[PATCH] mtd: phram: use div_u64_rem to stop overwrite len in phram_setup

yangerkun
2020-12-30T02:17:19Z

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 | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/devices/phram.c b/drivers/mtd/devices/phram.c
index cfd170946ba4..6e72b0abcb71 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 +264,9 @@ static int phram_setup(const char *val)
}
}

+ 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