From: Joe Perches

Sent: 20 December 2021 12:13

On Fri, 2021-12-17 at 15:41 +0100, Anders Roxell wrote:

quoted

From: Nathan Chancellor <redacted>

commit 6a953dc4dbd1c7057fb765a24f37a5e953c85fb0 upstream.

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
                                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~

[]

quoted

diff --git a/drivers/net/wireless/marvell/mwifiex/fw.h b/drivers/net/wireless/marvell/mwifiex/fw.h

[]

quoted

@@ -512,10 +512,10 @@ 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))

Perhaps this would be better as a static inline

static inline u16 HostCmd_SET_SEQ_NO_BSS_INFO(u16 seq, u8 num, u8 type)
{
	return (type & 0x000f) << 12 | (num & 0x000f) << 8 | (seq & 0x00ff);
}

Just writing in on one line helps readability!
It is also used exactly twice, both with a cpu_to_le16().
I wonder how well the compiler handles that on BE?
The #define is more likely to be handled better.

I've only made a cursory glance at the code, but I get splitting
host_cmd->seq_num into two u8 fields would give better code!

	David

-
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