Re: [PATCH 3/9] block: factor out a bd_end_claim helper from blkdev_put

Jan Kara
2023-05-08T13:01:40Z

On Fri 05-05-23 13:51:26, Christoph Hellwig wrote:
> Move all the logic to release an exclusive claim into a helper.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Nice. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

Honza

> ---
> block/bdev.c | 63 +++++++++++++++++++++++++++-------------------------
> 1 file changed, 33 insertions(+), 30 deletions(-)
>
> diff --git a/block/bdev.c b/block/bdev.c
> index 850852fe4b78e1..f2c7181b0bba7d 100644
> --- a/block/bdev.c
> +++ b/block/bdev.c
> @@ -578,6 +578,37 @@ void bd_abort_claiming(struct block_device *bdev, void *holder)
> }
> EXPORT_SYMBOL(bd_abort_claiming);
>
> +static void bd_end_claim(struct block_device *bdev)
> +{
> + struct block_device *whole = bdev_whole(bdev);
> + bool unblock = false;
> +
> + /*
> + * Release a claim on the device. The holder fields are protected with
> + * bdev_lock. open_mutex is used to synchronize disk_holder unlinking.
> + */
> + spin_lock(&bdev_lock);
> + WARN_ON_ONCE(--bdev->bd_holders < 0);
> + WARN_ON_ONCE(--whole->bd_holders < 0);
> + if (!bdev->bd_holders) {
> + bdev->bd_holder = NULL;
> + if (bdev->bd_write_holder)
> + unblock = true;
> + }
> + if (!whole->bd_holders)
> + whole->bd_holder = NULL;
> + spin_unlock(&bdev_lock);
> +
> + /*
> + * If this was the last claim, remove holder link and unblock evpoll if
> + * it was a write holder.
> + */
> + if (unblock) {
> + disk_unblock_events(bdev->bd_disk);
> + bdev->bd_write_holder = false;
> + }
> +}
> +
> static void blkdev_flush_mapping(struct block_device *bdev)
> {
> WARN_ON_ONCE(bdev->bd_holders);
> @@ -832,36 +863,8 @@ void blkdev_put(struct block_device *bdev, fmode_t mode)
> sync_blockdev(bdev);
>
> mutex_lock(&disk->open_mutex);
> - if (mode & FMODE_EXCL) {
> - struct block_device *whole = bdev_whole(bdev);
> - bool bdev_free;
> -
> - /*
> - * Release a claim on the device. The holder fields
> - * are protected with bdev_lock. open_mutex is to
> - * synchronize disk_holder unlinking.
> - */
> - spin_lock(&bdev_lock);
> -
> - WARN_ON_ONCE(--bdev->bd_holders < 0);
> - WARN_ON_ONCE(--whole->bd_holders < 0);
> -
> - if ((bdev_free = !bdev->bd_holders))
> - bdev->bd_holder = NULL;
> - if (!whole->bd_holders)
> - whole->bd_holder = NULL;
> -
> - spin_unlock(&bdev_lock);
> -
> - /*
> - * If this was the last claim, remove holder link and
> - * unblock evpoll if it was a write holder.
> - */
> - if (bdev_free && bdev->bd_write_holder) {
> - disk_unblock_events(disk);
> - bdev->bd_write_holder = false;
> - }
> - }
> + if (mode & FMODE_EXCL)
> + bd_end_claim(bdev);
>
> /*
> * Trigger event checking and tell drivers to flush MEDIA_CHANGE
> --
> 2.39.2
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR