From: Thomas Gleixner <tglx@linutronix.de>
Date: Sun, 26 Jul 2009 19:39:56 +0200
Subject: rt: Add the preempt-rt lock replacement APIs
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git
Git-commit: f34d077c6f288513698392d940031b5391f7408f
Patch-mainline: Queued in subsystem maintainer repository
References: SLE15 Realtime Extension
Map spinlocks, rwlocks, rw_semaphores and semaphores to the rt_mutex
based locking functions for preempt-rt.
This also introduces RT's sleeping locks.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Mike Galbraith <mgalbraith@suse.de>
---
include/linux/kernel.h | 4
include/linux/locallock.h | 6
include/linux/mutex.h | 20 -
include/linux/mutex_rt.h | 130 +++++++++
include/linux/rtmutex.h | 41 ++
include/linux/rwlock_rt.h | 99 +++++++
include/linux/rwlock_types_rt.h | 33 ++
include/linux/rwsem.h | 6
include/linux/rwsem_rt.h | 167 +++++++++++
include/linux/sched.h | 8
include/linux/sched/wake_q.h | 11
include/linux/spinlock.h | 12
include/linux/spinlock_api_smp.h | 4
include/linux/spinlock_rt.h | 159 +++++++++++
include/linux/spinlock_types.h | 11
include/linux/spinlock_types_rt.h | 48 +++
kernel/futex.c | 11
kernel/locking/Makefile | 9
kernel/locking/rt.c | 521 +++++++++++++++++++++++++++++++++++++
kernel/locking/rtmutex.c | 534 ++++++++++++++++++++++++++++++++++----
kernel/locking/rtmutex_common.h | 10
kernel/locking/spinlock.c | 7
kernel/locking/spinlock_debug.c | 5
kernel/sched/core.c | 7
24 files changed, 1783 insertions(+), 80 deletions(-)
create mode 100644 include/linux/mutex_rt.h
create mode 100644 include/linux/rwlock_rt.h
create mode 100644 include/linux/rwlock_types_rt.h
create mode 100644 include/linux/rwsem_rt.h
create mode 100644 include/linux/spinlock_rt.h
create mode 100644 include/linux/spinlock_types_rt.h
create mode 100644 kernel/locking/rt.c
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -206,6 +206,9 @@ extern int _cond_resched(void);
*/
# define might_sleep() \
do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
+
+# define might_sleep_no_state_check() \
+ do { ___might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
# define sched_annotate_sleep() (current->task_state_change = 0)
#else
static inline void ___might_sleep(const char *file, int line,
@@ -213,6 +216,7 @@ extern int _cond_resched(void);
static inline void __might_sleep(const char *file, int line,
int preempt_offset) { }
# define might_sleep() do { might_resched(); } while (0)
+# define might_sleep_no_state_check() do { might_resched(); } while (0)
# define sched_annotate_sleep() do { } while (0)
#endif
--- a/include/linux/locallock.h
+++ b/include/linux/locallock.h
@@ -42,9 +42,15 @@ struct local_irq_lock {
* already takes care of the migrate_disable/enable
* for CONFIG_PREEMPT_BASE map to the normal spin_* calls.
*/
+#ifdef CONFIG_PREEMPT_RT_FULL
+# define spin_lock_local(lock) rt_spin_lock__no_mg(lock)
+# define spin_trylock_local(lock) rt_spin_trylock__no_mg(lock)
+# define spin_unlock_local(lock) rt_spin_unlock__no_mg(lock)
+#else
# define spin_lock_local(lock) spin_lock(lock)
# define spin_trylock_local(lock) spin_trylock(lock)
# define spin_unlock_local(lock) spin_unlock(lock)
+#endif
static inline void __local_lock(struct local_irq_lock *lv)
{
--- a/include/linux/mutex.h
+++ b/include/linux/mutex.h
@@ -22,6 +22,17 @@
struct ww_acquire_ctx;
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+# define __DEP_MAP_MUTEX_INITIALIZER(lockname) \
+ , .dep_map = { .name = #lockname }
+#else
+# define __DEP_MAP_MUTEX_INITIALIZER(lockname)
+#endif
+
+#ifdef CONFIG_PREEMPT_RT_FULL
+# include <linux/mutex_rt.h>
+#else
+
/*
* Simple, straightforward mutexes with strict semantics:
*
@@ -113,13 +124,6 @@ do { \
__mutex_init((mutex), #mutex, &__key); \
} while (0)
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-# define __DEP_MAP_MUTEX_INITIALIZER(lockname) \
- , .dep_map = { .name = #lockname }
-#else
-# define __DEP_MAP_MUTEX_INITIALIZER(lockname)
-#endif
-
#define __MUTEX_INITIALIZER(lockname) \
{ .owner = ATOMIC_LONG_INIT(0) \
, .wait_lock = __SPIN_LOCK_UNLOCKED(lockname.wait_lock) \
@@ -227,4 +231,6 @@ mutex_trylock_recursive(struct mutex *lo
return mutex_trylock(lock);
}
+#endif /* !PREEMPT_RT_FULL */
+
#endif /* __LINUX_MUTEX_H */
--- /dev/null
+++ b/include/linux/mutex_rt.h
@@ -0,0 +1,130 @@
+#ifndef __LINUX_MUTEX_RT_H
+#define __LINUX_MUTEX_RT_H
+
+#ifndef __LINUX_MUTEX_H
+#error "Please include mutex.h"
+#endif
+
+#include <linux/rtmutex.h>
+
+/* FIXME: Just for __lockfunc */
+#include <linux/spinlock.h>
+
+struct mutex {
+ struct rt_mutex lock;
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ struct lockdep_map dep_map;
+#endif
+};
+
+#define __MUTEX_INITIALIZER(mutexname) \
+ { \
+ .lock = __RT_MUTEX_INITIALIZER(mutexname.lock) \
+ __DEP_MAP_MUTEX_INITIALIZER(mutexname) \
+ }
+
+#define DEFINE_MUTEX(mutexname) \
+ struct mutex mutexname = __MUTEX_INITIALIZER(mutexname)
+
+extern void __mutex_do_init(struct mutex *lock, const char *name, struct lock_class_key *key);
+extern void __lockfunc _mutex_lock(struct mutex *lock);
+extern void __lockfunc _mutex_lock_io(struct mutex *lock);
+extern void __lockfunc _mutex_lock_io_nested(struct mutex *lock, int subclass);
+extern int __lockfunc _mutex_lock_interruptible(struct mutex *lock);
+extern int __lockfunc _mutex_lock_killable(struct mutex *lock);
+extern void __lockfunc _mutex_lock_nested(struct mutex *lock, int subclass);
+extern void __lockfunc _mutex_lock_nest_lock(struct mutex *lock, struct lockdep_map *nest_lock);
+extern int __lockfunc _mutex_lock_interruptible_nested(struct mutex *lock, int subclass);
+extern int __lockfunc _mutex_lock_killable_nested(struct mutex *lock, int subclass);
+extern int __lockfunc _mutex_trylock(struct mutex *lock);
+extern void __lockfunc _mutex_unlock(struct mutex *lock);
+
+#define mutex_is_locked(l) rt_mutex_is_locked(&(l)->lock)
+#define mutex_lock(l) _mutex_lock(l)
+#define mutex_lock_interruptible(l) _mutex_lock_interruptible(l)
+#define mutex_lock_killable(l) _mutex_lock_killable(l)
+#define mutex_trylock(l) _mutex_trylock(l)
+#define mutex_unlock(l) _mutex_unlock(l)
+#define mutex_lock_io(l) _mutex_lock_io(l);
+
+#define __mutex_owner(l) ((l)->lock.owner)
+
+#ifdef CONFIG_DEBUG_MUTEXES
+#define mutex_destroy(l) rt_mutex_destroy(&(l)->lock)
+#else
+static inline void mutex_destroy(struct mutex *lock) {}
+#endif
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+# define mutex_lock_nested(l, s) _mutex_lock_nested(l, s)
+# define mutex_lock_interruptible_nested(l, s) \
+ _mutex_lock_interruptible_nested(l, s)
+# define mutex_lock_killable_nested(l, s) \
+ _mutex_lock_killable_nested(l, s)
+# define mutex_lock_io_nested(l, s) _mutex_lock_io_nested(l, s)
+
+# define mutex_lock_nest_lock(lock, nest_lock) \
+do { \
+ typecheck(struct lockdep_map *, &(nest_lock)->dep_map); \
+ _mutex_lock_nest_lock(lock, &(nest_lock)->dep_map); \
+} while (0)
+
+#else
+# define mutex_lock_nested(l, s) _mutex_lock(l)
+# define mutex_lock_interruptible_nested(l, s) \
+ _mutex_lock_interruptible(l)
+# define mutex_lock_killable_nested(l, s) \
+ _mutex_lock_killable(l)
+# define mutex_lock_nest_lock(lock, nest_lock) mutex_lock(lock)
+# define mutex_lock_io_nested(l, s) _mutex_lock_io(l)
+#endif
+
+# define mutex_init(mutex) \
+do { \
+ static struct lock_class_key __key; \
+ \
+ rt_mutex_init(&(mutex)->lock); \
+ __mutex_do_init((mutex), #mutex, &__key); \
+} while (0)
+
+# define __mutex_init(mutex, name, key) \
+do { \
+ rt_mutex_init(&(mutex)->lock); \
+ __mutex_do_init((mutex), name, key); \
+} while (0)
+
+/**
+ * These values are chosen such that FAIL and SUCCESS match the
+ * values of the regular mutex_trylock().
