Re: [Devel] [PATCH hci-8.1 v4 02/11] dm-ploop: fix lost wakeup in ploop_allocator()

[no-reply@sashiko.virtuozzo.com]

> ploop_allocator() checks prealloc_size and kthread_should_stop() before
> setting TASK_INTERRUPTIBLE. If ploop_req_prealloc() sets prealloc_size
> and calls wake_up_process() in between, the wakeup finds the task
> running and is lost, so the allocator goes to sleep with a pending
> preallocation request. Later requests for the same size return early
> without waking it up, so the request may stay pending forever and
> waiters on dispatcher_wq_prealloc hang. The same applies to
> kthread_stop().
> 
> Set the task state before checking the conditions, as the canonical
> kthread loop does. set_current_state() implies a full barrier, which
> pairs with the one in try_to_wake_up().
> 
> https://virtuozzo.atlassian.net/browse/VSTOR-148171
> Feature: dm-ploop: ploop target driver
> 
> Signed-off-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.vzint.dev/#/patchset/20261012132646.41494-1-alexander.ivanov@virtuozzo.com?part=2


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