Subject: [PATCH net-next] xprtrdma: Use struct_size() in kzalloc()

From: "Gustavo A. R. Silva" <[email-masked]>
Date: Wed, 30 Jan 2019 18:46:22 -0600

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[];
};

instance = kzalloc(sizeof(struct foo) + count * sizeof(struct boo), 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, entry, count), GFP_KERNEL);

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <[email-masked]>
---
 net/sunrpc/xprtrdma/verbs.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index 4994e75945b8..9e8cf7456840 100644
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -811,8 +811,7 @@ static struct rpcrdma_sendctx *rpcrdma_sendctx_create(struct rpcrdma_ia *ia)
 {
 	struct rpcrdma_sendctx *sc;
 
-	sc = kzalloc(sizeof(*sc) +
-		     ia->ri_max_send_sges * sizeof(struct ib_sge),
+	sc = kzalloc(struct_size(sc, sc_sges, ia->ri_max_send_sges),
 		     GFP_KERNEL);
 	if (!sc)
 		return NULL;
-- 
2.20.1