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From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Shawn Lin <shawn.lin@rock-chips.com>
Cc: Minchan Kim <minchan@kernel.org>, Nitin Gupta <ngupta@vflare.org>,
	Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
	linux-kernel@vger.kernel.org,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] zram: clean up valid_io_request
Date: Thu, 18 Aug 2016 12:25:11 +0900	[thread overview]
Message-ID: <20160818032511.GE500@swordfish> (raw)
In-Reply-To: <1471489681-4027-1-git-send-email-shawn.lin@rock-chips.com>

Hi,

On (08/18/16 11:08), Shawn Lin wrote:
[..]
> diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
> index 04365b1..1094e95 100644
> --- a/drivers/block/zram/zram_drv.c
> +++ b/drivers/block/zram/zram_drv.c
> @@ -120,15 +120,15 @@ static inline bool valid_io_request(struct zram *zram,
>  	u64 end, bound;
>  
>  	/* unaligned request */
> -	if (unlikely(start & (ZRAM_SECTOR_PER_LOGICAL_BLOCK - 1)))
> +	if (unlikely(!IS_ALIGNED(start, ZRAM_SECTOR_PER_LOGICAL_BLOCK)))
>  		return false;
> -	if (unlikely(size & (ZRAM_LOGICAL_BLOCK_SIZE - 1)))
> +	if (unlikely(!IS_ALIGNED(size, ZRAM_LOGICAL_BLOCK_SIZE)))
>  		return false;

ok.

>  	end = start + (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))
>  		return false;

why did you drop `start > end'? what if `start + (size >> SECTOR_SHIFT)'
overflows and `start' becomes greater than `end'?

	-ss

      reply	other threads:[~2016-08-18  3:25 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-18  3:08 [PATCH] zram: clean up valid_io_request Shawn Lin
2016-08-18  3:25 ` Sergey Senozhatsky [this message]

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