Cleanup non-arch xtime uses, use get_seconds() or current_kernel_time().

This avoids use of the kernel-internal "xtime" variable directly outside of the actual time-related functions. Instead, use the helper functions that we already have available to us. This doesn't actually change any behaviour, but this will allow us to fix the fact that "xtime" isn't updated very often with CONFIG_NO_HZ (because much of the realtime information is maintained as separate offsets to 'xtime'), which has caused interfaces that use xtime directly to get a time that is out of sync with the real-time clock by up to a third of a second or so. Signed-off-by: John Stultz <johnstul@us.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Cleanup non-arch xtime uses, use get_seconds() or current_kernel_time().
This avoids use of the kernel-internal "xtime" variable directly outside of the actual time-related functions. Instead, use the helper functions that we already have available to us. This doesn't actually change any behaviour, but this will allow us to fix the fact that "xtime" isn't updated very often with CONFIG_NO_HZ (because much of the realtime information is maintained as separate offsets to 'xtime'), which has caused interfaces that use xtime directly to get a time that is out of sync with the real-time clock by up to a third of a second or so. Signed-off-by: John Stultz <johnstul@us.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
john stultz · Linus Torvalds
1 parent 0de085bb47
Showing 13 changed files with 34 additions and 33 deletions Side-by-side Diff
drivers/rtc/class.c
drivers/s390/net/ctcmain.c
drivers/s390/net/netiucv.c
include/linux/time.h
kernel/acct.c
kernel/hrtimer.c
kernel/time.c
kernel/time/timekeeping.c
kernel/tsacct.c
net/rxrpc/af_rxrpc.c
net/rxrpc/ar-connection.c
net/rxrpc/ar-transport.c
net/rxrpc/rxkad.c
@@ -46,6 +46,7 @@
 {
 	struct rtc_device	*rtc = to_rtc_device(dev);
 	struct rtc_time		tm;
+	struct timespec		ts = current_kernel_time();
  
 	if (strncmp(rtc->dev.bus_id,
 				CONFIG_RTC_HCTOSYS_DEVICE,
@@ -57,8 +58,8 @@
  
 	/* RTC precision is 1 second; adjust delta for avg 1/2 sec err */
 	set_normalized_timespec(&delta,
-				xtime.tv_sec - oldtime,
-				xtime.tv_nsec - (NSEC_PER_SEC >> 1));
+				ts.tv_sec - oldtime,
+				ts.tv_nsec - (NSEC_PER_SEC >> 1));
  
 	return 0;
 }
@@ -674,7 +674,7 @@
 	int first = 1;
 	int i;
 	unsigned long duration;
-	struct timespec done_stamp = xtime;
+	struct timespec done_stamp = current_kernel_time();
  
 	DBF_TEXT(trace, 4, __FUNCTION__);
  
@@ -730,7 +730,7 @@
 		spin_unlock(&ch->collect_lock);
 		ch->ccw[1].count = ch->trans_skb->len;
 		fsm_addtimer(&ch->timer, CTC_TIMEOUT_5SEC, CH_EVENT_TIMER, ch);
-		ch->prof.send_stamp = xtime;
+		ch->prof.send_stamp = current_kernel_time();
 		rc = ccw_device_start(ch->cdev, &ch->ccw[0],
 				      (unsigned long) ch, 0xff, 0);
 		ch->prof.doios_multi++;
@@ -2281,7 +2281,7 @@
 		fsm_newstate(ch->fsm, CH_STATE_TX);
 		fsm_addtimer(&ch->timer, CTC_TIMEOUT_5SEC, CH_EVENT_TIMER, ch);
 		spin_lock_irqsave(get_ccwdev_lock(ch->cdev), saveflags);
-		ch->prof.send_stamp = xtime;
+		ch->prof.send_stamp = current_kernel_time();
 		rc = ccw_device_start(ch->cdev, &ch->ccw[ccw_idx],
 				      (unsigned long) ch, 0xff, 0);
 		spin_unlock_irqrestore(get_ccwdev_lock(ch->cdev), saveflags);
@@ -753,7 +753,7 @@
  
