From: Ed Cashin <ecashin@coraid.com>
Date: Thu, 25 Oct 2012 01:15:20 +0000 (+1100)
Subject: aoe: print warning regarding a common reason for dropped transmits
X-Git-Tag: next-20121029~1^2~12
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=5bd24a455f3c5d1afd6681b7751c4fb80614ab88;p=karo-tx-linux.git

aoe: print warning regarding a common reason for dropped transmits

Dropped transmits are not common, but when they do occur, increasing
the transmit queue length often helps.

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/drivers/block/aoe/aoenet.c b/drivers/block/aoe/aoenet.c
index 162c6471275c..a1bb692663df 100644
--- a/drivers/block/aoe/aoenet.c
+++ b/drivers/block/aoe/aoenet.c
@@ -50,7 +50,11 @@ __setup("aoe_iflist=", aoe_iflist_setup);
 static spinlock_t txlock;
 static struct sk_buff_head skbtxq;
 
-/* enters with txlock held */
+/* enters with txlock held
+ *
+ * Use __must_hold(&txlock) for sparse when upcoming patch adds it to
+ * compiler.h.
+ */
 static int
 tx(void)
 {
@@ -58,7 +62,10 @@ tx(void)
 
 	while ((skb = skb_dequeue(&skbtxq))) {
 		spin_unlock_irq(&txlock);
-		dev_queue_xmit(skb);
+		if (dev_queue_xmit(skb) == NET_XMIT_DROP && net_ratelimit())
+			pr_warn("aoe: packet could not be sent on %s.  %s\n",
+				skb->dev ? skb->dev->name : "netif",
+				"consider increasing tx_queue_len");
 		spin_lock_irq(&txlock);
 	}
 	return 0;