mac80211: allow configure_filter callback to sleep

Over time, a whole bunch of drivers have come up
with their own scheme to delay the configure_filter
operation to a workqueue. To be able to simplify
things, allow configure_filter to sleep, and add
a new prepare_multicast callback that drivers that
need the multicast address list implement. This new
callback must be atomic, but most drivers either
don't care or just calculate a hash which can be
done atomically and then uploaded to the hardware
non-atomically.

A cursory look suggests that at76c50x-usb, ar9170,
mwl8k (which is actually very broken now), rt2x00,
wl1251, wl1271 and zd1211 should make use of this
new capability.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ar9170/main.c

@@ -2100,10 +2100,29 @@ unlock:
 	mutex_unlock(&ar->mutex);
 }
 
+static u64 ar9170_op_prepare_multicast(struct ieee80211_hw *hw, int mc_count,
+				       struct dev_addr_list *mclist)
+{
+	u64 mchash;
+	int i;
+
+	/* always get broadcast frames */
+	mchash = 1ULL << (0xff >> 2);
+
+	for (i = 0; i < mc_count; i++) {
+		if (WARN_ON(!mclist))
+			break;
+		mchash |= 1ULL << (mclist->dmi_addr[5] >> 2);
+		mclist = mclist->next;
+	}
+
+	return mchash;
+}
+
 static void ar9170_op_configure_filter(struct ieee80211_hw *hw,
 				       unsigned int changed_flags,
 				       unsigned int *new_flags,
-				       int mc_count, struct dev_mc_list *mclist)
+				       u64 multicast)
 {
 	struct ar9170 *ar = hw->priv;
 
@@ -2116,24 +2135,11 @@ static void ar9170_op_configure_filter(struct ieee80211_hw *hw,
 	 * then checking the error flags, later.
 	 */
 
-	if (changed_flags & FIF_ALLMULTI) {
-		if (*new_flags & FIF_ALLMULTI) {
-			ar->want_mc_hash = ~0ULL;
-		} else {
-			u64 mchash;
-			int i;
+	if (changed_flags & FIF_ALLMULTI && *new_flags & FIF_ALLMULTI)
+			multicast = ~0ULL;
 
-			/* always get broadcast frames */
-			mchash = 1ULL << (0xff >> 2);
-
-			for (i = 0; i < mc_count; i++) {
-				if (WARN_ON(!mclist))
-					break;
-				mchash |= 1ULL << (mclist->dmi_addr[5] >> 2);
-				mclist = mclist->next;
-			}
-		ar->want_mc_hash = mchash;
-		}
+	if (multicast != ar->want_mc_hash) {
+		ar->want_mc_hash = multicast;
 		set_bit(AR9170_FILTER_CHANGED_MULTICAST, &ar->filter_changed);
 	}
 
@@ -2543,6 +2549,7 @@ static const struct ieee80211_ops ar9170_ops = {
 	.add_interface		= ar9170_op_add_interface,
 	.remove_interface	= ar9170_op_remove_interface,
 	.config			= ar9170_op_config,
+	.prepare_multicast	= ar9170_op_prepare_multicast,
 	.configure_filter	= ar9170_op_configure_filter,
 	.conf_tx		= ar9170_conf_tx,
 	.bss_info_changed	= ar9170_op_bss_info_changed,

drivers/net/wireless/ath/ath5k/base.c

@@ -229,10 +229,12 @@ static int ath5k_add_interface(struct ieee80211_hw *hw,
 static void ath5k_remove_interface(struct ieee80211_hw *hw,
 		struct ieee80211_if_init_conf *conf);
 static int ath5k_config(struct ieee80211_hw *hw, u32 changed);
+static u64 ath5k_prepare_multicast(struct ieee80211_hw *hw,
+				   int mc_count, struct dev_addr_list *mc_list);
 static void ath5k_configure_filter(struct ieee80211_hw *hw,
 		unsigned int changed_flags,
 		unsigned int *new_flags,
-		int mc_count, struct dev_mc_list *mclist);
+		u64 multicast);
 static int ath5k_set_key(struct ieee80211_hw *hw,
 		enum set_key_cmd cmd,
 		struct ieee80211_vif *vif, struct ieee80211_sta *sta,
@@ -260,6 +262,7 @@ static const struct ieee80211_ops ath5k_hw_ops = {
 	.add_interface 	= ath5k_add_interface,
 	.remove_interface = ath5k_remove_interface,
 	.config 	= ath5k_config,
+	.prepare_multicast = ath5k_prepare_multicast,
 	.configure_filter = ath5k_configure_filter,
 	.set_key 	= ath5k_set_key,
 	.get_stats 	= ath5k_get_stats,
@@ -2853,6 +2856,37 @@ unlock:
 	return ret;
 }
 
