From: Gustavo A. R. Silva <gustavo@embeddedor.com>
Date: Tue, 8 Jan 2019 18:37:20 +0000 (-0600)
Subject: powerpc/spufs: use struct_size() in kmalloc()
X-Git-Tag: v5.1-rc1~128^2~159
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=00def7130af8b3fad1bdef98429c94a67dbbd896;p=thirdparty%2Fkernel%2Flinux.git

powerpc/spufs: use struct_size() in kmalloc()

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 = kmalloc(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 = kmalloc(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: Michael Ellerman <mpe@ellerman.id.au>
---

diff --git a/arch/powerpc/platforms/cell/spufs/file.c b/arch/powerpc/platforms/cell/spufs/file.c
index ae8123edddc67..48c2477e7e2a2 100644
--- a/arch/powerpc/platforms/cell/spufs/file.c
+++ b/arch/powerpc/platforms/cell/spufs/file.c
@@ -2338,9 +2338,8 @@ static int spufs_switch_log_open(struct inode *inode, struct file *file)
 		goto out;
 	}
 
-	ctx->switch_log = kmalloc(sizeof(struct switch_log) +
-		SWITCH_LOG_BUFSIZE * sizeof(struct switch_log_entry),
-		GFP_KERNEL);
+	ctx->switch_log = kmalloc(struct_size(ctx->switch_log, log,
+				  SWITCH_LOG_BUFSIZE), GFP_KERNEL);
 
 	if (!ctx->switch_log) {
 		rc = -ENOMEM;