* [PATCH] mtdblock: tolerate corrected bit-flips
@ 2023-03-23 14:03 Bang Li
2023-03-28 12:58 ` Miquel Raynal
0 siblings, 1 reply; 6+ messages in thread
From: Bang Li @ 2023-03-23 14:03 UTC (permalink / raw)
To: miquel.raynal, richard, vigneshr; +Cc: linux-mtd, linux-kernel, Bang Li
mtd_read() may return -EUCLEAN in case of corrected bit-flips.This
particular condition should not be treated like an error.
Signed-off-by: Bang Li <libang.linuxer@gmail.com>
---
drivers/mtd/mtdblock.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/drivers/mtd/mtdblock.c b/drivers/mtd/mtdblock.c
index 1e94e7d10b8b..a0a1194dc1d9 100644
--- a/drivers/mtd/mtdblock.c
+++ b/drivers/mtd/mtdblock.c
@@ -153,7 +153,7 @@ static int do_cached_write (struct mtdblk_dev *mtdblk, unsigned long pos,
mtdblk->cache_state = STATE_EMPTY;
ret = mtd_read(mtd, sect_start, sect_size,
&retlen, mtdblk->cache_data);
- if (ret)
+ if (ret && !mtd_is_bitflip(ret))
return ret;
if (retlen != sect_size)
return -EIO;
@@ -188,8 +188,12 @@ static int do_cached_read (struct mtdblk_dev *mtdblk, unsigned long pos,
pr_debug("mtdblock: read on \"%s\" at 0x%lx, size 0x%x\n",
mtd->name, pos, len);
- if (!sect_size)
- return mtd_read(mtd, pos, len, &retlen, buf);
+ if (!sect_size) {
+ ret = mtd_read(mtd, pos, len, &retlen, buf);
+ if (ret && !mtd_is_bitflip(ret))
+ return ret;
+ return 0;
+ }
while (len > 0) {
unsigned long sect_start = (pos/sect_size)*sect_size;
@@ -209,7 +213,7 @@ static int do_cached_read (struct mtdblk_dev *mtdblk, unsigned long pos,
memcpy (buf, mtdblk->cache_data + offset, size);
} else {
ret = mtd_read(mtd, pos, size, &retlen, buf);
- if (ret)
+ if (ret && !mtd_is_bitflip(ret))
return ret;
if (retlen != size)
return -EIO;
--
2.25.1
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^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] mtdblock: tolerate corrected bit-flips
2023-03-23 14:03 [PATCH] mtdblock: tolerate corrected bit-flips Bang Li
@ 2023-03-28 12:58 ` Miquel Raynal
2023-03-28 13:21 ` Richard Weinberger
0 siblings, 1 reply; 6+ messages in thread
From: Miquel Raynal @ 2023-03-28 12:58 UTC (permalink / raw)
To: Bang Li; +Cc: richard, vigneshr, linux-mtd, linux-kernel
Hello,
libang.linuxer@gmail.com wrote on Thu, 23 Mar 2023 22:03:50 +0800:
> mtd_read() may return -EUCLEAN in case of corrected bit-flips.This
> particular condition should not be treated like an error.
I'm fine with the patch, Richard, are you okay as well?
> Signed-off-by: Bang Li <libang.linuxer@gmail.com>
> ---
> drivers/mtd/mtdblock.c | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mtd/mtdblock.c b/drivers/mtd/mtdblock.c
> index 1e94e7d10b8b..a0a1194dc1d9 100644
> --- a/drivers/mtd/mtdblock.c
> +++ b/drivers/mtd/mtdblock.c
> @@ -153,7 +153,7 @@ static int do_cached_write (struct mtdblk_dev *mtdblk, unsigned long pos,
> mtdblk->cache_state = STATE_EMPTY;
> ret = mtd_read(mtd, sect_start, sect_size,
> &retlen, mtdblk->cache_data);
> - if (ret)
> + if (ret && !mtd_is_bitflip(ret))
> return ret;
> if (retlen != sect_size)
> return -EIO;
> @@ -188,8 +188,12 @@ static int do_cached_read (struct mtdblk_dev *mtdblk, unsigned long pos,
> pr_debug("mtdblock: read on \"%s\" at 0x%lx, size 0x%x\n",
> mtd->name, pos, len);
>
> - if (!sect_size)
> - return mtd_read(mtd, pos, len, &retlen, buf);
> + if (!sect_size) {
> + ret = mtd_read(mtd, pos, len, &retlen, buf);
> + if (ret && !mtd_is_bitflip(ret))
> + return ret;
> + return 0;
> + }
>
> while (len > 0) {
> unsigned long sect_start = (pos/sect_size)*sect_size;
> @@ -209,7 +213,7 @@ static int do_cached_read (struct mtdblk_dev *mtdblk, unsigned long pos,
> memcpy (buf, mtdblk->cache_data + offset, size);
> } else {
> ret = mtd_read(mtd, pos, size, &retlen, buf);
> - if (ret)
> + if (ret && !mtd_is_bitflip(ret))
> return ret;
> if (retlen != size)
> return -EIO;
Thanks,
Miquèl
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http://lists.infradead.org/mailman/listinfo/linux-mtd/
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] mtdblock: tolerate corrected bit-flips
2023-03-28 12:58 ` Miquel Raynal
@ 2023-03-28 13:21 ` Richard Weinberger
2023-03-28 14:00 ` Miquel Raynal
0 siblings, 1 reply; 6+ messages in thread
From: Richard Weinberger @ 2023-03-28 13:21 UTC (permalink / raw)
To: Miquel Raynal; +Cc: Bang Li, Vignesh Raghavendra, linux-mtd, linux-kernel
Hi!
