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>
diff --git a/drivers/net/wireless/libertas_tf/main.c b/drivers/net/wireless/libertas_tf/main.c
index 4872345..019431d 100644
--- a/drivers/net/wireless/libertas_tf/main.c
+++ b/drivers/net/wireless/libertas_tf/main.c
@@ -366,15 +366,35 @@
 	return 0;
 }
 
+static u64 lbtf_op_prepare_multicast(struct ieee80211_hw *hw,
+				     int mc_count, struct dev_addr_list *mclist)
+{
+	struct lbtf_private *priv = hw->priv;
+	int i;
+
+	if (!mc_count || mc_count > MRVDRV_MAX_MULTICAST_LIST_SIZE)
+		return mc_count;
+
+	priv->nr_of_multicastmacaddr = mc_count;
+	for (i = 0; i < mc_count; i++) {
+		if (!mclist)
+			break;
+		memcpy(&priv->multicastlist[i], mclist->da_addr,
+				ETH_ALEN);
+		mclist = mclist->next;
+	}
+
+	return mc_count;
+}
+
 #define SUPPORTED_FIF_FLAGS  (FIF_PROMISC_IN_BSS | FIF_ALLMULTI)
 static void lbtf_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 lbtf_private *priv = hw->priv;
 	int old_mac_control = priv->mac_control;
-	int i;
 	changed_flags &= SUPPORTED_FIF_FLAGS;
 	*new_flags &= SUPPORTED_FIF_FLAGS;
 
@@ -386,20 +406,12 @@
 	else
 		priv->mac_control &= ~CMD_ACT_MAC_PROMISCUOUS_ENABLE;
 	if (*new_flags & (FIF_ALLMULTI) ||
-	    mc_count > MRVDRV_MAX_MULTICAST_LIST_SIZE) {
+	    multicast > MRVDRV_MAX_MULTICAST_LIST_SIZE) {
 		priv->mac_control |= CMD_ACT_MAC_ALL_MULTICAST_ENABLE;
 		priv->mac_control &= ~CMD_ACT_MAC_MULTICAST_ENABLE;
-	} else if (mc_count) {
+	} else if (multicast) {
 		priv->mac_control |= CMD_ACT_MAC_MULTICAST_ENABLE;
 		priv->mac_control &= ~CMD_ACT_MAC_ALL_MULTICAST_ENABLE;
-		priv->nr_of_multicastmacaddr = mc_count;
-		for (i = 0; i < mc_count; i++) {
-			if (!mclist)
-				break;
-			memcpy(&priv->multicastlist[i], mclist->da_addr,
-					ETH_ALEN);
-			mclist = mclist->next;
-		}
 		lbtf_cmd_set_mac_multicast_addr(priv);
 	} else {
 		priv->mac_control &= ~(CMD_ACT_MAC_MULTICAST_ENABLE |
@@ -461,6 +473,7 @@
 	.add_interface		= lbtf_op_add_interface,
 	.remove_interface	= lbtf_op_remove_interface,
 	.config			= lbtf_op_config,
+	.prepare_multicast	= lbtf_op_prepare_multicast,
 	.configure_filter	= lbtf_op_configure_filter,
 	.bss_info_changed	= lbtf_op_bss_info_changed,
 };