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usbnet: Omit needless locking around usbnet_isdying. 

Now that is tested and set with atomic_load/store, there is no need
to hold the lock -- which means we can set it while the core lock is
held during, e.g., a reset sequence, and use that to interrupt the
sequence so it doesn't get stuck waiting to time out when the device
is physically removed.
This commit is contained in:
riastradh 2022-03-03 05:50:47 +00:00
parent 4c7e9da15d
commit 839d7b202a
1 changed files with 6 additions and 18 deletions
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24
sys/dev/usb/usbnet.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: usbnet.c,v 1.73 2022/03/03 05:50:39 riastradh Exp $ */
/* $NetBSD: usbnet.c,v 1.74 2022/03/03 05:50:47 riastradh Exp $ */
/*
* Copyright (c) 2019 Matthew R. Green
@ -31,7 +31,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: usbnet.c,v 1.73 2022/03/03 05:50:39 riastradh Exp $");
__KERNEL_RCSID(0, "$NetBSD: usbnet.c,v 1.74 2022/03/03 05:50:47 riastradh Exp $");
#include <sys/param.h>
#include <sys/kernel.h>
@ -1075,12 +1075,11 @@ usbnet_mcast_task(void *arg)
{
USBNETHIST_FUNC();
struct usbnet * const un = arg;
struct usbnet_private * const unp = un->un_pri;
struct ifnet * const ifp = usbnet_ifp(un);
bool dying;
struct ifreq ifr;
USBNETHIST_CALLARGSN(10, "%jd: enter", unp->unp_number, 0, 0, 0);
USBNETHIST_CALLARGSN(10, "%jd: enter",
un->un_pri->unp_number, 0, 0, 0);
/*
* If we're detaching, we must check usbnet_isdying _before_
@ -1091,10 +1090,7 @@ usbnet_mcast_task(void *arg)
* issuing if_detach, and necessary, so that we don't touch
* IFNET_LOCK after if_detach. See usbnet_detach for details.
*/
mutex_enter(&unp->unp_core_lock);
dying = usbnet_isdying(un);
mutex_exit(&unp->unp_core_lock);
if (dying)
if (usbnet_isdying(un))
return;
/*
@ -1288,7 +1284,6 @@ usbnet_if_init(struct ifnet *ifp)
{
USBNETHIST_FUNC(); USBNETHIST_CALLED();
struct usbnet * const un = ifp->if_softc;
bool dying;
int error;
KASSERTMSG(IFNET_LOCKED(ifp), "%s", ifp->if_xname);
@ -1297,10 +1292,7 @@ usbnet_if_init(struct ifnet *ifp)
* Prevent anyone from bringing the interface back up once
* we're detaching.
*/
mutex_enter(&un->un_pri->unp_core_lock);
dying = usbnet_isdying(un);
mutex_exit(&un->un_pri->unp_core_lock);
if (dying)
if (usbnet_isdying(un))
return EIO;
mutex_enter(&un->un_pri->unp_core_lock);
@ -1591,9 +1583,7 @@ usbnet_detach(device_t self, int flags)
* Prevent new activity. After we stop the interface, it
* cannot be brought back up.
*/
mutex_enter(&unp->unp_core_lock);
atomic_store_relaxed(&unp->unp_dying, true);
mutex_exit(&unp->unp_core_lock);
/*
* If we're still running on the network, stop and wait for all
@ -1720,9 +1710,7 @@ usbnet_activate(device_t self, devact_t act)
case DVACT_DEACTIVATE:
if_deactivate(ifp);
mutex_enter(&unp->unp_core_lock);
atomic_store_relaxed(&unp->unp_dying, true);
mutex_exit(&unp->unp_core_lock);
mutex_enter(&unp->unp_rxlock);
mutex_enter(&unp->unp_txlock);