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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-13 04:04:25 +0300 |
|---|---|---|
| committer | Jason Gunthorpe <jgg@mellanox.com> | 2020-02-20 20:33:51 +0300 |
| commit | 5b361328ca649534d721e4eae20c96ccbe702ce7 (patch) | |
| tree | aecd94c8ba19a810b66a90a2914b5834ba2832a4 /drivers/infiniband/ulp/opa_vnic | |
| parent | 52c5e9e7497b728b53a84cbd5873c4b707d10d55 (diff) | |
| download | linux-5b361328ca649534d721e4eae20c96ccbe702ce7.tar.xz | |
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/ulp/opa_vnic')
| -rw-r--r-- | drivers/infiniband/ulp/opa_vnic/opa_vnic_encap.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/infiniband/ulp/opa_vnic/opa_vnic_encap.h b/drivers/infiniband/ulp/opa_vnic/opa_vnic_encap.h index 4480092c68e0..0b3570dc606d 100644 --- a/drivers/infiniband/ulp/opa_vnic/opa_vnic_encap.h +++ b/drivers/infiniband/ulp/opa_vnic/opa_vnic_encap.h @@ -258,7 +258,7 @@ struct opa_veswport_mactable { __be16 offset; __be16 num_entries; __be32 mac_tbl_digest; - struct opa_veswport_mactable_entry tbl_entries[0]; + struct opa_veswport_mactable_entry tbl_entries[]; } __packed; /** @@ -440,7 +440,7 @@ struct opa_veswport_iface_macs { __be16 num_macs_in_msg; __be16 tot_macs_in_lst; __be16 gen_count; - struct opa_vnic_iface_mac_entry entry[0]; + struct opa_vnic_iface_mac_entry entry[]; } __packed; /** |