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author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-12 19:04:25 -0600 |
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committer | Jason Gunthorpe <jgg@mellanox.com> | 2020-02-20 13:33:51 -0400 |
commit | 5b361328ca649534d721e4eae20c96ccbe702ce7 (patch) | |
tree | aecd94c8ba19a810b66a90a2914b5834ba2832a4 /drivers/infiniband/sw | |
parent | 52c5e9e7497b728b53a84cbd5873c4b707d10d55 (diff) | |
download | linux-5b361328ca649534d721e4eae20c96ccbe702ce7.tar.gz linux-5b361328ca649534d721e4eae20c96ccbe702ce7.tar.bz2 linux-5b361328ca649534d721e4eae20c96ccbe702ce7.zip |
RDMA: 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")
Link: https://lore.kernel.org/r/20200213010425.GA13068@embeddedor.com
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com> # added a few more
Diffstat (limited to 'drivers/infiniband/sw')
-rw-r--r-- | drivers/infiniband/sw/rxe/rxe_queue.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/infiniband/sw/rxe/rxe_queue.h b/drivers/infiniband/sw/rxe/rxe_queue.h index acd0a925481c..8ef17d617022 100644 --- a/drivers/infiniband/sw/rxe/rxe_queue.h +++ b/drivers/infiniband/sw/rxe/rxe_queue.h @@ -63,7 +63,7 @@ struct rxe_queue_buf { __u32 pad_2[31]; __u32 consumer_index; __u32 pad_3[31]; - __u8 data[0]; + __u8 data[]; }; struct rxe_queue { |