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

[Carlos Maiolino <cmaiolino@redhat.com>]

On Sat, Aug 11, 2018 at 08:35:28AM -0700, 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>
> ---

Reviewed-by: Carlos Maiolino <cmaiolino@redhat.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;
>  	}
> 

-- 
Carlos