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Commit 6feeb8aa authored by Johannes Berg's avatar Johannes Berg Committed by John W. Linville
Browse files

mac80211: make alignment warning optional 



Driver authors should be aware of the alignment requirements, but
not everybody cares about the warning. This patch makes it depend
on a new Kconfig symbol MAC80211_DEBUG_PACKET_ALIGNMENT which can
be enabled regardless of MAC80211_DEBUG and is recommended for
driver authors (only). This also restricts the warning to data
packets so other packets need not be realigned to not trigger the
warning.

Signed-off-by: default avatarJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 24e1c13c

net/mac80211/Kconfig

+12 −0
Original line number Diff line number Diff line
@@ -98,6 +98,18 @@ config MAC80211_DEBUGFS 


	  Say N unless you know you need this.



config MAC80211_DEBUG_PACKET_ALIGNMENT

	bool "Enable packet alignment debugging"

	depends on MAC80211

	help

	  This option is recommended for driver authors and strongly

	  discouraged for everybody else, it will trigger a warning

	  when a driver hands mac80211 a buffer that is aligned in

	  a way that will cause problems with the IP stack on some

	  architectures.



	  Say N unless you're writing a mac80211 based driver.



config MAC80211_DEBUG

	bool "Enable debugging output"

	depends on MAC80211

net/mac80211/rx.c

+7 −0
Original line number Diff line number Diff line
@@ -340,11 +340,15 @@ static u32 ieee80211_rx_load_stats(struct ieee80211_local *local, 
	return load;

}



#ifdef CONFIG_MAC80211_DEBUG_PACKET_ALIGNMENT

static ieee80211_txrx_result

ieee80211_rx_h_verify_ip_alignment(struct ieee80211_txrx_data *rx)

{

	int hdrlen;



	if (!WLAN_FC_DATA_PRESENT(rx->fc))

		return TXRX_CONTINUE;



	/*

	 * Drivers are required to align the payload data in a way that

	 * guarantees that the contained IP header is aligned to a four-
@@ -371,11 +375,14 @@ ieee80211_rx_h_verify_ip_alignment(struct ieee80211_txrx_data *rx) 


	return TXRX_CONTINUE;

}

#endif



ieee80211_rx_handler ieee80211_rx_pre_handlers[] =

{

	ieee80211_rx_h_parse_qos,

#ifdef CONFIG_MAC80211_DEBUG_PACKET_ALIGNMENT

	ieee80211_rx_h_verify_ip_alignment,

#endif

	NULL

};