Commit cc5b48b5 authored by Gustavo A. R. Silva's avatar Gustavo A. R. Silva Committed by David S. Miller

freescale: 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 040efdb1
......@@ -163,7 +163,7 @@ struct enetc_int_vector {
char name[ENETC_INT_NAME_MAX];
struct enetc_bdr rx_ring ____cacheline_aligned_in_smp;
struct enetc_bdr tx_ring[0];
struct enetc_bdr tx_ring[];
};
struct enetc_cls_rule {
......
......@@ -588,7 +588,7 @@ struct tgs_gcl_data {
__le32 bth;
__le32 ct;
__le32 cte;
struct gce entry[0];
struct gce entry[];
};
struct enetc_cbd {
......
......@@ -584,7 +584,7 @@ struct fec_enet_private {
int pps_enable;
unsigned int next_counter;
u64 ethtool_stats[0];
u64 ethtool_stats[];
};
void fec_ptp_init(struct platform_device *pdev, int irq_idx);
......
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