Peter Zijlstra
eabe06595d
block/mq: Cure cpu hotplug lock inversion
By poking at /debug/sched_features I triggered the following splat:
[] ======================================================
[] WARNING: possible circular locking dependency detected
[] 4.11.0-00873-g964c8b7-dirty #694 Not tainted
[] ------------------------------------------------------
[] bash/2109 is trying to acquire lock:
[] (cpu_hotplug_lock.rw_sem){++++++}, at: [<ffffffff8120cb8b>] static_key_slow_dec+0x1b/0x50
[]
[] but task is already holding lock:
[] (&sb->s_type->i_mutex_key#4){+++++.}, at: [<ffffffff81140216>] sched_feat_write+0x86/0x170
[]
[] which lock already depends on the new lock.
[]
[]
[] the existing dependency chain (in reverse order) is:
[]
[] -> #2 (&sb->s_type->i_mutex_key#4){+++++.}:
[] lock_acquire+0x100/0x210
[] down_write+0x28/0x60
[] start_creating+0x5e/0xf0
[] debugfs_create_dir+0x13/0x110
[] blk_mq_debugfs_register+0x21/0x70
[] blk_mq_register_dev+0x64/0xd0
[] blk_register_queue+0x6a/0x170
[] device_add_disk+0x22d/0x440
[] loop_add+0x1f3/0x280
[] loop_init+0x104/0x142
[] do_one_initcall+0x43/0x180
[] kernel_init_freeable+0x1de/0x266
[] kernel_init+0xe/0x100
[] ret_from_fork+0x31/0x40
[]
[] -> #1 (all_q_mutex){+.+.+.}:
[] lock_acquire+0x100/0x210
[] __mutex_lock+0x6c/0x960
[] mutex_lock_nested+0x1b/0x20
[] blk_mq_init_allocated_queue+0x37c/0x4e0
[] blk_mq_init_queue+0x3a/0x60
[] loop_add+0xe5/0x280
[] loop_init+0x104/0x142
[] do_one_initcall+0x43/0x180
[] kernel_init_freeable+0x1de/0x266
[] kernel_init+0xe/0x100
[] ret_from_fork+0x31/0x40
[] *** DEADLOCK ***
[]
[] 3 locks held by bash/2109:
[] #0: (sb_writers#11){.+.+.+}, at: [<ffffffff81292bcd>] vfs_write+0x17d/0x1a0
[] #1: (debugfs_srcu){......}, at: [<ffffffff8155a90d>] full_proxy_write+0x5d/0xd0
[] #2: (&sb->s_type->i_mutex_key#4){+++++.}, at: [<ffffffff81140216>] sched_feat_write+0x86/0x170
[]
[] stack backtrace:
[] CPU: 9 PID: 2109 Comm: bash Not tainted 4.11.0-00873-g964c8b7-dirty #694
[] Hardware name: Intel Corporation S2600GZ/S2600GZ, BIOS SE5C600.86B.02.02.0002.122320131210 12/23/2013
[] Call Trace:
[] lock_acquire+0x100/0x210
[] get_online_cpus+0x2a/0x90
[] static_key_slow_dec+0x1b/0x50
[] static_key_disable+0x20/0x30
[] sched_feat_write+0x131/0x170
[] full_proxy_write+0x97/0xd0
[] __vfs_write+0x28/0x120
[] vfs_write+0xb5/0x1a0
[] SyS_write+0x49/0xa0
[] entry_SYSCALL_64_fastpath+0x23/0xc2
This is because of the cpu hotplug lock rework. Break the chain at #1
by reversing the lock acquisition order. This way i_mutex_key#4 no
longer depends on cpu_hotplug_lock and things are good.
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
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2017-05-04 07:57:13 -06:00 |
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partitions
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badblocks.c
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bfq-cgroup.c
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block, bfq: split bfq-iosched.c into multiple source files
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2017-04-19 08:48:24 -06:00 |
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bfq-iosched.c
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block, bfq: don't dereference bic before null checking it
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2017-04-20 08:19:23 -06:00 |
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bfq-iosched.h
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bfq: fix compile error if CONFIG_CGROUPS=n
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2017-04-20 09:39:12 -06:00 |
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bfq-wf2q.c
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block, bfq: split bfq-iosched.c into multiple source files
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2017-04-19 08:48:24 -06:00 |
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bio-integrity.c
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bio.c
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block: trace completion of all bios.
