- Mar 05, 2022
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Zhang Wensheng authored
KASAN reports a use-after-free report when doing normal scsi-mq test [69832.239032] ================================================================== [69832.241810] BUG: KASAN: use-after-free in bfq_dispatch_request+0x1045/0x44b0 [69832.243267] Read of size 8 at addr ffff88802622ba88 by task kworker/3:1H/155 [69832.244656] [69832.245007] CPU: 3 PID: 155 Comm: kworker/3:1H Not tainted 5.10.0-10295-g576c6382529e #8 [69832.246626] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 [69832.249069] Workqueue: kblockd blk_mq_run_work_fn [69832.250022] Call Trace: [69832.250541] dump_stack+0x9b/0xce [69832.251232] ? bfq_dispatch_request+0x1045/0x44b0 [69832.252243] print_address_description.constprop.6+0x3e/0x60 [69832.253381] ? __cpuidle_text_end+0x5/0x5 [69832.254211] ? vprintk_func+0x6b/0x120 [69832.254994] ? bfq_dispatch_request+0x1045/0x44b0 [69832.255952] ? bfq_dispatch_request+0x1045/0x44b0 [69832.256914] kasan_report.cold.9+0x22/0x3a [69832.257753] ? bfq_dispatch_request+0x1045/0x44b0 [69832.258755] check_memory_region+0x1c1/0x1e0 [69832.260248] bfq_dispatch_request+0x1045/0x44b0 [69832.261181] ? bfq_bfqq_expire+0x2440/0x2440 [69832.262032] ? blk_mq_delay_run_hw_queues+0xf9/0x170 [69832.263022] __blk_mq_do_dispatch_sched+0x52f/0x830 [69832.264011] ? blk_mq_sched_request_inserted+0x100/0x100 [69832.265101] __blk_mq_sched_dispatch_requests+0x398/0x4f0 [69832.266206] ? blk_mq_do_dispatch_ctx+0x570/0x570 [69832.267147] ? __switch_to+0x5f4/0xee0 [69832.267898] blk_mq_sched_dispatch_requests+0xdf/0x140 [69832.268946] __blk_mq_run_hw_queue+0xc0/0x270 [69832.269840] blk_mq_run_work_fn+0x51/0x60 [69832.278170] process_one_work+0x6d4/0xfe0 [69832.278984] worker_thread+0x91/0xc80 [69832.279726] ? __kthread_parkme+0xb0/0x110 [69832.280554] ? process_one_work+0xfe0/0xfe0 [69832.281414] kthread+0x32d/0x3f0 [69832.282082] ? kthread_park+0x170/0x170 [69832.282849] ret_from_fork+0x1f/0x30 [69832.283573] [69832.283886] Allocated by task 7725: [69832.284599] kasan_save_stack+0x19/0x40 [69832.285385] __kasan_kmalloc.constprop.2+0xc1/0xd0 [69832.286350] kmem_cache_alloc_node+0x13f/0x460 [69832.287237] bfq_get_queue+0x3d4/0x1140 [69832.287993] bfq_get_bfqq_handle_split+0x103/0x510 [69832.289015] bfq_init_rq+0x337/0x2d50 [69832.289749] bfq_insert_requests+0x304/0x4e10 [69832.290634] blk_mq_sched_insert_requests+0x13e/0x390 [69832.291629] blk_mq_flush_plug_list+0x4b4/0x760 [69832.292538] blk_flush_plug_list+0x2c5/0x480 [69832.293392] io_schedule_prepare+0xb2/0xd0 [69832.294209] io_schedule_timeout+0x13/0x80 [69832.295014] wait_for_common_io.constprop.1+0x13c/0x270 [69832.296137] submit_bio_wait+0x103/0x1a0 [69832.296932] blkdev_issue_discard+0xe6/0x160 [69832.297794] blk_ioctl_discard+0x219/0x290 [69832.298614] blkdev_common_ioctl+0x50a/0x1750 [69832.304715] blkdev_ioctl+0x470/0x600 [69832.305474] block_ioctl+0xde/0x120 [69832.306232] vfs_ioctl+0x6c/0xc0 [69832.306877] __se_sys_ioctl+0x90/0xa0 [69832.307629] do_syscall_64+0x2d/0x40 [69832.308362] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [69832.309382] [69832.309701] Freed by task 155: [69832.310328] kasan_save_stack+0x19/0x40 [69832.311121] kasan_set_track+0x1c/0x30 [69832.311868] kasan_set_free_info+0x1b/0x30 [69832.312699] __kasan_slab_free+0x111/0x160 [69832.313524] kmem_cache_free+0x94/0x460 [69832.314367] bfq_put_queue+0x582/0x940 [69832.315112] __bfq_bfqd_reset_in_service+0x166/0x1d0 [69832.317275] bfq_bfqq_expire+0xb27/0x2440 [69832.318084] bfq_dispatch_request+0x697/0x44b0 [69832.318991] __blk_mq_do_dispatch_sched+0x52f/0x830 [69832.319984] __blk_mq_sched_dispatch_requests+0x398/0x4f0 [69832.321087] blk_mq_sched_dispatch_requests+0xdf/0x140 [69832.322225] __blk_mq_run_hw_queue+0xc0/0x270 [69832.323114] blk_mq_run_work_fn+0x51/0x60 [69832.323942] process_one_work+0x6d4/0xfe0 [69832.324772] worker_thread+0x91/0xc80 [69832.325518] kthread+0x32d/0x3f0 [69832.326205] ret_from_fork+0x1f/0x30 [69832.326932] [69832.338297] The