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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-03-20 00:21:53 +0300 |
|---|---|---|
| committer | Moritz Fischer <mdf@kernel.org> | 2020-04-30 06:37:12 +0300 |
| commit | 5a53881580f90a5e4404954af16a5646ee9d7842 (patch) | |
| tree | 64138feb83479528bc6239ef47e4350127149fbb /drivers/fpga | |
| parent | fd0d094531db812750bba0367a8822d10a43f444 (diff) | |
| download | linux-5a53881580f90a5e4404954af16a5646ee9d7842.tar.xz | |
fpga: dfl.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: Moritz Fischer <mdf@kernel.org>
Diffstat (limited to 'drivers/fpga')
| -rw-r--r-- | drivers/fpga/dfl.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/fpga/dfl.h b/drivers/fpga/dfl.h index 4a9a33cd9979..74784d3cfe7c 100644 --- a/drivers/fpga/dfl.h +++ b/drivers/fpga/dfl.h @@ -235,7 +235,7 @@ struct dfl_feature_platform_data { int open_count; void *private; int num; - struct dfl_feature features[0]; + struct dfl_feature features[]; }; static inline |