+ */
+enum mutex_trylock_recursive_enum {
+ MUTEX_TRYLOCK_FAILED = 0,
+ MUTEX_TRYLOCK_SUCCESS = 1,
+ MUTEX_TRYLOCK_RECURSIVE,
+};
+/**
+ * mutex_trylock_recursive - trylock variant that allows recursive locking
+ * @lock: mutex to be locked
+ *
+ * This function should not be used, _ever_. It is purely for hysterical GEM
+ * raisins, and once those are gone this will be removed.
+ *
+ * Returns:
+ * MUTEX_TRYLOCK_FAILED - trylock failed,
+ * MUTEX_TRYLOCK_SUCCESS - lock acquired,
+ * MUTEX_TRYLOCK_RECURSIVE - we already owned the lock.
+ */
+int __rt_mutex_owner_current(struct rt_mutex *lock);
+
+static inline /* __deprecated */ __must_check enum mutex_trylock_recursive_enum
+mutex_trylock_recursive(struct mutex *lock)
+{
+ if (unlikely(__rt_mutex_owner_current(&lock->lock)))
+ return MUTEX_TRYLOCK_RECURSIVE;
+
+ return mutex_trylock(lock);
+}
+
+extern int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock);
+
+#endif
--- a/include/linux/rtmutex.h
+++ b/include/linux/rtmutex.h
@@ -13,11 +13,15 @@
#define __LINUX_RT_MUTEX_H
#include <linux/linkage.h>
-#include <linux/rbtree.h>
#include <linux/spinlock_types_raw.h>
+#include <linux/rbtree.h>
extern int max_lock_depth; /* for sysctl */
+#ifdef CONFIG_DEBUG_MUTEXES
+#include <linux/debug_locks.h>
+#endif
+
/**
* The rt_mutex structure
*
@@ -30,8 +34,8 @@ struct rt_mutex {
raw_spinlock_t wait_lock;
struct rb_root_cached waiters;
struct task_struct *owner;
-#ifdef CONFIG_DEBUG_RT_MUTEXES
int save_state;
+#ifdef CONFIG_DEBUG_RT_MUTEXES
const char *name, *file;
int line;
void *magic;
@@ -57,20 +61,21 @@ struct hrtimer_sleeper;
# define rt_mutex_debug_check_no_locks_held(task) do { } while (0)
#endif
+# define rt_mutex_init(mutex) \
+ do { \
+ static struct lock_class_key __key; \
+ raw_spin_lock_init(&(mutex)->wait_lock); \
+ __rt_mutex_init(mutex, #mutex, &__key); \
+ } while (0)
+
+
#ifdef CONFIG_DEBUG_RT_MUTEXES
# define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
, .name = #mutexname, .file = __FILE__, .line = __LINE__
-# define rt_mutex_init(mutex) \
-do { \
- static struct lock_class_key __key; \
- __rt_mutex_init(mutex, __func__, &__key); \
-} while (0)
-
extern void rt_mutex_debug_task_free(struct task_struct *tsk);
#else
# define __DEBUG_RT_MUTEX_INITIALIZER(mutexname)
-# define rt_mutex_init(mutex) __rt_mutex_init(mutex, NULL, NULL)
# define rt_mutex_debug_task_free(t) do { } while (0)
#endif
@@ -81,12 +86,19 @@ do { \
#define __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)
#endif
-#define __RT_MUTEX_INITIALIZER(mutexname) \
- { .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(mutexname.wait_lock) \
+#define __RT_MUTEX_INITIALIZER_PLAIN(mutexname) \
+ .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(mutexname.wait_lock) \
, .waiters = RB_ROOT_CACHED \
, .owner = NULL \
__DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
- __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)}
+ __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)
+
+#define __RT_MUTEX_INITIALIZER(mutexname) \
+ { __RT_MUTEX_INITIALIZER_PLAIN(mutexname) }
+
+#define __RT_MUTEX_INITIALIZER_SAVE_STATE(mutexname) \
+ { __RT_MUTEX_INITIALIZER_PLAIN(mutexname) \
+ , .save_state = 1 }
#define DEFINE_RT_MUTEX(mutexname) \
struct rt_mutex mutexname = __RT_MUTEX_INITIALIZER(mutexname)
@@ -116,4 +128,9 @@ extern int rt_mutex_trylock(struct rt_mu
extern void rt_mutex_unlock(struct rt_mutex *lock);
+/* lockdep-less calls, for derived types */
+extern int __rt_mutex_lock_state(struct rt_mutex *lock, int state);
+extern int __rt_mutex_trylock(struct rt_mutex *lock);
+extern void __rt_mutex_unlock(struct rt_mutex *lock);
+
#endif
--- /dev/null
+++ b/include/linux/rwlock_rt.h
@@ -0,0 +1,99 @@
+#ifndef __LINUX_RWLOCK_RT_H
+#define __LINUX_RWLOCK_RT_H
+
+#ifndef __LINUX_SPINLOCK_H
+#error Do not include directly. Use spinlock.h
+#endif
+
+#define rwlock_init(rwl) \
+do { \
+ static struct lock_class_key __key; \
+ \
+ rt_mutex_init(&(rwl)->lock); \
+ __rt_rwlock_init(rwl, #rwl, &__key); \
+} while (0)
+
+extern void __lockfunc rt_write_lock(rwlock_t *rwlock);
+extern void __lockfunc rt_read_lock(rwlock_t *rwlock);
+extern int __lockfunc rt_write_trylock(rwlock_t *rwlock);
+extern int __lockfunc rt_write_trylock_irqsave(rwlock_t *trylock, unsigned long *flags);
+extern int __lockfunc rt_read_trylock(rwlock_t *rwlock);
+extern void __lockfunc rt_write_unlock(rwlock_t *rwlock);
+extern void __lockfunc rt_read_unlock(rwlock_t *rwlock);
+extern unsigned long __lockfunc rt_write_lock_irqsave(rwlock_t *rwlock);
+extern unsigned long __lockfunc rt_read_lock_irqsave(rwlock_t *rwlock);
+extern void __rt_rwlock_init(rwlock_t *rwlock, char *name, struct lock_class_key *key);
+
+#define read_trylock(lock) __cond_lock(lock, rt_read_trylock(lock))
+#define write_trylock(lock) __cond_lock(lock, rt_write_trylock(lock))
+
+#define write_trylock_irqsave(lock, flags) \
+ __cond_lock(lock, rt_write_trylock_irqsave(lock, &flags))
+
+#define read_lock_irqsave(lock, flags) \
+ do { \
+ typecheck(unsigned long, flags); \
+ flags = rt_read_lock_irqsave(lock); \
+ } while (0)
+
+#define write_lock_irqsave(lock, flags) \
+ do { \
+ typecheck(unsigned long, flags); \
+ flags = rt_write_lock_irqsave(lock); \
+ } while (0)
+
+#define read_lock(lock) rt_read_lock(lock)
+
+#define read_lock_bh(lock) \
+ do { \
+ local_bh_disable(); \
+ rt_read_lock(lock); \
+ } while (0)
+
+#define read_lock_irq(lock) read_lock(lock)
+
+#define write_lock(lock) rt_write_lock(lock)
+
+#define write_lock_bh(lock) \
+ do { \
+ local_bh_disable(); \
+ rt_write_lock(lock); \
+ } while (0)
+
+#define write_lock_irq(lock) write_lock(lock)
+
+#define read_unlock(lock) rt_read_unlock(lock)
+
+#define read_unlock_bh(lock) \
+ do { \
+ rt_read_unlock(lock); \
+ local_bh_enable(); \
+ } while (0)
+
+#define read_unlock_irq(lock) read_unlock(lock)
+
+#define write_unlock(lock) rt_write_unlock(lock)
+
+#define write_unlock_bh(lock) \
+ do { \
+ rt_write_unlock(lock); \
+ local_bh_enable(); \
+ } while (0)
+
+#define write_unlock_irq(lock) write_unlock(lock)
+
+#define read_unlock_irqrestore(lock, flags) \
+ do { \
+ typecheck(unsigned long, flags); \
+ (void) flags; \
+ rt_read_unlock(lock); \
+ } while (0)
+
+#define write_unlock_irqrestore(lock, flags) \
+ do { \
+ typecheck(unsigned long, flags); \
+ (void) flags; \
+ rt_write_unlock(lock); \
+ } while (0)
+
+#endif
--- /dev/null
+++ b/include/linux/rwlock_types_rt.h
@@ -0,0 +1,33 @@
+#ifndef __LINUX_RWLOCK_TYPES_RT_H
+#define __LINUX_RWLOCK_TYPES_RT_H
+
+#ifndef __LINUX_SPINLOCK_TYPES_H
+#error "Do not include directly. Include spinlock_types.h instead"
+#endif
+
+/*
+ * rwlocks - rtmutex which allows single reader recursion
+ */
+typedef struct {
+ struct rt_mutex lock;
+ int read_depth;
+ unsigned int break_lock;
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ struct lockdep_map dep_map;
+#endif
+} rwlock_t;
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+# define RW_DEP_MAP_INIT(lockname) .dep_map = { .name = #lockname }
+#else
+# define RW_DEP_MAP_INIT(lockname)
+#endif
+
+#define __RW_LOCK_UNLOCKED(name) \
+ { .lock = __RT_MUTEX_INITIALIZER_SAVE_STATE(name.lock), \
+ RW_DEP_MAP_INIT(name) }
+
+#define DEFINE_RWLOCK(name) \
+ rwlock_t name = __RW_LOCK_UNLOCKED(name)
+
+#endif
--- a/include/linux/rwsem.h
+++ b/include/linux/rwsem.h
@@ -19,6 +19,10 @@
#include <linux/osq_lock.h>
#endif
+#ifdef CONFIG_PREEMPT_RT_FULL
+#include <linux/rwsem_rt.h>
+#else /* PREEMPT_RT_FULL */
+
struct rw_semaphore;
#ifdef CONFIG_RWSEM_GENERIC_SPINLOCK
@@ -185,4 +189,6 @@ extern void up_read_non_owner(struct rw_
# define up_read_non_owner(sem) up_read(sem)
#endif
+#endif /* !PREEMPT_RT_FULL */
+
#endif /* _LINUX_RWSEM_H */
--- /dev/null
+++ b/include/linux/rwsem_rt.h
@@ -0,0 +1,167 @@
+#ifndef _LINUX_RWSEM_RT_H
+#define _LINUX_RWSEM_RT_H
+
+#ifndef _LINUX_RWSEM_H
+#error "Include rwsem.h"
+#endif
+
+/*
+ * RW-semaphores are a spinlock plus a reader-depth count.
