mac80211: add improved HW queue control

mac80211 currently only supports one hardware queue
per AC. This is already problematic for off-channel
uses since if we go off channel while the BE queue
is full and then try to send an off-channel frame
the frame will never go out. This will become worse
when we support multi-channel since then a queue on
one channel might be full, but we have to stop the
software queue for all channels. That is obviously
not desirable.

To address this problem allow drivers to register
more hardware queues, and allow them to map them to
virtual interfaces. When they stop a hardware queue
the corresponding AC software queues on the correct
interfaces will be stopped as well. Additionally,
there's an off-channel queue to solve that problem
and a per-interface after-DTIM beacon queue. This
allows drivers to manage software queues closer to
how the hardware works.

Currently, there's a limit of 16 hardware queues.
This may or may not be sufficient, we can adjust it
as needed.

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

1 files changed, 62 insertions, 0 deletions

diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 2b88cb278fc4..ed297649c577 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -149,6 +149,34 @@ static int ieee80211_check_concurrent_iface(struct ieee80211_sub_if_data *sdata,
         return 0;
 }
 
+static int ieee80211_check_queues(struct ieee80211_sub_if_data *sdata)
+{
+        int n_queues = sdata->local->hw.queues;
+        int i;
+
+        for (i = 0; i < IEEE80211_NUM_ACS; i++) {
+                if (WARN_ON_ONCE(sdata->vif.hw_queue[i] ==
+                                 IEEE80211_INVAL_HW_QUEUE))
+                        return -EINVAL;
+                if (WARN_ON_ONCE(sdata->vif.hw_queue[i] >=
+                                 n_queues))
+                        return -EINVAL;
+        }
+
+        if (sdata->vif.type != NL80211_IFTYPE_AP) {
+                sdata->vif.cab_queue = IEEE80211_INVAL_HW_QUEUE;
+                return 0;
+        }
+
+        if (WARN_ON_ONCE(sdata->vif.cab_queue == IEEE80211_INVAL_HW_QUEUE))
+                return -EINVAL;
+
+        if (WARN_ON_ONCE(sdata->vif.cab_queue >= n_queues))
+                return -EINVAL;
+
+        return 0;
+}
+
 void ieee80211_adjust_monitor_flags(struct ieee80211_sub_if_data *sdata,
                                     const int offset)
 {
@@ -169,6 +197,20 @@ void ieee80211_adjust_monitor_flags(struct ieee80211_sub_if_data *sdata,
 #undef ADJUST
 }
 
+static void ieee80211_set_default_queues(struct ieee80211_sub_if_data *sdata)
+{
+        struct ieee80211_local *local = sdata->local;
+        int i;
+
+        for (i = 0; i < IEEE80211_NUM_ACS; i++) {
+                if (local->hw.flags & IEEE80211_HW_QUEUE_CONTROL)
+                        sdata->vif.hw_queue[i] = IEEE80211_INVAL_HW_QUEUE;
+                else
+                        sdata->vif.hw_queue[i] = i;
+        }
+        sdata->vif.cab_queue = IEEE80211_INVAL_HW_QUEUE;
+}
+
 static int ieee80211_add_virtual_monitor(struct ieee80211_local *local)
 {
         struct ieee80211_sub_if_data *sdata;
@@ -190,6 +232,8 @@ static int ieee80211_add_virtual_monitor(struct ieee80211_local *local)
         snprintf(sdata->name, IFNAMSIZ, "%s-monitor",
                  wiphy_name(local->hw.wiphy));
 
+        ieee80211_set_default_queues(sdata);
+
         ret = drv_add_interface(local, sdata);
         if (WARN_ON(ret)) {
                 /* ok .. stupid driver, it asked for this! */
@@ -197,6 +241,12 @@ static int ieee80211_add_virtual_monitor(struct ieee80211_local *local)
                 return ret;
         }
 
+        ret = ieee80211_check_queues(sdata);
+        if (ret) {
+                kfree(sdata);
+                return ret;
+        }
+
         rcu_assign_pointer(local->monitor_sdata, sdata);
 
         return 0;
@@ -344,6 +394,9 @@ static int ieee80211_do_open(struct net_device *dev, bool coming_up)
                         res = drv_add_interface(local, sdata);
                         if (res)
                                 goto err_stop;
+                        res = ieee80211_check_queues(sdata);
+                        if (res)
+                                goto err_del_interface;
                 }
 
                 if (sdata->vif.type == NL80211_IFTYPE_AP) {
@@ -1040,6 +1093,13 @@ static int ieee80211_runtime_change_iftype(struct ieee80211_sub_if_data *sdata,
         if (ret)
                 type = sdata->vif.type;
 
+        /*
+         * Ignore return value here, there's not much we can do since
+         * the driver changed the interface type internally already.
+         * The warnings will hopefully make driver authors fix it :-)
+         */
+        ieee80211_check_queues(sdata);
+
         ieee80211_setup_sdata(sdata, type);
 
         err = ieee80211_do_open(sdata->dev, false);
@@ -1266,6 +1326,8 @@ int ieee80211_if_add(struct ieee80211_local *local, const char *name,
                                sizeof(sdata->rc_rateidx_mcs_mask[i]));
         }
 
+        ieee80211_set_default_queues(sdata);
+
         /* setup type-dependent data */
         ieee80211_setup_sdata(sdata, type);