Re: [PATCH -next 3/5] blk-iocost: prevent configuration update concurrent with io throttling

From: Tejun Heo
Date: Tue Oct 11 2022 - 13:03:22 EST

On Tue, Oct 11, 2022 at 04:35:45PM +0800, Yu Kuai wrote:
> From: Yu Kuai <yukuai3@xxxxxxxxxx>
> This won't cause any severe problem currently, however, this doesn't
> seems appropriate:
> 1) 'ioc->params' is read from multiple places without holding
> 'ioc->lock', unexpected value might be read if writing it concurrently.
> 2) If configuration is changed while io is throttling, the functionality
> might be affected. For example, if module params is updated and cost
> becomes smaller, waiting for timer that is caculated under old
> configuration is not appropriate.
> Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>

Acked-by: Tejun Heo <tj@xxxxxxxxxx>