On Tue, Sep 1, 2020 at 12:08 AM Nathan Chancellor
<natechancellor@xxxxxxxxx> wrote:
>
> A new warning in clang points out when macro expansion might result in a
> GNU C statement expression. There is an instance of this in the mwifiex
> driver:
>
> drivers/net/wireless/marvell/mwifiex/cmdevt.c:217:34: warning: '}' and
> ')' tokens terminating statement expression appear in different macro
> expansion contexts [-Wcompound-token-split-by-macro]
> host_cmd->seq_num = cpu_to_le16(HostCmd_SET_SEQ_NO_BSS_INFO
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/net/wireless/marvell/mwifiex/fw.h:519:46: note: expanded from
> macro 'HostCmd_SET_SEQ_NO_BSS_INFO'
> (((type) & 0x000f) << 12); }
> ^
>
> This does not appear to be a real issue. Removing the braces and
> replacing them with parentheses will fix the warning and not change the
> meaning of the code.
>
> Fixes: 5e6e3a92b9a4 ("wireless: mwifiex: initial commit for Marvell mwifiex driver")
> Link: https://github.com/ClangBuiltLinux/linux/issues/1146
> Reported-by: Andy Lavr <andy.lavr@xxxxxxxxx>
> Signed-off-by: Nathan Chancellor <natechancellor@xxxxxxxxx>
Wow, that's tricky. The unnecessary extra parens mix with the extra
curly braces to form a GNU C statement expression. Thanks for the
patch.
Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
> ---
> drivers/net/wireless/marvell/mwifiex/cmdevt.c | 4 ++--
> drivers/net/wireless/marvell/mwifiex/fw.h | 8 ++++----
> 2 files changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/wireless/marvell/mwifiex/cmdevt.c b/drivers/net/wireless/marvell/mwifiex/cmdevt.c
> index d068b9075c32..3a11342a6bde 100644
> --- a/drivers/net/wireless/marvell/mwifiex/cmdevt.c
> +++ b/drivers/net/wireless/marvell/mwifiex/cmdevt.c
> @@ -322,9 +322,9 @@ static int mwifiex_dnld_sleep_confirm_cmd(struct mwifiex_adapter *adapter)
>
> adapter->seq_num++;
> sleep_cfm_buf->seq_num =
> - cpu_to_le16((HostCmd_SET_SEQ_NO_BSS_INFO
> + cpu_to_le16(HostCmd_SET_SEQ_NO_BSS_INFO
> (adapter->seq_num, priv->bss_num,
> - priv->bss_type)));
> + priv->bss_type));
>
> mwifiex_dbg(adapter, CMD,
> "cmd: DNLD_CMD: %#x, act %#x, len %d, seqno %#x\n",
> diff --git a/drivers/net/wireless/marvell/mwifiex/fw.h b/drivers/net/wireless/marvell/mwifiex/fw.h
> index 8047e307892e..1f02c5058aed 100644
> --- a/drivers/net/wireless/marvell/mwifiex/fw.h
> +++ b/drivers/net/wireless/marvell/mwifiex/fw.h
> @@ -513,10 +513,10 @@ enum mwifiex_channel_flags {
>
> #define RF_ANTENNA_AUTO 0xFFFF
>
> -#define HostCmd_SET_SEQ_NO_BSS_INFO(seq, num, type) { \
> - (((seq) & 0x00ff) | \
> - (((num) & 0x000f) << 8)) | \
> - (((type) & 0x000f) << 12); }
> +#define HostCmd_SET_SEQ_NO_BSS_INFO(seq, num, type) \
> + ((((seq) & 0x00ff) | \
> + (((num) & 0x000f) << 8)) | \
> + (((type) & 0x000f) << 12))
>
> #define HostCmd_GET_SEQ_NO(seq) \
> ((seq) & HostCmd_SEQ_NUM_MASK)
> --
--
Thanks,
~Nick Desaulniers
