From 040efdb14c39327da35d2fed902b31fcf4056188 Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Mon, 24 Feb 2020 10:41:06 -0600 Subject: intel: 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 Signed-off-by: David S. Miller --- drivers/net/ethernet/intel/fm10k/fm10k.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'drivers/net/ethernet/intel/fm10k') diff --git a/drivers/net/ethernet/intel/fm10k/fm10k.h b/drivers/net/ethernet/intel/fm10k/fm10k.h index f306084ca12c..5b78362b82ac 100644 --- a/drivers/net/ethernet/intel/fm10k/fm10k.h +++ b/drivers/net/ethernet/intel/fm10k/fm10k.h @@ -41,7 +41,7 @@ struct fm10k_l2_accel { u16 count; u16 dglort; struct rcu_head rcu; - struct net_device *macvlan[0]; + struct net_device *macvlan[]; }; enum fm10k_ring_state_t { @@ -198,7 +198,7 @@ struct fm10k_q_vector { struct rcu_head rcu; /* to avoid race with update stats on free */ /* for dynamic allocation of rings associated with this q_vector */ - struct fm10k_ring ring[0] ____cacheline_internodealigned_in_smp; + struct fm10k_ring ring[] ____cacheline_internodealigned_in_smp; }; enum fm10k_ring_f_enum { @@ -218,7 +218,7 @@ struct fm10k_iov_data { unsigned int num_vfs; unsigned int next_vf_mbx; struct rcu_head rcu; - struct fm10k_vf_info vf_info[0]; + struct fm10k_vf_info vf_info[]; }; struct fm10k_udp_port { -- cgit v1.2.3