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Subject[PATCH] rhashtable: use struct_size() in kvzalloc()
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;
struct boo entry[];
};

size = sizeof(struct foo) + count * sizeof(struct boo);
instance = kvzalloc(size, GFP_KERNEL);

Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:

instance = kvzalloc(struct_size(instance, entry, count), GFP_KERNEL);

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
lib/rhashtable.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index a8583af43b59..9c84f5cef69c 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -175,8 +175,7 @@ static struct bucket_table *bucket_table_alloc(struct rhashtable *ht,
int i;
static struct lock_class_key __key;

- size = sizeof(*tbl) + nbuckets * sizeof(tbl->buckets[0]);
- tbl = kvzalloc(size, gfp);
+ tbl = kvzalloc(struct_size(tbl, buckets, nbuckets), gfp);

size = nbuckets;

--
2.21.0
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