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mii(4): Make mii_down wait for concurrent mii_phy_auto to finish. 

This is important for callers in if_stop routines to guarantee that
all concurrent access to the mii registers has ended.

Drivers must not call this from softint context.  Drivers with custom
watchdog timers (not if_watchdog) that do if_stop from callout must
defer to thread context instead, e.g. via workqueue(9) -- as they
should be doing anyway for heavyweight operations like if_stop.
This commit is contained in:
riastradh 2022-08-20 11:12:46 +00:00
parent 877c0de281
commit e83eef3e0a
1 changed files with 15 additions and 31 deletions
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46
sys/dev/mii/mii_physubr.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: mii_physubr.c,v 1.99 2022/08/14 20:34:26 riastradh Exp $ */
/* $NetBSD: mii_physubr.c,v 1.100 2022/08/20 11:12:46 riastradh Exp $ */
/*-
* Copyright (c) 1998, 1999, 2000, 2001 The NetBSD Foundation, Inc.
@ -35,7 +35,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: mii_physubr.c,v 1.99 2022/08/14 20:34:26 riastradh Exp $");
__KERNEL_RCSID(0, "$NetBSD: mii_physubr.c,v 1.100 2022/08/20 11:12:46 riastradh Exp $");
#include <sys/param.h>
#include <sys/device.h>
@ -435,23 +435,18 @@ mii_phy_down(struct mii_softc *sc)
KASSERT(mii_locked(sc->mii_pdata));
if ((sc->mii_flags & (MIIF_DOINGAUTO|MIIF_AUTOTSLEEP)) ==
(MIIF_DOINGAUTO|MIIF_AUTOTSLEEP)) {
/*
* Try to stop it.
*
* - If we stopped it before it expired, callout_stop
* returns 0, and it is our responsibility to clear
* MIIF_DOINGAUTO.
*
* - Otherwise, we're too late -- the callout has
* already begun, and we must leave MIIF_DOINGAUTO
* set so mii_phy_detach will wait for it to
* complete.
*/
if (!callout_stop(&sc->mii_nway_ch))
sc->mii_flags &= ~MIIF_DOINGAUTO;
if (sc->mii_flags & MIIF_AUTOTSLEEP) {
while (sc->mii_flags & MIIF_DOINGAUTO) {
cv_wait(&sc->mii_nway_cv,
sc->mii_pdata->mii_media.ifm_lock);
}
} else {
if (sc->mii_flags & MIIF_DOINGAUTO) {
callout_halt(&sc->mii_nway_ch,
sc->mii_pdata->mii_media.ifm_lock);
}
}
KASSERT((sc->mii_flags & MIIF_DOINGAUTO) == 0);
}
void
@ -691,19 +686,8 @@ mii_phy_detach(device_t self, int flags)
{
struct mii_softc *sc = device_private(self);
mii_lock(sc->mii_pdata);
if (sc->mii_flags & MIIF_AUTOTSLEEP) {
while (sc->mii_flags & MIIF_DOINGAUTO) {
cv_wait(&sc->mii_nway_cv,
sc->mii_pdata->mii_media.ifm_lock);
}
} else {
if (sc->mii_flags & MIIF_DOINGAUTO) {
callout_halt(&sc->mii_nway_ch,
sc->mii_pdata->mii_media.ifm_lock);
}
}
mii_unlock(sc->mii_pdata);
/* No mii_lock because mii_flags should be stable by now. */
KASSERT((sc->mii_flags & MIIF_DOINGAUTO) == 0);
if (sc->mii_flags & MIIF_AUTOTSLEEP)
cv_destroy(&sc->mii_nway_cv);