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>

7 files changed, 77 insertions, 43 deletions

diff --git a/net/mac80211/driver-ops.h b/net/mac80211/driver-ops.h
index 4100c361a99d..d231c9323ad1 100644
--- a/net/mac80211/driver-ops.h
+++ b/net/mac80211/driver-ops.h
@@ -55,16 +55,32 @@ static inline void drv_bss_info_changed(struct ieee80211_local *local,
         trace_drv_bss_info_changed(local, vif, info, changed);
 }
 
+static inline u64 drv_prepare_multicast(struct ieee80211_local *local,
+                                        int mc_count,
+                                        struct dev_addr_list *mc_list)
+{
+        u64 ret = 0;
+
+        if (local->ops->prepare_multicast)
+                ret = local->ops->prepare_multicast(&local->hw, mc_count,
+                                                    mc_list);
+
+        trace_drv_prepare_multicast(local, mc_count, ret);
+
+        return ret;
+}
+
 static inline void drv_configure_filter(struct ieee80211_local *local,
                                         unsigned int changed_flags,
                                         unsigned int *total_flags,
-                                        int mc_count,
-                                        struct dev_addr_list *mc_list)
+                                        u64 multicast)
 {
+        might_sleep();
+
         local->ops->configure_filter(&local->hw, changed_flags, total_flags,
-                                     mc_count, mc_list);
+                                     multicast);
         trace_drv_configure_filter(local, changed_flags, total_flags,
-                                            mc_count);
+                                   multicast);
 }
 
 static inline int drv_set_tim(struct ieee80211_local *local,
diff --git a/net/mac80211/driver-trace.h b/net/mac80211/driver-trace.h
index 5a10da2d70fd..37b9051afcf3 100644
--- a/net/mac80211/driver-trace.h
+++ b/net/mac80211/driver-trace.h
@@ -191,31 +191,55 @@ TRACE_EVENT(drv_bss_info_changed,
         )
 );
 
+TRACE_EVENT(drv_prepare_multicast,
+        TP_PROTO(struct ieee80211_local *local, int mc_count, u64 ret),
+
+        TP_ARGS(local, mc_count, ret),
+
+        TP_STRUCT__entry(
+                LOCAL_ENTRY
+                __field(int, mc_count)
+                __field(u64, ret)
+        ),
+
+        TP_fast_assign(
+                LOCAL_ASSIGN;
+                __entry->mc_count = mc_count;
+                __entry->ret = ret;
+        ),
+
+        TP_printk(
+                LOCAL_PR_FMT " prepare mc (%d): %llx",
+                LOCAL_PR_ARG, __entry->mc_count,
+                (unsigned long long) __entry->ret
+        )
+);
+
 TRACE_EVENT(drv_configure_filter,
         TP_PROTO(struct ieee80211_local *local,
                  unsigned int changed_flags,
                  unsigned int *total_flags,
-                 int mc_count),
+                 u64 multicast),
 
-        TP_ARGS(local, changed_flags, total_flags, mc_count),
+        TP_ARGS(local, changed_flags, total_flags, multicast),
 
         TP_STRUCT__entry(
                 LOCAL_ENTRY
                 __field(unsigned int, changed)
                 __field(unsigned int, total)
-                __field(int, mc)
+                __field(u64, multicast)
         ),
 
         TP_fast_assign(
                 LOCAL_ASSIGN;
                 __entry->changed = changed_flags;
                 __entry->total = *total_flags;
-                __entry->mc = mc_count;
+                __entry->multicast = multicast;
         ),
 
         TP_printk(
-                LOCAL_PR_FMT " changed:%#x total:%#x mc:%d",
-                LOCAL_PR_ARG, __entry->changed, __entry->total, __entry->mc
+                LOCAL_PR_FMT " changed:%#x total:%#x",
+                LOCAL_PR_ARG, __entry->changed, __entry->total
         )
 );
 
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index a6abc7dfd903..a07f01736a91 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -636,6 +636,9 @@ struct ieee80211_local {
         /* protects the aggregated multicast list and filter calls */
         spinlock_t filter_lock;
 