+static u64 ath5k_prepare_multicast(struct ieee80211_hw *hw,
+				   int mc_count, struct dev_addr_list *mclist)
+{
+	u32 mfilt[2], val;
+	int i;
+	u8 pos;
+
+	mfilt[0] = 0;
+	mfilt[1] = 1;
+
+	for (i = 0; i < mc_count; i++) {
+		if (!mclist)
+			break;
+		/* calculate XOR of eight 6-bit values */
+		val = get_unaligned_le32(mclist->dmi_addr + 0);
+		pos = (val >> 18) ^ (val >> 12) ^ (val >> 6) ^ val;
+		val = get_unaligned_le32(mclist->dmi_addr + 3);
+		pos ^= (val >> 18) ^ (val >> 12) ^ (val >> 6) ^ val;
+		pos &= 0x3f;
+		mfilt[pos / 32] |= (1 << (pos % 32));
+		/* XXX: we might be able to just do this instead,
+		* but not sure, needs testing, if we do use this we'd
+		* neet to inform below to not reset the mcast */
+		/* ath5k_hw_set_mcast_filterindex(ah,
+		 *      mclist->dmi_addr[5]); */
+		mclist = mclist->next;
+	}
+
+	return ((u64)(mfilt[1]) << 32) | mfilt[0];
+}
+
 #define SUPPORTED_FIF_FLAGS \
 	FIF_PROMISC_IN_BSS |  FIF_ALLMULTI | FIF_FCSFAIL | \
 	FIF_PLCPFAIL | FIF_CONTROL | FIF_OTHER_BSS | \
@@ -2878,16 +2912,14 @@ unlock:
 static void ath5k_configure_filter(struct ieee80211_hw *hw,
 		unsigned int changed_flags,
 		unsigned int *new_flags,
-		int mc_count, struct dev_mc_list *mclist)
+		u64 multicast)
 {
 	struct ath5k_softc *sc = hw->priv;
 	struct ath5k_hw *ah = sc->ah;
-	u32 mfilt[2], val, rfilt;
-	u8 pos;
-	int i;
+	u32 mfilt[2], rfilt;
 
-	mfilt[0] = 0;
-	mfilt[1] = 0;
+	mfilt[0] = multicast;
+	mfilt[1] = multicast >> 32;
 
 	/* Only deal with supported flags */
 	changed_flags &= SUPPORTED_FIF_FLAGS;
@@ -2913,24 +2945,6 @@ static void ath5k_configure_filter(struct ieee80211_hw *hw,
 	if (*new_flags & FIF_ALLMULTI) {
 		mfilt[0] =  ~0;
 		mfilt[1] =  ~0;
-	} else {
-		for (i = 0; i < mc_count; i++) {
-			if (!mclist)
-				break;
-			/* calculate XOR of eight 6-bit values */
-			val = get_unaligned_le32(mclist->dmi_addr + 0);
-			pos = (val >> 18) ^ (val >> 12) ^ (val >> 6) ^ val;
-			val = get_unaligned_le32(mclist->dmi_addr + 3);
-			pos ^= (val >> 18) ^ (val >> 12) ^ (val >> 6) ^ val;
-			pos &= 0x3f;
-			mfilt[pos / 32] |= (1 << (pos % 32));
-			/* XXX: we might be able to just do this instead,
-			* but not sure, needs testing, if we do use this we'd
-			* neet to inform below to not reset the mcast */
-			/* ath5k_hw_set_mcast_filterindex(ah,
-			 *      mclist->dmi_addr[5]); */
-			mclist = mclist->next;
-		}
 	}
 
 	/* This is the best we can do */

drivers/net/wireless/ath/ath9k/main.c

@@ -2394,8 +2394,7 @@ skip_chan_change:
 static void ath9k_configure_filter(struct ieee80211_hw *hw,
 				   unsigned int changed_flags,
 				   unsigned int *total_flags,
-				   int mc_count,
-				   struct dev_mc_list *mclist)
+				   u64 multicast)
 {
 	struct ath_wiphy *aphy = hw->priv;
 	struct ath_softc *sc = aphy->sc;