[PATCH] add write_seqlock to cpufreq change notifier for TSC

From: Stephen Hemminger (shemminger@osdl.org)
Date: Tue Mar 18 2003 - 18:00:18 EST


The CPU frequency change detection code can change the values used to
compute time of day with TSC; but there was no locking around it.

--- timer_tsc.c.orig 2003-03-18 14:52:25.000000000 -0800
+++ timer_tsc.c 2003-03-18 14:55:13.000000000 -0800
@@ -213,6 +213,7 @@
 {
         struct cpufreq_freqs *freq = data;
 
+ write_seqlock(&xtime_lock);
         if (!ref_freq) {
                 ref_freq = freq->old;
                 loops_per_jiffy_ref = cpu_data[freq->cpu].loops_per_jiffy;
@@ -232,6 +233,7 @@
                 }
 #endif
         }
+ write_sequnlock(&xtime_lock);
 
         return 0;
 }

-
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