----- Ursprüngliche Mail -----
> libang.linuxer@gmail.com wrote on Thu, 23 Mar 2023 22:03:50 +0800:
>
>> mtd_read() may return -EUCLEAN in case of corrected bit-flips.This
>> particular condition should not be treated like an error.
>
> I'm fine with the patch, Richard, are you okay as well?
Hm yes. I see the bug. I think it broke about 10 years ago
by e47f68587b82 ("mtd: check for max_bitflips in mtd_read_oob()").
In the early day I'd expect someone to hit this bug but I guess
on the last 10 years mtdblock had no real users.
Thanks,
//richard
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] mtdblock: tolerate corrected bit-flips
2023-03-28 13:21 ` Richard Weinberger
@ 2023-03-28 14:00 ` Miquel Raynal
0 siblings, 0 replies; 6+ messages in thread
From: Miquel Raynal @ 2023-03-28 14:00 UTC (permalink / raw)
To: Richard Weinberger; +Cc: Bang Li, Vignesh Raghavendra, linux-mtd, linux-kernel
Hi Richard,
richard@nod.at wrote on Tue, 28 Mar 2023 15:21:50 +0200 (CEST):
> Hi!
>
> ----- Ursprüngliche Mail -----
> > libang.linuxer@gmail.com wrote on Thu, 23 Mar 2023 22:03:50 +0800:
> >
> >> mtd_read() may return -EUCLEAN in case of corrected bit-flips.This
> >> particular condition should not be treated like an error.
> >
> > I'm fine with the patch, Richard, are you okay as well?
>
> Hm yes. I see the bug. I think it broke about 10 years ago
> by e47f68587b82 ("mtd: check for max_bitflips in mtd_read_oob()").
>
> In the early day I'd expect someone to hit this bug but I guess
> on the last 10 years mtdblock had no real users.
Right.
Well, anyhow I guess this patch deserves a Fixes/Cc: stable # v3.7+
Li, can you please re-send with the proper tags? Thanks.
Thanks,
Miquèl
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http://lists.infradead.org/mailman/listinfo/linux-mtd/
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH] mtdblock: tolerate corrected bit-flips
@ 2023-03-14 16:56 Bang Li
2023-03-22 16:08 ` Miquel Raynal
0 siblings, 1 reply; 6+ messages in thread
From: Bang Li @ 2023-03-14 16:56 UTC (permalink / raw)
To: miquel.raynal, richard, vigneshr; +Cc: linux-mtd, linux-kernel, Bang Li
mtd_read() may return -EUCLEAN in case of corrected bit-flips.This
particular condition should not be treated like an error.
Signed-off-by: Bang Li <libang.linuxer@gmail.com>
---
drivers/mtd/mtdblock_ro.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/mtd/mtdblock_ro.c b/drivers/mtd/mtdblock_ro.c
index 7c51952ce55d..66ffc9f1ead2 100644
--- a/drivers/mtd/mtdblock_ro.c
+++ b/drivers/mtd/mtdblock_ro.c
@@ -16,8 +16,10 @@ static int mtdblock_readsect(struct mtd_blktrans_dev *dev,
unsigned long block, char *buf)
{
size_t retlen;
+ int err;
- if (mtd_read(dev->mtd, (block * 512), 512, &retlen, buf))
+ err = mtd_read(dev->mtd, (block * 512), 512, &retlen, buf);
+ if (err && !mtd_is_bitflip(err))
return 1;
return 0;
}
--
2.25.1
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^ permalink raw reply related [flat|nested] 6+ messages in thread
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2023-03-23 14:03 [PATCH] mtdblock: tolerate corrected bit-flips Bang Li
2023-03-28 12:58 ` Miquel Raynal
2023-03-28 13:21 ` Richard Weinberger
2023-03-28 14:00 ` Miquel Raynal
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