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: NJohn Stultz <johnstul@us.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/class.c

@@ -46,6 +46,7 @@ static int rtc_suspend(struct device *dev, pm_message_t mesg)
 {
 	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 @@ static int rtc_suspend(struct device *dev, pm_message_t mesg)
 
 	/* 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;
 }

drivers/s390/net/ctcmain.c

@@ -674,7 +674,7 @@ ch_action_txdone(fsm_instance * fi, int event, void *arg)
 	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 @@ ch_action_txdone(fsm_instance * fi, int event, void *arg)
 		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 @@ transmit_skb(struct channel *ch, struct sk_buff *skb)
 		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);

drivers/s390/net/netiucv.c

@@ -753,7 +753,7 @@ static void conn_action_txdone(fsm_instance *fi, int event, void *arg)
 
 	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 @@ static int netiucv_transmit_skb(struct iucv_connection *conn,
 		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;

include/linux/time.h

@@ -107,7 +107,7 @@ static inline unsigned long get_seconds(void)
 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);

kernel/acct.c

@@ -468,7 +468,7 @@ static void do_acct_process(struct file *file)
 	}
 #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;

kernel/hrtimer.c

@@ -144,7 +144,7 @@ static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base)
 #ifdef CONFIG_NO_HZ
 		getnstimeofday(&xts);
 #else
-		xts = xtime;
+		xts = current_kernel_time();
 #endif
 		tom = wall_to_monotonic;
 	} while (read_seqretry(&xtime_lock, seq));

kernel/time.c

@@ -215,22 +215,6 @@ asmlinkage long sys_adjtimex(struct timex __user *txc_p)
 	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.

kernel/time/timekeeping.c

@@ -509,3 +509,19 @@ void monotonic_to_bootbased(struct timespec *ts)
 {
 	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);

kernel/tsacct.c

@@ -39,7 +39,7 @@ void bacct_add_tsk(struct taskstats *stats, struct task_struct *tsk)
 	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)

net/rxrpc/af_rxrpc.c

@@ -787,7 +787,7 @@ static int __init af_rxrpc_init(void)
 
 	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(

net/rxrpc/ar-connection.c

@@ -791,7 +791,7 @@ void rxrpc_put_connection(struct rxrpc_connection *conn)
 
 	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 @@ void rxrpc_connection_reaper(struct work_struct *work)
 
 	_enter("");
 
-	now = xtime.tv_sec;
+	now = get_seconds();
 	earliest = ULONG_MAX;
 
 	write_lock_bh(&rxrpc_connection_lock);

net/rxrpc/ar-transport.c

@@ -183,7 +183,7 @@ void rxrpc_put_transport(struct rxrpc_transport *trans)
 
 	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 @@ static void rxrpc_transport_reaper(struct work_struct *work)
 
 	_enter("");
 
-	now = xtime.tv_sec;
+	now = get_seconds();
 	earliest = ULONG_MAX;
 
 	/* extract all the transports that have been dead too long */

net/rxrpc/rxkad.c

@@ -916,7 +916,7 @@ static int rxkad_decrypt_ticket(struct rxrpc_connection *conn,
 		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 */