cfg80211: mark ieee80211_hdrlen const (633adf1a) · Commits · 戴 / test

This function analyses only its single, value-passed argument, and has no side effects. Thus it can be const, which makes mac80211 smaller, for example: text data bss dec hex filename 362518 16720 884 380122 5ccda mac80211.ko (before) 362358 16720 884 379962 5cc3a mac80211.ko (after) a 160 byte saving in text size, and an optimisation because the function won't be called as often. Signed-off-by:

Johannes Berg <johannes.berg@intel.com> Signed-off-by:

John W. Linville <linville@tuxdriver.com>

include/net/cfg80211.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -1715,7 +1715,7 @@ unsigned int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb);
		* ieee80211_hdrlen - get header length in bytes from frame control
		* @fc: frame control field in little-endian format
		*/
		unsigned int ieee80211_hdrlen(__le16 fc);
		unsigned int __attribute_const__ ieee80211_hdrlen(__le16 fc);

		/**
		* ieee80211_data_to_8023 - convert an 802.11 data frame to 802.3

net/wireless/util.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -221,7 +221,7 @@ const unsigned char bridge_tunnel_header[] __aligned(2) =
		{ 0xaa, 0xaa, 0x03, 0x00, 0x00, 0xf8 };
		EXPORT_SYMBOL(bridge_tunnel_header);

		unsigned int ieee80211_hdrlen(__le16 fc)
		unsigned int __attribute_const__ ieee80211_hdrlen(__le16 fc)
		{
		unsigned int hdrlen = 24;

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