7 files changed, 25 insertions, 31 deletions

diff --git a/drivers/clocksource/i8253.c b/drivers/clocksource/i8253.c
index e7cab2da910f..14ee3efcc404 100644
--- a/drivers/clocksource/i8253.c
+++ b/drivers/clocksource/i8253.c
@@ -35,7 +35,7 @@ static cycle_t i8253_read(struct clocksource *cs)
 
         raw_spin_lock_irqsave(&i8253_lock, flags);
         /*
-         * Although our caller may have the read side of xtime_lock,
+         * Although our caller may have the read side of jiffies_lock,
          * this is now a seqlock, and we are cheating in this routine
          * by having side effects on state that we cannot undo if
          * there is a collision on the seqlock and our caller has to
diff --git a/include/linux/jiffies.h b/include/linux/jiffies.h
index 6b87413da9d6..82ed068b1ebe 100644
--- a/include/linux/jiffies.h
+++ b/include/linux/jiffies.h
@@ -70,11 +70,12 @@ extern int register_refined_jiffies(long clock_tick_rate);
 
 /*
  * The 64-bit value is not atomic - you MUST NOT read it
- * without sampling the sequence number in xtime_lock.
+ * without sampling the sequence number in jiffies_lock.
  * get_jiffies_64() will do this for you as appropriate.
  */
 extern u64 __jiffy_data jiffies_64;
 extern unsigned long volatile __jiffy_data jiffies;
+extern seqlock_t jiffies_lock;
 
 #if (BITS_PER_LONG < 64)
 u64 get_jiffies_64(void);
diff --git a/kernel/time/jiffies.c b/kernel/time/jiffies.c
index 25f5b2699d37..7a925ba456fb 100644
--- a/kernel/time/jiffies.c
+++ b/kernel/time/jiffies.c
@@ -67,6 +67,8 @@ static struct clocksource clocksource_jiffies = {
         .shift          = JIFFIES_SHIFT,
 };
 
+__cacheline_aligned_in_smp DEFINE_SEQLOCK(jiffies_lock);
+
 #if (BITS_PER_LONG < 64)
 u64 get_jiffies_64(void)
 {
@@ -74,9 +76,9 @@ u64 get_jiffies_64(void)
         u64 ret;
 
         do {
-                seq = read_seqbegin(&xtime_lock);
+                seq = read_seqbegin(&jiffies_lock);
                 ret = jiffies_64;
-        } while (read_seqretry(&xtime_lock, seq));
+        } while (read_seqretry(&jiffies_lock, seq));
         return ret;
 }
 EXPORT_SYMBOL(get_jiffies_64);
diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index da6c9ecad4e4..b1600a6973f4 100644
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -63,13 +63,13 @@ int tick_is_oneshot_available(void)
 static void tick_periodic(int cpu)
 {
         if (tick_do_timer_cpu == cpu) {
-                write_seqlock(&xtime_lock);
+                write_seqlock(&jiffies_lock);
 
                 /* Keep track of the next tick event */
                 tick_next_period = ktime_add(tick_next_period, tick_period);
 
                 do_timer(1);
-                write_sequnlock(&xtime_lock);
+                write_sequnlock(&jiffies_lock);
         }
 
         update_process_times(user_mode(get_irq_regs()));
@@ -130,9 +130,9 @@ void tick_setup_periodic(struct clock_event_device *dev, int broadcast)
                 ktime_t next;
 
                 do {
-                        seq = read_seqbegin(&xtime_lock);
+                        seq = read_seqbegin(&jiffies_lock);
                         next = tick_next_period;
-                } while (read_seqretry(&xtime_lock, seq));
+                } while (read_seqretry(&jiffies_lock, seq));
 
                 clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT);
 
diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h
index 4e265b901fed..cf3e59ed6dc0 100644
--- a/kernel/time/tick-internal.h
+++ b/kernel/time/tick-internal.h
@@ -141,4 +141,3 @@ static inline int tick_device_is_functional(struct clock_event_device *dev)
 #endif
 
 extern void do_timer(unsigned long ticks);
-extern seqlock_t xtime_lock;
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index a40260885265..a678046c3e5e 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -31,7 +31,7 @@
 static DEFINE_PER_CPU(struct tick_sched, tick_cpu_sched);
 
 /*
- * The time, when the last jiffy update happened. Protected by xtime_lock.
+ * The time, when the last jiffy update happened. Protected by jiffies_lock.
  */
 static ktime_t last_jiffies_update;
 