+        /* used for uploading changed mc list */
+        struct work_struct reconfig_filter;
+
         /* aggregated multicast list */
         struct dev_addr_list *mc_list;
         int mc_count;
diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index e8fb03b91a44..b161301056df 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -227,9 +227,7 @@ static int ieee80211_open(struct net_device *dev)
                 if (sdata->u.mntr_flags & MONITOR_FLAG_OTHER_BSS)
                         local->fif_other_bss++;
 
-                spin_lock_bh(&local->filter_lock);
                 ieee80211_configure_filter(local);
-                spin_unlock_bh(&local->filter_lock);
                 break;
         default:
                 conf.vif = &sdata->vif;
@@ -241,17 +239,13 @@ static int ieee80211_open(struct net_device *dev)
 
                 if (ieee80211_vif_is_mesh(&sdata->vif)) {
                         local->fif_other_bss++;
-                        spin_lock_bh(&local->filter_lock);
                         ieee80211_configure_filter(local);
-                        spin_unlock_bh(&local->filter_lock);
 
                         ieee80211_start_mesh(sdata);
                 } else if (sdata->vif.type == NL80211_IFTYPE_AP) {
                         local->fif_pspoll++;
 
-                        spin_lock_bh(&local->filter_lock);
                         ieee80211_configure_filter(local);
-                        spin_unlock_bh(&local->filter_lock);
                 }
 
                 changed |= ieee80211_reset_erp_info(sdata);
@@ -404,10 +398,11 @@ static int ieee80211_stop(struct net_device *dev)
         spin_lock_bh(&local->filter_lock);
         __dev_addr_unsync(&local->mc_list, &local->mc_count,
                           &dev->mc_list, &dev->mc_count);
-        ieee80211_configure_filter(local);
         spin_unlock_bh(&local->filter_lock);
         netif_addr_unlock_bh(dev);
 
+        ieee80211_configure_filter(local);
+
         del_timer_sync(&local->dynamic_ps_timer);
         cancel_work_sync(&local->dynamic_ps_enable_work);
 
@@ -458,9 +453,7 @@ static int ieee80211_stop(struct net_device *dev)
                 if (sdata->u.mntr_flags & MONITOR_FLAG_OTHER_BSS)
                         local->fif_other_bss--;
 
-                spin_lock_bh(&local->filter_lock);
                 ieee80211_configure_filter(local);
-                spin_unlock_bh(&local->filter_lock);
                 break;
         case NL80211_IFTYPE_STATION:
                 del_timer_sync(&sdata->u.mgd.chswitch_timer);
@@ -503,9 +496,7 @@ static int ieee80211_stop(struct net_device *dev)
                         local->fif_other_bss--;
                         atomic_dec(&local->iff_allmultis);
 
-                        spin_lock_bh(&local->filter_lock);
                         ieee80211_configure_filter(local);
-                        spin_unlock_bh(&local->filter_lock);
 
                         ieee80211_stop_mesh(sdata);
                 }
@@ -622,8 +613,8 @@ static void ieee80211_set_multicast_list(struct net_device *dev)
         spin_lock_bh(&local->filter_lock);
         __dev_addr_sync(&local->mc_list, &local->mc_count,
                         &dev->mc_list, &dev->mc_count);
-        ieee80211_configure_filter(local);
         spin_unlock_bh(&local->filter_lock);
+        ieee80211_queue_work(&local->hw, &local->reconfig_filter);
 }
 
 /*
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index b03fd84777fa..05f923575fee 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -50,9 +50,9 @@ struct ieee80211_tx_status_rtap_hdr {
 } __attribute__ ((packed));
 
 
-/* must be called under mdev tx lock */
 void ieee80211_configure_filter(struct ieee80211_local *local)
 {
+        u64 mc;
         unsigned int changed_flags;
         unsigned int new_flags = 0;
 
@@ -62,7 +62,7 @@ void ieee80211_configure_filter(struct ieee80211_local *local)
         if (atomic_read(&local->iff_allmultis))
                 new_flags |= FIF_ALLMULTI;
 
