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
76497732932f ("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/20200504201224.GA32282@embeddedor
u8 peer_addr[ETH_ALEN];
struct completion cmpln;
u32 buf_len;
- u8 buf[0];
+ u8 buf[];
};
struct ath_pktlog_hdr {
u16 size;
u32 timestamp;
u32 type_specific_data;
- u8 payload[0];
+ u8 payload[];
};
#define ATH11K_HTT_PEER_STATS_RESET BIT(16)
*/
struct htt_tx_pdev_stats_tried_mpdu_cnt_hist_tlv_v {
u32 hist_bin_size;
- u32 tried_mpdu_cnt_hist[0]; /* HTT_TX_PDEV_TRIED_MPDU_CNT_HIST */
+ u32 tried_mpdu_cnt_hist[]; /* HTT_TX_PDEV_TRIED_MPDU_CNT_HIST */
};
/* == SOC ERROR STATS == */
struct htt_tx_hwq_difs_latency_stats_tlv_v {
u32 hist_intvl;
/* histogram of ppdu post to hwsch - > cmd status received */
- u32 difs_latency_hist[0]; /* HTT_TX_HWQ_MAX_DIFS_LATENCY_BINS */
+ u32 difs_latency_hist[]; /* HTT_TX_HWQ_MAX_DIFS_LATENCY_BINS */
};
/* NOTE: Variable length TLV, use length spec to infer array size */
struct htt_tx_hwq_tried_mpdu_cnt_hist_tlv_v {
u32 hist_bin_size;
/* Histogram of number of mpdus on tried mpdu */
- u32 tried_mpdu_cnt_hist[0]; /* HTT_TX_HWQ_TRIED_MPDU_CNT_HIST */
+ u32 tried_mpdu_cnt_hist[]; /* HTT_TX_HWQ_TRIED_MPDU_CNT_HIST */
};
/* NOTE: Variable length TLV, use length spec to infer array size
struct htt_pdev_stats_twt_sessions_tlv {
u32 pdev_id;
u32 num_sessions;
- struct htt_pdev_stats_twt_session_tlv twt_session[0];
+ struct htt_pdev_stats_twt_session_tlv twt_session[];
};
enum htt_rx_reo_resource_sample_id_enum {
struct hal_tlv_hdr {
u32 tl;
- u8 value[0];
+ u8 value[];
} __packed;
#define RX_MPDU_DESC_INFO0_MSDU_COUNT GENMASK(7, 0)
u32 processed_total_bytes;
u32 info5;
u32 rsvd[3];
- struct hal_rx_reo_queue_ext ext_desc[0];
+ struct hal_rx_reo_queue_ext ext_desc[];
} __packed;
/* hal_rx_reo_queue
struct hal_rx_mon_status_tlv_hdr {
u32 hdr;
- u8 value[0];
+ u8 value[];
};
enum hal_rx_su_mu_coding {
struct ath11k_fw_ie {
__le32 id;
__le32 len;
- u8 data[0];
+ u8 data[];
};
enum ath11k_bd_ie_board_type {
struct wmi_tlv {
u32 header;
- u8 value[0];
+ u8 value[];
} __packed;
#define WMI_TLV_LEN GENMASK(15, 0)
projects / platform / kernel / linux-starfive.git / commitdiff