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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-02-17 23:02:36 +0300
committerDavid S. Miller <davem@davemloft.net>2020-02-18 06:05:06 +0300
commitfbfc8502af526578039dc89426224943d199c019 (patch)
tree18195e815c9a498ec24b9d8d2d656a0b76333f01 /net/switchdev
parent45a4296b6e55ef2fbbe5946582822daf8f0f2e71 (diff)
downloadlinux-fbfc8502af526578039dc89426224943d199c019.tar.xz
net: switchdev: Replace zero-length array with flexible-array member
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/switchdev')
-rw-r--r--net/switchdev/switchdev.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c
index 3a1d428c1336..60630762a748 100644
--- a/net/switchdev/switchdev.c
+++ b/net/switchdev/switchdev.c
@@ -29,7 +29,7 @@ struct switchdev_deferred_item {
struct list_head list;
struct net_device *dev;
switchdev_deferred_func_t *func;
- unsigned long data[0];
+ unsigned long data[];
};
static struct switchdev_deferred_item *switchdev_deferred_dequeue(void)