buggy address belongs to the object at ffff88802622b968 [69832.338297] which belongs to the cache bfq_queue of size 512 [69832.340766] The buggy address is located 288 bytes inside of [69832.340766] 512-byte region [ffff88802622b968, ffff88802622bb68) [69832.343091] The buggy address belongs to the page: [69832.344097] page:ffffea0000988a00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88802622a528 pfn:0x26228 [69832.346214] head:ffffea0000988a00 order:2 compound_mapcount:0 compound_pincount:0 [69832.347719] flags: 0x1fffff80010200(slab|head) [69832.348625] raw: 001fffff80010200 ffffea0000dbac08 ffff888017a57650 ffff8880179fe840 [69832.354972] raw: ffff88802622a528 0000000000120008 00000001ffffffff 0000000000000000 [69832.356547] page dumped because: kasan: bad access detected [69832.357652] [69832.357970] Memory state around the buggy address: [69832.358926] ffff88802622b980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [69832.360358] ffff88802622ba00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [69832.361810] >ffff88802622ba80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [69832.363273] ^ [69832.363975] ffff88802622bb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc [69832.375960] ffff88802622bb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [69832.377405] ================================================================== In bfq_dispatch_requestfunction, it may have function call: bfq_dispatch_request __bfq_dispatch_request bfq_select_queue bfq_bfqq_expire __bfq_bfqd_reset_in_service bfq_put_queue kmem_cache_free In this function call, in_serv_queue has beed expired and meet the conditions to free. In the function bfq_dispatch_request, the address of in_serv_queue pointing to has been released. For getting the value of idle_timer_disabled, it will get flags value from the address which in_serv_queue pointing to, then the problem of use-after-free happens; Fix the problem by check in_serv_queue == bfqd->in_service_queue, to get the value of idle_timer_disabled if in_serve_queue is equel to bfqd->in_service_queue. If the space of in_serv_queue pointing has been released, this judge will aviod use-after-free problem. And if in_serv_queue may be expired or finished, the idle_timer_disabled will be false which would not give effects to bfq_update_dispatch_stats. Reported-by:
Hulk Robot <hulkci@huawei.com> Signed-off-by:
Zhang Wensheng <zhangwensheng5@huawei.com> Link: https://lore.kernel.org/r/20220303070334.3020168-1-zhangwensheng5@huawei.com Signed-off-by:
Jens Axboe <axboe@kernel.dk>
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- Feb 28, 2022
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Eric Biggers authored
Add sysfs files that expose the inline encryption capabilities of request queues: /sys/block/$disk/queue/crypto/max_dun_bits /sys/block/$disk/queue/crypto/modes/$mode /sys/block/$disk/queue/crypto/num_keyslots Userspace can use these new files to decide what encryption settings to use, or whether to use inline encryption at all. This also brings the crypto capabilities in line with the other queue properties, which are already discoverable via the queue directory in sysfs. Design notes: - Place the new files in a new subdirectory "crypto" to group them together and to avoid complicating the main "queue" directory. This also makes it possible to replace "crypto" with a symlink later if we ever make the blk_crypto_profiles into real kobjects (see below). - It was necessary to define a new kobject that corresponds to the crypto subdirectory. For now, this kobject just contains a pointer to the blk_crypto_profile. Note that mult... -
Eric Biggers authored
