diff options
| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-12 19:04:25 -0600 |
|---|---|---|
| committer | Jason Gunthorpe <jgg@mellanox.com> | 2020-02-20 13:33:51 -0400 |
| commit | 5b361328ca649534d721e4eae20c96ccbe702ce7 (patch) | |
| tree | aecd94c8ba19a810b66a90a2914b5834ba2832a4 /drivers/infiniband/hw/mthca | |
| parent | 52c5e9e7497b728b53a84cbd5873c4b707d10d55 (diff) | |
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/hw/mthca')
| -rw-r--r-- | drivers/infiniband/hw/mthca/mthca_memfree.c | 2 | ||||
| -rw-r--r-- | drivers/infiniband/hw/mthca/mthca_memfree.h | 2 |
2 files changed, 2 insertions, 2 deletions
diff --git a/drivers/infiniband/hw/mthca/mthca_memfree.c b/drivers/infiniband/hw/mthca/mthca_memfree.c index 78a48aea3faf..fa808582b08b 100644 --- a/drivers/infiniband/hw/mthca/mthca_memfree.c +++ b/drivers/infiniband/hw/mthca/mthca_memfree.c @@ -58,7 +58,7 @@ struct mthca_user_db_table { u64 uvirt; struct scatterlist mem; int refcount; - } page[0]; + } page[]; }; static void mthca_free_icm_pages(struct mthca_dev *dev, struct mthca_icm_chunk *chunk) diff --git a/drivers/infiniband/hw/mthca/mthca_memfree.h b/drivers/infiniband/hw/mthca/mthca_memfree.h index da9b8f9b884f..f9a2e65e2ff5 100644 --- a/drivers/infiniband/hw/mthca/mthca_memfree.h +++ b/drivers/infiniband/hw/mthca/mthca_memfree.h @@ -68,7 +68,7 @@ struct mthca_icm_table { int lowmem; int coherent; struct mutex mutex; - struct mthca_icm *icm[0]; + struct mthca_icm *icm[]; }; struct mthca_icm_iter { |