 	header.next = 0;
 	memcpy(skb_put(conn->tx_buff, NETIUCV_HDRLEN), &header, NETIUCV_HDRLEN);
-	conn->prof.send_stamp = xtime;
+	conn->prof.send_stamp = current_kernel_time();
 	txmsg.class = 0;
 	txmsg.tag = 0;
 	rc = iucv_message_send(conn->path, &txmsg, 0, 0,
@@ -1185,7 +1185,7 @@
 		memcpy(skb_put(nskb, NETIUCV_HDRLEN), &header,  NETIUCV_HDRLEN);
  
 		fsm_newstate(conn->fsm, CONN_STATE_TX);
-		conn->prof.send_stamp = xtime;
+		conn->prof.send_stamp = current_kernel_time();
  
 		msg.tag = 1;
 		msg.class = 0;
@@ -107,7 +107,7 @@
 struct timespec current_kernel_time(void);
  
 #define CURRENT_TIME		(current_kernel_time())
-#define CURRENT_TIME_SEC	((struct timespec) { xtime.tv_sec, 0 })
+#define CURRENT_TIME_SEC	((struct timespec) { get_seconds(), 0 })
  
 extern void do_gettimeofday(struct timeval *tv);
 extern int do_settimeofday(struct timespec *tv);
@@ -468,7 +468,7 @@
 	}
 #endif
 	do_div(elapsed, AHZ);
-	ac.ac_btime = xtime.tv_sec - elapsed;
+	ac.ac_btime = get_seconds() - elapsed;
 	/* we really need to bite the bullet and change layout */
 	ac.ac_uid = current->uid;
 	ac.ac_gid = current->gid;
@@ -144,7 +144,7 @@
 #ifdef CONFIG_NO_HZ
 		getnstimeofday(&xts);
 #else
-		xts = xtime;
+		xts = current_kernel_time();
 #endif
 		tom = wall_to_monotonic;
 	} while (read_seqretry(&xtime_lock, seq));
@@ -215,22 +215,6 @@
 	return copy_to_user(txc_p, &txc, sizeof(struct timex)) ? -EFAULT : ret;
 }
  
-inline struct timespec current_kernel_time(void)
-{
-        struct timespec now;
-        unsigned long seq;
-
-	do {
-		seq = read_seqbegin(&xtime_lock);
-		
-		now = xtime;
-	} while (read_seqretry(&xtime_lock, seq));
-
-	return now; 
-}
-
-EXPORT_SYMBOL(current_kernel_time);
-
 /**
  * current_fs_time - Return FS time
  * @sb: Superblock.
@@ -509,4 +509,20 @@
 {
 	ts->tv_sec += total_sleep_time;
 }
+
+struct timespec current_kernel_time(void)
+{
+	struct timespec now;
+	unsigned long seq;
+
+	do {
+		seq = read_seqbegin(&xtime_lock);
+
+		now = xtime;
+	} while (read_seqretry(&xtime_lock, seq));
+
+	return now;
+}
+
+EXPORT_SYMBOL(current_kernel_time);
@@ -39,7 +39,7 @@
 	ac_etime = timespec_to_ns(&ts);
 	do_div(ac_etime, NSEC_PER_USEC);
 	stats->ac_etime = ac_etime;
-	stats->ac_btime = xtime.tv_sec - ts.tv_sec;
+	stats->ac_btime = get_seconds() - ts.tv_sec;
 	if (thread_group_leader(tsk)) {
 		stats->ac_exitcode = tsk->exit_code;
 		if (tsk->flags & PF_FORKNOEXEC)
@@ -787,7 +787,7 @@
  
 	BUILD_BUG_ON(sizeof(struct rxrpc_skb_priv) > sizeof(dummy_skb->cb));
  
-	rxrpc_epoch = htonl(xtime.tv_sec);
+	rxrpc_epoch = htonl(get_seconds());
  
 	ret = -ENOMEM;
 	rxrpc_call_jar = kmem_cache_create(
@@ -791,7 +791,7 @@
  
 	ASSERTCMP(atomic_read(&conn->usage), >, 0);
  
-	conn->put_time = xtime.tv_sec;
+	conn->put_time = get_seconds();
 	if (atomic_dec_and_test(&conn->usage)) {
 		_debug("zombie");
 		rxrpc_queue_delayed_work(&rxrpc_connection_reap, 0);
@@ -835,7 +835,7 @@
  
