time: Provide get_xtime_and_monotonic_offset()

The hrtimer code accesses timekeeping variables under
xtime_lock. Provide a sensible accessor function and use it.

[ tglx: Removed the conditionals, unused variable, fixed codingstyle
  	and massaged changelog ]

Signed-off-by: Torben Hohn <torbenh@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: johnstul@us.ibm.com
Cc: yong.zhang0@gmail.com
Cc: hch@infradead.org
LKML-Reference: <20110127145905.23248.30458.stgit@localhost>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

3 files changed, 19 insertions, 11 deletions

diff --git a/include/linux/time.h b/include/linux/time.h
index 86a9c487fdd8..4007a12a1b50 100644
--- a/include/linux/time.h
+++ b/include/linux/time.h
@@ -127,6 +127,7 @@ struct timespec current_kernel_time(void);
 struct timespec __current_kernel_time(void); /* does not take xtime_lock */
 struct timespec __get_wall_to_monotonic(void); /* does not take xtime_lock */
 struct timespec get_monotonic_coarse(void);
+void get_xtime_and_monotonic_offset(struct timespec *xtim, struct timespec *wtom);
 
 #define CURRENT_TIME            (current_kernel_time())
 #define CURRENT_TIME_SEC        ((struct timespec) { get_seconds(), 0 })
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 0c8d7c048615..57c4d33c9a9d 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -85,13 +85,8 @@ static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base)
 {
         ktime_t xtim, tomono;
         struct timespec xts, tom;
-        unsigned long seq;
 
-        do {
-                seq = read_seqbegin(&xtime_lock);
-                xts = __current_kernel_time();
-                tom = __get_wall_to_monotonic();
-        } while (read_seqretry(&xtime_lock, seq));
+        get_xtime_and_monotonic_offset(&xts, &tom);
 
         xtim = timespec_to_ktime(xts);
         tomono = timespec_to_ktime(tom);
@@ -612,15 +607,11 @@ static void retrigger_next_event(void *arg)
 {
         struct hrtimer_cpu_base *base;
         struct timespec realtime_offset, wtm;
-        unsigned long seq;
 
         if (!hrtimer_hres_active())
                 return;
 
-        do {
-                seq = read_seqbegin(&xtime_lock);
-                wtm = __get_wall_to_monotonic();
-        } while (read_seqretry(&xtime_lock, seq));
+        get_xtime_and_monotonic_offset(&realtime_offset, &wtm);
         set_normalized_timespec(&realtime_offset, -wtm.tv_sec, -wtm.tv_nsec);
 
         base = &__get_cpu_var(hrtimer_bases);
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index c1a178ca0f50..c50aaf6cd01d 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -958,3 +958,19 @@ void do_timer(unsigned long ticks)
         update_wall_time();
         calc_global_load(ticks);
 }
+
+/**
+ * get_xtime_and_monotonic_offset() - get xtime and wall_to_monotonic
+ * @xtim:       pointer to timespec to be set with xtime
+ * @wtom:       pointer to timespec to be set with wall_to_monotonic
+ */
+void get_xtime_and_monotonic_offset(struct timespec *xtim, struct timespec *wtom)
+{
+        unsigned long seq;
+
+        do {
+                seq = read_seqbegin(&xtime_lock);
+                *xtim = xtime;
+                *wtom = wall_to_monotonic;
+        } while (read_seqretry(&xtime_lock, seq));
+}