove BIO_PAGE_REFFEDChristoph Hellwig
Now that all block direct I/O helpers use page pinning, this flag is unused. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Christian Brauner <brauner@kernel.org> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: David Howells <dhowells@redhat.com> Link: https://lore.kernel.org/r/20230614140341.521331-4-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-16scsi: block: Improve ioprio value validity checksDamien Le Moal
The introduction of the macro IOPRIO_PRIO_LEVEL() in commit eca2040972b4 ("scsi: block: ioprio: Clean up interface definition") results in an iopriority level to always be masked using the macro IOPRIO_LEVEL_MASK, and thus to the kernel always seeing an acceptable value for an I/O priority level when checked in ioprio_check_cap(). Before this patch, this function would return an error for some (but not all) invalid values for a level valid range of [0..7]. Restore and improve the detection of invalid priority levels by introducing the inline function ioprio_value() to check an ioprio class, level and hint value before combining these fields into a single value to be used with ioprio_set() or AIOs. If an invalid value for the class, level or hint of an ioprio is detected, ioprio_value() returns an ioprio using the class IOPRIO_CLASS_INVALID, indicating an invalid value and causing ioprio_check_cap() to return -EINVAL. Fixes: 6c913257226a ("scsi: block: Introduce ioprio hints") Fixes: eca2040972b4 ("scsi: block: ioprio: Clean up interface definition") Signed-off-by: Damien Le Moal <dlemoal@kernel.org> Link: https://lore.kernel.org/r/20230608095556.124001-1-dlemoal@kernel.org Reviewed-by: Niklas Cassel <niklas.cassel@wdc.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2023-06-14block: fix blktrace debugfs entries leakageYu Kuai
Commit 99d055b4fd4b ("block: remove per-disk debugfs files in blk_unregister_queue") moves blk_trace_shutdown() from blk_release_queue() to blk_unregister_queue(), this is safe if blktrace is created through sysfs, however, there is a regression in corner case. blktrace can still be enabled after del_gendisk() through ioctl if the disk is opened before del_gendisk(), and if blktrace is not shutdown through ioctl before closing the disk, debugfs entries will be leaked. Fix this problem by shutdown blktrace in disk_release(), this is safe because blk_trace_remove() is reentrant. Fixes: 99d055b4fd4b ("block: remove per-disk debugfs files in blk_unregister_queue") Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230610022003.2557284-4-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-14blk-mq: check on cpu id when there is only one ctx mappingEd Tsai
commit f168420c62e7 ("blk-mq: don't redirect completion for hctx withs only one ctx mapping") When nvme applies a 1:1 mapping of hctx and ctx, there will be no remote request. But for ufs, the submission and completion queues could be asymmetric. (e.g. Multiple SQs share one CQ) Therefore, 1:1 mapping of hctx and ctx won't complete request on the submission cpu. In this situation, this nr_ctx check could violate the QUEUE_FLAG_SAME_FORCE, as a result, check on cpu id when there is only one ctx mapping. Signed-off-by: Ed Tsai <ed.tsai@mediatek.com> Signed-off-by: Po-Wen Kao <powen.kao@mediatek.com> Suggested-by: Keith Busch <kbusch@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230614002529.6636-1-ed.tsai@mediatek.com [axboe: fixed up indentation] Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-12blk-mq: fix potential io hang by wrong 'wake_batch'Yu Kuai
In __blk_mq_tag_busy/idle(), updating 'active_queues' and calculating 'wake_batch' is not atomic: t1: t2: _blk_mq_tag_busy blk_mq_tag_busy inc active_queues // assume 1->2 inc active_queues // 2 -> 3 blk_mq_update_wake_batch // calculate based on 3 blk_mq_update_wake_batch /* calculate based on 2, while active_queues is actually 3. */ Fix this problem by protecting them wih 'tags->lock', this is not a hot path, so performance should not be concerned. And now that all writers are inside the lock, switch 'actives_queues' from atomic to unsigned int. Fixes: 180dccb0dba4 ("blk-mq: fix tag_get wait task can't be awakened") Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20230610023043.2559121-1-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-12block: store the holder in file->private_dataChristoph Hellwig
Store the file struct used as the holder in file->private_data as an indicator that this file descriptor was opened exclusively to remove the last use of FMODE_EXCL. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Link: https://lore.kernel.org/r/20230608110258.189493-30-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-12block: always use I_BDEV on file->f_mapping->host to find the bdevChristoph Hellwig
Always use I_BDEV(file->f_mapping->host) to find the bdev for a file to free up file->private_data for other uses. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Acked-by: Christian Brauner <brauner@kernel.org> Link: https://lore.kernel.org/r/20230608110258.189493-29-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-12block: replace fmode_t with a block-specific type for block open flagsChristoph Hellwig
The only overlap between the block open flags mapped into the fmode_t and other uses of fmode_t are FMODE_READ and FMODE_WRITE. Define a new blk_mode_t instead for use in blkdev_get_by_{dev,path}, ->open and ->ioctl and stop abusing fmode_t. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Jack Wang <jinpu.wang@ionos.com> [rnbd] Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Christian Brauner <brauner@kernel.org> Link: https://lore.kernel.org/r/20230608110258.189493-28-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-12block: remove unused fmode_t arguments from ioctl handlersChristoph Hellwig