 	_enter("");
  
-	now = xtime.tv_sec;
+	now = get_seconds();
 	earliest = ULONG_MAX;
  
 	write_lock_bh(&rxrpc_connection_lock);
@@ -183,7 +183,7 @@
  
 	ASSERTCMP(atomic_read(&trans->usage), >, 0);
  
-	trans->put_time = xtime.tv_sec;
+	trans->put_time = get_seconds();
 	if (unlikely(atomic_dec_and_test(&trans->usage)))
 		_debug("zombie");
 		/* let the reaper determine the timeout to avoid a race with
@@ -219,7 +219,7 @@
  
 	_enter("");
  
-	now = xtime.tv_sec;
+	now = get_seconds();
 	earliest = ULONG_MAX;
  
 	/* extract all the transports that have been dead too long */
@@ -916,7 +916,7 @@
 		issue = be32_to_cpu(stamp);
 	}
 	p += 4;
-	now = xtime.tv_sec;
+	now = get_seconds();
 	_debug("KIV ISSUE: %lx [%lx]", issue, now);
  
 	/* check the ticket is in date */
...	...	@@ -46,6 +46,7 @@
46	46	{
47	47	struct rtc_device *rtc = to_rtc_device(dev);
48	48	struct rtc_time tm;
	49	+ struct timespec ts = current_kernel_time();
49	50
50	51	if (strncmp(rtc->dev.bus_id,
51	52	CONFIG_RTC_HCTOSYS_DEVICE,
...	...	@@ -57,8 +58,8 @@
57	58
58	59	/* RTC precision is 1 second; adjust delta for avg 1/2 sec err */
59	60	set_normalized_timespec(&delta,
60		- xtime.tv_sec - oldtime,
61		- xtime.tv_nsec - (NSEC_PER_SEC >> 1));
	61	+ ts.tv_sec - oldtime,
	62	+ ts.tv_nsec - (NSEC_PER_SEC >> 1));
62	63
63	64	return 0;
64	65	}
...	...	@@ -674,7 +674,7 @@
674	674	int first = 1;
675	675	int i;
676	676	unsigned long duration;
677		- struct timespec done_stamp = xtime;
	677	+ struct timespec done_stamp = current_kernel_time();
678	678
679	679	DBF_TEXT(trace, 4, __FUNCTION__);
680	680
...	...	@@ -730,7 +730,7 @@
730	730	spin_unlock(&ch->collect_lock);
731	731	ch->ccw[1].count = ch->trans_skb->len;
732	732	fsm_addtimer(&ch->timer, CTC_TIMEOUT_5SEC, CH_EVENT_TIMER, ch);
733		- ch->prof.send_stamp = xtime;
	733	+ ch->prof.send_stamp = current_kernel_time();
734	734	rc = ccw_device_start(ch->cdev, &ch->ccw[0],
735	735	(unsigned long) ch, 0xff, 0);
736	736	ch->prof.doios_multi++;
...	...	@@ -2281,7 +2281,7 @@
2281	2281	fsm_newstate(ch->fsm, CH_STATE_TX);
2282	2282	fsm_addtimer(&ch->timer, CTC_TIMEOUT_5SEC, CH_EVENT_TIMER, ch);
2283	2283	spin_lock_irqsave(get_ccwdev_lock(ch->cdev), saveflags);
2284		- ch->prof.send_stamp = xtime;
	2284	+ ch->prof.send_stamp = current_kernel_time();
2285	2285	rc = ccw_device_start(ch->cdev, &ch->ccw[ccw_idx],
2286	2286	(unsigned long) ch, 0xff, 0);
2287	2287	spin_unlock_irqrestore(get_ccwdev_lock(ch->cdev), saveflags);
...	...	@@ -753,7 +753,7 @@
753	753
754	754	header.next = 0;
755	755	memcpy(skb_put(conn->tx_buff, NETIUCV_HDRLEN), &header, NETIUCV_HDRLEN);
756		- conn->prof.send_stamp = xtime;
	756	+ conn->prof.send_stamp = current_kernel_time();
757	757	txmsg.class = 0;
758	758	txmsg.tag = 0;
759	759	rc = iucv_message_send(conn->path, &txmsg, 0, 0,
...	...	@@ -1185,7 +1185,7 @@