kobjects aren't supposed to be deleted before their child kobjects are deleted. Apparently this is usually benign; however, a WARN will be triggered if one of the child kobjects has a named attribute group: sysfs group 'modes' not found for kobject 'crypto' WARNING: CPU: 0 PID: 1 at fs/sysfs/group.c:278 sysfs_remove_group+0x72/0x80 ... Call Trace: sysfs_remove_groups+0x29/0x40 fs/sysfs/group.c:312 __kobject_del+0x20/0x80 lib/kobject.c:611 kobject_cleanup+0xa4/0x140 lib/kobject.c:696 kobject_release lib/kobject.c:736 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x53/0x70 lib/kobject.c:753 blk_crypto_sysfs_unregister+0x10/0x20 block/blk-crypto-sysfs.c:159 blk_unregister_queue+0xb0/0x110 block/blk-sysfs.c:962 del_gendisk+0x117/0x250 block/genhd.c:610 Fix this by moving the kobject_del() and the corresponding kobject_uevent() to the correct place. Fixes: 2c2086af ("block: Protect less code with sysfs_lock in blk_{un,}register_queue()") Reviewed-by:Hannes Reinecke <hare@suse.de> Reviewed-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by:
Bart Van Assche <bvanassche@acm.org> Signed-off-by:
Eric Biggers <ebiggers@google.com> Reviewed-by:
Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20220124215938.2769-3-ebiggers@kernel.org Signed-off-by:
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Eric Biggers authored
Make elv_unregister_queue() a no-op if q->elevator is NULL or is not registered. This simplifies the existing callers, as well as the future caller in the error path of blk_register_queue(). Also don't bother checking whether q is NULL, since it never is. Reviewed-by:
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Nian Yanchuan authored
Remove redundant semicolon from block/bdev.c Signed-off-by:
Nian Yanchuan <yanchuan@nfschina.com> Link: https://lore.kernel.org/r/20220227170124.GA14658@localhost.localdomain Signed-off-by:
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Christoph Hellwig authored
As Luis reported, losetup currently doesn't properly create the loop device without this if the device node already exists because old scripts created it manually. So default to y for now and remove the aggressive removal schedule. Reported-by:
Luis Chamberlain <mcgrof@kernel.org> Signed-off-by:
Chaitanya Kulkarni <kch@nvidia.com> Link: https://lore.kernel.org/r/20220225181440.1351591-1-hch@lst.de Signed-off-by:
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- Feb 22, 2022
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Zhang Wensheng authored
When the inflight IOs are slow and no new IOs are issued, we expect iostat could manifest the IO hang problem. However after commit 5b18b5a7 ("block: delete part_round_stats and switch to less precise counting"), io_tick and time_in_queue will not be updated until the end of IO, and the avgqu-sz and %util columns of iostat will be zero. Because it has using stat.nsecs accumulation to express time_in_queue which is not suitable to change, and may %util will express the status better when io hang occur. To fix io_ticks, we use update_io_ticks and inflight to update io_ticks when diskstats_show and part_stat_show been called. Fixes: 5b18b5a7 ("block: delete part_round_stats and switch to less precise counting") Signed-off-by:
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- Feb 18, 2022
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Yu Kuai authored
Our test report a UAF: [ 2073.019181] ================================================================== [ 2073.019188] BUG: KASAN: use-after-free in __bfq_put_async_bfqq+0xa0/0x168 [ 2073.019191] Write of size 8 at addr ffff8000ccf64128 by task rmmod/72584 [ 2073.019192] [ 2073.019196] CPU: 0 PID: 72584 Comm: rmmod Kdump: loaded Not tainted 4.19.90-yk #5 [ 2073.019198] Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 [ 2073.019200] Call trace: [ 2073.019203] dump_backtrace+0x0/0x310 [ 2073.019206] show_stack+0x28/0x38 [ 2073.019210] dump_stack+0xec/0x15c [ 2073.019216] print_address_description+0x68/0x2d0 [ 2073.019220] kasan_report+0x238/0x2f0 [ 2073.019224] __asan_store8+0x88/0xb0 [ 2073.019229] __bfq_put_async_bfqq+0xa0/0x168 [ 2073.019233] bfq_put_async_queues+0xbc/0x208 [ 2073.019236] bfq_pd_offline+0x178/0x238 [ 2073.019240] blkcg_deactivate_policy+0x1f0/0x420 [ 2073.019244] bfq_exit_queue+0x128/0x178 [ 2073.019249] blk_mq_exit_sched+0x12c/...
