Commit-ID: f5a2e34375a5e2b711aea488ac3ae50eeba6d57c
Gitweb: http://git.kernel.org/tip/f5a2e34375a5e2b711aea488ac3ae50eeba6d57c
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Thu, 25 Apr 2013 20:31:45 +0000
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Thu, 16 May 2013 11:09:15 +0200
clocksource: Allow clocksource select to skip current clocksource
Preparatory patch for clocksource unbind support.
Split out code from clocksource_select and modify it, so it skips the
current clocksource on request and tries to find a fallback
clocksource. Convert all existing users. No functional change.
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: John Stultz <john.stultz@xxxxxxxxxx>
Cc: Magnus Damm <magnus.damm@xxxxxxxxx>
Link: http://lkml.kernel.org/r/20130425143435.834965397@xxxxxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
kernel/time/clocksource.c | 31 ++++++++++++++++++++-----------
1 file changed, 20 insertions(+), 11 deletions(-)
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 1923a34..9782997 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -553,7 +553,7 @@ static u64 clocksource_max_deferment(struct clocksource *cs)
#ifndef CONFIG_ARCH_USES_GETTIMEOFFSET
-static struct clocksource *clocksource_find_best(bool oneshot)
+static struct clocksource *clocksource_find_best(bool oneshot, bool skipcur)
{
struct clocksource *cs;
@@ -566,6 +566,8 @@ static struct clocksource *clocksource_find_best(bool oneshot)
* the best rating.
*/
list_for_each_entry(cs, &clocksource_list, list) {
+ if (skipcur && cs == curr_clocksource)
+ continue;
if (oneshot && !(cs->flags & CLOCK_SOURCE_VALID_FOR_HRES))
continue;
return cs;
@@ -573,26 +575,20 @@ static struct clocksource *clocksource_find_best(bool oneshot)
return NULL;
}
-/**
- * clocksource_select - Select the best clocksource available
- *
- * Private function. Must hold clocksource_mutex when called.
- *
- * Select the clocksource with the best rating, or the clocksource,
- * which is selected by userspace override.
- */
-static void clocksource_select(void)
+static void __clocksource_select(bool skipcur)
{
bool oneshot = tick_oneshot_mode_active();
struct clocksource *best, *cs;
/* Find the best suitable clocksource */
- best = clocksource_find_best(oneshot);
+ best = clocksource_find_best(oneshot, skipcur);
if (!best)
return;
/* Check for the override clocksource. */
list_for_each_entry(cs, &clocksource_list, list) {
+ if (skipcur && cs == curr_clocksource)
+ continue;
if (strcmp(cs->name, override_name) != 0)
continue;
/*
@@ -618,6 +614,19 @@ static void clocksource_select(void)
}
}
+/**
+ * clocksource_select - Select the best clocksource available
+ *
+ * Private function. Must hold clocksource_mutex when called.
+ *
+ * Select the clocksource with the best rating, or the clocksource,
+ * which is selected by userspace override.
+ */
+static void clocksource_select(void)
+{
+ return __clocksource_select(false);
+}
+
#else /* !CONFIG_ARCH_USES_GETTIMEOFFSET */
static inline void clocksource_select(void) { }
--
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