+ *
+ * Note that the semantics are different from the usual
+ * Linux rw-sems, in PREEMPT_RT mode we do not allow
+ * multiple readers to hold the lock at once, we only allow
+ * a read-lock owner to read-lock recursively. This is
+ * better for latency, makes the implementation inherently
+ * fair and makes it simpler as well.
+ */
+
+#include <linux/rtmutex.h>
+
+struct rw_semaphore {
+ struct rt_mutex lock;
+ int read_depth;
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ struct lockdep_map dep_map;
+#endif
+};
+
+#define __RWSEM_INITIALIZER(name) \
+ { .lock = __RT_MUTEX_INITIALIZER(name.lock), \
+ RW_DEP_MAP_INIT(name) }
+
+#define DECLARE_RWSEM(lockname) \
+ struct rw_semaphore lockname = __RWSEM_INITIALIZER(lockname)
+
+extern void __rt_rwsem_init(struct rw_semaphore *rwsem, const char *name,
+ struct lock_class_key *key);
+
+#define __rt_init_rwsem(sem, name, key) \
+ do { \
+ rt_mutex_init(&(sem)->lock); \
+ __rt_rwsem_init((sem), (name), (key));\
+ } while (0)
+
+#define __init_rwsem(sem, name, key) __rt_init_rwsem(sem, name, key)
+
+# define rt_init_rwsem(sem) \
+do { \
+ static struct lock_class_key __key; \
+ \
+ __rt_init_rwsem((sem), #sem, &__key); \
+} while (0)
+
+extern void rt_down_write(struct rw_semaphore *rwsem);
+extern int rt_down_write_killable(struct rw_semaphore *rwsem);
+extern void rt_down_read_nested(struct rw_semaphore *rwsem, int subclass);
+extern void rt_down_write_nested(struct rw_semaphore *rwsem, int subclass);
+extern int rt_down_write_killable_nested(struct rw_semaphore *rwsem,
+ int subclass);
+extern void rt_down_write_nested_lock(struct rw_semaphore *rwsem,
+ struct lockdep_map *nest);
+extern void rt__down_read(struct rw_semaphore *rwsem);
+extern void rt_down_read(struct rw_semaphore *rwsem);
+extern int rt_down_write_trylock(struct rw_semaphore *rwsem);
+extern int rt__down_read_trylock(struct rw_semaphore *rwsem);
+extern int rt_down_read_trylock(struct rw_semaphore *rwsem);
+extern void __rt_up_read(struct rw_semaphore *rwsem);
+extern void rt_up_read(struct rw_semaphore *rwsem);
+extern void rt_up_write(struct rw_semaphore *rwsem);
+extern void rt_downgrade_write(struct rw_semaphore *rwsem);
+
+#define init_rwsem(sem) rt_init_rwsem(sem)
+#define rwsem_is_locked(s) rt_mutex_is_locked(&(s)->lock)
+
+static inline int rwsem_is_contended(struct rw_semaphore *sem)
+{
+ /* rt_mutex_has_waiters() */
+ return !RB_EMPTY_ROOT(&sem->lock.waiters);
+}
+
+static inline void __down_read(struct rw_semaphore *sem)
+{
+ rt__down_read(sem);
+}
+
+static inline void down_read(struct rw_semaphore *sem)
+{
+ rt_down_read(sem);
+}
+
+static inline int __down_read_trylock(struct rw_semaphore *sem)
+{
+ return rt__down_read_trylock(sem);
+}
+
+static inline int down_read_trylock(struct rw_semaphore *sem)
+{
+ return rt_down_read_trylock(sem);
+}
+
+static inline void down_write(struct rw_semaphore *sem)
+{
+ rt_down_write(sem);
+}
+
+static inline int down_write_killable(struct rw_semaphore *sem)
+{
+ return rt_down_write_killable(sem);
+}
+
+static inline int down_write_trylock(struct rw_semaphore *sem)
+{
+ return rt_down_write_trylock(sem);
+}
+
+static inline void __up_read(struct rw_semaphore *sem)
+{
+ __rt_up_read(sem);
+}
+
+static inline void up_read(struct rw_semaphore *sem)
+{
+ rt_up_read(sem);
+}
+
+static inline void up_write(struct rw_semaphore *sem)
+{
+ rt_up_write(sem);
+}
+
+static inline void downgrade_write(struct rw_semaphore *sem)
+{
+ rt_downgrade_write(sem);
+}
+
+static inline void down_read_nested(struct rw_semaphore *sem, int subclass)
+{
+ return rt_down_read_nested(sem, subclass);
+}
+
+static inline void down_write_nested(struct rw_semaphore *sem, int subclass)
+{
+ rt_down_write_nested(sem, subclass);
+}
+
+static inline int down_write_killable_nested(struct rw_semaphore *sem,
+ int subclass)
+{
+ return rt_down_write_killable_nested(sem, subclass);
+}
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+static inline void down_write_nest_lock(struct rw_semaphore *sem,
+ struct rw_semaphore *nest_lock)
+{
+ rt_down_write_nested_lock(sem, &nest_lock->dep_map);
+}
+
+#else
+
+static inline void down_write_nest_lock(struct rw_semaphore *sem,
+ struct rw_semaphore *nest_lock)
+{
+ rt_down_write_nested_lock(sem, NULL);
+}
+#endif
+#endif
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -123,6 +123,11 @@ struct task_group;
smp_store_mb(current->state, (state_value)); \
} while (0)
+#define __set_current_state_no_track(state_value) \
+ current->state = (state_value);
+#define set_current_state_no_track(state_value) \
+ smp_store_mb(current->state, (state_value));
+
#else
/*
* set_current_state() includes a barrier so that the write of current->state
@@ -160,6 +165,9 @@ struct task_group;
*/
#define __set_current_state(state_value) do { current->state = (state_value); } while (0)
#define set_current_state(state_value) smp_store_mb(current->state, (state_value))
+
+#define __set_current_state_no_track(state_value) __set_current_state(state_value)
+#define set_current_state_no_track(state_value) set_current_state(state_value)
#endif
/* Task command name length: */
--- a/include/linux/sched/wake_q.h
+++ b/include/linux/sched/wake_q.h
@@ -52,6 +52,15 @@ static inline void wake_q_init(struct wa
extern void wake_q_add(struct wake_q_head *head, struct task_struct *task);
extern void wake_q_add_safe(struct wake_q_head *head, struct task_struct *task);
-extern void wake_up_q(struct wake_q_head *head);
+extern void __wake_up_q(struct wake_q_head *head, bool sleeper);
+static inline void wake_up_q(struct wake_q_head *head)
+{
+ __wake_up_q(head, false);
+}
+
+static inline void wake_up_q_sleeper(struct wake_q_head *head)
+{
+ __wake_up_q(head, true);
+}
#endif /* _LINUX_SCHED_WAKE_Q_H */
--- a/include/linux/spinlock.h
+++ b/include/linux/spinlock.h
@@ -268,7 +268,11 @@ static inline void do_raw_spin_unlock(ra
#define raw_spin_can_lock(lock) (!raw_spin_is_locked(lock))
/* Include rwlock functions */
-#include <linux/rwlock.h>
+#ifdef CONFIG_PREEMPT_RT_FULL
+# include <linux/rwlock_rt.h>
+#else
+# include <linux/rwlock.h>
+#endif
/*
* Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
@@ -279,6 +283,10 @@ static inline void do_raw_spin_unlock(ra
# include <linux/spinlock_api_up.h>
#endif
+#ifdef CONFIG_PREEMPT_RT_FULL
+# include <linux/spinlock_rt.h>
+#else /* PREEMPT_RT_FULL */
+
/*
* Map the spin_lock functions to the raw variants for PREEMPT_RT=n
*/
@@ -391,6 +399,8 @@ static __always_inline int spin_can_lock
#define assert_spin_locked(lock) assert_raw_spin_locked(&(lock)->rlock)
+#endif /* !PREEMPT_RT_FULL */
+
/*
* Pull the atomic_t declaration:
* (asm-mips/atomic.h needs above definitions)
--- a/include/linux/spinlock_api_smp.h
