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blktrace: switch trace spinlock to a raw spinlock

Wander Lairson Costa requested to merge walac/centos-stream-9:bz1938117-smp-processor-id into main

Bugzilla: http://bugzilla.redhat.com/1905749

commit 361c81dbc58c8aa230e1f2d556045fa7bc3eb4a3 Author: Wander Lairson Costa wander@redhat.com Date: Mon Dec 20 16:28:27 2021 -0300

blktrace: switch trace spinlock to a raw spinlock

The running_trace_lock protects running_trace_list and is acquired
within the tracepoint which implies disabled preemption. The spinlock_t
typed lock can not be acquired with disabled preemption on PREEMPT_RT
because it becomes a sleeping lock.
The runtime of the tracepoint depends on the number of entries in
running_trace_list and has no limit. The blk-tracer is considered debug
code and higher latencies here are okay.

Make running_trace_lock a raw_spinlock_t.

Signed-off-by: Wander Lairson Costa <wander@redhat.com>
Link: https://lore.kernel.org/r/20211220192827.38297-1-wander@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Signed-off-by: Wander Lairson Costa wander@redhat.com

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