Re: [PATCH 16/45] block: switch bdgrab to use igrab

Hannes Reinecke
2020-11-30T07:15:20Z

On 11/28/20 5:14 PM, Christoph Hellwig wrote:
> All of the current callers already have a reference, but to prepare for
> additional users ensure bdgrab returns NULL if the block device is beeing
> freed.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> fs/block_dev.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/fs/block_dev.c b/fs/block_dev.c
> index d707ab376da86e..962fabe8a67b83 100644
> --- a/fs/block_dev.c
> +++ b/fs/block_dev.c
> @@ -894,10 +894,14 @@ static struct block_device *bdget(dev_t dev)
> /**
> * bdgrab -- Grab a reference to an already referenced block device
> * @bdev: Block device to grab a reference to.
> + *
> + * Returns the block_device with an additional reference when successful,
> + * or NULL if the inode is already beeing freed.
> */
> struct block_device *bdgrab(struct block_device *bdev)
> {
> - ihold(bdev->bd_inode);
> + if (!igrab(bdev->bd_inode))
> + return NULL;
> return bdev;
> }
> EXPORT_SYMBOL(bdgrab);
>
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
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