+++ b/include/linux/spinlock_api_smp.h
@@ -187,6 +187,8 @@ static inline int __raw_spin_trylock_bh(
return 0;
}
-#include <linux/rwlock_api_smp.h>
+#ifndef CONFIG_PREEMPT_RT_FULL
+# include <linux/rwlock_api_smp.h>
+#endif
#endif /* __LINUX_SPINLOCK_API_SMP_H */
--- /dev/null
+++ b/include/linux/spinlock_rt.h
@@ -0,0 +1,159 @@
+#ifndef __LINUX_SPINLOCK_RT_H
+#define __LINUX_SPINLOCK_RT_H
+
+#ifndef __LINUX_SPINLOCK_H
+#error Do not include directly. Use spinlock.h
+#endif
+
+#include <linux/bug.h>
+
+extern void
+__rt_spin_lock_init(spinlock_t *lock, const char *name, struct lock_class_key *key);
+
+#define spin_lock_init(slock) \
+do { \
+ static struct lock_class_key __key; \
+ \
+ rt_mutex_init(&(slock)->lock); \
+ __rt_spin_lock_init(slock, #slock, &__key); \
+} while (0)
+
+void __lockfunc rt_spin_lock__no_mg(spinlock_t *lock);
+void __lockfunc rt_spin_unlock__no_mg(spinlock_t *lock);
+int __lockfunc rt_spin_trylock__no_mg(spinlock_t *lock);
+
+extern void __lockfunc rt_spin_lock(spinlock_t *lock);
+extern unsigned long __lockfunc rt_spin_lock_trace_flags(spinlock_t *lock);
+extern void __lockfunc rt_spin_lock_nested(spinlock_t *lock, int subclass);
+extern void __lockfunc rt_spin_unlock(spinlock_t *lock);
+extern void __lockfunc rt_spin_unlock_wait(spinlock_t *lock);
+extern int __lockfunc rt_spin_trylock_irqsave(spinlock_t *lock, unsigned long *flags);
+extern int __lockfunc rt_spin_trylock_bh(spinlock_t *lock);
+extern int __lockfunc rt_spin_trylock(spinlock_t *lock);
+extern int atomic_dec_and_spin_lock(atomic_t *atomic, spinlock_t *lock);
+
+/*
+ * lockdep-less calls, for derived types like rwlock:
+ * (for trylock they can use rt_mutex_trylock() directly.
+ */
+extern void __lockfunc __rt_spin_lock__no_mg(struct rt_mutex *lock);
+extern void __lockfunc __rt_spin_lock(struct rt_mutex *lock);
+extern void __lockfunc __rt_spin_unlock(struct rt_mutex *lock);
+
+#define spin_lock(lock) rt_spin_lock(lock)
+
+#define spin_lock_bh(lock) \
+ do { \
+ local_bh_disable(); \
+ rt_spin_lock(lock); \
+ } while (0)
+
+#define spin_lock_irq(lock) spin_lock(lock)
+
+#define spin_do_trylock(lock) __cond_lock(lock, rt_spin_trylock(lock))
+
+#define spin_trylock(lock) \
+({ \
+ int __locked; \
+ __locked = spin_do_trylock(lock); \
+ __locked; \
+})
+
+#ifdef CONFIG_LOCKDEP
+# define spin_lock_nested(lock, subclass) \
+ do { \
+ rt_spin_lock_nested(lock, subclass); \
+ } while (0)
+
+#define spin_lock_bh_nested(lock, subclass) \
+ do { \
+ local_bh_disable(); \
+ rt_spin_lock_nested(lock, subclass); \
+ } while (0)
+
+# define spin_lock_irqsave_nested(lock, flags, subclass) \
+ do { \
+ typecheck(unsigned long, flags); \
+ flags = 0; \
+ rt_spin_lock_nested(lock, subclass); \
+ } while (0)
+#else
+# define spin_lock_nested(lock, subclass) spin_lock(lock)
+# define spin_lock_bh_nested(lock, subclass) spin_lock_bh(lock)
+
+# define spin_lock_irqsave_nested(lock, flags, subclass) \
+ do { \
+ typecheck(unsigned long, flags); \
+ flags = 0; \
+ spin_lock(lock); \
+ } while (0)
+#endif
+
+#define spin_lock_irqsave(lock, flags) \
+ do { \
+ typecheck(unsigned long, flags); \
+ flags = 0; \
+ spin_lock(lock); \
+ } while (0)
+
+static inline unsigned long spin_lock_trace_flags(spinlock_t *lock)
+{
+ unsigned long flags = 0;
+#ifdef CONFIG_TRACE_IRQFLAGS
+ flags = rt_spin_lock_trace_flags(lock);
+#else
+ spin_lock(lock); /* lock_local */
+#endif
+ return flags;
+}
+
+/* FIXME: we need rt_spin_lock_nest_lock */
+#define spin_lock_nest_lock(lock, nest_lock) spin_lock_nested(lock, 0)
+
+#define spin_unlock(lock) rt_spin_unlock(lock)
+
+#define spin_unlock_bh(lock) \
+ do { \
+ rt_spin_unlock(lock); \
+ local_bh_enable(); \
+ } while (0)
+
+#define spin_unlock_irq(lock) spin_unlock(lock)
+
+#define spin_unlock_irqrestore(lock, flags) \
+ do { \
+ typecheck(unsigned long, flags); \
+ (void) flags; \
+ spin_unlock(lock); \
+ } while (0)
+
+#define spin_trylock_bh(lock) __cond_lock(lock, rt_spin_trylock_bh(lock))
+#define spin_trylock_irq(lock) spin_trylock(lock)
+
+#define spin_trylock_irqsave(lock, flags) \
+ rt_spin_trylock_irqsave(lock, &(flags))
+
+#define spin_unlock_wait(lock) rt_spin_unlock_wait(lock)
+
+#ifdef CONFIG_GENERIC_LOCKBREAK
+# define spin_is_contended(lock) ((lock)->break_lock)
+#else
+# define spin_is_contended(lock) (((void)(lock), 0))
+#endif
+
+static inline int spin_can_lock(spinlock_t *lock)
+{
+ return !rt_mutex_is_locked(&lock->lock);
+}
+
+static inline int spin_is_locked(spinlock_t *lock)
+{
+ return rt_mutex_is_locked(&lock->lock);
+}
+
+static inline void assert_spin_locked(spinlock_t *lock)
+{
+ BUG_ON(!spin_is_locked(lock));
+}
+
+#endif
--- a/include/linux/spinlock_types.h
+++ b/include/linux/spinlock_types.h
@@ -11,8 +11,13 @@
#include <linux/spinlock_types_raw.h>
-#include <linux/spinlock_types_nort.h>
-
-#include <linux/rwlock_types.h>
+#ifndef CONFIG_PREEMPT_RT_FULL
+# include <linux/spinlock_types_nort.h>
+# include <linux/rwlock_types.h>
+#else
+# include <linux/rtmutex.h>
+# include <linux/spinlock_types_rt.h>
+# include <linux/rwlock_types_rt.h>
+#endif
#endif /* __LINUX_SPINLOCK_TYPES_H */
--- /dev/null
+++ b/include/linux/spinlock_types_rt.h
@@ -0,0 +1,48 @@
+#ifndef __LINUX_SPINLOCK_TYPES_RT_H
+#define __LINUX_SPINLOCK_TYPES_RT_H
+
+#ifndef __LINUX_SPINLOCK_TYPES_H
+#error "Do not include directly. Include spinlock_types.h instead"
+#endif
+
+#include <linux/cache.h>
+
+/*
+ * PREEMPT_RT: spinlocks - an RT mutex plus lock-break field:
+ */
+typedef struct spinlock {
+ struct rt_mutex lock;
+ unsigned int break_lock;
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ struct lockdep_map dep_map;
+#endif
+} spinlock_t;
+
+#ifdef CONFIG_DEBUG_RT_MUTEXES
+# define __RT_SPIN_INITIALIZER(name) \
+ { \
+ .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(name.wait_lock), \
+ .save_state = 1, \
+ .file = __FILE__, \
+ .line = __LINE__ , \
+ }
+#else
+# define __RT_SPIN_INITIALIZER(name) \
+ { \
+ .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(name.wait_lock), \
+ .save_state = 1, \
+ }
+#endif
+
+/*
+.wait_list = PLIST_HEAD_INIT_RAW((name).lock.wait_list, (name).lock.wait_lock)
+*/
+
+#define __SPIN_LOCK_UNLOCKED(name) \
+ { .lock = __RT_SPIN_INITIALIZER(name.lock), \
+ SPIN_DEP_MAP_INIT(name) }
+
+#define DEFINE_SPINLOCK(name) \
+ spinlock_t name = __SPIN_LOCK_UNLOCKED(name)
+
+#endif
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -1494,6 +1494,7 @@ static int wake_futex_pi(u32 __user *uad
struct task_struct *new_owner;
bool postunlock = false;
DEFINE_WAKE_Q(wake_q);
+ DEFINE_WAKE_Q(wake_sleeper_q);
int ret = 0;
new_owner = rt_mutex_next_owner(&pi_state->pi_mutex);
@@ -1543,14 +1544,15 @@ static int wake_futex_pi(u32 __user *uad
* not fail.
