timers, sched/clock: Match scope of read and write seqcounts

[linux-2.6-microblaze.git] / kernel / time / sched_clock.c

diff --git a/kernel/time/sched_clock.c b/kernel/time/sched_clock.c
index 01d2d15..1751e95 100644 (file)
--- a/kernel/time/sched_clock.c
+++ b/kernel/time/sched_clock.c
@@ -58,23 +58,21 @@ static inline u64 notrace cyc_to_ns(u64 cyc, u32 mult, u32 shift)
 
 unsigned long long notrace sched_clock(void)
 {
-       u64 epoch_ns;
-       u64 epoch_cyc;
-       u64 cyc;
+       u64 cyc, res;
        unsigned long seq;
 
-       if (cd.suspended)
-               return cd.epoch_ns;
-
        do {
                seq = raw_read_seqcount_begin(&cd.seq);
-               epoch_cyc = cd.epoch_cyc;
-               epoch_ns = cd.epoch_ns;
+
+               res = cd.epoch_ns;
+               if (!cd.suspended) {
+                       cyc = read_sched_clock();
+                       cyc = (cyc - cd.epoch_cyc) & sched_clock_mask;
+                       res += cyc_to_ns(cyc, cd.mult, cd.shift);
+               }
        } while (read_seqcount_retry(&cd.seq, seq));
 
-       cyc = read_sched_clock();
-       cyc = (cyc - epoch_cyc) & sched_clock_mask;
-       return epoch_ns + cyc_to_ns(cyc, cd.mult, cd.shift);
+       return res;
 }
 
 /*
@@ -111,7 +109,6 @@ void __init sched_clock_register(u64 (*read)(void), int bits,
 {
        u64 res, wrap, new_mask, new_epoch, cyc, ns;
        u32 new_mult, new_shift;
-       ktime_t new_wrap_kt;
        unsigned long r;
        char r_unit;
 
@@ -124,10 +121,11 @@ void __init sched_clock_register(u64 (*read)(void), int bits,
        clocks_calc_mult_shift(&new_mult, &new_shift, rate, NSEC_PER_SEC, 3600);
 
        new_mask = CLOCKSOURCE_MASK(bits);
+       cd.rate = rate;
 
-       /* calculate how many ns until we wrap */
-       wrap = clocks_calc_max_nsecs(new_mult, new_shift, 0, new_mask);
-       new_wrap_kt = ns_to_ktime(wrap - (wrap >> 3));
+       /* calculate how many nanosecs until we risk wrapping */
+       wrap = clocks_calc_max_nsecs(new_mult, new_shift, 0, new_mask, NULL);
+       cd.wrap_kt = ns_to_ktime(wrap);
 
        /* update epoch for new counter and update epoch_ns from old counter*/
        new_epoch = read();
@@ -138,8 +136,6 @@ void __init sched_clock_register(u64 (*read)(void), int bits,
        raw_write_seqcount_begin(&cd.seq);
        read_sched_clock = read;
        sched_clock_mask = new_mask;
-       cd.rate = rate;
-       cd.wrap_kt = new_wrap_kt;
        cd.mult = new_mult;
        cd.shift = new_shift;
        cd.epoch_cyc = new_epoch;