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| author |   Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-21 10:00:05 -0600 |
|---|---|---|
| committer |   Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> | 2020-03-02 16:32:17 +0100 |
| commit | 451787d3e2ac3a25abae91792b7154ee533b65c6 (patch) | |
| tree | a02afdc4fb56590b6267d31a13a5abcfffa62e30 /drivers | |
| parent | video: fbdev: radeon: Remove dead code (diff) | |
| download | linux-dev-451787d3e2ac3a25abae91792b7154ee533b65c6.tar.xz linux-dev-451787d3e2ac3a25abae91792b7154ee533b65c6.zip | |
video: 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: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200221160005.GA13552@embeddedor
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/video/fbdev/mmp/hw/mmp_ctrl.h | 2 | ||||
| -rw-r--r-- | drivers/video/fbdev/ssd1307fb.c | 2 |
2 files changed, 2 insertions, 2 deletions
diff --git a/drivers/video/fbdev/mmp/hw/mmp_ctrl.h b/drivers/video/fbdev/mmp/hw/mmp_ctrl.h index 335d4983dc52..167585a889d3 100644 --- a/drivers/video/fbdev/mmp/hw/mmp_ctrl.h +++ b/drivers/video/fbdev/mmp/hw/mmp_ctrl.h @@ -1406,7 +1406,7 @@ struct mmphw_ctrl { /*pathes*/ int path_num; - struct mmphw_path_plat path_plats[0]; + struct mmphw_path_plat path_plats[]; }; static inline int overlay_is_vid(struct mmp_overlay *overlay) diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c index 1a0bd78f9345..12fa1050f3eb 100644 --- a/drivers/video/fbdev/ssd1307fb.c +++ b/drivers/video/fbdev/ssd1307fb.c @@ -89,7 +89,7 @@ struct ssd1307fb_par { struct ssd1307fb_array { u8 type; - u8 data[0]; + u8 data[]; }; static const struct fb_fix_screeninfo ssd1307fb_fix = { |