*/
pi_state_update_owner(pi_state, new_owner);
- postunlock = __rt_mutex_futex_unlock(&pi_state->pi_mutex, &wake_q);
+ postunlock = __rt_mutex_futex_unlock(&pi_state->pi_mutex, &wake_q,
+ &wake_sleeper_q);
}
out_unlock:
raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
if (postunlock)
- rt_mutex_postunlock(&wake_q);
+ rt_mutex_postunlock(&wake_q, &wake_sleeper_q);
return ret;
}
@@ -2866,7 +2868,7 @@ retry_private:
goto no_block;
}
- rt_mutex_init_waiter(&rt_waiter);
+ rt_mutex_init_waiter(&rt_waiter, false);
/*
* On PREEMPT_RT_FULL, when hb->lock becomes an rt_mutex, we must not
@@ -3239,7 +3241,7 @@ static int futex_wait_requeue_pi(u32 __u
* The waiter is allocated on our stack, manipulated by the requeue
* code while we sleep on uaddr.
*/
- rt_mutex_init_waiter(&rt_waiter);
+ rt_mutex_init_waiter(&rt_waiter, false);
ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2, VERIFY_WRITE);
if (unlikely(ret != 0))
--- a/kernel/locking/Makefile
+++ b/kernel/locking/Makefile
@@ -2,7 +2,7 @@
# and is generally not a function of system call inputs.
KCOV_INSTRUMENT := n
-obj-y += mutex.o semaphore.o rwsem.o percpu-rwsem.o
+obj-y += semaphore.o percpu-rwsem.o
ifdef CONFIG_FUNCTION_TRACER
CFLAGS_REMOVE_lockdep.o = $(CC_FLAGS_FTRACE)
@@ -11,7 +11,11 @@ CFLAGS_REMOVE_mutex-debug.o = $(CC_FLAGS
CFLAGS_REMOVE_rtmutex-debug.o = $(CC_FLAGS_FTRACE)
endif
+ifneq ($(CONFIG_PREEMPT_RT_FULL),y)
+obj-y += mutex.o
obj-$(CONFIG_DEBUG_MUTEXES) += mutex-debug.o
+obj-y += rwsem.o
+endif
obj-$(CONFIG_LOCKDEP) += lockdep.o
ifeq ($(CONFIG_PROC_FS),y)
obj-$(CONFIG_LOCKDEP) += lockdep_proc.o
@@ -24,8 +28,11 @@ obj-$(CONFIG_RT_MUTEXES) += rtmutex.o
obj-$(CONFIG_DEBUG_RT_MUTEXES) += rtmutex-debug.o
obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o
obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
+ifneq ($(CONFIG_PREEMPT_RT_FULL),y)
obj-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
obj-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem-xadd.o
+endif
+obj-$(CONFIG_PREEMPT_RT_FULL) += rt.o
obj-$(CONFIG_QUEUED_RWLOCKS) += qrwlock.o
obj-$(CONFIG_LOCK_TORTURE_TEST) += locktorture.o
obj-$(CONFIG_WW_MUTEX_SELFTEST) += test-ww_mutex.o
--- /dev/null
+++ b/kernel/locking/rt.c
@@ -0,0 +1,521 @@
+/*
+ * kernel/rt.c
+ *
+ * Real-Time Preemption Support
+ *
+ * started by Ingo Molnar:
+ *
+ * Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ * Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
+ *
+ * historic credit for proving that Linux spinlocks can be implemented via
+ * RT-aware mutexes goes to many people: The Pmutex project (Dirk Grambow
+ * and others) who prototyped it on 2.4 and did lots of comparative
+ * research and analysis; TimeSys, for proving that you can implement a
+ * fully preemptible kernel via the use of IRQ threading and mutexes;
+ * Bill Huey for persuasively arguing on lkml that the mutex model is the
+ * right one; and to MontaVista, who ported pmutexes to 2.6.
+ *
+ * This code is a from-scratch implementation and is not based on pmutexes,
+ * but the idea of converting spinlocks to mutexes is used here too.
+ *
+ * lock debugging, locking tree, deadlock detection:
+ *
+ * Copyright (C) 2004, LynuxWorks, Inc., Igor Manyilov, Bill Huey
+ * Released under the General Public License (GPL).
+ *
+ * Includes portions of the generic R/W semaphore implementation from:
+ *
+ * Copyright (c) 2001 David Howells (dhowells@redhat.com).
+ * - Derived partially from idea by Andrea Arcangeli <andrea@suse.de>
+ * - Derived also from comments by Linus
+ *
+ * Pending ownership of locks and ownership stealing:
+ *
+ * Copyright (C) 2005, Kihon Technologies Inc., Steven Rostedt
+ *
+ * (also by Steven Rostedt)
+ * - Converted single pi_lock to individual task locks.
+ *
+ * By Esben Nielsen:
+ * Doing priority inheritance with help of the scheduler.
+ *
+ * Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
+ * - major rework based on Esben Nielsens initial patch
+ * - replaced thread_info references by task_struct refs
+ * - removed task->pending_owner dependency
+ * - BKL drop/reacquire for semaphore style locks to avoid deadlocks
+ * in the scheduler return path as discussed with Steven Rostedt
+ *
+ * Copyright (C) 2006, Kihon Technologies Inc.
+ * Steven Rostedt <rostedt@goodmis.org>
+ * - debugged and patched Thomas Gleixner's rework.
+ * - added back the cmpxchg to the rework.
+ * - turned atomic require back on for SMP.
