From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Date: Mon, 5 Aug 2019 19:18:25 -0500
Subject: [PATCH] dm raid1: use struct_size() with kzalloc()
Git-commit: bcd676542cdd44b3a91e0b695cc1d7a1d35679cd
Patch-mainline: v5.4-rc1
References: bsc#1175995,jsc#SLE-15608
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 mirror_set {
...
struct mirror mirror[0];
};
size = sizeof(struct mirror_set) + count * sizeof(struct mirror);
instance = kzalloc(size, GFP_KERNEL)
Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:
instance = kzalloc(struct_size(instance, mirror, count), GFP_KERNEL)
Notice that, in this case, variable len is not necessary, hence it
is removed.
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Hannes Reinecke <hare@suse.com>
---
drivers/md/dm-raid1.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index 5a51151f680d..089aed57e083 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -878,12 +878,9 @@ static struct mirror_set *alloc_context(unsigned int nr_mirrors,
struct dm_target *ti,
struct dm_dirty_log *dl)
{
- size_t len;
- struct mirror_set *ms = NULL;
-
- len = sizeof(*ms) + (sizeof(ms->mirror[0]) * nr_mirrors);
+ struct mirror_set *ms =
+ kzalloc(struct_size(ms, mirror, nr_mirrors), GFP_KERNEL);
- ms = kzalloc(len, GFP_KERNEL);
if (!ms) {
ti->error = "Cannot allocate mirror context";
return NULL;
--
2.16.4