linux-kernel - [PATCH] sparc: use struct

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Date:   Tue, 8 Jan 2019 10:13:56 -0600
From:   "Gustavo A. R. Silva" <gustavo@...eddedor.com>
To:     "David S. Miller" <davem@...emloft.net>
Cc:     sparclinux@...r.kernel.org, linux-kernel@...r.kernel.org,
        "Gustavo A. R. Silva" <gustavo@...eddedor.com>
Subject: [PATCH] sparc: 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@...eddedor.com>
---
 arch/sparc/kernel/cpumap.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/sparc/kernel/cpumap.c b/arch/sparc/kernel/cpumap.c
index d1d52822603d..1cb62bfeaa1f 100644
--- a/arch/sparc/kernel/cpumap.c
+++ b/arch/sparc/kernel/cpumap.c
@@ -194,8 +194,7 @@ static struct cpuinfo_tree *build_cpuinfo_tree(void)
 
 	n = enumerate_cpuinfo_nodes(tmp_level);
 
-	new_tree = kzalloc(sizeof(struct cpuinfo_tree) +
-	                   (sizeof(struct cpuinfo_node) * n), GFP_ATOMIC);
+	new_tree = kzalloc(struct_size(new_tree, nodes, n), GFP_ATOMIC);
 	if (!new_tree)
 		return NULL;
 
-- 
2.20.1