+ */
+
+#include <linux/spinlock.h>
+#include <linux/rtmutex.h>
+#include <linux/sched.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/kallsyms.h>
+#include <linux/syscalls.h>
+#include <linux/interrupt.h>
+#include <linux/plist.h>
+#include <linux/fs.h>
+#include <linux/futex.h>
+#include <linux/hrtimer.h>
+
+#include "rtmutex_common.h"
+
+/*
+ * struct mutex functions
+ */
+void __mutex_do_init(struct mutex *mutex, const char *name,
+ struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ /*
+ * Make sure we are not reinitializing a held lock:
+ */
+ debug_check_no_locks_freed((void *)mutex, sizeof(*mutex));
+ lockdep_init_map(&mutex->dep_map, name, key, 0);
+#endif
+ mutex->lock.save_state = 0;
+}
+EXPORT_SYMBOL(__mutex_do_init);
+
+void __lockfunc _mutex_lock(struct mutex *lock)
+{
+ mutex_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+ __rt_mutex_lock_state(&lock->lock, TASK_UNINTERRUPTIBLE);
+}
+EXPORT_SYMBOL(_mutex_lock);
+
+void __lockfunc _mutex_lock_io(struct mutex *lock)
+{
+ int token;
+
+ token = io_schedule_prepare();
+ _mutex_lock(lock);
+ io_schedule_finish(token);
+}
+EXPORT_SYMBOL_GPL(_mutex_lock_io);
+
+int __lockfunc _mutex_lock_interruptible(struct mutex *lock)
+{
+ int ret;
+
+ mutex_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+ ret = __rt_mutex_lock_state(&lock->lock, TASK_INTERRUPTIBLE);
+ if (ret)
+ mutex_release(&lock->dep_map, 1, _RET_IP_);
+ return ret;
+}
+EXPORT_SYMBOL(_mutex_lock_interruptible);
+
+int __lockfunc _mutex_lock_killable(struct mutex *lock)
+{
+ int ret;
+
+ mutex_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+ ret = __rt_mutex_lock_state(&lock->lock, TASK_KILLABLE);
+ if (ret)
+ mutex_release(&lock->dep_map, 1, _RET_IP_);
+ return ret;
+}
+EXPORT_SYMBOL(_mutex_lock_killable);
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+void __lockfunc _mutex_lock_nested(struct mutex *lock, int subclass)
+{
+ mutex_acquire_nest(&lock->dep_map, subclass, 0, NULL, _RET_IP_);
+ __rt_mutex_lock_state(&lock->lock, TASK_UNINTERRUPTIBLE);
+}
+EXPORT_SYMBOL(_mutex_lock_nested);
+
+void __lockfunc _mutex_lock_io_nested(struct mutex *lock, int subclass)
+{
+ int token;
+
+ token = io_schedule_prepare();
+
+ mutex_acquire_nest(&lock->dep_map, subclass, 0, NULL, _RET_IP_);
+ __rt_mutex_lock_state(&lock->lock, TASK_UNINTERRUPTIBLE);
+
+ io_schedule_finish(token);
+}
+EXPORT_SYMBOL_GPL(_mutex_lock_io_nested);
+
+void __lockfunc _mutex_lock_nest_lock(struct mutex *lock, struct lockdep_map *nest)
+{
+ mutex_acquire_nest(&lock->dep_map, 0, 0, nest, _RET_IP_);
+ __rt_mutex_lock_state(&lock->lock, TASK_UNINTERRUPTIBLE);
+}
+EXPORT_SYMBOL(_mutex_lock_nest_lock);
+
+int __lockfunc _mutex_lock_interruptible_nested(struct mutex *lock, int subclass)
+{
+ int ret;
+
+ mutex_acquire_nest(&lock->dep_map, subclass, 0, NULL, _RET_IP_);
+ ret = __rt_mutex_lock_state(&lock->lock, TASK_INTERRUPTIBLE);
+ if (ret)
+ mutex_release(&lock->dep_map, 1, _RET_IP_);
+ return ret;
+}
+EXPORT_SYMBOL(_mutex_lock_interruptible_nested);
+
+int __lockfunc _mutex_lock_killable_nested(struct mutex *lock, int subclass)
+{
+ int ret;
+
+ mutex_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
+ ret = __rt_mutex_lock_state(&lock->lock, TASK_KILLABLE);
+ if (ret)
+ mutex_release(&lock->dep_map, 1, _RET_IP_);
+ return ret;
+}
+EXPORT_SYMBOL(_mutex_lock_killable_nested);
+#endif
+
+int __lockfunc _mutex_trylock(struct mutex *lock)
+{
+ int ret = __rt_mutex_trylock(&lock->lock);
+
+ if (ret)
+ mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
+
+ return ret;
+}
+EXPORT_SYMBOL(_mutex_trylock);
+
+void __lockfunc _mutex_unlock(struct mutex *lock)
+{
+ mutex_release(&lock->dep_map, 1, _RET_IP_);
+ __rt_mutex_unlock(&lock->lock);
+}
+EXPORT_SYMBOL(_mutex_unlock);
+
+/*
+ * rwlock_t functions
+ */
+int __lockfunc rt_write_trylock(rwlock_t *rwlock)
+{
+ int ret;
+
+ migrate_disable();
+ ret = __rt_mutex_trylock(&rwlock->lock);
+ if (ret)
+ rwlock_acquire(&rwlock->dep_map, 0, 1, _RET_IP_);
+ else
+ migrate_enable();
+
+ return ret;
+}
+EXPORT_SYMBOL(rt_write_trylock);
+
+int __lockfunc rt_write_trylock_irqsave(rwlock_t *rwlock, unsigned long *flags)
+{
+ int ret;
+
+ *flags = 0;
+ ret = rt_write_trylock(rwlock);
+ return ret;
+}
+EXPORT_SYMBOL(rt_write_trylock_irqsave);
+
+int __lockfunc rt_read_trylock(rwlock_t *rwlock)
+{
+ struct rt_mutex *lock = &rwlock->lock;
+ int ret = 1;
+
+ /*
+ * recursive read locks succeed when current owns the lock,
+ * but not when read_depth == 0 which means that the lock is
+ * write locked.
+ */
+ if (rt_mutex_owner(lock) != current) {
+ migrate_disable();
+ ret = __rt_mutex_trylock(lock);
+ if (ret)
+ rwlock_acquire(&rwlock->dep_map, 0, 1, _RET_IP_);
+ else
+ migrate_enable();
+
+ } else if (!rwlock->read_depth) {
+ ret = 0;
+ }
+
+ if (ret)
+ rwlock->read_depth++;
+
+ return ret;
+}
+EXPORT_SYMBOL(rt_read_trylock);
+
+void __lockfunc rt_write_lock(rwlock_t *rwlock)
+{
+ rwlock_acquire(&rwlock->dep_map, 0, 0, _RET_IP_);
+ __rt_spin_lock(&rwlock->lock);
+}
+EXPORT_SYMBOL(rt_write_lock);
+
+void __lockfunc rt_read_lock(rwlock_t *rwlock)
+{
+ struct rt_mutex *lock = &rwlock->lock;
+
+
+ /*
+ * recursive read locks succeed when current owns the lock
+ */
+ if (rt_mutex_owner(lock) != current) {
+ rwlock_acquire(&rwlock->dep_map, 0, 0, _RET_IP_);
+ __rt_spin_lock(lock);
+ }
+ rwlock->read_depth++;
+}
+
+EXPORT_SYMBOL(rt_read_lock);
+
+void __lockfunc rt_write_unlock(rwlock_t *rwlock)
+{
+ /* NOTE: we always pass in '1' for nested, for simplicity */
+ rwlock_release(&rwlock->dep_map, 1, _RET_IP_);
+ __rt_spin_unlock(&rwlock->lock);
+ migrate_enable();
+}
+EXPORT_SYMBOL(rt_write_unlock);
+
+void __lockfunc rt_read_unlock(rwlock_t *rwlock)
+{
+ /* Release the lock only when read_depth is down to 0 */
+ if (--rwlock->read_depth == 0) {
+ rwlock_release(&rwlock->dep_map, 1, _RET_IP_);
+ __rt_spin_unlock(&rwlock->lock);
+ migrate_enable();
+ }
+}
+EXPORT_SYMBOL(rt_read_unlock);
+
+unsigned long __lockfunc rt_write_lock_irqsave(rwlock_t *rwlock)
+{
+ rt_write_lock(rwlock);
+
+ return 0;
+}
+EXPORT_SYMBOL(rt_write_lock_irqsave);
+
+unsigned long __lockfunc rt_read_lock_irqsave(rwlock_t *rwlock)
+{
+ rt_read_lock(rwlock);
+
+ return 0;
+}
+EXPORT_SYMBOL(rt_read_lock_irqsave);
+
+void __rt_rwlock_init(rwlock_t *rwlock, char *name, struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ /*
+ * Make sure we are not reinitializing a held lock:
+ */
+ debug_check_no_locks_freed((void *)rwlock, sizeof(*rwlock));
+ lockdep_init_map(&rwlock->dep_map, name, key, 0);
+#endif
+ rwlock->lock.save_state = 1;
+ rwlock->read_depth = 0;
+}
+EXPORT_SYMBOL(__rt_rwlock_init);
+
+/*
+ * rw_semaphores
+ */
+
+void rt_up_write(struct rw_semaphore *rwsem)
+{
+ rwsem_release(&rwsem->dep_map, 1, _RET_IP_);
+ __rt_mutex_unlock(&rwsem->lock);
+}
+EXPORT_SYMBOL(rt_up_write);
+
