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| author | Gustavo A. R. Silva <gustavoars@kernel.org> | 2020-05-07 21:59:35 +0300 |
|---|---|---|
| committer | Saeed Mahameed <saeedm@mellanox.com> | 2020-05-11 04:05:38 +0300 |
| commit | b6ca09cb156d349e6fdde8a8466ec15b902d1419 (patch) | |
| tree | 66f9cf34186c1bf862fd8cc39a824f9777baca43 /include/linux/mlx5/driver.h | |
| parent | c6bc6041b10f70b617f2d13894311fe62027d292 (diff) | |
| download | linux-b6ca09cb156d349e6fdde8a8466ec15b902d1419.tar.xz | |
net/mlx5: Replace zero-length array with flexible-array
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]
sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.
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 <gustavoars@kernel.org>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Diffstat (limited to 'include/linux/mlx5/driver.h')
| -rw-r--r-- | include/linux/mlx5/driver.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/mlx5/driver.h b/include/linux/mlx5/driver.h index 267dfcc5493e..24e04901f92e 100644 --- a/include/linux/mlx5/driver.h +++ b/include/linux/mlx5/driver.h @@ -201,7 +201,7 @@ struct mlx5_rsc_debug { void *object; enum dbg_rsc_type type; struct dentry *root; - struct mlx5_field_desc fields[0]; + struct mlx5_field_desc fields[]; }; enum mlx5_dev_event { |