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Yu Kuai authored
Moving bfqq to it's parent bfqg is pointless. Signed-off-by:
Yu Kuai <yukuai3@huawei.com> Link: https://lore.kernel.org/r/20220129015924.3958918-3-yukuai3@huawei.com Signed-off-by:
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Yu Kuai authored
Use bfq_group() instead, which do the same thing. Signed-off-by:
Jan Kara <jack@suse.cz> Acked-by:
Paolo Valente <paolo.valente@linaro.org> Link: https://lore.kernel.org/r/20220129015924.3958918-2-yukuai3@huawei.com Signed-off-by:
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- Feb 17, 2022
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Yahu Gao authored
The return value is ioprio * BFQ_WEIGHT_CONVERSION_COEFF or 0. What we want is ioprio or 0. Correct this by changing the calculation. Signed-off-by:
Yahu Gao <gaoyahu19@gmail.com> Acked-by:
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David Jeffery authored
When blk_mq_delay_run_hw_queues sets an hctx to run in the future, it can reset the delay length for an already pending delayed work run_work. This creates a scenario where multiple hctx may have their queues set to run, but if one runs first and finds nothing to do, it can reset the delay of another hctx and stall the other hctx's ability to run requests. To avoid this I/O stall when an hctx's run_work is already pending, leave it untouched to run at its current designated time rather than extending its delay. The work will still run which keeps closed the race calling blk_mq_delay_run_hw_queues is needed for while also avoiding the I/O stall. Signed-off-by:
David Jeffery <djeffery@redhat.com> Reviewed-by:
Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220131203337.GA17666@redhat Signed-off-by:
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Christoph Hellwig authored
Implement the ->free_disk method to free the virtio_blk structure only once the last gendisk reference goes away instead of keeping a local refcount. Signed-off-by:
Stefan Hajnoczi <stefanha@redhat.com> Acked-by:
Michael S. Tsirkin <mst@redhat.com> Link: https://lore.kernel.org/r/20220215094514.3828912-6-hch@lst.de Signed-off-by:
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Christoph Hellwig authored
Implement the ->free_disk method to free the msb_data structure only once the last gendisk reference goes away instead of keeping a local refcount. Signed-off-by:
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Christoph Hellwig authored
Use set_disk_ro to propagate the read-only state to the block layer instead of checking for it in ->open and leaking a reference in case of a read-only device. Signed-off-by:
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Christoph Hellwig authored
Implement the ->free_disk method to free the msb_data structure only once the last gendisk reference goes away instead of keeping a local refcount. Signed-off-by:
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Christoph Hellwig authored
Add a method to notify the driver that the gendisk is about to be freed. This allows drivers to tie the lifetime of their private data to that of the gendisk and thus deal with device removal races without expensive synchronization and boilerplate code. A new flag is added so that ->free_disk is only called after a successful call to add_disk, which significantly simplifies the error handling path during probing. Signed-off-by:
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Ming Lei authored
Revert commit 4f1e9630 ("blk-throtl: optimize IOPS throttle for large IO scenarios") since we have another easier way to address this issue and get better iops throttling result. Acked-by:
Tejun Heo <tj@kernel.org> Signed-off-by:
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Ming Lei authored
We need to throttle split bio in case of IOPS limit even though the split bio has been marked as BIO_THROTTLED since block layer accounts split bio actually. If only throughput throttle is setup, no need to throttle any more if BIO_THROTTLED is set since we have accounted & considered the whole bio bytes already. Add one flag of THROTL_TG_HAS_IOPS_LIMIT for serving this purpose. Acked-by:
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Ming Lei authored
