diff options
| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-25 03:06:47 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-02-27 03:43:09 +0300 |
| commit | 62f19142512885f4876928fcfbfa02838278de41 (patch) | |
| tree | 4d5c56ce3cbc689dea83e37db6a2b27cc9089ca8 /drivers/net/ethernet/sfc | |
| parent | 4a34d825b8939606c3a318341a9de7a4e4d350e7 (diff) | |
| download | linux-62f19142512885f4876928fcfbfa02838278de41.tar.xz | |
sfc: 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>
Acked-by: Martin Habets <mhabets@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ethernet/sfc')
| -rw-r--r-- | drivers/net/ethernet/sfc/falcon/net_driver.h | 2 | ||||
| -rw-r--r-- | drivers/net/ethernet/sfc/net_driver.h | 2 |
2 files changed, 2 insertions, 2 deletions
diff --git a/drivers/net/ethernet/sfc/falcon/net_driver.h b/drivers/net/ethernet/sfc/falcon/net_driver.h index a49ea2e719b6..a529ff395ead 100644 --- a/drivers/net/ethernet/sfc/falcon/net_driver.h +++ b/drivers/net/ethernet/sfc/falcon/net_driver.h @@ -288,7 +288,7 @@ struct ef4_rx_buffer { struct ef4_rx_page_state { dma_addr_t dma_addr; - unsigned int __pad[0] ____cacheline_aligned; + unsigned int __pad[] ____cacheline_aligned; }; /** diff --git a/drivers/net/ethernet/sfc/net_driver.h b/drivers/net/ethernet/sfc/net_driver.h index 9f9886f222c8..392bd5b7017e 100644 --- a/drivers/net/ethernet/sfc/net_driver.h +++ b/drivers/net/ethernet/sfc/net_driver.h @@ -336,7 +336,7 @@ struct efx_rx_buffer { struct efx_rx_page_state { dma_addr_t dma_addr; - unsigned int __pad[0] ____cacheline_aligned; + unsigned int __pad[] ____cacheline_aligned; }; /** |