linux/include/drm/bridge
Gustavo A. R. Silva 78a7b61aef drm/bridge/mhl.h: 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>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20200305110011.GA21056@embeddedor
2020-03-06 11:52:01 +01:00
..
analogix_dp.h drm/rockchip: Use the helpers for PSR 2019-07-26 14:48:03 -04:00
dw_hdmi.h drm main pull for 5.5-rc1 2019-11-27 17:45:48 -08:00
dw_mipi_dsi.h drm/bridge/synopsys: dsi: driver-specific configuration of phy timings 2019-12-16 12:01:58 +01:00
mhl.h drm/bridge/mhl.h: Replace zero-length array with flexible-array member 2020-03-06 11:52:01 +01:00