diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2021-08-15 23:28:28 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2021-08-17 17:50:51 +0200 |
| commit | 8282947f67345246b4a6344dbceb07484d3d4dad (patch) | |
| tree | aeb316bc3ec77d94c819bb6bea21e45c7296fcd9 /include/linux/rwlock_types.h | |
| parent | 0f383b6dc96e976dfbf2721b0bf10bd96103b341 (diff) | |
locking/rwlock: Provide RT variant
Similar to rw_semaphores, on RT the rwlock substitution is not writer fair,
because it's not feasible to have a writer inherit its priority to
multiple readers. Readers blocked on a writer follow the normal rules of
priority inheritance. Like RT spinlocks, RT rwlocks are state preserving
across the slow lock operations (contended case).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211303.882793524@linutronix.de
Diffstat (limited to 'include/linux/rwlock_types.h')
| -rw-r--r-- | include/linux/rwlock_types.h | 49 |
1 files changed, 37 insertions, 12 deletions
diff --git a/include/linux/rwlock_types.h b/include/linux/rwlock_types.h index 0ad226b5d8fd..1948442e7750 100644 --- a/include/linux/rwlock_types.h +++ b/include/linux/rwlock_types.h @@ -5,9 +5,19 @@ # error "Do not include directly, include spinlock_types.h" #endif +#ifdef CONFIG_DEBUG_LOCK_ALLOC +# define RW_DEP_MAP_INIT(lockname) \ + .dep_map = { \ + .name = #lockname, \ + .wait_type_inner = LD_WAIT_CONFIG, \ + } +#else +# define RW_DEP_MAP_INIT(lockname) +#endif + +#ifndef CONFIG_PREEMPT_RT /* - * include/linux/rwlock_types.h - generic rwlock type definitions - * and initializers + * generic rwlock type definitions and initializers * * portions Copyright 2005, Red Hat, Inc., Ingo Molnar * Released under the General Public License (GPL). @@ -25,16 +35,6 @@ typedef struct { #define RWLOCK_MAGIC 0xdeaf1eed -#ifdef CONFIG_DEBUG_LOCK_ALLOC -# define RW_DEP_MAP_INIT(lockname) \ - .dep_map = { \ - .name = #lockname, \ - .wait_type_inner = LD_WAIT_CONFIG, \ - } -#else -# define RW_DEP_MAP_INIT(lockname) -#endif - #ifdef CONFIG_DEBUG_SPINLOCK #define __RW_LOCK_UNLOCKED(lockname) \ (rwlock_t) { .raw_lock = __ARCH_RW_LOCK_UNLOCKED, \ @@ -50,4 +50,29 @@ typedef struct { #define DEFINE_RWLOCK(x) rwlock_t x = __RW_LOCK_UNLOCKED(x) +#else /* !CONFIG_PREEMPT_RT */ + +#include <linux/rwbase_rt.h> + +typedef struct { + struct rwbase_rt rwbase; + atomic_t readers; +#ifdef CONFIG_DEBUG_LOCK_ALLOC + struct lockdep_map dep_map; +#endif +} rwlock_t; + +#define __RWLOCK_RT_INITIALIZER(name) \ +{ \ + .rwbase = __RWBASE_INITIALIZER(name), \ + RW_DEP_MAP_INIT(name) \ +} + +#define __RW_LOCK_UNLOCKED(name) __RWLOCK_RT_INITIALIZER(name) + +#define DEFINE_RWLOCK(name) \ + rwlock_t name = __RW_LOCK_UNLOCKED(name) + +#endif /* CONFIG_PREEMPT_RT */ + #endif /* __LINUX_RWLOCK_TYPES_H */ |