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-rw-r--r--kernel/time.c22
1 files changed, 20 insertions, 2 deletions
diff --git a/kernel/time.c b/kernel/time.c
index 5cb80533d8b5..8e8dc6d705c9 100644
--- a/kernel/time.c
+++ b/kernel/time.c
@@ -645,7 +645,7 @@ u64 nsec_to_clock_t(u64 x)
645} 645}
646 646
647/** 647/**
648 * nsecs_to_jiffies - Convert nsecs in u64 to jiffies 648 * nsecs_to_jiffies64 - Convert nsecs in u64 to jiffies64
649 * 649 *
650 * @n: nsecs in u64 650 * @n: nsecs in u64
651 * 651 *
@@ -657,7 +657,7 @@ u64 nsec_to_clock_t(u64 x)
657 * NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512) 657 * NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512)
658 * ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years 658 * ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years
659 */ 659 */
660unsigned long nsecs_to_jiffies(u64 n) 660u64 nsecs_to_jiffies64(u64 n)
661{ 661{
662#if (NSEC_PER_SEC % HZ) == 0 662#if (NSEC_PER_SEC % HZ) == 0
663 /* Common case, HZ = 100, 128, 200, 250, 256, 500, 512, 1000 etc. */ 663 /* Common case, HZ = 100, 128, 200, 250, 256, 500, 512, 1000 etc. */
@@ -674,6 +674,24 @@ unsigned long nsecs_to_jiffies(u64 n)
674#endif 674#endif
675} 675}
676 676
677/**
678 * nsecs_to_jiffies - Convert nsecs in u64 to jiffies
679 *
680 * @n: nsecs in u64
681 *
682 * Unlike {m,u}secs_to_jiffies, type of input is not unsigned int but u64.
683 * And this doesn't return MAX_JIFFY_OFFSET since this function is designed
684 * for scheduler, not for use in device drivers to calculate timeout value.
685 *
686 * note:
687 * NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512)
688 * ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years
689 */
690unsigned long nsecs_to_jiffies(u64 n)
691{
692 return (unsigned long)nsecs_to_jiffies64(n);
693}
694
677/* 695/*
678 * Add two timespec values and do a safety check for overflow. 696 * Add two timespec values and do a safety check for overflow.
679 * It's assumed that both values are valid (>= 0) 697 * It's assumed that both values are valid (>= 0)