diff options
| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-03-24 00:45:36 +0300 |
|---|---|---|
| committer | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-04-18 23:44:54 +0300 |
| commit | 5a58ec8cfc8621f5bdbd610202f62f817e5da204 (patch) | |
| tree | bff8a4872fa159de28db3f47541fc6e387eed086 /include | |
| parent | f36aaf8be421099103193c49796a14213d3be315 (diff) | |
| download | linux-5a58ec8cfc8621f5bdbd610202f62f817e5da204.tar.xz | |
blk_types: 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>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/blk_types.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index 70254ae11769..31eb92876be7 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -198,7 +198,7 @@ struct bio { * double allocations for a small number of bio_vecs. This member * MUST obviously be kept at the very end of the bio. */ - struct bio_vec bi_inline_vecs[0]; + struct bio_vec bi_inline_vecs[]; }; #define BIO_RESET_BYTES offsetof(struct bio, bi_max_vecs) |