From: Arik Nemtsov <arik@wizery.com>
Date: Mon, 27 Feb 2012 22:41:31 +0000 (+0200)
Subject: wl12xx: avoid starving the system hlid
X-Git-Tag: firefly_0821_release~3680^2~3338^2~108^2~39^2~15
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=49c9cd26445aa8bc8348c384c943b758c57c47a9;p=firefly-linux-kernel-4.4.55.git

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>
---

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;