wlcore: tx_flush - optimize flow and force Tx during the flush

Force Tx during the flush if there are packets pending in the driver.
This actually solves a bug where we would get called from the mac80211
wq context, which would prevent tx_work from getting queued, even when
the mutex is unlocked.

Don't stop the queues needlessly if there's nothing to flush. Use a
larger delay when sleeping to give the driver a chance to flush and
avoid cpu busy looping. Re-arrange the loop so the last iteration is
not wasted.

Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: Luciano Coelho <luca@coelho.fi>

diff --git a/drivers/net/wireless/ti/wlcore/tx.c b/drivers/net/wireless/ti/wlcore/tx.c
index d89e0db8a6f9f14f40e45ac2b86aec2a8617e8f8..f9c26b19bff07867aea9f76cb505de43bd5ec77d 100644 (file)
--- a/drivers/net/wireless/ti/wlcore/tx.c
+++ b/drivers/net/wireless/ti/wlcore/tx.c
@@ -1084,22 +1084,32 @@ void wl1271_tx_flush(struct wl1271 *wl)
        /* only one flush should be in progress, for consistent queue state */
        mutex_lock(&wl->flush_mutex);
 
+       mutex_lock(&wl->mutex);
+       if (wl->tx_frames_cnt == 0 && wl1271_tx_total_queue_count(wl) == 0) {
+               mutex_unlock(&wl->mutex);
+               goto out;
+       }
+
        wlcore_stop_queues(wl, WLCORE_QUEUE_STOP_REASON_FLUSH);
 
        while (!time_after(jiffies, timeout)) {
-               mutex_lock(&wl->mutex);
                wl1271_debug(DEBUG_MAC80211, "flushing tx buffer: %d %d",
                             wl->tx_frames_cnt,
                             wl1271_tx_total_queue_count(wl));
+
+               /* force Tx and give the driver some time to flush data */
+               mutex_unlock(&wl->mutex);
+               if (wl1271_tx_total_queue_count(wl))
+                       wl1271_tx_work(&wl->tx_work);
+               msleep(20);
+               mutex_lock(&wl->mutex);
+
                if ((wl->tx_frames_cnt == 0) &&
                    (wl1271_tx_total_queue_count(wl) == 0)) {
-                       mutex_unlock(&wl->mutex);
                        wl1271_debug(DEBUG_MAC80211, "tx flush took %d ms",
                                     jiffies_to_msecs(jiffies - start_time));
-                       goto out;
+                       goto out_wake;
                }
-               mutex_unlock(&wl->mutex);
-               msleep(1);
        }
 
        wl1271_warning("Unable to flush all TX buffers, "
@@ -1107,13 +1117,13 @@ void wl1271_tx_flush(struct wl1271 *wl)
                       WL1271_TX_FLUSH_TIMEOUT / 1000);
 
        /* forcibly flush all Tx buffers on our queues */
-       mutex_lock(&wl->mutex);
        for (i = 0; i < WL12XX_MAX_LINKS; i++)
                wl1271_tx_reset_link_queues(wl, i);
-       mutex_unlock(&wl->mutex);
 
-out:
+out_wake:
        wlcore_wake_queues(wl, WLCORE_QUEUE_STOP_REASON_FLUSH);
+       mutex_unlock(&wl->mutex);
+out:
        mutex_unlock(&wl->flush_mutex);
 }
 EXPORT_SYMBOL_GPL(wl1271_tx_flush);