Re: [PATCH] md/raid10: Use struct_size() in kmalloc()
From: Song Liu <hidden>
Date: 2019-01-07 23:01:52
Also in:
lkml
On Fri, Jan 4, 2019 at 1:14 PM Gustavo A. R. Silva [off-list ref] wrote:
One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:
struct foo {
int stuff;
void *entry[];
};
instance = kmalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);
Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:
instance = kmalloc(struct_size(instance, entry, count), GFP_KERNEL);
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <redacted>Acked-by: Song Liu <redacted>
quoted hunk ↗ jump to hunk
--- drivers/md/raid10.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index abb5d382f64d..320cb430cca6 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c@@ -4788,8 +4788,7 @@ static int handle_reshape_read_error(struct mddev *mddev, int idx = 0; struct page **pages; - r10b = kmalloc(sizeof(*r10b) + - sizeof(struct r10dev) * conf->copies, GFP_NOIO); + r10b = kmalloc(struct_size(r10b, devs, conf->copies), GFP_NOIO); if (!r10b) { set_bit(MD_RECOVERY_INTR, &mddev->recovery); return -ENOMEM; --2.20.1