[tip:timers/core] clocksource: Don't walk the clocksource list for empty override

[tip-bot for Baolin Wang]

Commit-ID:  7f852afe448c95691ead6b57bae5f37562d060b5
Gitweb:     https://git.kernel.org/tip/7f852afe448c95691ead6b57bae5f37562d060b5
Author:     Baolin Wang <baolin.wang@xxxxxxxxxx>
AuthorDate: Wed, 17 Jan 2018 14:01:28 +0800
Committer:  Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Wed, 28 Feb 2018 14:04:52 +0100

clocksource: Don't walk the clocksource list for empty override

If the override clocksource name is empty there is no point in walking the
clocksource list for a match.

Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: arnd@xxxxxxxx
Cc: sboyd@xxxxxxxxxxxxxx
Cc: broonie@xxxxxxxxxx
Cc: john.stultz@xxxxxxxxxx
Link: https://lkml.kernel.org/r/069ce2a605546bcad6552968cff755f0a03f9f10.1516167691.git.baolin.wang@xxxxxxxxxx

---
 kernel/time/clocksource.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 65f9e3f24dde..c5fdcb13200f 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -594,6 +594,9 @@ static void __clocksource_select(bool skipcur)
 	if (!best)
 		return;
 
+	if (!strlen(override_name))
+		goto found;
+
 	/* Check for the override clocksource. */
 	list_for_each_entry(cs, &clocksource_list, list) {
 		if (skipcur && cs == curr_clocksource)
@@ -625,6 +628,7 @@ static void __clocksource_select(bool skipcur)
 		break;
 	}
 
+found:
 	if (curr_clocksource != best && !timekeeping_notify(best)) {
 		pr_info("Switched to clocksource %s\n", best->name);
 		curr_clocksource = best;