Re: [PATCH 5/6] iomap: fix WARN_ON_ONCE on uninitialized variable

[Allison Henderson <allison.henderson@oracle.com>]

On 08/11/2018 08:35 AM, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> In commit 9dc55f1389f9569 ("iomap: add support for sub-pagesize buffered
> I/O without buffer heads") we moved the initialization of poff (it's
> computed from pos) into a separate helper function.  Inline data only
> ever deals with pos == 0, hence the WARN_ON_ONCE, but now we're testing
> an uninitialized variable.
> 
> Therefore, change the test to check the parameter directly.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
>   fs/iomap.c |    2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> 
> diff --git a/fs/iomap.c b/fs/iomap.c
> index 8bd54c08deee..8a18163dc432 100644
> --- a/fs/iomap.c
> +++ b/fs/iomap.c
> @@ -290,7 +290,7 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
>   	sector_t sector;
>   
>   	if (iomap->type == IOMAP_INLINE) {
> -		WARN_ON_ONCE(poff);
> +		WARN_ON_ONCE(pos);
>   		iomap_read_inline_data(inode, page, iomap);
>   		return PAGE_SIZE;
>   	}
> 
Ok, looks good.
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>