Commit 2ab80d46 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

cpuidle: Use s64 as exit_latency_ns and target_residency_ns data type 



Subsequent changes will cause the exit_latency_ns and target_residency_ns
fields in struct cpuidle_state to be used in computations in which data
type conversions to u64 may turn a negative number close to zero into
a verly large positive number leading to incorrect results.

In preparation for that, change the data type of the fields mentioned
above to s64, but ensure that they will not be negative themselves.

No intentional functional impact.

Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 4c81cb7e

drivers/cpuidle/driver.c

+4 −0
Original line number Diff line number Diff line
@@ -181,9 +181,13 @@ static void __cpuidle_driver_init(struct cpuidle_driver *drv) 
		 */

		if (s->target_residency > 0)

			s->target_residency_ns = s->target_residency * NSEC_PER_USEC;

		else if (s->target_residency_ns < 0)

			s->target_residency_ns = 0;



		if (s->exit_latency > 0)

			s->exit_latency_ns = s->exit_latency * NSEC_PER_USEC;

		else if (s->exit_latency_ns < 0)

			s->exit_latency_ns =  0;

	}

}

include/linux/cpuidle.h

+2 −2
Original line number Diff line number Diff line
@@ -49,8 +49,8 @@ struct cpuidle_state { 
	char		name[CPUIDLE_NAME_LEN];

	char		desc[CPUIDLE_DESC_LEN];



	u64		exit_latency_ns;

	u64		target_residency_ns;

	s64		exit_latency_ns;

	s64		target_residency_ns;

	unsigned int	flags;

	unsigned int	exit_latency; /* in US */

	int		power_usage; /* in mW */