@@ -49,14 +49,14 @@ static void tick_do_update_jiffies64(ktime_t now)
         ktime_t delta;
 
         /*
-         * Do a quick check without holding xtime_lock:
+         * Do a quick check without holding jiffies_lock:
          */
         delta = ktime_sub(now, last_jiffies_update);
         if (delta.tv64 < tick_period.tv64)
                 return;
 
-        /* Reevalute with xtime_lock held */
-        write_seqlock(&xtime_lock);
+        /* Reevalute with jiffies_lock held */
+        write_seqlock(&jiffies_lock);
 
         delta = ktime_sub(now, last_jiffies_update);
         if (delta.tv64 >= tick_period.tv64) {
@@ -79,7 +79,7 @@ static void tick_do_update_jiffies64(ktime_t now)
                 /* Keep the tick_next_period variable up to date */
                 tick_next_period = ktime_add(last_jiffies_update, tick_period);
         }
-        write_sequnlock(&xtime_lock);
+        write_sequnlock(&jiffies_lock);
 }
 
 /*
@@ -89,12 +89,12 @@ static ktime_t tick_init_jiffy_update(void)
 {
         ktime_t period;
 
-        write_seqlock(&xtime_lock);
+        write_seqlock(&jiffies_lock);
         /* Did we start the jiffies update yet ? */
         if (last_jiffies_update.tv64 == 0)
                 last_jiffies_update = tick_next_period;
         period = last_jiffies_update;
-        write_sequnlock(&xtime_lock);
+        write_sequnlock(&jiffies_lock);
         return period;
 }
 
@@ -282,11 +282,11 @@ static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts,
 
         /* Read jiffies and the time when jiffies were updated last */
         do {
-                seq = read_seqbegin(&xtime_lock);
+                seq = read_seqbegin(&jiffies_lock);
                 last_update = last_jiffies_update;
                 last_jiffies = jiffies;
                 time_delta = timekeeping_max_deferment();
-        } while (read_seqretry(&xtime_lock, seq));
+        } while (read_seqretry(&jiffies_lock, seq));
 
         if (rcu_needs_cpu(cpu, &rcu_delta_jiffies) || printk_needs_cpu(cpu) ||
             arch_needs_cpu(cpu)) {
@@ -658,7 +658,7 @@ static void tick_nohz_handler(struct clock_event_device *dev)
          * concurrency: This happens only when the cpu in charge went
          * into a long sleep. If two cpus happen to assign themself to
          * this duty, then the jiffies update is still serialized by
-         * xtime_lock.
+         * jiffies_lock.
          */
         if (unlikely(tick_do_timer_cpu == TICK_DO_TIMER_NONE))
                 tick_do_timer_cpu = cpu;
@@ -810,7 +810,7 @@ static enum hrtimer_restart tick_sched_timer(struct hrtimer *timer)
          * concurrency: This happens only when the cpu in charge went
          * into a long sleep. If two cpus happen to assign themself to
          * this duty, then the jiffies update is still serialized by
-         * xtime_lock.
+         * jiffies_lock.
          */
         if (unlikely(tick_do_timer_cpu == TICK_DO_TIMER_NONE))
                 tick_do_timer_cpu = cpu;
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index e424970bb562..4c7de02eacdc 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -25,12 +25,6 @@
 
 static struct timekeeper timekeeper;
 
-/*
- * This read-write spinlock protects us from races in SMP while
- * playing with xtime.
- */
-__cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock);
-
 /* flag for if timekeeping is suspended */
 int __read_mostly timekeeping_suspended;
 
@@ -1299,9 +1293,7 @@ struct timespec get_monotonic_coarse(void)
 }
 
 /*
- * The 64-bit jiffies value is not atomic - you MUST NOT read it
- * without sampling the sequence number in xtime_lock.
- * jiffies is defined in the linker script...
+ * Must hold jiffies_lock
  */
 void do_timer(unsigned long ticks)
 {
@@ -1389,7 +1381,7 @@ EXPORT_SYMBOL_GPL(ktime_get_monotonic_offset);
  */
 void xtime_update(unsigned long ticks)
 {
-        write_seqlock(&xtime_lock);
+        write_seqlock(&jiffies_lock);
         do_timer(ticks);
-        write_sequnlock(&xtime_lock);
+        write_sequnlock(&jiffies_lock);
 }