svn commit: r309348 - head/sys/dev/hyperv/netvsc

[Sepherosa Ziehau]

Author: sephe
Date: Thu Dec  1 03:39:34 2016
New Revision: 309348
URL: https://svnweb.freebsd.org/changeset/base/309348

Log:
  hyperv/hn: Don't hold txdesc, if no BPFs are attached.
  
  MFC after:	1 week
  Sponsored by:	Microsoft
  Differential Revision:	https://reviews.freebsd.org/D8675

Modified:
  head/sys/dev/hyperv/netvsc/if_hn.c

Modified: head/sys/dev/hyperv/netvsc/if_hn.c
==============================================================================
--- head/sys/dev/hyperv/netvsc/if_hn.c	Thu Dec  1 03:34:04 2016	(r309347)
+++ head/sys/dev/hyperv/netvsc/if_hn.c	Thu Dec  1 03:39:34 2016	(r309348)
@@ -1924,17 +1924,20 @@ done:
 static int
 hn_txpkt(struct ifnet *ifp, struct hn_tx_ring *txr, struct hn_txdesc *txd)
 {
-	int error, send_failed = 0;
+	int error, send_failed = 0, has_bpf;
 
 again:
-	/*
-	 * Make sure that this txd and any aggregated txds are not freed
-	 * before ETHER_BPF_MTAP.
-	 */
-	hn_txdesc_hold(txd);
+	has_bpf = bpf_peers_present(ifp->if_bpf);
+	if (has_bpf) {
+		/*
+		 * Make sure that this txd and any aggregated txds are not
+		 * freed before ETHER_BPF_MTAP.
+		 */
+		hn_txdesc_hold(txd);
+	}
 	error = txr->hn_sendpkt(txr, txd);
 	if (!error) {
-		if (bpf_peers_present(ifp->if_bpf)) {
+		if (has_bpf) {
 			const struct hn_txdesc *tmp_txd;
 
 			ETHER_BPF_MTAP(ifp, txd->m);
@@ -1957,7 +1960,8 @@ again:
 		txr->hn_pkts += txr->hn_stat_pkts;
 		txr->hn_sends++;
 	}
-	hn_txdesc_put(txr, txd);
+	if (has_bpf)
+		hn_txdesc_put(txr, txd);
 
 	if (__predict_false(error)) {
 		int freed;