On 07/14/2017 02:41 AM, Ming Lei wrote:
> From: Ming Lei <[email protected]>
>
> When blk_mq_get_request() failed, preempt counter isn't
> released, and blk_mq_make_request() doesn't release the counter
> too.
>
> This patch fixes the issue, and makes sure that preempt counter
> is only held if rq is allocated successfully. The same policy is
> applied on .q_usage_counter too.
Can you replace the 'get_cpu' bool with just a ctx, and change
the logic to put it if set? I think that would be cleaner to read,
generally I hate bool 'do_something' variables that are set. It's
much cleaner to have:
if (likely(!data->ctx))
data->ctx = local_ctx = blk_mq_get_ctx(q);
and have the put case be
if (local_ctx)
blk_mq_put_ctx(local_ctx);
Either that, or at least just have blk_mq_get_request() do:
drop_ctx = data->ctx == NULL;
instead. The 'get_cpu' naming is confusing, we're worried about dropping
the sw queue here, the fact that it's related to get/put_cpu() need not
bubble up here.
--
Jens Axboe
