From 026659b9774e4c586baeb457557fcfc4e0ad144b Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sun, 15 Aug 2021 23:29:28 +0200 Subject: [PATCH] locking/local_lock: Add PREEMPT_RT support On PREEMPT_RT enabled kernels local_lock maps to a per CPU 'sleeping' spinlock which protects the critical section while staying preemptible. CPU locality is established by disabling migration. Provide the necessary types and macros to substitute the non-RT variant. Co-developed-by: Sebastian Andrzej Siewior Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20210815211306.023630962@linutronix.de --- include/linux/local_lock_internal.h | 44 +++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) diff --git a/include/linux/local_lock_internal.h b/include/linux/local_lock_internal.h index 3f02b81..975e33b 100644 --- a/include/linux/local_lock_internal.h +++ b/include/linux/local_lock_internal.h @@ -6,6 +6,8 @@ #include #include +#ifndef CONFIG_PREEMPT_RT + typedef struct { #ifdef CONFIG_DEBUG_LOCK_ALLOC struct lockdep_map dep_map; @@ -95,3 +97,45 @@ do { \ local_lock_release(this_cpu_ptr(lock)); \ local_irq_restore(flags); \ } while (0) + +#else /* !CONFIG_PREEMPT_RT */ + +/* + * On PREEMPT_RT local_lock maps to a per CPU spinlock, which protects the + * critical section while staying preemptible. + */ +typedef spinlock_t local_lock_t; + +#define INIT_LOCAL_LOCK(lockname) __LOCAL_SPIN_LOCK_UNLOCKED((lockname)) + +#define __local_lock_init(l) \ + do { \ + local_spin_lock_init((l)); \ + } while (0) + +#define __local_lock(__lock) \ + do { \ + migrate_disable(); \ + spin_lock(this_cpu_ptr((__lock))); \ + } while (0) + +#define __local_lock_irq(lock) __local_lock(lock) + +#define __local_lock_irqsave(lock, flags) \ + do { \ + typecheck(unsigned long, flags); \ + flags = 0; \ + __local_lock(lock); \ + } while (0) + +#define __local_unlock(__lock) \ + do { \ + spin_unlock(this_cpu_ptr((__lock))); \ + migrate_enable(); \ + } while (0) + +#define __local_unlock_irq(lock) __local_unlock(lock) + +#define __local_unlock_irqrestore(lock, flags) __local_unlock(lock) + +#endif /* CONFIG_PREEMPT_RT */ -- 2.7.4