On Thu 18-05-23 06:23:13, Christoph Hellwig wrote:
> blk_mark_disk_dead does very similar work a a section of del_gendisk:
>
> - set the GD_DEAD flag
> - set the capacity to zero
> - start a queue drain
>
> but del_gendisk also sets QUEUE_FLAG_DYING on the queue if it is owned by
> the disk, sets the capacity to zero before starting the drain, and both
> with sending a uevent and kernel message for this fake capacity change.
>
> Move the exact logic from the more heavily used del_gendisk into
> blk_mark_disk_dead and then call blk_mark_disk_dead from del_gendisk.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Looks good to me. I've convinced myself the removed notification of device
capacity going to 0 before KOBJ_REMOVE event should not matter to userspace
;). Feel free to add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
> block/genhd.c | 26 ++++++++++++--------------
> 1 file changed, 12 insertions(+), 14 deletions(-)
>
> diff --git a/block/genhd.c b/block/genhd.c
> index 1cb489b927d50a..d8fe40c7d1f0a2 100644
> --- a/block/genhd.c
> +++ b/block/genhd.c
> @@ -572,13 +572,22 @@ EXPORT_SYMBOL(device_add_disk);
> */
> void blk_mark_disk_dead(struct gendisk *disk)
> {
> + /*
> + * Fail any new I/O.
> + */
> set_bit(GD_DEAD, &disk->state);
> - blk_queue_start_drain(disk->queue);
> + if (test_bit(GD_OWNS_QUEUE, &disk->state))
> + blk_queue_flag_set(QUEUE_FLAG_DYING, disk->queue);
>
> /*
> * Stop buffered writers from dirtying pages that can't be written out.
> */
> - set_capacity_and_notify(disk, 0);
> + set_capacity(disk, 0);
> +
> + /*
> + * Prevent new I/O from crossing bio_queue_enter().
> + */
> + blk_queue_start_drain(disk->queue);
> }
> EXPORT_SYMBOL_GPL(blk_mark_disk_dead);
>
> @@ -620,18 +629,7 @@ void del_gendisk(struct gendisk *disk)
> fsync_bdev(disk->part0);
> __invalidate_device(disk->part0, true);
>
> - /*
> - * Fail any new I/O.
> - */
> - set_bit(GD_DEAD, &disk->state);
> - if (test_bit(GD_OWNS_QUEUE, &disk->state))
> - blk_queue_flag_set(QUEUE_FLAG_DYING, q);
> - set_capacity(disk, 0);
> -
> - /*
> - * Prevent new I/O from crossing bio_queue_enter().
> - */
> - blk_queue_start_drain(q);
> + blk_mark_disk_dead(disk);
>
> if (!(disk->flags & GENHD_FL_HIDDEN)) {
> sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi");
> --
> 2.39.2
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