A few ioctl handlers have fmode_t arguments that are entirely unused, remove them. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Christian Brauner <brauner@kernel.org> Reviewed-by: Hannes Reinecke <hare@suse.de> Link: https://lore.kernel.org/r/20230608110258.189493-27-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-12block: move a few internal definitions out of blkdev.hChristoph Hellwig
All these helpers are only used in core block code, so move them out of the public header. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Acked-by: Christian Brauner <brauner@kernel.org> Link: https://lore.kernel.org/r/20230608110258.189493-26-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-12scsi: replace the fmode_t argument to ->sg_io_fn with a simple boolChristoph Hellwig
Instead of passing a fmode_t and only checking it for FMODE_WRITE, pass a bool open_for_write to prepare for callers that won't have the fmode_t. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Acked-by: Christian Brauner <brauner@kernel.org> Link: https://lore.kernel.org/r/20230608110258.189493-21-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-12block: use the holder as indication for exclusive opensChristoph Hellwig
The current interface for exclusive opens is rather confusing as it requires both the FMODE_EXCL flag and a holder. Remove the need to pass FMODE_EXCL and just key off the exclusive open off a non-NULL holder. For blkdev_put this requires adding the holder argument, which provides better debug checking that only the holder actually releases the hold, but at the same time allows removing the now superfluous mode argument. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Acked-by: Christian Brauner <brauner@kernel.org> Acked-by: David Sterba <dsterba@suse.com> [btrfs] Acked-by: Jack Wang <jinpu.wang@ionos.com> [rnbd] Link: https://lore.kernel.org/r/20230608110258.189493-16-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-12block: rename blkdev_close to blkdev_releaseChristoph Hellwig
Make the function name match the method name. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Acked-by: Christian Brauner <brauner@kernel.org> Link: https://lore.kernel.org/r/20230608110258.189493-11-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-12block: remove the unused mode argument to ->releaseChristoph Hellwig
The mode argument to the ->release block_device_operation is never used, so remove it. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Acked-by: Christian Brauner <brauner@kernel.org> Acked-by: Jack Wang <jinpu.wang@ionos.com> [rnbd] Link: https://lore.kernel.org/r/20230608110258.189493-10-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-12block: pass a gendisk to ->openChristoph Hellwig
->open is only called on the whole device. Make that explicit by passing a gendisk instead of the block_device. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Acked-by: Christian Brauner <brauner@kernel.org> Acked-by: Jack Wang <jinpu.wang@ionos.com> [rnbd] Link: https://lore.kernel.org/r/20230608110258.189493-9-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-12block: pass a gendisk on bdev_check_media_changeChristoph Hellwig
bdev_check_media_change should only ever be called for the whole device. Pass a gendisk to make that explicit and rename the function to disk_check_media_change. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Acked-by: Christian Brauner <brauner@kernel.org> Link: https://lore.kernel.org/r/20230608110258.189493-8-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-12block: also call ->open for incremental partition opensChristoph Hellwig
For whole devices ->open is called for each open, but for partitions it is only called on the first open of a partition, e.g.: open("/dev/vdb", ...) open("/dev/vdb", ...) - 2 call to ->open open("/dev/vdb1", ...) open("/dev/vdb", ...) - 2 call to ->open open("/dev/vdb", ...) open("/dev/vdb", ...) - just open call to ->open This is problematic as various block drivers look at open flags and might not do all the required setup if the earlier open was with an odd flag like O_NDELAY or the magic 3 ioctl-only open mode. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Phillip Potter <phil@philpotter.co.uk> Reviewed-by: Hannes Reinecke <hare@suse.de> Acked-by: Christian Brauner <brauner@kernel.org> Link: https://lore.kernel.org/r/20230608110258.189493-2-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-11blk-cgroup: Flush stats before releasing blkcg_gqMing Lei
As noted by Michal, the blkg_iostat_set's in the lockless list hold reference to blkg's to protect against their removal. Those blkg's hold reference to blkcg. When a cgroup is being destroyed, cgroup_rstat_flush() is only called at css_release_work_fn() which is called when the blkcg reference count reaches 0. This circular dependency will prevent blkcg and some blkgs from being freed after they are made offline. It is less a problem if the cgroup to be destroyed also has other controllers like memory that will call cgroup_rstat_flush() which will clean up the reference count. If block is the only controller that uses rstat, these offline blkcg and blkgs may never be freed leaking more and more memory over time. To prevent this potential memory leak: - flush blkcg per-cpu stats list in __blkg_release(), when no new stat can be added - add global blkg_stat_lock for covering concurrent parent blkg stat update - don't grab bio->bi_blkg reference when adding the stats into blkcg's per-cpu stat list since all stats are guaranteed to be consumed before releasing blkg instance, and grabbing blkg reference for stats was the most fragile part of original patch Based on Waiman's patch: https://lore.kernel.org/linux-block/20221215033132.230023-3-longman@redhat.com/ Fixes: 3b8cc6298724 ("blk-cgroup: Optimize blkcg_rstat_flush()") Cc: stable@vger.kernel.org Reported-by: Jay Shin <jaeshin@redhat.com> Acked-by: Tejun Heo <tj@kernel.org> Cc: Waiman Long <longman@redhat.com> Cc: mkoutny@suse.com Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20230609234249.1412858-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>