+void __rt_up_read(struct rw_semaphore *rwsem)
+{
+ if (--rwsem->read_depth == 0)
+ __rt_mutex_unlock(&rwsem->lock);
+}
+
+void rt_up_read(struct rw_semaphore *rwsem)
+{
+ rwsem_release(&rwsem->dep_map, 1, _RET_IP_);
+ __rt_up_read(rwsem);
+}
+EXPORT_SYMBOL(rt_up_read);
+
+/*
+ * downgrade a write lock into a read lock
+ * - just wake up any readers at the front of the queue
+ */
+void rt_downgrade_write(struct rw_semaphore *rwsem)
+{
+ BUG_ON(rt_mutex_owner(&rwsem->lock) != current);
+ rwsem->read_depth = 1;
+}
+EXPORT_SYMBOL(rt_downgrade_write);
+
+int rt_down_write_trylock(struct rw_semaphore *rwsem)
+{
+ int ret = __rt_mutex_trylock(&rwsem->lock);
+
+ if (ret)
+ rwsem_acquire(&rwsem->dep_map, 0, 1, _RET_IP_);
+ return ret;
+}
+EXPORT_SYMBOL(rt_down_write_trylock);
+
+void rt_down_write(struct rw_semaphore *rwsem)
+{
+ rwsem_acquire(&rwsem->dep_map, 0, 0, _RET_IP_);
+ __rt_mutex_lock_state(&rwsem->lock, TASK_UNINTERRUPTIBLE);
+}
+EXPORT_SYMBOL(rt_down_write);
+
+int rt_down_write_killable(struct rw_semaphore *rwsem)
+{
+ int ret;
+
+ rwsem_acquire(&rwsem->dep_map, 0, 0, _RET_IP_);
+ ret = __rt_mutex_lock_state(&rwsem->lock, TASK_KILLABLE);
+ if (ret)
+ rwsem_release(&rwsem->dep_map, 1, _RET_IP_);
+ return ret;
+}
+EXPORT_SYMBOL(rt_down_write_killable);
+
+int rt_down_write_killable_nested(struct rw_semaphore *rwsem, int subclass)
+{
+ int ret;
+
+ rwsem_acquire(&rwsem->dep_map, subclass, 0, _RET_IP_);
+ ret = __rt_mutex_lock_state(&rwsem->lock, TASK_KILLABLE);
+ if (ret)
+ rwsem_release(&rwsem->dep_map, 1, _RET_IP_);
+ return ret;
+}
+EXPORT_SYMBOL(rt_down_write_killable_nested);
+
+void rt_down_write_nested(struct rw_semaphore *rwsem, int subclass)
+{
+ rwsem_acquire(&rwsem->dep_map, subclass, 0, _RET_IP_);
+ __rt_mutex_lock_state(&rwsem->lock, TASK_UNINTERRUPTIBLE);
+}
+EXPORT_SYMBOL(rt_down_write_nested);
+
+void rt_down_write_nested_lock(struct rw_semaphore *rwsem,
+ struct lockdep_map *nest)
+{
+ rwsem_acquire_nest(&rwsem->dep_map, 0, 0, nest, _RET_IP_);
+ __rt_mutex_lock_state(&rwsem->lock, TASK_UNINTERRUPTIBLE);
+}
+EXPORT_SYMBOL(rt_down_write_nested_lock);
+
+int rt__down_read_trylock(struct rw_semaphore *rwsem)
+{
+ struct rt_mutex *lock = &rwsem->lock;
+ int ret = 1;
+
+ /*
+ * recursive read locks succeed when current owns the rwsem,
+ * but not when read_depth == 0 which means that the rwsem is
+ * write locked.
+ */
+ if (rt_mutex_owner(lock) != current)
+ ret = __rt_mutex_trylock(&rwsem->lock);
+ else if (!rwsem->read_depth)
+ ret = 0;
+
+ if (ret)
+ rwsem->read_depth++;
+ return ret;
+
+}
+
+int rt_down_read_trylock(struct rw_semaphore *rwsem)
+{
+ int ret;
+
+ ret = rt__down_read_trylock(rwsem);
+ if (ret)
+ rwsem_acquire(&rwsem->dep_map, 0, 1, _RET_IP_);
+
+ return ret;
+}
+EXPORT_SYMBOL(rt_down_read_trylock);
+
+void rt__down_read(struct rw_semaphore *rwsem)
+{
+ struct rt_mutex *lock = &rwsem->lock;
+
+ if (rt_mutex_owner(lock) != current)
+ __rt_mutex_lock_state(&rwsem->lock, TASK_UNINTERRUPTIBLE);
+ rwsem->read_depth++;
+}
+EXPORT_SYMBOL(rt__down_read);
+
+static void __rt_down_read(struct rw_semaphore *rwsem, int subclass)
+{
+ rwsem_acquire_read(&rwsem->dep_map, subclass, 0, _RET_IP_);
+ rt__down_read(rwsem);
+}
+
+void rt_down_read(struct rw_semaphore *rwsem)
+{
+ __rt_down_read(rwsem, 0);
+}
+EXPORT_SYMBOL(rt_down_read);
+
+void rt_down_read_nested(struct rw_semaphore *rwsem, int subclass)
+{
+ __rt_down_read(rwsem, subclass);
+}
+EXPORT_SYMBOL(rt_down_read_nested);
+
+void __rt_rwsem_init(struct rw_semaphore *rwsem, const char *name,
+ struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ /*
+ * Make sure we are not reinitializing a held lock:
+ */
+ debug_check_no_locks_freed((void *)rwsem, sizeof(*rwsem));
+ lockdep_init_map(&rwsem->dep_map, name, key, 0);
+#endif
+ rwsem->read_depth = 0;
+ rwsem->lock.save_state = 0;
+}
+EXPORT_SYMBOL(__rt_rwsem_init);
+
+/**
+ * atomic_dec_and_mutex_lock - return holding mutex if we dec to 0
+ * @cnt: the atomic which we are to dec
+ * @lock: the mutex to return holding if we dec to 0
+ *
+ * return true and hold lock if we dec to 0, return false otherwise
+ */
+int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock)
+{
+ /* dec if we can't possibly hit 0 */
+ if (atomic_add_unless(cnt, -1, 1))
+ return 0;
+ /* we might hit 0, so take the lock */
+ mutex_lock(lock);
+ if (!atomic_dec_and_test(cnt)) {
+ /* when we actually did the dec, we didn't hit 0 */
+ mutex_unlock(lock);
+ return 0;
+ }
+ /* we hit 0, and we hold the lock */
+ return 1;
+}
+EXPORT_SYMBOL(atomic_dec_and_mutex_lock);
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -7,6 +7,11 @@
* Copyright (C) 2005-2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com>
* Copyright (C) 2005 Kihon Technologies Inc., Steven Rostedt
* Copyright (C) 2006 Esben Nielsen
+ * Adaptive Spinlocks:
+ * Copyright (C) 2008 Novell, Inc., Gregory Haskins, Sven Dietrich,
+ * and Peter Morreale,
+ * Adaptive Spinlocks simplification:
+ * Copyright (C) 2008 Red Hat, Inc., Steven Rostedt <srostedt@redhat.com>
*
* See Documentation/locking/rt-mutex-design.txt for details.
*/
@@ -230,6 +235,9 @@ static inline bool unlock_rt_mutex_safe(
}
#endif
+#define STEAL_NORMAL 0
+#define STEAL_LATERAL 1
+
/*
* Only use with rt_mutex_waiter_{less,equal}()
*/
@@ -238,11 +246,15 @@ static inline bool unlock_rt_mutex_safe(
static inline int
rt_mutex_waiter_less(struct rt_mutex_waiter *left,
- struct rt_mutex_waiter *right)
+ struct rt_mutex_waiter *right, int mode)
{
- if (left->prio < right->prio)
- return 1;
-
+ if (mode == STEAL_NORMAL) {
+ if (left->prio < right->prio)
+ return 1;
+ } else {
+ if (left->prio <= right->prio)
+ return 1;
+ }
/*
* If both waiters have dl_prio(), we check the deadlines of the
* associated tasks.
@@ -285,7 +297,7 @@ rt_mutex_enqueue(struct rt_mutex *lock,
while (*link) {
parent = *link;
entry = rb_entry(parent, struct rt_mutex_waiter, tree_entry);
- if (rt_mutex_waiter_less(waiter, entry)) {
+ if (rt_mutex_waiter_less(waiter, entry, STEAL_NORMAL)) {
link = &parent->rb_left;
} else {
link = &parent->rb_right;
@@ -318,7 +330,7 @@ rt_mutex_enqueue_pi(struct task_struct *
while (*link) {
parent = *link;
entry = rb_entry(parent, struct rt_mutex_waiter, pi_tree_entry);
- if (rt_mutex_waiter_less(waiter, entry)) {
+ if (rt_mutex_waiter_less(waiter, entry, STEAL_NORMAL)) {
link = &parent->rb_left;
} else {
link = &parent->rb_right;
@@ -378,6 +390,14 @@ static bool rt_mutex_cond_detect_deadloc
return debug_rt_mutex_detect_deadlock(waiter, chwalk);
}
+static void rt_mutex_wake_waiter(struct rt_mutex_waiter *waiter)
+{
+ if (waiter->savestate)
+ wake_up_lock_sleeper(waiter->task);
+ else
+ wake_up_process(waiter->task);
+}
+
/*
* Max number of times we'll walk the boosting chain:
*/
@@ -703,13 +723,16 @@ static int rt_mutex_adjust_prio_chain(st
* follow here. This is the end of the chain we are walking.
