On Thu, May 01, 2025 at 03:25:01PM +0530, Nilay Shroff wrote:
>
>
> On 4/30/25 10:05 AM, Ming Lei wrote:
> > Move blk_queue_registered() check into elv_iosched_store() and prepare
> > for using elevator_change() for covering any kind of elevator change in
> > adding/deleting disk and updating nr_hw_queue.
> >
> > Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
> > ---
> > block/elevator.c | 8 ++++----
> > 1 file changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/block/elevator.c b/block/elevator.c
> > index df3e59107a2a..ac72c4f5a542 100644
> > --- a/block/elevator.c
> > +++ b/block/elevator.c
> > @@ -676,10 +676,6 @@ int elevator_switch(struct request_queue *q, const char *name)
> > */
> > static int elevator_change(struct request_queue *q, const char *elevator_name)
> > {
> > - /* Make sure queue is not in the middle of being removed */
> > - if (!blk_queue_registered(q))
> > - return -ENOENT;
> > -
> > if (q->elevator && elevator_match(q->elevator->type, elevator_name))
> > return 0;
> >
> > @@ -708,6 +704,10 @@ ssize_t elv_iosched_store(struct gendisk *disk, const char *buf,
> > struct request_queue *q = disk->queue;
> > struct blk_mq_tag_set *set = q->tag_set;
> >
> > + /* Make sure queue is not in the middle of being removed */
> > + if (!blk_queue_registered(q))
> > + return -ENOENT;
> > +
> > /*
> > * If the attribute needs to load a module, do it before freezing the
> > * queue to ensure that the module file can be read when the request
>
> Shouldn't blk_queue_registered needs protection? For instance, I see here a race
I think it isn't needed because both blk_queue_flag_set() and blk_queue_registered()
are atomic operation, and almost all check of blk_queue_registered() isn't
protected too.
thanks,
Ming
