netdev - [PATCH V2] net/switchdev: use struct_size over open coded arithmetic

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Message-Id: <20220210061008.1608468-1-chi.minghao@zte.com.cn>
Date:   Thu, 10 Feb 2022 06:10:08 +0000
From:   cgel.zte@...il.com
To:     jiri@...nulli.us
Cc:     ivecera@...hat.com, davem@...emloft.net, kuba@...nel.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        Minghao Chi <chi.minghao@....com.cn>,
        Zeal Robot <zealci@....com.cn>
Subject: [PATCH V2] net/switchdev: use struct_size over open coded arithmetic

From: Minghao Chi (CGEL ZTE) <chi.minghao@....com.cn>

Replace zero-length array with flexible-array member and make use
of the struct_size() helper in kmalloc(). For example:

struct switchdev_deferred_item {
    ...
    unsigned long data[];
};

Make use of the struct_size() helper instead of an open-coded version
in order to avoid any potential type mistakes.

Reported-by: Zeal Robot <zealci@....com.cn>
Signed-off-by: Minghao Chi (CGEL ZTE) <chi.minghao@....com.cn>
---
 net/switchdev/switchdev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c
index b62565278fac..12e6b4146bfb 100644
--- a/net/switchdev/switchdev.c
+++ b/net/switchdev/switchdev.c
@@ -85,7 +85,7 @@ static int switchdev_deferred_enqueue(struct net_device *dev,
 {
 	struct switchdev_deferred_item *dfitem;
 
-	dfitem = kmalloc(sizeof(*dfitem) + data_len, GFP_ATOMIC);
+	dfitem = kmalloc(struct_size(dfitem, data, data_len), GFP_ATOMIC);
 	if (!dfitem)
 		return -ENOMEM;
 	dfitem->dev = dev;
-- 
2.25.1