Commit 111be883 ("block-throttle: avoid double charge") marks bio as BIO_THROTTLED unconditionally if __blk_throtl_bio() is called on this bio, then this bio won't be called into __blk_throtl_bio() any more. This way is to avoid double charge in case of bio splitting. It is reasonable for read/write throughput limit, but not reasonable for IOPS limit because block layer provides io accounting against split bio. Chunguang Xu has already observed this issue and fixed it in commit 4f1e9630 ("blk-throtl: optimize IOPS throttle for large IO scenarios"). However, that patch only covers bio splitting in __blk_queue_split(), and we have other kind of bio splitting, such as bio_split() & submit_bio_noacct() and other ways. This patch tries to fix the issue in one generic way by always charging the bio for iops limit in blk_throtl_bio(). This way is reasonable: re-submission & fast-cloned bio is charged if it is submitted to same disk/queue, and BIO_THROTTLED will be cleared if bio->bi_bdev is changed. This new approach can get much more smooth/stable iops limit compared with commit 4f1e9630 ("blk-throtl: optimize IOPS throttle for large IO scenarios") since that commit can't throttle current split bios actually. Also this way won't cause new double bio iops charge in blk_throtl_dispatch_work_fn() in which blk_throtl_bio() won't be called any more. Reported-by:
Ning Li <lining2020x@163.com> Acked-by:
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Ming Lei authored
Now submit_bio_checks() is only called by submit_bio_noacct(), so merge it into submit_bio_noacct(). Suggested-by:
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Ming Lei authored
The bio has been checked already before throttling, so no need to check it again before dispatching it from throttle queue. Add a helper of submit_bio_noacct_nocheck() for this purpose. Signed-off-by:
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Ming Lei authored
submit_bio_checks() won't be called outside of block/blk-core.c any more since commit 9d497e29 ("block: don't protect submit_bio_checks by q_usage_counter"), so mark it as one local helper. Reviewed-by:
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Ming Lei authored
blk_crypto_bio_prep() is called for both bio based and blk-mq drivers, so move it out of blk-mq.c, then we can unify this kind of handling. Reviewed-by:
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Ming Lei authored
It is more clean & readable to check bio when starting to submit it, instead of just before calling ->submit_bio() or blk_mq_submit_bio(). Also it provides us chance to optimize bio submission without checking bio. Reviewed-by:
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Christoph Hellwig authored
Fold dm_dispatch_clone_request into it's only caller, and use a switch statement to single dispatch for the handling of the different return values from blk_insert_cloned_request. Signed-off-by:
Mike Snitzer <snitzer@redhat.com> Link: https://lore.kernel.org/r/20220215100540.3892965-6-hch@lst.de Signed-off-by:
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Christoph Hellwig authored
Both ->start_time_ns and the RQF_IO_STAT are set when the request is allocated using blk_mq_alloc_request by dm-mpath in blk_mq_rq_ctx_init. The block layer also ensures ->start_time_ns is only set when actually needed. Signed-off-by:
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Christoph Hellwig authored
The request must be submitted to the queue it was allocated for, so remove the extra request_queue argument. Signed-off-by:
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Christoph Hellwig authored
Fold blk_cloned_rq_check_limits into its only caller. Signed-off-by:
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Christoph Hellwig authored
The code to stack blk-mq drivers is only used by dm-multipath, and will preferably stay that way. Make it optional and only selected by device mapper, so that the buildbots more easily catch abuses like the one that slipped in in the ufs driver in the last merged window. Another positive side effects is that kernel builds without device mapper shrink a little bit as well. Signed-off-by:
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- Feb 16, 2022
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Chengming Zhou authored
Don't need to do blkg_iostat_set for top blkg iostat on each CPU, so move it after percpu stat aggregation. Fixes: ef45fe47 ("blk-cgroup: show global disk stats in root cgroup io.stat") Signed-off-by:
Chengming Zhou <zhouchengming@bytedance.com> Acked-by:
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- Feb 15, 2022
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Chaitanya Kulkarni authored