-        if (local->monitors)
+        if (local->monitors || local->scanning)
                 new_flags |= FIF_BCN_PRBRESP_PROMISC;
 
         if (local->fif_fcsfail)
@@ -80,20 +80,30 @@ void ieee80211_configure_filter(struct ieee80211_local *local)
         if (local->fif_pspoll)
                 new_flags |= FIF_PSPOLL;
 
+        spin_lock_bh(&local->filter_lock);
         changed_flags = local->filter_flags ^ new_flags;
 
+        mc = drv_prepare_multicast(local, local->mc_count, local->mc_list);
+        spin_unlock_bh(&local->filter_lock);
+
         /* be a bit nasty */
         new_flags |= (1<<31);
 
-        drv_configure_filter(local, changed_flags, &new_flags,
-                             local->mc_count,
-                             local->mc_list);
+        drv_configure_filter(local, changed_flags, &new_flags, mc);
 
         WARN_ON(new_flags & (1<<31));
 
         local->filter_flags = new_flags & ~(1<<31);
 }
 
+static void ieee80211_reconfig_filter(struct work_struct *work)
+{
+        struct ieee80211_local *local =
+                container_of(work, struct ieee80211_local, reconfig_filter);
+
+        ieee80211_configure_filter(local);
+}
+
 int ieee80211_hw_config(struct ieee80211_local *local, u32 changed)
 {
         struct ieee80211_channel *chan, *scan_chan;
@@ -692,6 +702,8 @@ struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len,
 
         INIT_WORK(&local->restart_work, ieee80211_restart_work);
 
+        INIT_WORK(&local->reconfig_filter, ieee80211_reconfig_filter);
+
         INIT_WORK(&local->dynamic_ps_enable_work,
                   ieee80211_dynamic_ps_enable_work);
         INIT_WORK(&local->dynamic_ps_disable_work,
@@ -946,6 +958,8 @@ void ieee80211_unregister_hw(struct ieee80211_hw *hw)
 
         rtnl_unlock();
 
+        cancel_work_sync(&local->reconfig_filter);
+
         ieee80211_clear_tx_pending(local);
         sta_info_stop(local);
         rate_control_deinitialize(local);
diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index e091cbc3434f..1e04be6b9129 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -292,13 +292,7 @@ void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
         if (was_hw_scan)
                 goto done;
 
-        spin_lock_bh(&local->filter_lock);
-        local->filter_flags &= ~FIF_BCN_PRBRESP_PROMISC;
-        drv_configure_filter(local, FIF_BCN_PRBRESP_PROMISC,
-                             &local->filter_flags,
-                             local->mc_count,
-                             local->mc_list);
-        spin_unlock_bh(&local->filter_lock);
+        ieee80211_configure_filter(local);
 
         drv_sw_scan_complete(local);
 
@@ -376,13 +370,7 @@ static int ieee80211_start_sw_scan(struct ieee80211_local *local)
         local->next_scan_state = SCAN_DECISION;
         local->scan_channel_idx = 0;
 
-        spin_lock_bh(&local->filter_lock);
-        local->filter_flags |= FIF_BCN_PRBRESP_PROMISC;
-        drv_configure_filter(local, FIF_BCN_PRBRESP_PROMISC,
-                             &local->filter_flags,
-                             local->mc_count,
-                             local->mc_list);
-        spin_unlock_bh(&local->filter_lock);
+        ieee80211_configure_filter(local);
 
         /* TODO: start scan as soon as all nullfunc frames are ACKed */
         ieee80211_queue_delayed_work(&local->hw,
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index e55d57f559ec..5eb306377c63 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -1076,9 +1076,7 @@ int ieee80211_reconfig(struct ieee80211_local *local)
         /* reconfigure hardware */
         ieee80211_hw_config(local, ~0);
 
-        spin_lock_bh(&local->filter_lock);
         ieee80211_configure_filter(local);
-        spin_unlock_bh(&local->filter_lock);
 
         /* Finally also reconfigure all the BSS information */
         list_for_each_entry(sdata, &local->interfaces, list) {