1185	1185	memcpy(skb_put(nskb, NETIUCV_HDRLEN), &header, NETIUCV_HDRLEN);
1186	1186
1187	1187	fsm_newstate(conn->fsm, CONN_STATE_TX);
1188		- conn->prof.send_stamp = xtime;
	1188	+ conn->prof.send_stamp = current_kernel_time();
1189	1189
1190	1190	msg.tag = 1;
1191	1191	msg.class = 0;
...	...	@@ -107,7 +107,7 @@
107	107	struct timespec current_kernel_time(void);
108	108
109	109	#define CURRENT_TIME (current_kernel_time())
110		-#define CURRENT_TIME_SEC ((struct timespec) { xtime.tv_sec, 0 })
	110	+#define CURRENT_TIME_SEC ((struct timespec) { get_seconds(), 0 })
111	111
112	112	extern void do_gettimeofday(struct timeval *tv);
113	113	extern int do_settimeofday(struct timespec *tv);
...	...	@@ -468,7 +468,7 @@
468	468	}
469	469	#endif
470	470	do_div(elapsed, AHZ);
471		- ac.ac_btime = xtime.tv_sec - elapsed;
	471	+ ac.ac_btime = get_seconds() - elapsed;
472	472	/* we really need to bite the bullet and change layout */
473	473	ac.ac_uid = current->uid;
474	474	ac.ac_gid = current->gid;
...	...	@@ -144,7 +144,7 @@
144	144	#ifdef CONFIG_NO_HZ
145	145	getnstimeofday(&xts);
146	146	#else
147		- xts = xtime;
	147	+ xts = current_kernel_time();
148	148	#endif
149	149	tom = wall_to_monotonic;
150	150	} while (read_seqretry(&xtime_lock, seq));
...	...	@@ -215,22 +215,6 @@
215	215	return copy_to_user(txc_p, &txc, sizeof(struct timex)) ? -EFAULT : ret;
216	216	}
217	217
218		-inline struct timespec current_kernel_time(void)
219		-{
220		- struct timespec now;
221		- unsigned long seq;
222		-
223		- do {
224		- seq = read_seqbegin(&xtime_lock);
225		-
226		- now = xtime;
227		- } while (read_seqretry(&xtime_lock, seq));
228		-
229		- return now;
230		-}
231		-
232		-EXPORT_SYMBOL(current_kernel_time);
233		-
234	218	/**
235	219	* current_fs_time - Return FS time
236	220	* @sb: Superblock.
...	...	@@ -509,4 +509,20 @@
509	509	{
510	510	ts->tv_sec += total_sleep_time;
511	511	}
	512	+
	513	+struct timespec current_kernel_time(void)
	514	+{
	515	+ struct timespec now;
	516	+ unsigned long seq;
	517	+
	518	+ do {
	519	+ seq = read_seqbegin(&xtime_lock);
	520	+
	521	+ now = xtime;
	522	+ } while (read_seqretry(&xtime_lock, seq));
	523	+
	524	+ return now;
	525	+}
	526	+
	527	+EXPORT_SYMBOL(current_kernel_time);
...	...	@@ -39,7 +39,7 @@
39	39	ac_etime = timespec_to_ns(&ts);
40	40	do_div(ac_etime, NSEC_PER_USEC);
41	41	stats->ac_etime = ac_etime;
42		- stats->ac_btime = xtime.tv_sec - ts.tv_sec;
	42	+ stats->ac_btime = get_seconds() - ts.tv_sec;
43	43	if (thread_group_leader(tsk)) {
44	44	stats->ac_exitcode = tsk->exit_code;
45	45	if (tsk->flags & PF_FORKNOEXEC)
...	...	@@ -787,7 +787,7 @@
787	787
788	788	BUILD_BUG_ON(sizeof(struct rxrpc_skb_priv) > sizeof(dummy_skb->cb));
789	789
790		- rxrpc_epoch = htonl(xtime.tv_sec);
	790	+ rxrpc_epoch = htonl(get_seconds());
791	791
792	792	ret = -ENOMEM;
793	793	rxrpc_call_jar = kmem_cache_create(