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Do not use Giant to prevent parallel calls to CLOCK_SETTIME(). Use

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private mtx in resettodr(), no implementation of CLOCK_SETTIME() is
allowed to sleep.

Reviewed by:	  imp, jhb
Sponsored by:	  The FreeBSD Foundation
Approved by:	  re (gjb)
X-Differential revision:	https://reviews.freebsd.org/D6825
This commit is contained in:
Konstantin Belousov 2016-06-28 16:42:40 +00:00
parent 6f56cb8dbf
commit 3a0e6f920a
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=302251
2 changed files with 10 additions and 3 deletions
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4
sys/kern/subr_clock.c
View File

@ -67,8 +67,8 @@ sysctl_machdep_adjkerntz(SYSCTL_HANDLER_ARGS)
resettodr();
return (error);
}
SYSCTL_PROC(_machdep, OID_AUTO, adjkerntz, CTLTYPE_INT|CTLFLAG_RW,
&adjkerntz, 0, sysctl_machdep_adjkerntz, "I",
SYSCTL_PROC(_machdep, OID_AUTO, adjkerntz, CTLTYPE_INT | CTLFLAG_RW |
CTLFLAG_MPSAFE, &adjkerntz, 0, sysctl_machdep_adjkerntz, "I",
"Local offset from UTC in seconds");
static int ct_debug;

9
sys/kern/subr_rtc.c
View File

@ -62,6 +62,8 @@ __FBSDID("$FreeBSD$");
#include <sys/kernel.h>
#include <sys/bus.h>
#include <sys/clock.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/sysctl.h>
#ifdef FFCLOCK
#include <sys/timeffc.h>
@ -73,6 +75,8 @@ __FBSDID("$FreeBSD$");
static device_t clock_dev = NULL;
static long clock_res;
static struct timespec clock_adj;
static struct mtx resettodr_lock;
MTX_SYSINIT(resettodr_init, &resettodr_lock, "tod2rl", MTX_DEF);
/* XXX: should be kern. now, it's no longer machdep. */
static int disable_rtc_set;
@ -168,11 +172,14 @@ resettodr(void)
if (disable_rtc_set || clock_dev == NULL)
return;
mtx_lock(&resettodr_lock);
getnanotime(&ts);
timespecadd(&ts, &clock_adj);
ts.tv_sec -= utc_offset();
/* XXX: We should really set all registered RTCs */
if ((error = CLOCK_SETTIME(clock_dev, &ts)) != 0)
error = CLOCK_SETTIME(clock_dev, &ts);
mtx_unlock(&resettodr_lock);
if (error != 0)
printf("warning: clock_settime failed (%d), time-of-day clock "
"not adjusted to system time\n", error);
}