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>

1 files changed, 27 insertions, 7 deletions

diff --git a/drivers/net/wireless/mwl8k.c b/drivers/net/wireless/mwl8k.c
index 8a6d3afe4122..f84387083e73 100644
--- a/drivers/net/wireless/mwl8k.c
+++ b/drivers/net/wireless/mwl8k.c
@@ -3251,31 +3251,50 @@ mwl8k_configure_filter_exit:
         return rc;
 }
 
+static u64 mwl8k_prepare_multicast(struct ieee80211_hw *hw,
+                                   int mc_count, struct dev_addr_list *mclist)
+{
+        struct mwl8k_configure_filter_worker *worker;
+
+        worker = kzalloc(sizeof(*worker), GFP_ATOMIC);
+
+        if (!worker)
+                return 0;
+
+        /*
+         * XXX: This is _HORRIBLY_ broken!!
+         *
+         *      No locking, the mclist pointer might be invalid as soon as this
+         *      function returns, something in the list might be invalidated
+         *      once we get to the worker, etc...
+         */
+        worker->mc_count = mc_count;
+        worker->mclist = mclist;
+
+        return (u64)worker;
+}
+
 static void mwl8k_configure_filter(struct ieee80211_hw *hw,
                                    unsigned int changed_flags,
                                    unsigned int *total_flags,
-                                   int mc_count,
-                                   struct dev_addr_list *mclist)
+                                   u64 multicast)
 {
 
-        struct mwl8k_configure_filter_worker *worker;
+        struct mwl8k_configure_filter_worker *worker = (void *)multicast;
         struct mwl8k_priv *priv = hw->priv;
 
         /* Clear unsupported feature flags */
         *total_flags &= MWL8K_SUPPORTED_IF_FLAGS;
 
-        if (!(changed_flags & MWL8K_SUPPORTED_IF_FLAGS) && !mc_count)
+        if (!(changed_flags & MWL8K_SUPPORTED_IF_FLAGS))
                 return;
 
-        worker = kzalloc(sizeof(*worker), GFP_ATOMIC);
         if (worker == NULL)
                 return;
 
         worker->header.options = MWL8K_WQ_QUEUE_ONLY | MWL8K_WQ_TX_WAIT_EMPTY;
         worker->changed_flags = changed_flags;
         worker->total_flags = total_flags;
-        worker->mc_count = mc_count;
-        worker->mclist = mclist;
 
         mwl8k_queue_work(hw, &worker->header, priv->config_wq,
                          mwl8k_configure_filter_wt);
@@ -3441,6 +3460,7 @@ static const struct ieee80211_ops mwl8k_ops = {
         .remove_interface       = mwl8k_remove_interface,
         .config                 = mwl8k_config,
         .bss_info_changed       = mwl8k_bss_info_changed,
+        .prepare_multicast      = mwl8k_prepare_multicast,
         .configure_filter       = mwl8k_configure_filter,
         .set_rts_threshold      = mwl8k_set_rts_threshold,
         .conf_tx                = mwl8k_conf_tx,