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2017-04-07 09:40:52 -06:00 |
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blk-cgroup.c
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blkcg: allocate struct blkcg_gq outside request queue spinlock
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2017-03-29 11:27:19 -06:00 |
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blk-core.c
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blk-mq: unify hctx delay_work and run_work
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2017-04-28 08:11:43 -06:00 |
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blk-exec.c
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block: remove the errors field from struct request
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2017-04-20 12:16:10 -06:00 |
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blk-flush.c
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block: make __blk_end_bidi_request private
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2017-04-19 10:19:47 -06:00 |
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blk-integrity.c
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block: fix blk_integrity_register to use template's interval_exp if not 0
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2017-04-23 12:59:56 -06:00 |
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blk-ioc.c
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Merge branch 'for-linus' of git://git.kernel.dk/linux-block
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2017-03-03 10:53:35 -08:00 |
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blk-lib.c
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block: remove the discard_zeroes_data flag
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2017-04-08 11:25:38 -06:00 |
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blk-map.c
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sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h>
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2017-03-02 08:42:36 +01:00 |
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blk-merge.c
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block: implement splitting of REQ_OP_WRITE_ZEROES bios
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2017-04-08 11:25:38 -06:00 |
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blk-mq-cpumap.c
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blk-mq-debugfs.c
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blk-mq: Add blk_mq_ops.show_rq()
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2017-04-26 15:09:04 -06:00 |
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blk-mq-pci.c
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blk-mq-pci: Fix two spelling mistakes
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2017-03-29 11:09:51 -06:00 |
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blk-mq-sched.c
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blk-mq-sched: remove hack that bypasses scheduler for reserved requests
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2017-05-02 07:52:08 -06:00 |
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blk-mq-sched.h
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blk-mq: Remove blk_mq_sched_move_to_dispatch()
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2017-04-20 17:28:30 -06:00 |
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blk-mq-sysfs.c
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blk-mq: Only unregister hctxs for which registration succeeded
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2017-04-26 15:09:04 -06:00 |
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blk-mq-tag.c
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blk-mq: add shallow depth option for blk_mq_get_tag()
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2017-04-14 14:06:54 -06:00 |
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blk-mq-tag.h
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blk-mq-sched: Allocate sched reserved tags as specified in the original queue tagset
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2017-03-02 08:56:04 -07:00 |
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blk-mq-virtio.c
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blk-mq: provide a default queue mapping for virtio device
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2017-02-27 20:54:05 +02:00 |
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blk-mq.c
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block/mq: Cure cpu hotplug lock inversion
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2017-05-04 07:57:13 -06:00 |
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blk-mq.h
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blk-mq-debugfs: Rename functions for registering and unregistering the mq directory
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2017-04-26 15:09:04 -06:00 |
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blk-settings.c
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block: remove the discard_zeroes_data flag
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2017-04-08 11:25:38 -06:00 |
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blk-softirq.c
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sched/headers: Prepare for new header dependencies before moving code to <linux/sched/topology.h>
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2017-03-02 08:42:26 +01:00 |
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blk-stat.c
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blk-stat: kill blk_stat_rq_ddir()
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2017-04-21 07:56:23 -06:00 |
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blk-stat.h
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blk-stat: kill blk_stat_rq_ddir()
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2017-04-21 07:56:23 -06:00 |
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blk-sysfs.c
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blk-mq: Register <dev>/queue/mq after having registered <dev>/queue
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2017-04-26 15:09:04 -06:00 |
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blk-tag.c
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blk-throttle.c
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blk-throttle: fix unused variable warning with BLK_DEV_THROTTLING_LOW=n
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2017-04-20 09:41:36 -06:00 |
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blk-timeout.c
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block: remove the errors field from struct request
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2017-04-20 12:16:10 -06:00 |
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blk-wbt.c
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blk-stat: kill blk_stat_rq_ddir()
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2017-04-21 07:56:23 -06:00 |
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blk-wbt.h
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block: Make writeback throttling defaults consistent for SQ devices
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2017-04-19 08:49:03 -06:00 |
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blk-zoned.c
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blk.h
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block: Export blk_init_request_from_bio()
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2017-04-19 17:38:30 -06:00 |
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bounce.c
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bsg-lib.c
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scsi: introduce a result field in struct scsi_request
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2017-04-20 12:16:10 -06:00 |
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bsg.c
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scsi: introduce a result field in struct scsi_request
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2017-04-20 12:16:10 -06:00 |
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cfq-iosched.c
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cfq: Disable writeback throttling by default
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2017-04-05 08:15:08 -06:00 |
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cmdline-parser.c
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compat_ioctl.c
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block: remove the discard_zeroes_data flag
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2017-04-08 11:25:38 -06:00 |
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deadline-iosched.c
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elevator.c
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block: don't call blk_mq_quiesce_queue() after queue is frozen
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2017-05-02 11:33:08 -06:00 |
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genhd.c
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block: hide badblocks attribute by default
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2017-04-28 08:26:42 -06:00 |
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ioctl.c
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block: remove the discard_zeroes_data flag
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2017-04-08 11:25:38 -06:00 |
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ioprio.c
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block: Optimize ioprio_best()
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2017-04-19 17:38:36 -06:00 |
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Kconfig
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blk-throttle: add configure option for new .low interface
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2017-03-28 08:02:20 -06:00 |
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Kconfig.iosched
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block, bfq: add full hierarchical scheduling and cgroups support
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2017-04-19 08:30:26 -06:00 |
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kyber-iosched.c
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blk-stat: convert blk-stat bucket callback to signed
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2017-04-20 15:29:16 -06:00 |
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Makefile
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block, bfq: split bfq-iosched.c into multiple source files
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2017-04-19 08:48:24 -06:00 |
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mq-deadline.c
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noop-iosched.c
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opal_proto.h
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partition-generic.c
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block: get rid of blk_integrity_revalidate()
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2017-04-21 14:17:27 -06:00 |
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scsi_ioctl.c
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scsi: introduce a result field in struct scsi_request
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2017-04-20 12:16:10 -06:00 |
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sed-opal.c
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block: sed-opal: Tone down all the pr_* to debugs
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2017-04-07 14:24:16 -06:00 |
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t10-pi.c
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block: constify struct blk_integrity_profile
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2017-03-24 20:34:39 -06:00 |