diff options
| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-03-23 16:43:39 -0500 |
|---|---|---|
| committer | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-04-18 15:44:54 -0500 |
| commit | f36aaf8be421099103193c49796a14213d3be315 (patch) | |
| tree | 9fca686271a805ea635ee60afc5aa3438385fa3d /include | |
| parent | 0a368bf00e3a7c57a57efc1bf79b79facb97639c (diff) | |
blk-mq: 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-mq.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index f389d7c724bd..b45148ba3291 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -173,7 +173,7 @@ struct blk_mq_hw_ctx { * blocking (BLK_MQ_F_BLOCKING). Must be the last member - see also * blk_mq_hw_ctx_size(). */ - struct srcu_struct srcu[0]; + struct srcu_struct srcu[]; }; /** |