diff options
author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-24 10:30:24 -0600 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2020-02-24 15:26:17 -0800 |
commit | 65dc2f1a44df01eab3c93b7ecdd3fb393f9e81a2 (patch) | |
tree | e63527dd8045b57f18bdb791c2de7256717b21a1 /drivers/net/ethernet/chelsio/libcxgb/libcxgb_ppm.h | |
parent | 59bc954c7a2572e1c903012ab722eba942a5d65c (diff) |
chelsio: 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>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ethernet/chelsio/libcxgb/libcxgb_ppm.h')
-rw-r--r-- | drivers/net/ethernet/chelsio/libcxgb/libcxgb_ppm.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/net/ethernet/chelsio/libcxgb/libcxgb_ppm.h b/drivers/net/ethernet/chelsio/libcxgb/libcxgb_ppm.h index 7b02c200dd1e..1b4156461ba1 100644 --- a/drivers/net/ethernet/chelsio/libcxgb/libcxgb_ppm.h +++ b/drivers/net/ethernet/chelsio/libcxgb/libcxgb_ppm.h @@ -122,7 +122,7 @@ struct cxgbi_ppm_pool { unsigned int base; /* base index */ unsigned int next; /* next possible free index */ spinlock_t lock; /* ppm pool lock */ - unsigned long bmap[0]; + unsigned long bmap[]; } ____cacheline_aligned_in_smp; struct cxgbi_ppm { @@ -145,7 +145,7 @@ struct cxgbi_ppm { unsigned int next; unsigned int max_index_in_edram; unsigned long *ppod_bmap; - struct cxgbi_ppod_data ppod_data[0]; + struct cxgbi_ppod_data ppod_data[]; }; #define DDP_THRESHOLD 512 |