mac80211: implement off-channel TX using hw r-o-c offload

When the driver has remain-on-channel offload,
implement off-channel transmission using that
primitive.

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

3 files changed, 81 insertions, 10 deletions

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 168a6ba8fc28..4bc8a9250cfd 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1641,6 +1641,7 @@ static int ieee80211_remain_on_channel(struct wiphy *wiphy,
                 ret = ieee80211_remain_on_channel_hw(local, dev,
                                                      chan, channel_type,
                                                      duration, cookie);
+                local->hw_roc_for_tx = false;
                 mutex_unlock(&local->mtx);
 
                 return ret;
@@ -1783,6 +1784,49 @@ static int ieee80211_mgmt_tx(struct wiphy *wiphy, struct net_device *dev,
 
         *cookie = (unsigned long) skb;
 
+        if (is_offchan && local->ops->remain_on_channel) {
+                unsigned int duration;
+                int ret;
+
+                mutex_lock(&local->mtx);
+                /*
+                 * If the duration is zero, then the driver
+                 * wouldn't actually do anything. Set it to
+                 * 100 for now.
+                 *
+                 * TODO: cancel the off-channel operation
+                 *       when we get the SKB's TX status and
+                 *       the wait time was zero before.
+                 */
+                duration = 100;
+                if (wait)
+                        duration = wait;
+                ret = ieee80211_remain_on_channel_hw(local, dev, chan,
+                                                     channel_type,
+                                                     duration, cookie);
+                if (ret) {
+                        kfree_skb(skb);
+                        mutex_unlock(&local->mtx);
+                        return ret;
+                }
+
+                local->hw_roc_for_tx = true;
+                local->hw_roc_duration = wait;
+
+                /*
+                 * queue up frame for transmission after
+                 * ieee80211_ready_on_channel call
+                 */
+
+                /* modify cookie to prevent API mismatches */
+                *cookie ^= 2;
+                IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_CTL_TX_OFFCHAN;
+                local->hw_roc_skb = skb;
+                mutex_unlock(&local->mtx);
+
+                return 0;
+        }
+
         /*
          * Can transmit right away if the channel was the
          * right one and there's no wait involved... If a
@@ -1823,6 +1867,21 @@ static int ieee80211_mgmt_tx_cancel_wait(struct wiphy *wiphy,
         int ret = -ENOENT;
 
         mutex_lock(&local->mtx);
+
+        if (local->ops->cancel_remain_on_channel) {
+                cookie ^= 2;
+                ret = ieee80211_cancel_remain_on_channel_hw(local, cookie);
+
+                if (ret == 0) {
+                        kfree_skb(local->hw_roc_skb);
+                        local->hw_roc_skb = NULL;
+                }
+
+                mutex_unlock(&local->mtx);
+
+                return ret;
+        }
+
         list_for_each_entry(wk, &local->work_list, list) {
                 if (wk->sdata != sdata)
                         continue;
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index f866af8de5ac..c47d7c0e48a4 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -953,10 +953,12 @@ struct ieee80211_local {
 
         struct ieee80211_channel *hw_roc_channel;
         struct net_device *hw_roc_dev;
+        struct sk_buff *hw_roc_skb;
         struct work_struct hw_roc_start, hw_roc_done;
         enum nl80211_channel_type hw_roc_channel_type;
         unsigned int hw_roc_duration;
         u32 hw_roc_cookie;
+        bool hw_roc_for_tx;
 
         /* dummy netdev for use w/ NAPI */
         struct net_device napi_dev;
diff --git a/net/mac80211/offchannel.c b/net/mac80211/offchannel.c
index 49b9ec22d9b6..b4e52676f3fb 100644
--- a/net/mac80211/offchannel.c
+++ b/net/mac80211/offchannel.c
@@ -196,6 +196,7 @@ static void ieee80211_hw_roc_start(struct work_struct *work)
 {
         struct ieee80211_local *local =
                 container_of(work, struct ieee80211_local, hw_roc_start);
+        struct ieee80211_sub_if_data *sdata;
 
         mutex_lock(&local->mtx);
 
@@ -206,11 +207,19 @@ static void ieee80211_hw_roc_start(struct work_struct *work)
 
         ieee80211_recalc_idle(local);
 
-        cfg80211_ready_on_channel(local->hw_roc_dev, local->hw_roc_cookie,
-                                  local->hw_roc_channel,
-                                  local->hw_roc_channel_type,
-                                  local->hw_roc_duration,
-                                  GFP_KERNEL);
+        if (local->hw_roc_skb) {
+                sdata = IEEE80211_DEV_TO_SUB_IF(local->hw_roc_dev);
+                ieee80211_tx_skb(sdata, local->hw_roc_skb);
+                local->hw_roc_skb = NULL;
+        } else {
+                cfg80211_ready_on_channel(local->hw_roc_dev,
+                                          local->hw_roc_cookie,
+                                          local->hw_roc_channel,
+                                          local->hw_roc_channel_type,
+                                          local->hw_roc_duration,
+                                          GFP_KERNEL);
+        }
+
         mutex_unlock(&local->mtx);
 }
 
@@ -236,11 +245,12 @@ static void ieee80211_hw_roc_done(struct work_struct *work)
                 return;
         }
 
-        cfg80211_remain_on_channel_expired(local->hw_roc_dev,
-                                           local->hw_roc_cookie,
-                                           local->hw_roc_channel,
-                                           local->hw_roc_channel_type,
-                                           GFP_KERNEL);
+        if (!local->hw_roc_for_tx)
+                cfg80211_remain_on_channel_expired(local->hw_roc_dev,
+                                                   local->hw_roc_cookie,
+                                                   local->hw_roc_channel,
+                                                   local->hw_roc_channel_type,
+                                                   GFP_KERNEL);
 
         local->hw_roc_channel = NULL;
         local->hw_roc_cookie = 0;