wl12xx: Avoid redundant TX work

TX might be handled in the threaded IRQ handler, in which case, TX work
might be scheduled just to discover it has nothing to do.

Save a few context switches by cancelling redundant TX work in case TX
is about to be handled in the threaded IRQ handler. Also, avoid
scheduling TX work from wl1271_op_tx if not needed.

Signed-off-by: Ido Yariv <ido@wizery.com>
Reviewed-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>

diff --git a/drivers/net/wireless/wl12xx/main.c b/drivers/net/wireless/wl12xx/main.c
index f408c5a84cc912ff65784e0e6cbb6534499b05ca..2679abcf5a056a891086a43a270f72be77a288ef 100644 (file)
--- a/drivers/net/wireless/wl12xx/main.c
+++ b/drivers/net/wireless/wl12xx/main.c
@@ -668,6 +668,11 @@ irqreturn_t wl1271_irq(int irq, void *cookie)
        struct wl1271 *wl = (struct wl1271 *)cookie;
        bool done = false;
        unsigned int defer_count;
+       unsigned long flags;
+
+       /* TX might be handled here, avoid redundant work */
+       set_bit(WL1271_FLAG_TX_PENDING, &wl->flags);
+       cancel_work_sync(&wl->tx_work);
 
        mutex_lock(&wl->mutex);
 
@@ -712,13 +717,17 @@ irqreturn_t wl1271_irq(int irq, void *cookie)
                        wl1271_rx(wl, &wl->fw_status->common);
 
                        /* Check if any tx blocks were freed */
+                       spin_lock_irqsave(&wl->wl_lock, flags);
                        if (!test_bit(WL1271_FLAG_FW_TX_BUSY, &wl->flags) &&
                            wl->tx_queue_count) {
+                               spin_unlock_irqrestore(&wl->wl_lock, flags);
                                /*
                                 * In order to avoid starvation of the TX path,
                                 * call the work function directly.
                                 */
                                wl1271_tx_work_locked(wl);
+                       } else {
+                               spin_unlock_irqrestore(&wl->wl_lock, flags);
                        }
 
                        /* check for tx results */
@@ -754,6 +763,14 @@ irqreturn_t wl1271_irq(int irq, void *cookie)
        wl1271_ps_elp_sleep(wl);
 
 out:
+       spin_lock_irqsave(&wl->wl_lock, flags);
+       /* In case TX was not handled here, queue TX work */
+       clear_bit(WL1271_FLAG_TX_PENDING, &wl->flags);
+       if (!test_bit(WL1271_FLAG_FW_TX_BUSY, &wl->flags) &&
+           wl->tx_queue_count)
+               ieee80211_queue_work(wl->hw, &wl->tx_work);
+       spin_unlock_irqrestore(&wl->wl_lock, flags);
+
        mutex_unlock(&wl->mutex);
 
        return IRQ_HANDLED;
@@ -1068,7 +1085,13 @@ static void wl1271_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
        int q;
        u8 hlid = 0;
 
+       q = wl1271_tx_get_queue(skb_get_queue_mapping(skb));
+
+       if (wl->bss_type == BSS_TYPE_AP_BSS)
+               hlid = wl1271_tx_get_hlid(skb);
+
        spin_lock_irqsave(&wl->wl_lock, flags);
+
        wl->tx_queue_count++;
 
        /*
@@ -1081,12 +1104,8 @@ static void wl1271_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
                set_bit(WL1271_FLAG_TX_QUEUE_STOPPED, &wl->flags);
        }
 
-       spin_unlock_irqrestore(&wl->wl_lock, flags);
-
        /* queue the packet */
-       q = wl1271_tx_get_queue(skb_get_queue_mapping(skb));
        if (wl->bss_type == BSS_TYPE_AP_BSS) {
-               hlid = wl1271_tx_get_hlid(skb);
                wl1271_debug(DEBUG_TX, "queue skb hlid %d q %d", hlid, q);
                skb_queue_tail(&wl->links[hlid].tx_queue[q], skb);
        } else {
@@ -1098,8 +1117,11 @@ static void wl1271_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
         * before that, the tx_work will not be initialized!
         */
 
-       if (!test_bit(WL1271_FLAG_FW_TX_BUSY, &wl->flags))
+       if (!test_bit(WL1271_FLAG_FW_TX_BUSY, &wl->flags) &&
+           !test_bit(WL1271_FLAG_TX_PENDING, &wl->flags))
                ieee80211_queue_work(wl->hw, &wl->tx_work);
+
+       spin_unlock_irqrestore(&wl->wl_lock, flags);
 }
 
 static struct notifier_block wl1271_dev_notifier = {

diff --git a/drivers/net/wireless/wl12xx/wl12xx.h b/drivers/net/wireless/wl12xx/wl12xx.h
index e395c0c4ebbda7dd7afcf7d340a6f3dbce1cb7e5..86be83e25ec556c0a8304250e7e4d70fcd990e8b 100644 (file)
--- a/drivers/net/wireless/wl12xx/wl12xx.h
+++ b/drivers/net/wireless/wl12xx/wl12xx.h
@@ -317,6 +317,7 @@ enum wl12xx_flags {
        WL1271_FLAG_JOINED,
        WL1271_FLAG_GPIO_POWER,
        WL1271_FLAG_TX_QUEUE_STOPPED,
+       WL1271_FLAG_TX_PENDING,
        WL1271_FLAG_IN_ELP,
        WL1271_FLAG_PSM,
        WL1271_FLAG_PSM_REQUESTED,