Module Name: src
Committed By: jmcneill
Date: Tue Jan 22 12:04:59 UTC 2013
Modified Files:
src/sys/dev/usb: if_urtwn.c
Log Message:
simplify the locking in urtwn_start
To generate a diff of this commit:
cvs rdiff -u -r1.16 -r1.17 src/sys/dev/usb/if_urtwn.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/dev/usb/if_urtwn.c
diff -u src/sys/dev/usb/if_urtwn.c:1.16 src/sys/dev/usb/if_urtwn.c:1.17
--- src/sys/dev/usb/if_urtwn.c:1.16 Mon Jan 21 23:42:45 2013
+++ src/sys/dev/usb/if_urtwn.c Tue Jan 22 12:04:58 2013
@@ -1,4 +1,4 @@
-/* $NetBSD: if_urtwn.c,v 1.16 2013/01/21 23:42:45 jmcneill Exp $ */
+/* $NetBSD: if_urtwn.c,v 1.17 2013/01/22 12:04:58 jmcneill Exp $ */
/* $OpenBSD: if_urtwn.c,v 1.20 2011/11/26 06:39:33 ckuethe Exp $ */
/*-
@@ -22,7 +22,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_urtwn.c,v 1.16 2013/01/21 23:42:45 jmcneill Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_urtwn.c,v 1.17 2013/01/22 12:04:58 jmcneill Exp $");
#ifdef _KERNEL_OPT
#include "opt_inet.h"
@@ -2331,22 +2331,22 @@ urtwn_start(struct ifnet *ifp)
data = NULL;
for (;;) {
mutex_enter(&sc->sc_tx_mtx);
- if (data == NULL) {
+ if (data == NULL && !TAILQ_EMPTY(&sc->tx_free_list)) {
data = TAILQ_FIRST(&sc->tx_free_list);
- if (data == NULL) {
- mutex_exit(&sc->sc_tx_mtx);
- ifp->if_flags |= IFF_OACTIVE;
- DPRINTFN(DBG_TX, ("%s: empty tx_free_list\n",
- device_xname(sc->sc_dev)));
- return;
- }
TAILQ_REMOVE(&sc->tx_free_list, data, next);
}
+ mutex_exit(&sc->sc_tx_mtx);
+
+ if (data == NULL) {
+ ifp->if_flags |= IFF_OACTIVE;
+ DPRINTFN(DBG_TX, ("%s: empty tx_free_list\n",
+ device_xname(sc->sc_dev)));
+ return;
+ }
/* Send pending management frames first. */
IF_DEQUEUE(&ic->ic_mgtq, m);
if (m != NULL) {
- mutex_exit(&sc->sc_tx_mtx);
ni = (void *)m->m_pkthdr.rcvif;
m->m_pkthdr.rcvif = NULL;
goto sendit;
@@ -2359,8 +2359,6 @@ urtwn_start(struct ifnet *ifp)
if (m == NULL)
break;
- mutex_exit(&sc->sc_tx_mtx);
-
if (m->m_len < (int)sizeof(*eh) &&
(m = m_pullup(m, sizeof(*eh))) == NULL) {
ifp->if_oerrors++;
@@ -2398,6 +2396,7 @@ urtwn_start(struct ifnet *ifp)
}
/* Return the Tx buffer to the free list */
+ mutex_enter(&sc->sc_tx_mtx);
TAILQ_INSERT_TAIL(&sc->tx_free_list, data, next);
mutex_exit(&sc->sc_tx_mtx);
}
