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ath10k: Replace zero-length array with flexible-array

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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]

sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.

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: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200507041127.GA31587@embeddedor
This commit is contained in:
Gustavo A. R. Silva
2020-05-08 05:55:52 +03:00
committed by Kalle Valo
parent 27143fa93c
commit d3ed0cf047
8 changed files with 51 additions and 51 deletions
Download Patch File Download Diff File Expand all files Collapse all files

42
drivers/net/wireless/ath/ath10k/wmi.h
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@@ -2292,7 +2292,7 @@ struct wmi_service_ready_event {
* where FW can access this memory directly (or) by DMA.
*/
__le32 num_mem_reqs;
struct wlan_host_mem_req mem_reqs[0];
struct wlan_host_mem_req mem_reqs[];
} __packed;
/* This is the definition from 10.X firmware branch */
@@ -2331,7 +2331,7 @@ struct wmi_10x_service_ready_event {
*/
__le32 num_mem_reqs;
struct wlan_host_mem_req mem_reqs[0];
struct wlan_host_mem_req mem_reqs[];
} __packed;
#define WMI_SERVICE_READY_TIMEOUT_HZ (5 * HZ)
@@ -3086,19 +3086,19 @@ struct wmi_chan_list_entry {
struct wmi_chan_list {
__le32 tag; /* WMI_CHAN_LIST_TAG */
__le32 num_chan;
struct wmi_chan_list_entry channel_list[0];
struct wmi_chan_list_entry channel_list[];
} __packed;
struct wmi_bssid_list {
__le32 tag; /* WMI_BSSID_LIST_TAG */
__le32 num_bssid;
struct wmi_mac_addr bssid_list[0];
struct wmi_mac_addr bssid_list[];
} __packed;
struct wmi_ie_data {
__le32 tag; /* WMI_IE_TAG */
__le32 ie_len;
u8 ie_data[0];
u8 ie_data[];
} __packed;
struct wmi_ssid {
@@ -3109,7 +3109,7 @@ struct wmi_ssid {
struct wmi_ssid_list {
__le32 tag; /* WMI_SSID_LIST_TAG */
__le32 num_ssids;
struct wmi_ssid ssids[0];
struct wmi_ssid ssids[];
} __packed;
/* prefix used by scan requestor ids on the host */
@@ -3311,7 +3311,7 @@ struct wmi_stop_scan_arg {
struct wmi_scan_chan_list_cmd {
__le32 num_scan_chans;
struct wmi_channel chan_info[0];
struct wmi_channel chan_info[];
} __packed;
struct wmi_scan_chan_list_arg {
@@ -3395,12 +3395,12 @@ struct wmi_mgmt_rx_hdr_v2 {
struct wmi_mgmt_rx_event_v1 {
struct wmi_mgmt_rx_hdr_v1 hdr;
u8 buf[0];
u8 buf[];
} __packed;
struct wmi_mgmt_rx_event_v2 {
struct wmi_mgmt_rx_hdr_v2 hdr;
u8 buf[0];
u8 buf[];
} __packed;
struct wmi_10_4_mgmt_rx_hdr {
@@ -3415,7 +3415,7 @@ struct wmi_10_4_mgmt_rx_hdr {
struct wmi_10_4_mgmt_rx_event {
struct wmi_10_4_mgmt_rx_hdr hdr;
u8 buf[0];
u8 buf[];
} __packed;
struct wmi_mgmt_rx_ext_info {
@@ -3455,14 +3455,14 @@ struct wmi_phyerr {
__le32 rssi_chains[4];
__le16 nf_chains[4];
__le32 buf_len;
u8 buf[0];
u8 buf[];
} __packed;
struct wmi_phyerr_event {
__le32 num_phyerrs;
__le32 tsf_l32;
__le32 tsf_u32;
struct wmi_phyerr phyerrs[0];
struct wmi_phyerr phyerrs[];
} __packed;
struct wmi_10_4_phyerr_event {
@@ -3479,7 +3479,7 @@ struct wmi_10_4_phyerr_event {
__le32 phy_err_mask[2];
__le32 tsf_timestamp;
__le32 buf_len;
u8 buf[0];
u8 buf[];
} __packed;
struct wmi_radar_found_info {
@@ -3592,7 +3592,7 @@ struct wmi_mgmt_tx_hdr {
struct wmi_mgmt_tx_cmd {
struct wmi_mgmt_tx_hdr hdr;
u8 buf[0];
u8 buf[];
} __packed;
struct wmi_echo_event {
@@ -4628,7 +4628,7 @@ struct wmi_stats_event {
* By having a zero sized array, the pointer to data area
* becomes available without increasing the struct size
*/
u8 data[0];
u8 data[];
} __packed;
struct wmi_10_2_stats_event {
@@ -4638,7 +4638,7 @@ struct wmi_10_2_stats_event {
__le32 num_vdev_stats;
__le32 num_peer_stats;
__le32 num_bcnflt_stats;
u8 data[0];
u8 data[];
} __packed;
/*
@@ -5033,7 +5033,7 @@ struct wmi_vdev_install_key_cmd {
__le32 key_rxmic_len;
/* contains key followed by tx mic followed by rx mic */
u8 key_data[0];
u8 key_data[];
} __packed;
struct wmi_vdev_install_key_arg {
@@ -5703,7 +5703,7 @@ struct wmi_bcn_tx_hdr {
struct wmi_bcn_tx_cmd {
struct wmi_bcn_tx_hdr hdr;
u8 *bcn[0];
u8 *bcn[];
} __packed;
struct wmi_bcn_tx_arg {
@@ -6120,7 +6120,7 @@ struct wmi_bcn_info {
struct wmi_host_swba_event {
__le32 vdev_map;
struct wmi_bcn_info bcn_info[0];
struct wmi_bcn_info bcn_info[];
} __packed;
struct wmi_10_2_4_bcn_info {
@@ -6130,7 +6130,7 @@ struct wmi_10_2_4_bcn_info {
struct wmi_10_2_4_host_swba_event {
__le32 vdev_map;
struct wmi_10_2_4_bcn_info bcn_info[0];
struct wmi_10_2_4_bcn_info bcn_info[];
} __packed;
/* 16 words = 512 client + 1 word = for guard */
@@ -6171,7 +6171,7 @@ struct wmi_10_4_bcn_info {
struct wmi_10_4_host_swba_event {
__le32 vdev_map;
struct wmi_10_4_bcn_info bcn_info[0];
struct wmi_10_4_bcn_info bcn_info[];
} __packed;
#define WMI_MAX_AP_VDEV 16