Commit 040efdb1 authored by Gustavo A. R. Silva's avatar Gustavo A. R. Silva Committed by David S. Miller

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 76497732 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 3f6e9633
......@@ -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 {
......
......@@ -334,13 +334,13 @@ int i40e_ddp_flash(struct net_device *netdev, struct ethtool_flash *flash);
struct i40e_ddp_profile_list {
u32 p_count;
struct i40e_profile_info p_info[0];
struct i40e_profile_info p_info[];
};
struct i40e_ddp_old_profile_list {
struct list_head list;
size_t old_ddp_size;
u8 old_ddp_buf[0];
u8 old_ddp_buf[];
};
/* macros related to FLX_PIT */
......
......@@ -306,7 +306,7 @@ struct igb_q_vector {
char name[IFNAMSIZ + 9];
/* for dynamic allocation of rings associated with this q_vector */
struct igb_ring ring[0] ____cacheline_internodealigned_in_smp;
struct igb_ring ring[] ____cacheline_internodealigned_in_smp;
};
enum e1000_ring_flags_t {
......
......@@ -326,7 +326,7 @@ struct igc_q_vector {
struct net_device poll_dev;
/* for dynamic allocation of rings associated with this q_vector */
struct igc_ring ring[0] ____cacheline_internodealigned_in_smp;
struct igc_ring ring[] ____cacheline_internodealigned_in_smp;
};
#define MAX_ETYPE_FILTER (4 - 1)
......
......@@ -462,7 +462,7 @@ struct ixgbe_q_vector {
char name[IFNAMSIZ + 9];
/* for dynamic allocation of rings associated with this q_vector */
struct ixgbe_ring ring[0] ____cacheline_internodealigned_in_smp;
struct ixgbe_ring ring[] ____cacheline_internodealigned_in_smp;
};
#ifdef CONFIG_IXGBE_HWMON
......
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