From: Boris Brezillon <boris.brezillon@free-electrons.com>
To: zengzhaoxiu@163.com
Cc: kgene@kernel.org, k.kozlowski@samsung.com, richard@nod.at,
dwmw2@infradead.org, computersforpeace@gmail.com,
linux-arm-kernel@lists.infradead.org,
linux-samsung-soc@vger.kernel.org, linux-mtd@lists.infradead.org,
linux-kernel@vger.kernel.org,
Zhaoxiu Zeng <zhaoxiu.zeng@gmail.com>
Subject: Re: [PATCH] mtd: nand: s3c2410: fix bug in s3c2410_nand_correct_data()
Date: Tue, 12 Apr 2016 13:34:24 +0200 [thread overview]
Message-ID: <20160412133424.6ac1193e@bbrezillon> (raw)
In-Reply-To: <1460446235-987-1-git-send-email-zengzhaoxiu@163.com>
On Tue, 12 Apr 2016 15:30:35 +0800
zengzhaoxiu@163.com wrote:
> From: Zhaoxiu Zeng <zhaoxiu.zeng@gmail.com>
>
> If there is only one bit difference in the ECC, the function should return 1.
> The result of "diff0 & ~(1<<fls(diff0))" is equal to diff0, so the function
> actually returns -1.
>
> Signed-off-by: Zhaoxiu Zeng <zhaoxiu.zeng@gmail.com>
Applied.
Thanks,
Boris
> ---
> drivers/mtd/nand/s3c2410.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mtd/nand/s3c2410.c b/drivers/mtd/nand/s3c2410.c
> index 9c9397b..86ffb73 100644
> --- a/drivers/mtd/nand/s3c2410.c
> +++ b/drivers/mtd/nand/s3c2410.c
> @@ -542,7 +542,8 @@ static int s3c2410_nand_correct_data(struct mtd_info *mtd, u_char *dat,
> diff0 |= (diff1 << 8);
> diff0 |= (diff2 << 16);
>
> - if ((diff0 & ~(1<<fls(diff0))) == 0)
> + /* equal to "(diff0 & ~(1 << __ffs(diff0)))" */
> + if ((diff0 & (diff0 - 1)) == 0)
> return 1;
>
> return -1;
--
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
WARNING: multiple messages have this Message-ID (diff)
From: boris.brezillon@free-electrons.com (Boris Brezillon)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] mtd: nand: s3c2410: fix bug in s3c2410_nand_correct_data()
Date: Tue, 12 Apr 2016 13:34:24 +0200 [thread overview]
Message-ID: <20160412133424.6ac1193e@bbrezillon> (raw)
In-Reply-To: <1460446235-987-1-git-send-email-zengzhaoxiu@163.com>
On Tue, 12 Apr 2016 15:30:35 +0800
zengzhaoxiu at 163.com wrote:
> From: Zhaoxiu Zeng <zhaoxiu.zeng@gmail.com>
>
> If there is only one bit difference in the ECC, the function should return 1.
> The result of "diff0 & ~(1<<fls(diff0))" is equal to diff0, so the function
> actually returns -1.
>
> Signed-off-by: Zhaoxiu Zeng <zhaoxiu.zeng@gmail.com>
Applied.
Thanks,
Boris
> ---
> drivers/mtd/nand/s3c2410.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mtd/nand/s3c2410.c b/drivers/mtd/nand/s3c2410.c
> index 9c9397b..86ffb73 100644
> --- a/drivers/mtd/nand/s3c2410.c
> +++ b/drivers/mtd/nand/s3c2410.c
> @@ -542,7 +542,8 @@ static int s3c2410_nand_correct_data(struct mtd_info *mtd, u_char *dat,
> diff0 |= (diff1 << 8);
> diff0 |= (diff2 << 16);
>
> - if ((diff0 & ~(1<<fls(diff0))) == 0)
> + /* equal to "(diff0 & ~(1 << __ffs(diff0)))" */
> + if ((diff0 & (diff0 - 1)) == 0)
> return 1;
>
> return -1;
--
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
next prev parent reply other threads:[~2016-04-12 11:34 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-07 16:48 [PATCH] mtd: nand: s3c2410: fix bug in s3c2410_nand_correct_data() zengzhaoxiu
2016-04-07 16:48 ` zengzhaoxiu at 163.com
2016-04-08 0:18 ` Boris Brezillon
2016-04-08 0:18 ` Boris Brezillon
2016-04-08 1:51 ` Zeng Zhaoxiu
2016-04-08 1:51 ` Zeng Zhaoxiu
2016-04-08 2:18 ` Boris Brezillon
2016-04-08 2:18 ` Boris Brezillon
2016-04-08 5:37 ` Zeng Zhaoxiu
2016-04-08 5:37 ` Zeng Zhaoxiu
2016-04-11 7:49 ` Boris Brezillon
2016-04-11 7:49 ` Boris Brezillon
2016-04-12 7:30 ` zengzhaoxiu
2016-04-12 7:30 ` zengzhaoxiu at 163.com
2016-04-12 11:34 ` Boris Brezillon [this message]
2016-04-12 11:34 ` Boris Brezillon
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