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SubjectRe: [PATCH] nftl: fix offset alignments
"Andrew Morton" <akpm@linux-foundation.org> a écrit :
> On Wed, 19 Aug 2009 00:06:28 +0200 (CEST) dimitri.gorokhovik@free.fr
> wrote:
> ...
> > + typeof(offs) mask = mtd->writesize - 1;
>
> I see no reason to use typeof here. Plain old
>
> loff_t mask = mtd->writesize - 1;
>
> would be more conventional.

I use typeoff in this way to guard masking code against absent-minded
modifications.

Attached is a corrected version as suggested.

Maybe Julia can come up with a clever rule for detecting unusual masking
operations automatically :-) ?

---
From: Dimitri Gorokhovik <dimitri.gorokhovik@free.fr>
Subject: nftl: fix offset alignments

Arithmetic conversion in the mask computation makes the upper word
of the second argument passed down to mtd->read_oob(), be always 0
(assuming 'offs' being a 64-bit signed long long type, and
'mtd->writesize' being a 32-bit unsigned int type).

This patch applies over the other one adding masking in nftl_write,
"nftl: write support is broken".

Signed-off-by: Dimitri Gorokhovik <dimitri.gorokhovik@free.fr>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Tim Gardner <tim.gardner@canonical.com>
Cc: Scott James Remnant <scott@canonical.com>
---
drivers/mtd/nftlcore.c | 15 +++++++++------
1 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/mtd/nftlcore.c b/drivers/mtd/nftlcore.c
index 665d3eb..1002e18 100644
--- a/drivers/mtd/nftlcore.c
+++ b/drivers/mtd/nftlcore.c
@@ -135,16 +135,17 @@ static void nftl_remove_dev(struct mtd_blktrans_dev *dev)
int nftl_read_oob(struct mtd_info *mtd, loff_t offs, size_t len,
size_t *retlen, uint8_t *buf)
{
+ loff_t mask = mtd->writesize - 1;
struct mtd_oob_ops ops;
int res;

ops.mode = MTD_OOB_PLACE;
- ops.ooboffs = offs & (mtd->writesize - 1);
+ ops.ooboffs = offs & mask;
ops.ooblen = len;
ops.oobbuf = buf;
ops.datbuf = NULL;

- res = mtd->read_oob(mtd, offs & ~(mtd->writesize - 1), &ops);
+ res = mtd->read_oob(mtd, offs & ~mask, &ops);
*retlen = ops.oobretlen;
return res;
}
@@ -155,16 +156,17 @@ int nftl_read_oob(struct mtd_info *mtd, loff_t offs, size_t len,
int nftl_write_oob(struct mtd_info *mtd, loff_t offs, size_t len,
size_t *retlen, uint8_t *buf)
{
+ loff_t mask = mtd->writesize - 1;
struct mtd_oob_ops ops;
int res;

ops.mode = MTD_OOB_PLACE;
- ops.ooboffs = offs & (mtd->writesize - 1);
+ ops.ooboffs = offs & mask;
ops.ooblen = len;
ops.oobbuf = buf;
ops.datbuf = NULL;

- res = mtd->write_oob(mtd, offs & ~(mtd->writesize - 1), &ops);
+ res = mtd->write_oob(mtd, offs & ~mask, &ops);
*retlen = ops.oobretlen;
return res;
}
@@ -177,17 +179,18 @@ int nftl_write_oob(struct mtd_info *mtd, loff_t offs, size_t len,
static int nftl_write(struct mtd_info *mtd, loff_t offs, size_t len,
size_t *retlen, uint8_t *buf, uint8_t *oob)
{
+ loff_t mask = mtd->writesize - 1;
struct mtd_oob_ops ops;
int res;

ops.mode = MTD_OOB_PLACE;
- ops.ooboffs = offs & (mtd->writesize - 1);
+ ops.ooboffs = offs & mask;
ops.ooblen = mtd->oobsize;
ops.oobbuf = oob;
ops.datbuf = buf;
ops.len = len;

- res = mtd->write_oob(mtd, offs & ~(mtd->writesize - 1), &ops);
+ res = mtd->write_oob(mtd, offs & ~mask, &ops);
*retlen = ops.retlen;
return res;
}
--
1.6.3.3
--
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