wl12xx: avoid starving the system hlid

Re-factor the Tx scheduler so that the system_hlid is taken into account
before restarting an iteration over the wlvifs. Previously this
hlid had a lower priority and would starve if some wlvif had many
packets.
In addition avoid iterating over wlvifs past last_wlvif when performing
the a second pass. If we had packets in those wlvifs they would have
been found earlier.

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

1 files changed, 13 insertions, 4 deletions

diff --git a/drivers/net/wireless/wl12xx/tx.c b/drivers/net/wireless/wl12xx/tx.c
index 8f5ab047aec8..6640c3975cfb 100644
--- a/drivers/net/wireless/wl12xx/tx.c
+++ b/drivers/net/wireless/wl12xx/tx.c
@@ -572,6 +572,7 @@ static struct sk_buff *wl1271_skb_dequeue(struct wl1271 *wl)
         struct wl12xx_vif *wlvif = wl->last_wlvif;
         struct sk_buff *skb = NULL;
 
+        /* continue from last wlvif (round robin) */
         if (wlvif) {
                 wl12xx_for_each_wlvif_continue(wl, wlvif) {
                         skb = wl12xx_vif_skb_dequeue(wl, wlvif);
@@ -582,7 +583,11 @@ static struct sk_buff *wl1271_skb_dequeue(struct wl1271 *wl)
                 }
         }
 
-        /* do another pass */
+        /* dequeue from the system HLID before the restarting wlvif list */
+        if (!skb)
+                skb = wl12xx_lnk_skb_dequeue(wl, &wl->links[wl->system_hlid]);
+
+        /* do a new pass over the wlvif list */
         if (!skb) {
                 wl12xx_for_each_wlvif(wl, wlvif) {
                         skb = wl12xx_vif_skb_dequeue(wl, wlvif);
@@ -590,12 +595,16 @@ static struct sk_buff *wl1271_skb_dequeue(struct wl1271 *wl)
                                 wl->last_wlvif = wlvif;
                                 break;
                         }
+
+                        /*
+                         * No need to continue after last_wlvif. The previous
+                         * pass should have found it.
+                         */
+                        if (wlvif == wl->last_wlvif)
+                                break;
                 }
         }
 
-        if (!skb)
-                skb = wl12xx_lnk_skb_dequeue(wl, &wl->links[wl->system_hlid]);
-
         if (!skb &&
             test_and_clear_bit(WL1271_FLAG_DUMMY_PACKET_PENDING, &wl->flags)) {
                 int q;