13 files changed, 56 insertions, 43 deletions

diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c
index 8b3cd31d6a61..10ab3b71ffc6 100644
--- a/drivers/rtc/class.c
+++ b/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;
 }
diff --git a/drivers/s390/net/ctcmain.c b/drivers/s390/net/ctcmain.c
index b20fd0681733..92e8a37b5022 100644
--- a/drivers/s390/net/ctcmain.c
+++ b/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);
diff --git a/drivers/s390/net/netiucv.c b/drivers/s390/net/netiucv.c
index 3d28e1a5bf79..268889474339 100644
--- a/drivers/s390/net/netiucv.c
+++ b/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;
diff --git a/include/linux/time.h b/include/linux/time.h
index e6aea5146e5d..6a5f503b4f1d 100644
--- a/include/linux/time.h
+++ b/include/linux/time.h
@@ -99,15 +99,11 @@ extern int update_persistent_clock(struct timespec now);
 extern int no_sync_cmos_clock __read_mostly;
 void timekeeping_init(void);
 
-static inline unsigned long get_seconds(void)
-{
-        return xtime.tv_sec;
-}
-
+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);
diff --git a/kernel/acct.c b/kernel/acct.c
index 70d0d88e5554..24f0f8b2ba72 100644
--- a/kernel/acct.c
+++ b/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;
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index eb1ddebd2c04..c21ca6bfaa66 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -141,11 +141,7 @@ static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base)
 
         do {
                 seq = read_seqbegin(&xtime_lock);
-#ifdef CONFIG_NO_HZ
-                getnstimeofday(&xts);
-#else
-                xts = xtime;
-#endif
+                xts = current_kernel_time();
                 tom = wall_to_monotonic;
         } while (read_seqretry(&xtime_lock, seq));
 
diff --git a/kernel/time.c b/kernel/time.c
index 5b81da08bbdb..2289a8d68314 100644
--- a/kernel/time.c
+++ b/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.
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 88c81026e003..acc417b5a9b7 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -47,10 +47,22 @@ EXPORT_SYMBOL(xtime_lock);
 struct timespec xtime __attribute__ ((aligned (16)));
 struct timespec wall_to_monotonic __attribute__ ((aligned (16)));
 static unsigned long total_sleep_time;          /* seconds */
-
 EXPORT_SYMBOL(xtime);
 
 
+#ifdef CONFIG_NO_HZ
+static struct timespec xtime_cache __attribute__ ((aligned (16)));
+static inline void update_xtime_cache(u64 nsec)
+{
+        xtime_cache = xtime;
+        timespec_add_ns(&xtime_cache, nsec);
+}
+#else
+#define xtime_cache xtime
+/* We do *not* want to evaluate the argument for this case */
+#define update_xtime_cache(n) do { } while (0)
+#endif
+
 static struct clocksource *clock; /* pointer to current clocksource */
 
 
@@ -478,6 +490,8 @@ void update_wall_time(void)
         xtime.tv_nsec = (s64)clock->xtime_nsec >> clock->shift;
         clock->xtime_nsec -= (s64)xtime.tv_nsec << clock->shift;
 
+        update_xtime_cache(cyc2ns(clock, offset));
+
         /* check to see if there is a new clocksource to use */
         change_clocksource();
         update_vsyscall(&xtime, clock);
@@ -509,3 +523,25 @@ void monotonic_to_bootbased(struct timespec *ts)
 {
         ts->tv_sec += total_sleep_time;
 }
+
+unsigned long get_seconds(void)
+{
+        return xtime_cache.tv_sec;
+}
+EXPORT_SYMBOL(get_seconds);
+
+
+struct timespec current_kernel_time(void)
+{
+        struct timespec now;
+        unsigned long seq;
+
+        do {
+                seq = read_seqbegin(&xtime_lock);
+
+                now = xtime_cache;
+        } while (read_seqretry(&xtime_lock, seq));
+
+        return now;
+}
+EXPORT_SYMBOL(current_kernel_time);
diff --git a/kernel/tsacct.c b/kernel/tsacct.c
index 658f638c402c..c122131a122f 100644
--- a/kernel/tsacct.c
+++ b/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)
diff --git a/net/rxrpc/af_rxrpc.c b/net/rxrpc/af_rxrpc.c
index 16a68df4e36b..c58fa0d1be26 100644
--- a/net/rxrpc/af_rxrpc.c
+++ b/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(
diff --git a/net/rxrpc/ar-connection.c b/net/rxrpc/ar-connection.c
index 482750efc235..372b24466dc7 100644
--- a/net/rxrpc/ar-connection.c
+++ b/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);
diff --git a/net/rxrpc/ar-transport.c b/net/rxrpc/ar-transport.c
index d43d78f19302..bb282a6a19f0 100644
--- a/net/rxrpc/ar-transport.c
+++ b/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 */
diff --git a/net/rxrpc/rxkad.c b/net/rxrpc/rxkad.c
index 5ec705144e10..ac3cabdca78c 100644
--- a/net/rxrpc/rxkad.c
+++ b/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 */