ACK: [Precise][SRU] zram: allow request end to coincide with disksize

[Steve Conklin]

On 11/04/2013 04:12 AM, Luis Henriques wrote:
> From: Sergey Senozhatsky <sergey.senozhatsky at gmail.com>
> 
> BugLink: http://bugs.launchpad.net/bugs/1246664
> 
> Pass valid_io_request() checks if request end coincides with disksize
> (end equals bound), only fail if we attempt to read beyond the bound.
> 
> mkfs.ext2 produces numerous errors:
> [ 2164.632747] quiet_error: 1 callbacks suppressed
> [ 2164.633260] Buffer I/O error on device zram0, logical block 153599
> [ 2164.633265] lost page write due to I/O error on zram0
> 
> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky at gmail.com>
> Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
> (back ported from commit 75c7caf5a052ffd8db3312fa7864ee2d142890c4)
> Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
> ---
>  drivers/staging/zram/zram_drv.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c
> index d197b3e..e1a4994 100644
> --- a/drivers/staging/zram/zram_drv.c
> +++ b/drivers/staging/zram/zram_drv.c
> @@ -553,7 +553,7 @@ static inline int valid_io_request(struct zram *zram, struct bio *bio)
>  	end = start + (bio->bi_size >> SECTOR_SHIFT);
>  	bound = zram->disksize >> SECTOR_SHIFT;
>  	/* out of range range */
> -	if (unlikely(start >= bound || end >= bound || start > end))
> +	if (unlikely(start >= bound || end > bound || start > end))
>  		return 0;
>  
>  	/* I/O request is valid */
>