[PATCH] PM/runtime: Do not needlessly call ktime_get

[Ladislav Michl]

pm_runtime_autosuspend_expiration calls ktime_get even when
its returned value may be unused. Therefore get current time
later and remove gotos while there.

Signed-off-by: Ladislav Michl <la...@linux-mips.org>
---
 NOTE: Depends on Vincent's "[PATCH v2] PM/runtime: Fix autosuspend_delay
       on 32bits arch"!

 drivers/base/power/runtime.c | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 457be03b744d..836b1b8784eb 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -129,24 +129,21 @@ static void pm_runtime_cancel_pending(struct device *dev)
 u64 pm_runtime_autosuspend_expiration(struct device *dev)
 {
        int autosuspend_delay;
-       u64 last_busy, expires = 0;
-       u64 now = ktime_to_ns(ktime_get());
+       u64 expires;
 
        if (!dev->power.use_autosuspend)
-               goto out;
+               return 0;
 
        autosuspend_delay = READ_ONCE(dev->power.autosuspend_delay);
        if (autosuspend_delay < 0)
-               goto out;
-
-       last_busy = READ_ONCE(dev->power.last_busy);
+               return 0;
 
-       expires = last_busy + (u64)autosuspend_delay * NSEC_PER_MSEC;
-       if (expires <= now)
-               expires = 0;    /* Already expired. */
+       expires  = READ_ONCE(dev->power.last_busy);
+       expires += (u64)autosuspend_delay * NSEC_PER_MSEC;
+       if (expires > ktime_to_ns(ktime_get()))
+               return expires; /* Expires in the future */
 
- out:
-       return expires;
+       return 0;
 }
 EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration);
 
-- 
2.20.1