openkylin
/
linux
mirror of https://gitee.com/openkylin/linux.git
9
0
Fork 0
Code Issues Projects Releases Wiki Activity

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 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Gustavo A. R. Silva 2020-02-24 10:41:06 -06:00 committed by David S. Miller
parent 3f6e963305
commit 040efdb14c
5 changed files with 8 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
drivers/net/ethernet/intel/fm10k/fm10k.h
View File

@ -41,7 +41,7 @@ struct fm10k_l2_accel {
u16 count; u16 count;
u16 dglort; u16 dglort;
struct rcu_head rcu; struct rcu_head rcu;
struct net_device *macvlan[0]; struct net_device *macvlan[];
}; };
enum fm10k_ring_state_t { 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 */ struct rcu_head rcu; /* to avoid race with update stats on free */
/* for dynamic allocation of rings associated with this q_vector */ /* 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 { enum fm10k_ring_f_enum {
@ -218,7 +218,7 @@ struct fm10k_iov_data {
unsigned int num_vfs; unsigned int num_vfs;
unsigned int next_vf_mbx; unsigned int next_vf_mbx;
struct rcu_head rcu; struct rcu_head rcu;
struct fm10k_vf_info vf_info[0]; struct fm10k_vf_info vf_info[];
}; };
struct fm10k_udp_port { struct fm10k_udp_port {

4
drivers/net/ethernet/intel/i40e/i40e.h
View File

@ -334,13 +334,13 @@ int i40e_ddp_flash(struct net_device *netdev, struct ethtool_flash *flash);
struct i40e_ddp_profile_list { struct i40e_ddp_profile_list {
u32 p_count; u32 p_count;
struct i40e_profile_info p_info[0]; struct i40e_profile_info p_info[];
}; };
struct i40e_ddp_old_profile_list { struct i40e_ddp_old_profile_list {
struct list_head list; struct list_head list;
size_t old_ddp_size; size_t old_ddp_size;
u8 old_ddp_buf[0]; u8 old_ddp_buf[];
}; };
/* macros related to FLX_PIT */ /* macros related to FLX_PIT */

2
drivers/net/ethernet/intel/igb/igb.h
View File

@ -306,7 +306,7 @@ struct igb_q_vector {
char name[IFNAMSIZ + 9]; char name[IFNAMSIZ + 9];
/* for dynamic allocation of rings associated with this q_vector */ /* 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 { enum e1000_ring_flags_t {

2
drivers/net/ethernet/intel/igc/igc.h
View File

@ -326,7 +326,7 @@ struct igc_q_vector {
struct net_device poll_dev; struct net_device poll_dev;
/* for dynamic allocation of rings associated with this q_vector */ /* 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) #define MAX_ETYPE_FILTER (4 - 1)

2
drivers/net/ethernet/intel/ixgbe/ixgbe.h
View File

@ -462,7 +462,7 @@ struct ixgbe_q_vector {
char name[IFNAMSIZ + 9]; char name[IFNAMSIZ + 9];
/* for dynamic allocation of rings associated with this q_vector */ /* 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 #ifdef CONFIG_IXGBE_HWMON