[src/trunk]: src/sys/dev/pci Introduce the lock for vioif_softc to avoid a ra...

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

details:   https://anonhg.NetBSD.org/src/rev/69c31f444a0f
branches:  trunk
changeset: 933355:69c31f444a0f
user:      yamaguchi <yamaguchi%NetBSD.org@localhost>
date:      Mon May 25 09:36:18 2020 +0000

description:
Introduce the lock for vioif_softc to avoid a race condition
in vioif_update_link_status()

The function is called in both vioif_init() and softint.

diffstat:

 sys/dev/pci/if_vioif.c |  15 +++++++++++++--
 1 files changed, 13 insertions(+), 2 deletions(-)

diffs (71 lines):

diff -r d9ef9a84ab90 -r 69c31f444a0f sys/dev/pci/if_vioif.c
--- a/sys/dev/pci/if_vioif.c    Mon May 25 09:31:09 2020 +0000
+++ b/sys/dev/pci/if_vioif.c    Mon May 25 09:36:18 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: if_vioif.c,v 1.61 2020/05/25 09:31:09 yamaguchi Exp $  */
+/*     $NetBSD: if_vioif.c,v 1.62 2020/05/25 09:36:18 yamaguchi Exp $  */
 
 /*
  * Copyright (c) 2010 Minoura Makoto.
@@ -26,7 +26,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_vioif.c,v 1.61 2020/05/25 09:31:09 yamaguchi Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_vioif.c,v 1.62 2020/05/25 09:36:18 yamaguchi Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_net_mpsafe.h"
@@ -205,6 +205,9 @@
  * + ctrlq_inuse is protected by ctrlq_wait_lock.
  *      - other fields in vioif_ctrlqueue are protected by ctrlq_inuse
  *      - txq_lock or rxq_lock cannot be held along with ctrlq_wait_lock
+ * + fields in vioif_softc except queues are protected by
+ *   sc->sc_lock(an adaptive mutex)
+ *      - the lock is held before acquisition of other locks
  */
 
 struct vioif_work {
@@ -279,6 +282,7 @@
 
 struct vioif_softc {
        device_t                sc_dev;
+       kmutex_t                sc_lock;
        struct sysctllog        *sc_sysctllog;
 
        struct virtio_softc     *sc_virtio;
@@ -793,6 +797,8 @@
        sc->sc_rx_intr_process_limit = VIOIF_RX_INTR_PROCESS_LIMIT;
        sc->sc_rx_process_limit = VIOIF_RX_PROCESS_LIMIT;
 
+       mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_NONE);
+
        snprintf(xnamebuf, sizeof(xnamebuf), "%s_txrx", device_xname(self));
        sc->sc_txrx_workqueue = vioif_workq_create(xnamebuf, VIOIF_WORKQUEUE_PRI,
            IPL_NET, WQ_PERCPU | WQ_MPSAFE);
@@ -1039,6 +1045,7 @@
                virtio_free_vq(vsc, &sc->sc_vqs[--nvqs]);
 
        vioif_free_queues(sc);
+       mutex_destroy(&sc->sc_lock);
        virtio_child_attach_failed(vsc);
        config_finalize_register(self, vioif_finalize_teardown);
 
@@ -2274,6 +2281,8 @@
        bool active, changed;
        int link, i;
 
+       mutex_enter(&sc->sc_lock);
+
        active = vioif_is_link_up(sc);
        changed = false;
 
@@ -2302,6 +2311,8 @@
 
                if_link_state_change(ifp, link);
        }
+
+       mutex_exit(&sc->sc_lock);
 }
 
 static int