xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

intel: Replace zero-length array with flexible-array member

Browse Source 
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
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 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 {