Re: [PATCH] hugetlbfs: fix an NULL vs IS_ERR() bug

[Sidhartha Kumar <sidhartha.kumar@oracle.com>]

On 9/27/23 10:17 PM, Dan Carpenter wrote:
> This code was converted from using find_lock_page() which returns NULL,
> to calling filemap_lock_hugetlb_folio() which returns -ENOENT.  The
> check needs to be updated to match.  Also IS_ERR() has an unlikely()
> built in so we can remove that.
> 
> Fixes: 4649d8d5bb81 ("mm/filemap: remove hugetlb special casing in filemap.c")
> Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
> ---
> filemap_lock_hugetlb_folio() can return NULL if huge tables are disabled
> but that isn't the case here so there is no need to check for that.
> 
>   fs/hugetlbfs/inode.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
> index 3f2f0a4bfad0..91034b6e5b69 100644
> --- a/fs/hugetlbfs/inode.c
> +++ b/fs/hugetlbfs/inode.c
> @@ -354,7 +354,7 @@ static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
>   
>   		/* Find the folio */
>   		folio = filemap_lock_hugetlb_folio(h, mapping, index);
> -		if (unlikely(folio == NULL)) {
> +		if (IS_ERR(folio)) {
>   			/*
>   			 * We have a HOLE, zero out the user-buffer for the
>   			 * length of the hole or request.
Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>