Commit 4a34d825 authored by Gustavo A. R. Silva's avatar Gustavo A. R. Silva Committed by David S. Miller

qlogic: 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 detected 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 3f02735e
...@@ -1316,7 +1316,7 @@ struct netxen_minidump_template_hdr { ...@@ -1316,7 +1316,7 @@ struct netxen_minidump_template_hdr {
u32 driver_info_word4; u32 driver_info_word4;
u32 saved_state_array[NX_DUMP_STATE_ARRAY_LEN]; u32 saved_state_array[NX_DUMP_STATE_ARRAY_LEN];
u32 capture_size_array[NX_DUMP_CAP_SIZE_ARRAY_LEN]; u32 capture_size_array[NX_DUMP_CAP_SIZE_ARRAY_LEN];
u32 rsvd[0]; u32 rsvd[];
}; };
/* Common Entry Header: Common to All Entry Types */ /* Common Entry Header: Common to All Entry Types */
......
...@@ -418,7 +418,7 @@ struct qlcnic_83xx_dump_template_hdr { ...@@ -418,7 +418,7 @@ struct qlcnic_83xx_dump_template_hdr {
u32 saved_state[16]; u32 saved_state[16];
u32 cap_sizes[8]; u32 cap_sizes[8];
u32 ocm_wnd_reg[16]; u32 ocm_wnd_reg[16];
u32 rsvd[0]; u32 rsvd[];
}; };
struct qlcnic_82xx_dump_template_hdr { struct qlcnic_82xx_dump_template_hdr {
...@@ -436,7 +436,7 @@ struct qlcnic_82xx_dump_template_hdr { ...@@ -436,7 +436,7 @@ struct qlcnic_82xx_dump_template_hdr {
u32 cap_sizes[8]; u32 cap_sizes[8];
u32 rsvd[7]; u32 rsvd[7];
u32 capabilities; u32 capabilities;
u32 rsvd1[0]; u32 rsvd1[];
}; };
#define QLC_PEX_DMA_READ_SIZE (PAGE_SIZE * 16) #define QLC_PEX_DMA_READ_SIZE (PAGE_SIZE * 16)
...@@ -740,7 +740,7 @@ struct qlcnic_hostrq_rx_ctx { ...@@ -740,7 +740,7 @@ struct qlcnic_hostrq_rx_ctx {
The following is packed: The following is packed:
- N hostrq_rds_rings - N hostrq_rds_rings
- N hostrq_sds_rings */ - N hostrq_sds_rings */
char data[0]; char data[];
} __packed; } __packed;
struct qlcnic_cardrsp_rds_ring{ struct qlcnic_cardrsp_rds_ring{
...@@ -769,7 +769,7 @@ struct qlcnic_cardrsp_rx_ctx { ...@@ -769,7 +769,7 @@ struct qlcnic_cardrsp_rx_ctx {
The following is packed: The following is packed:
- N cardrsp_rds_rings - N cardrsp_rds_rings
- N cardrs_sds_rings */ - N cardrs_sds_rings */
char data[0]; char data[];
} __packed; } __packed;
#define SIZEOF_HOSTRQ_RX(HOSTRQ_RX, rds_rings, sds_rings) \ #define SIZEOF_HOSTRQ_RX(HOSTRQ_RX, rds_rings, sds_rings) \
......
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