[src/trunk]: src/sys/dev/pci Fix wm_watchdog_txq() lock region.

[knakahara <knakahara%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/386d20aa7417
branches:  trunk
changeset: 358765:386d20aa7417
user:      knakahara <knakahara%NetBSD.org@localhost>
date:      Tue Jan 16 07:23:13 2018 +0000

description:
Fix wm_watchdog_txq() lock region.

Not only wm_txeof() but also wm_watchdog_txq() itself requires txq_lock
as it reads Tx descriptor management variables such as "txq_free".

There is almost no influence on performance.

diffstat:

 sys/dev/pci/if_wm.c |  18 ++++++++++++++----
 1 files changed, 14 insertions(+), 4 deletions(-)

diffs (53 lines):

diff -r fe079fccb98d -r 386d20aa7417 sys/dev/pci/if_wm.c
--- a/sys/dev/pci/if_wm.c       Tue Jan 16 07:05:24 2018 +0000
+++ b/sys/dev/pci/if_wm.c       Tue Jan 16 07:23:13 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: if_wm.c,v 1.554 2018/01/15 04:25:48 knakahara Exp $    */
+/*     $NetBSD: if_wm.c,v 1.555 2018/01/16 07:23:13 knakahara Exp $    */
 
 /*
  * Copyright (c) 2001, 2002, 2003, 2004 Wasabi Systems, Inc.
@@ -83,7 +83,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_wm.c,v 1.554 2018/01/15 04:25:48 knakahara Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_wm.c,v 1.555 2018/01/16 07:23:13 knakahara Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_net_mpsafe.h"
@@ -671,6 +671,7 @@
 static bool    wm_resume(device_t, const pmf_qual_t *);
 static void    wm_watchdog(struct ifnet *);
 static void    wm_watchdog_txq(struct ifnet *, struct wm_txqueue *);
+static void    wm_watchdog_txq_locked(struct ifnet *, struct wm_txqueue *);
 static void    wm_tick(void *);
 static int     wm_ifflags_cb(struct ethercom *);
 static int     wm_ioctl(struct ifnet *, u_long, void *);
@@ -2953,15 +2954,24 @@
 static void
 wm_watchdog_txq(struct ifnet *ifp, struct wm_txqueue *txq)
 {
+
+       mutex_enter(txq->txq_lock);
+       wm_watchdog_txq_locked(ifp, txq);
+       mutex_exit(txq->txq_lock);
+}
+
+static void
+wm_watchdog_txq_locked(struct ifnet *ifp, struct wm_txqueue *txq)
+{
        struct wm_softc *sc = ifp->if_softc;
 
+       KASSERT(mutex_owned(txq->txq_lock));
+
        /*
         * Since we're using delayed interrupts, sweep up
         * before we report an error.
         */
-       mutex_enter(txq->txq_lock);
        wm_txeof(sc, txq);
-       mutex_exit(txq->txq_lock);
 
        if (txq->txq_free != WM_NTXDESC(txq)) {
 #ifdef WM_DEBUG