From: Gustavo A. R. Silva <gustavo@embeddedor.com>
Date: Wed, 9 Jan 2019 17:23:54 +0000 (+0000)
Subject: afs: Use struct_size() in kzalloc()
X-Git-Tag: v5.0-rc3~32^2~5
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=c2b8bd49d35a768d3966c5e14e8f6971f2a63439;p=linux.git

afs: Use struct_size() in kzalloc()

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 = kzalloc(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 = kzalloc(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>
Signed-off-by: David Howells <dhowells@redhat.com>
---

diff --git a/fs/afs/server_list.c b/fs/afs/server_list.c
index 95d0761cdb34..155dc14caef9 100644
--- a/fs/afs/server_list.c
+++ b/fs/afs/server_list.c
@@ -42,9 +42,7 @@ struct afs_server_list *afs_alloc_server_list(struct afs_cell *cell,
 		if (vldb->fs_mask[i] & type_mask)
 			nr_servers++;
 
-	slist = kzalloc(sizeof(struct afs_server_list) +
-			sizeof(struct afs_server_entry) * nr_servers,
-			GFP_KERNEL);
+	slist = kzalloc(struct_size(slist, servers, nr_servers), GFP_KERNEL);
 	if (!slist)
 		goto error;