Re: [PATCH] block: Fix default IO priority if there is no IO context

[Yu Kuai <yukuai1@huaweicloud.com>]

在 2025/07/31 12:49, Guenter Roeck 写道:
> Upstream commit 53889bcaf536 ("block: make __get_task_ioprio() easier to
> read") changes the IO priority returned to the caller if no IO context
> is defined for the task. Prior to this commit, the returned IO priority
> was determined by task_nice_ioclass() and task_nice_ioprio(). Now it is
> always IOPRIO_DEFAULT, which translates to IOPRIO_CLASS_NONE with priority
> 0. However, task_nice_ioclass() returns IOPRIO_CLASS_IDLE, IOPRIO_CLASS_RT,
> or IOPRIO_CLASS_BE depending on the task scheduling policy, and
> task_nice_ioprio() returns a value determined by task_nice(). This causes
> regressions in test code checking the IO priority and class of IO
> operations on tasks with no IO context.
> 
> Fix the problem by returning the IO priority calculated from
> task_nice_ioclass() and task_nice_ioprio() if no IO context is defined
> to match earlier behavior.
> 
> Fixes: 53889bcaf536 ("block: make __get_task_ioprio() easier to read")
> Cc: Jens Axboe <axboe@kernel.dk>
> Cc: Bart Van Assche <bvanassche@acm.org>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> ---
>   include/linux/ioprio.h | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
LGTM
Reviewed-by: Yu Kuai <yukuai3@huawei.com>

Thanks