3.16.62-rc1 review patch. If anyone has any objections, please let me know.
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From: Catalin Marinas catalin.marinas@arm.com
commit 9bd616e3dbedfc103f158197c8ad93678849b1ed upstream.
The cpuidle_devices per-CPU variable is only defined when CPU_IDLE is enabled. Commit c8cc7d4de7a4 ("sched/idle: Reorganize the idle loop") removed the #ifdef CONFIG_CPU_IDLE around cpuidle_idle_call() with the compiler optimising away __this_cpu_read(cpuidle_devices). However, with CONFIG_UBSAN && !CONFIG_CPU_IDLE, this optimisation no longer happens and the kernel fails to link since cpuidle_devices is not defined.
This patch introduces an accessor function for the current CPU cpuidle device (returning NULL when !CONFIG_CPU_IDLE) and uses it in cpuidle_idle_call().
Signed-off-by: Catalin Marinas catalin.marinas@arm.com Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Ben Hutchings ben@decadent.org.uk --- include/linux/cpuidle.h | 3 +++ kernel/sched/idle.c | 2 +- 2 files changed, 4 insertions(+), 1 deletion(-)
--- a/include/linux/cpuidle.h +++ b/include/linux/cpuidle.h @@ -146,6 +146,8 @@ extern int cpuidle_play_dead(void); extern void cpuidle_use_deepest_state(bool enable);
extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev); +static inline struct cpuidle_device *cpuidle_get_device(void) +{return __this_cpu_read(cpuidle_devices); } #else static inline void disable_cpuidle(void) { } static inline int cpuidle_select(struct cpuidle_driver *drv, @@ -179,6 +181,7 @@ static inline int cpuidle_play_dead(void static inline void cpuidle_use_deepest_state(bool enable) {} static inline struct cpuidle_driver *cpuidle_get_cpu_driver( struct cpuidle_device *dev) {return NULL; } +static inline struct cpuidle_device *cpuidle_get_device(void) {return NULL; } #endif
#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -76,7 +76,7 @@ void __weak arch_cpu_idle(void) */ static void cpuidle_idle_call(void) { - struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices); + struct cpuidle_device *dev = cpuidle_get_device(); struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); int next_state, entered_state; bool broadcast;