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From: "Gustavo A. R. Silva" <>
To: Marcel Holtmann <>,
	Johan Hedberg <>,
	"David S. Miller" <>
	"Gustavo A. R. Silva" <>
Subject: [PATCH][next] Bluetooth: a2mp: Use struct_size() helper
Date: Thu, 7 Feb 2019 18:28:17 -0600
Message-ID: <20190208002817.GA15338@embeddedor> (raw)

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 = alloc(size, GFP_KERNEL)

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

size = struct_size(instance, entry, count);
instance = alloc(size, GFP_KERNEL)

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <>
 net/bluetooth/a2mp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/bluetooth/a2mp.c b/net/bluetooth/a2mp.c
index 58fc6333d412..5f918ea18b5a 100644
--- a/net/bluetooth/a2mp.c
+++ b/net/bluetooth/a2mp.c
@@ -174,7 +174,7 @@ static int a2mp_discover_req(struct amp_mgr *mgr, struct sk_buff *skb,
-	len = num_ctrl * sizeof(struct a2mp_cl) + sizeof(*rsp);
+	len = struct_size(rsp, cl, num_ctrl);
 	rsp = kmalloc(len, GFP_ATOMIC);
 	if (!rsp) {

             reply index

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-08  0:28 Gustavo A. R. Silva [this message]
2019-02-08  4:00 ` Joe Perches
2019-02-08  4:07   ` Gustavo A. R. Silva
2019-02-18 13:02 ` Marcel Holtmann
2019-02-18 17:50   ` Gustavo A. R. Silva

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