Based on the comment present in the bdev_get_queue() bdev->bd_queue can never be NULL. Remove the NULL check for the local variable q that is set from bdev_get_queue() for discard, write_same, and write_zeroes. Signed-off-by:
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Christoph Hellwig authored
This document is completely out of date and extremely misleading. In general the existing kerneldoc comment serve as a much better documentation of the still existing functionality, while the history blurbs are pretty much irrelevant today. Signed-off-by:
Johannes Thumshirn <johannes.thumshirn@wdc.com> Link: https://lore.kernel.org/r/20220215081047.3693582-1-hch@lst.de Signed-off-by:
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- Feb 12, 2022
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Barry Song authored
Since commit 7eaceacc ("block: remove per-queue plugging"), kernel has removed blk_run_address_space(), blk_unplug() and sync_buffer(), and moved to on-stack plugging. The document has been obsolete for years. Given that there is no obvious counterparts in the new mechinism to replace old APIs, this patch drops the content directly. Signed-off-by:
Barry Song <song.bao.hua@hisilicon.com> Link: https://lore.kernel.org/r/20220207074931.20067-1-song.bao.hua@hisilicon.com Signed-off-by:
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Ming Lei authored
Partition include/linux/blk-cgroup.h into two parts: one is public part, the other is block layer private part. Suggested by Christoph Hellwig. Signed-off-by:
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Ming Lei authored
q->blkg_list is only used by blkcg code, so move it into blkcg_init_queue. Reviewed-by:
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Ming Lei authored
No one uses THROTL_IOPS_MAX any more, so remove it. Signed-off-by:
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Yang Shi authored
Currently, rasdaemon uses the existing tracepoint block_rq_complete and filters out non-error cases in order to capture block disk errors. But there are a few problems with this approach: 1. Even kernel trace filter could do the filtering work, there is still some overhead after we enable this tracepoint. 2. The filter is merely based on errno, which does not align with kernel logic to check the errors for print_req_error(). 3. block_rq_complete only provides dev major and minor to identify the block device, it is not convenient to use in user-space. So introduce a new tracepoint block_rq_error just for the error case. With this patch, rasdaemon could switch to block_rq_error. Since the new tracepoint has the similar implementation with block_rq_complete, so move the existing code from TRACE_EVENT block_rq_complete() into new event class block_rq_completion(). Then add event for block_rq_complete and block_rq_err respectively from the newly created event class per the suggestion from Chaitanya Kulkarni. Cc: Jens Axboe <axboe@kernel.dk> Cc: Christoph Hellwig <hch@infradead.org> Reviewed-by:
Steven Rostedt <rostedt@goodmis.org> Signed-off-by:
Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by:
Yang Shi <shy828301@gmail.com> Reviewed-by:
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- Feb 08, 2022
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John Garry authored
Since __sbitmap_queue_get_shallow() was introduced in commit c05e6673 ("sbitmap: add sbitmap_get_shallow() operation"), it has not been used. Delete __sbitmap_queue_get_shallow() and rename public __sbitmap_queue_get_shallow() -> sbitmap_queue_get_shallow() as it is odd to have public __foo but no foo at all. Signed-off-by:
John Garry <john.garry@huawei.com> Link: https://lore.kernel.org/r/1644322024-105340-1-git-send-email-john.garry@huawei.com Signed-off-by:
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Ming Lei authored
Only the last sbitmap_word can have different depth, and all the others must have same depth of 1U << sb->shift, so not necessary to store it in sbitmap_word, and it can be retrieved easily and efficiently by adding one internal helper of __map_depth(sb, index). Remove 'depth' field from sbitmap_word, then the annotation of ____cacheline_aligned_in_smp for 'word' isn't needed any more. Not see performance effect when running high parallel IOPS test on null_blk. This way saves us one cacheline(usually 64 words) per each sbitmap_word. Cc: Martin Wilck <martin.wilck@suse.com> Signed-off-by:
Martin Wilck <mwilck@suse.com> Reviewed-by:
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