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author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-03-05 04:54:51 -0600 |
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committer | Rob Clark <robdclark@chromium.org> | 2020-03-19 12:09:04 -0700 |
commit | 4c145df18f71782007276b670d060d39393fd393 (patch) | |
tree | fed35518205357d9da071334671018b00b82c260 /drivers/gpu/drm/msm/msm_gem.h | |
parent | 66be340f827554cb1c8a1ed7dea97920b4085af2 (diff) | |
download | linux-4c145df18f71782007276b670d060d39393fd393.tar.gz linux-4c145df18f71782007276b670d060d39393fd393.tar.bz2 linux-4c145df18f71782007276b670d060d39393fd393.zip |
drm/msm/msm_gem.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 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Rob Clark <robdclark@chromium.org>
Diffstat (limited to 'drivers/gpu/drm/msm/msm_gem.h')
-rw-r--r-- | drivers/gpu/drm/msm/msm_gem.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/gpu/drm/msm/msm_gem.h b/drivers/gpu/drm/msm/msm_gem.h index 9e0953c2b7ce..37aa556c5f92 100644 --- a/drivers/gpu/drm/msm/msm_gem.h +++ b/drivers/gpu/drm/msm/msm_gem.h @@ -157,7 +157,7 @@ struct msm_gem_submit { uint32_t handle; }; uint64_t iova; - } bos[0]; + } bos[]; }; #endif /* __MSM_GEM_H__ */ |