* [PATCH V2] mtd: phram: use div_u64_rem to stop overwrite len in phram_setup
@ 2021-01-25 12:49 yangerkun
2021-01-27 12:46 ` Miquel Raynal
0 siblings, 1 reply; 2+ messages in thread
From: yangerkun @ 2021-01-25 12:49 UTC (permalink / raw)
To: zhongguohua1, joern, miquel.raynal, richard, patrick, linux-mtd; +Cc: yangerkun
We now support user to set erase page size, and use do_div between len
and erase size to determine the reasonableness for the erase size.
However, do_div is a macro and will overwrite the value of len. Which
results a mtd device with unexcepted size. Fix it by use div_u64_rem.
Fixes: ffad560394de ("mtd: phram: Allow the user to set the erase page size.")
Signed-off-by: yangerkun <yangerkun@huawei.com>
---
drivers/mtd/devices/phram.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/mtd/devices/phram.c b/drivers/mtd/devices/phram.c
index cfd170946ba4..5b04ae6c3057 100644
--- a/drivers/mtd/devices/phram.c
+++ b/drivers/mtd/devices/phram.c
@@ -222,6 +222,7 @@ static int phram_setup(const char *val)
uint64_t start;
uint64_t len;
uint64_t erasesize = PAGE_SIZE;
+ uint32_t rem;
int i, ret;
if (strnlen(val, sizeof(buf)) >= sizeof(buf))
@@ -263,8 +264,11 @@ static int phram_setup(const char *val)
}
}
+ if (erasesize)
+ div_u64_rem(len, (uint32_t)erasesize, &rem);
+
if (len == 0 || erasesize == 0 || erasesize > len
- || erasesize > UINT_MAX || do_div(len, (uint32_t)erasesize) != 0) {
+ || erasesize > UINT_MAX || rem) {
parse_err("illegal erasesize or len\n");
goto error;
}
--
2.25.4
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^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH V2] mtd: phram: use div_u64_rem to stop overwrite len in phram_setup
2021-01-25 12:49 [PATCH V2] mtd: phram: use div_u64_rem to stop overwrite len in phram_setup yangerkun
@ 2021-01-27 12:46 ` Miquel Raynal
0 siblings, 0 replies; 2+ messages in thread
From: Miquel Raynal @ 2021-01-27 12:46 UTC (permalink / raw)
To: yangerkun, zhongguohua1, joern, miquel.raynal, richard, patrick,
linux-mtd
On Mon, 2021-01-25 at 12:49:36 UTC, yangerkun wrote:
> We now support user to set erase page size, and use do_div between len
> and erase size to determine the reasonableness for the erase size.
> However, do_div is a macro and will overwrite the value of len. Which
> results a mtd device with unexcepted size. Fix it by use div_u64_rem.
>
> Fixes: ffad560394de ("mtd: phram: Allow the user to set the erase page size.")
> Signed-off-by: yangerkun <yangerkun@huawei.com>
Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git mtd/next, thanks.
Miquel
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