linux/net/xdp
Gustavo A. R. Silva 95e486f551 xdp: 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 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Acked-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-02-28 12:08:37 -08:00
..
Kconfig treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Makefile treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
xdp_umem.c mm, tree-wide: rename put_user_page*() to unpin_user_page*() 2020-01-31 10:30:38 -08:00
xdp_umem.h xdp: fix hang while unregistering device bound to xdp socket 2019-07-03 15:10:55 +02:00
xsk.c xsk: Publish global consumer pointers when NAPI is finished 2020-02-11 15:51:11 +01:00
xsk.h xsk: add support for need_wakeup flag in AF_XDP rings 2019-08-17 23:07:32 +02:00
xsk_diag.c xsk: lock the control mutex in sock_diag interface 2019-09-05 14:11:52 +02:00
xsk_queue.c xsk: Use struct_size() helper 2019-12-20 16:00:09 -08:00
xsk_queue.h xdp: Replace zero-length array with flexible-array member 2020-02-28 12:08:37 -08:00