diff options
| author | Bart Van Assche <bart.vanassche@wdc.com> | 2018-03-19 11:46:13 -0700 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2018-03-19 12:50:10 -0600 |
| commit | 818e0fa293ca836eba515615c64680ea916fd7cd (patch) | |
| tree | e3f01a690b1d58a1e316b9f7588c04a43a9a972c /lib/devres.c | |
| parent | 5f2b18ec8e1643410a2369f06888951cdedea0bf (diff) | |
block: Change a rcu_read_{lock,unlock}_sched() pair into rcu_read_{lock,unlock}()
scsi_device_quiesce() uses synchronize_rcu() to guarantee that the
effect of blk_set_preempt_only() will be visible for percpu_ref_tryget()
calls that occur after the queue unfreeze by using the approach
explained in https://lwn.net/Articles/573497/. The rcu read lock and
unlock calls in blk_queue_enter() form a pair with the synchronize_rcu()
call in scsi_device_quiesce(). Both scsi_device_quiesce() and
blk_queue_enter() must either use regular RCU or RCU-sched.
Since neither the RCU-protected code in blk_queue_enter() nor
blk_queue_usage_counter_release() sleeps, regular RCU protection
is sufficient. Note: scsi_device_quiesce() does not have to be
modified since it already uses synchronize_rcu().
Reported-by: Tejun Heo <tj@kernel.org>
Fixes: 3a0a529971ec ("block, scsi: Make SCSI quiesce and resume work reliably")
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Oleksandr Natalenko <oleksandr@natalenko.name>
Cc: Martin Steigerwald <martin@lichtvoll.de>
Cc: stable@vger.kernel.org # v4.15
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'lib/devres.c')
0 files changed, 0 insertions, 0 deletions