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From: Sean Bruno <sbruno@FreeBSD.org>
Date: Wed, 1 Apr 2015 19:36:55 +0000 (UTC)
To: src-committers@freebsd.org, svn-src-projects@freebsd.org
Subject: svn commit: r280965 - projects/em_mq/sys/dev/e1000
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Author: sbruno
Date: Wed Apr  1 19:36:54 2015
New Revision: 280965
URL: https://svnweb.freebsd.org/changeset/base/280965

Log:
  Always enqueue work first.  If unable to acquire a TXLOCK for this work,
  schedule a task to come back and do it later.
  
  Stolen from igb(4)

Modified:
  projects/em_mq/sys/dev/e1000/if_em.c

Modified: projects/em_mq/sys/dev/e1000/if_em.c
==============================================================================
--- projects/em_mq/sys/dev/e1000/if_em.c	Wed Apr  1 18:57:51 2015	(r280964)
+++ projects/em_mq/sys/dev/e1000/if_em.c	Wed Apr  1 19:36:54 2015	(r280965)
@@ -1002,11 +1002,15 @@ em_mq_start(if_t ifp, struct mbuf *m)
 
 	txr = &adapter->tx_rings[i];
 
+	error = drbr_enqueue(ifp, txr->br, m);
+	if (error)
+		return (error);
+
 	if (EM_TX_TRYLOCK(txr)) {
 		error = em_mq_start_locked(ifp, txr, m);
 		EM_TX_UNLOCK(txr);
 	} else 
-		error = drbr_enqueue(ifp, txr->br, m);
+		taskqueue_enqueue(txr->tq, &txr->tx_task);
 
 	return (error);
 }
@@ -1027,13 +1031,6 @@ em_mq_start_locked(if_t ifp, struct tx_r
 		return (err);
 	}
 
-	enq = 0;
-	if (m != NULL) {
-		err = drbr_enqueue(ifp, txr->br, m);
-		if (err)
-			return (err);
-	} 
-
 	/* Process the queue */
 	while ((next = drbr_peek(ifp, txr->br)) != NULL) {
 		if ((err = em_xmit(txr, &next)) != 0) {