[PATCH] clocksource: Remove the update callback

The clocksource code allows direct updates of the rating of a given
clocksource now.  Change TSC unstable tracking to use this interface and
remove the update callback.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 17 insertions, 37 deletions

diff --git a/arch/i386/kernel/tsc.c b/arch/i386/kernel/tsc.c
index a37654991788..b4b2be21d1c7 100644
--- a/arch/i386/kernel/tsc.c
+++ b/arch/i386/kernel/tsc.c
@@ -60,12 +60,6 @@ static inline int check_tsc_unstable(void)
         return tsc_unstable;
 }
 
-void mark_tsc_unstable(void)
-{
-        tsc_unstable = 1;
-}
-EXPORT_SYMBOL_GPL(mark_tsc_unstable);
-
 /* Accellerators for sched_clock()
  * convert from cycles(64bits) => nanoseconds (64bits)
  *  basic equation:
@@ -295,7 +289,6 @@ core_initcall(cpufreq_tsc);
 /* clock source code */
 
 static unsigned long current_tsc_khz = 0;
-static int tsc_update_callback(void);
 
 static cycle_t read_tsc(void)
 {
@@ -313,37 +306,28 @@ static struct clocksource clocksource_tsc = {
         .mask                   = CLOCKSOURCE_MASK(64),
         .mult                   = 0, /* to be set */
         .shift                  = 22,
-        .update_callback        = tsc_update_callback,
         .flags                  = CLOCK_SOURCE_IS_CONTINUOUS |
                                   CLOCK_SOURCE_MUST_VERIFY,
 };
 
-static int tsc_update_callback(void)
+void mark_tsc_unstable(void)
 {
-        int change = 0;
-
-        /* check to see if we should switch to the safe clocksource: */
-        if (clocksource_tsc.rating != 0 && check_tsc_unstable()) {
-                clocksource_change_rating(&clocksource_tsc, 0);
-                change = 1;
-        }
-
-        /* only update if tsc_khz has changed: */
-        if (current_tsc_khz != tsc_khz) {
-                current_tsc_khz = tsc_khz;
-                clocksource_tsc.mult = clocksource_khz2mult(current_tsc_khz,
-                                                        clocksource_tsc.shift);
-                change = 1;
+        if (!tsc_unstable) {
+                tsc_unstable = 1;
+                /* Can be called before registration */
+                if (clocksource_tsc.mult)
+                        clocksource_change_rating(&clocksource_tsc, 0);
+                else
+                        clocksource_tsc.rating = 0;
         }
-
-        return change;
 }
+EXPORT_SYMBOL_GPL(mark_tsc_unstable);
 
 static int __init dmi_mark_tsc_unstable(struct dmi_system_id *d)
 {
         printk(KERN_NOTICE "%s detected: marking TSC unstable.\n",
                        d->ident);
-        mark_tsc_unstable();
+        tsc_unstable = 1;
         return 0;
 }
 
@@ -415,11 +399,12 @@ __cpuinit int unsynchronized_tsc(void)
          * Intel systems are normally all synchronized.
          * Exceptions must mark TSC as unstable:
          */
-        if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)
-                return 0;
-
-        /* assume multi socket systems are not synchronized: */
-        return num_possible_cpus() > 1;
+        if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL) {
+                /* assume multi socket systems are not synchronized: */
+                if (num_possible_cpus() > 1)
+                        tsc_unstable = 1;
+        }
+        return tsc_unstable;
 }
 
 static int __init init_tsc_clocksource(void)
@@ -429,8 +414,7 @@ static int __init init_tsc_clocksource(void)
                 /* check blacklist */
                 dmi_check_system(bad_tsc_dmi_table);
 
-                if (unsynchronized_tsc()) /* mark unstable if unsynced */
-                        mark_tsc_unstable();
+                unsynchronized_tsc();
                 current_tsc_khz = tsc_khz;
                 clocksource_tsc.mult = clocksource_khz2mult(current_tsc_khz,
                                                         clocksource_tsc.shift);
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
index 45b0c310ae82..a585a29fe7c4 100644
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -44,7 +44,6 @@ typedef u64 cycle_t;
  *                      subtraction of non 64 bit counters
  * @mult:               cycle to nanosecond multiplier
  * @shift:              cycle to nanosecond divisor (power of two)
- * @update_callback:    called when safe to alter clocksource values
  * @flags:              flags describing special properties
  * @cycle_interval:     Used internally by timekeeping core, please ignore.
  * @xtime_interval:     Used internally by timekeeping core, please ignore.
@@ -57,7 +56,6 @@ struct clocksource {
         cycle_t mask;
         u32 mult;
         u32 shift;
-        int (*update_callback)(void);
         unsigned long flags;
 
         /* timekeeping specific data, ignore */
diff --git a/kernel/timer.c b/kernel/timer.c
index 1144ff2c2ea3..4b088fcadb3f 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -848,8 +848,6 @@ static int change_clocksource(void)
                 printk(KERN_INFO "Time: %s clocksource has been installed.\n",
                        clock->name);
                 return 1;
-        } else if (clock->update_callback) {
-                return clock->update_callback();
         }
         return 0;
 }