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>

diff --git a/include/linux/time.h b/include/linux/time.h
index 86a9c487fdd8bf25d809491dc4543328bd2b112d..4007a12a1b5054bf3097fd7ad5a2db2a54532721 100644 (file)
--- 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 0c8d7c04861542102960852c60150c6771180553..57c4d33c9a9d6197e65fb1148a7186794e78d231 100644 (file)
--- 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 c1a178ca0f50da3ebef2bd8935f5917edefb2255..c50aaf6cd01d781ebf732e3766681519e2b64570 100644 (file)
--- 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));
+}