*/
if (!rt_mutex_owner(lock)) {
+ struct rt_mutex_waiter *lock_top_waiter;
+
/*
* If the requeue [7] above changed the top waiter,
* then we need to wake the new top waiter up to try
* to get the lock.
*/
- if (prerequeue_top_waiter != rt_mutex_top_waiter(lock))
- wake_up_process(rt_mutex_top_waiter(lock)->task);
+ lock_top_waiter = rt_mutex_top_waiter(lock);
+ if (prerequeue_top_waiter != lock_top_waiter)
+ rt_mutex_wake_waiter(lock_top_waiter);
raw_spin_unlock_irq(&lock->wait_lock);
return 0;
}
@@ -812,8 +835,9 @@ static int rt_mutex_adjust_prio_chain(st
* @waiter: The waiter that is queued to the lock's wait tree if the
* callsite called task_blocked_on_lock(), otherwise NULL
*/
-static int try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
- struct rt_mutex_waiter *waiter)
+static int __try_to_take_rt_mutex(struct rt_mutex *lock,
+ struct task_struct *task,
+ struct rt_mutex_waiter *waiter, int mode)
{
lockdep_assert_held(&lock->wait_lock);
@@ -852,8 +876,10 @@ static int try_to_take_rt_mutex(struct r
* If waiter is not the highest priority waiter of
* @lock, give up.
*/
- if (waiter != rt_mutex_top_waiter(lock))
+ if (waiter != rt_mutex_top_waiter(lock)) {
+ /* XXX rt_mutex_waiter_less() ? */
return 0;
+ }
/*
* We can acquire the lock. Remove the waiter from the
@@ -871,15 +897,26 @@ static int try_to_take_rt_mutex(struct r
* not need to be dequeued.
*/
if (rt_mutex_has_waiters(lock)) {
+ struct task_struct *pown = rt_mutex_top_waiter(lock)->task;
+
+ if (task != pown)
+ return 0;
+
+ /*
+ * Note that RT tasks are excluded from lateral-steals
+ * to prevent the introduction of an unbounded latency.
+ */
+ if (rt_task(task))
+ mode = STEAL_NORMAL;
/*
* If @task->prio is greater than or equal to
* the top waiter priority (kernel view),
* @task lost.
*/
if (!rt_mutex_waiter_less(task_to_waiter(task),
- rt_mutex_top_waiter(lock)))
+ rt_mutex_top_waiter(lock),
+ mode))
return 0;
-
/*
* The current top waiter stays enqueued. We
* don't have to change anything in the lock
@@ -926,6 +963,339 @@ takeit:
return 1;
}
+#ifdef CONFIG_PREEMPT_RT_FULL
+/*
+ * preemptible spin_lock functions:
+ */
+static inline void rt_spin_lock_fastlock(struct rt_mutex *lock,
+ void (*slowfn)(struct rt_mutex *lock))
+{
+ might_sleep_no_state_check();
+
+ if (likely(rt_mutex_cmpxchg_acquire(lock, NULL, current)))
+ return;
+ else
+ slowfn(lock);
+}
+
+static inline void rt_spin_lock_fastunlock(struct rt_mutex *lock,
+ void (*slowfn)(struct rt_mutex *lock))
+{
+ if (likely(rt_mutex_cmpxchg_release(lock, current, NULL)))
+ return;
+ else
+ slowfn(lock);
+}
+#ifdef CONFIG_SMP
+/*
+ * Note that owner is a speculative pointer and dereferencing relies
+ * on rcu_read_lock() and the check against the lock owner.
+ */
+static int adaptive_wait(struct rt_mutex *lock,
+ struct task_struct *owner)
+{
+ int res = 0;
+
+ rcu_read_lock();
+ for (;;) {
+ if (owner != rt_mutex_owner(lock))
+ break;
+ /*
+ * Ensure that owner->on_cpu is dereferenced _after_
+ * checking the above to be valid.
+ */
+ barrier();
+ if (!owner->on_cpu) {
+ res = 1;
+ break;
+ }
+ cpu_relax();
+ }
+ rcu_read_unlock();
+ return res;
+}
+#else
+static int adaptive_wait(struct rt_mutex *lock,
+ struct task_struct *orig_owner)
+{
+ return 1;
+}
+#endif
+
+static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
+ struct rt_mutex_waiter *waiter,
+ struct task_struct *task,
+ enum rtmutex_chainwalk chwalk);
+/*
+ * Slow path lock function spin_lock style: this variant is very
+ * careful not to miss any non-lock wakeups.
+ *
+ * We store the current state under p->pi_lock in p->saved_state and
+ * the try_to_wake_up() code handles this accordingly.
+ */
+static void noinline __sched rt_spin_lock_slowlock(struct rt_mutex *lock)
+{
+ struct task_struct *lock_owner, *self = current;
+ struct rt_mutex_waiter waiter, *top_waiter;
+ unsigned long flags;
+ int ret;
+
+ rt_mutex_init_waiter(&waiter, true);
+
+ raw_spin_lock_irqsave(&lock->wait_lock, flags);
+
+ if (__try_to_take_rt_mutex(lock, self, NULL, STEAL_LATERAL)) {
+ raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+ return;
+ }
+
+ BUG_ON(rt_mutex_owner(lock) == self);
+
+ /*
+ * We save whatever state the task is in and we'll restore it
+ * after acquiring the lock taking real wakeups into account
+ * as well. We are serialized via pi_lock against wakeups. See
+ * try_to_wake_up().
+ */
+ raw_spin_lock(&self->pi_lock);
+ self->saved_state = self->state;
+ __set_current_state_no_track(TASK_UNINTERRUPTIBLE);
+ raw_spin_unlock(&self->pi_lock);
+
+ ret = task_blocks_on_rt_mutex(lock, &waiter, self, RT_MUTEX_MIN_CHAINWALK);
+ BUG_ON(ret);
+
+ for (;;) {
+ /* Try to acquire the lock again. */
+ if (__try_to_take_rt_mutex(lock, self, &waiter, STEAL_LATERAL))
+ break;
+
+ top_waiter = rt_mutex_top_waiter(lock);
+ lock_owner = rt_mutex_owner(lock);
+
+ raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+
+ debug_rt_mutex_print_deadlock(&waiter);
+
+ if (top_waiter != &waiter || adaptive_wait(lock, lock_owner))
+ schedule();
+
+ raw_spin_lock_irqsave(&lock->wait_lock, flags);
+
+ raw_spin_lock(&self->pi_lock);
+ __set_current_state_no_track(TASK_UNINTERRUPTIBLE);
+ raw_spin_unlock(&self->pi_lock);
+ }
+
+ /*
+ * Restore the task state to current->saved_state. We set it
+ * to the original state above and the try_to_wake_up() code
+ * has possibly updated it when a real (non-rtmutex) wakeup
+ * happened while we were blocked. Clear saved_state so
+ * try_to_wakeup() does not get confused.
+ */
+ raw_spin_lock(&self->pi_lock);
+ __set_current_state_no_track(self->saved_state);
+ self->saved_state = TASK_RUNNING;
+ raw_spin_unlock(&self->pi_lock);
+
+ /*
+ * try_to_take_rt_mutex() sets the waiter bit
+ * unconditionally. We might have to fix that up:
+ */
+ fixup_rt_mutex_waiters(lock);
+
+ BUG_ON(rt_mutex_has_waiters(lock) && &waiter == rt_mutex_top_waiter(lock));
+ BUG_ON(!RB_EMPTY_NODE(&waiter.tree_entry));
+
+ raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+
+ debug_rt_mutex_free_waiter(&waiter);
+}
+
+static bool __sched __rt_mutex_unlock_common(struct rt_mutex *lock,
+ struct wake_q_head *wake_q,
+ struct wake_q_head *wq_sleeper);
+/*
+ * Slow path to release a rt_mutex spin_lock style
+ */
+static void noinline __sched rt_spin_lock_slowunlock(struct rt_mutex *lock)
+{
+ unsigned long flags;
+ DEFINE_WAKE_Q(wake_q);
+ DEFINE_WAKE_Q(wake_sleeper_q);
+ bool postunlock;
+
+ raw_spin_lock_irqsave(&lock->wait_lock, flags);
+ postunlock = __rt_mutex_unlock_common(lock, &wake_q, &wake_sleeper_q);
+ raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+
+ if (postunlock)
+ rt_mutex_postunlock(&wake_q, &wake_sleeper_q);
+}
+
+void __lockfunc rt_spin_lock__no_mg(spinlock_t *lock)
+{
+ rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock);
+ spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+}
+EXPORT_SYMBOL(rt_spin_lock__no_mg);
+
+void __lockfunc rt_spin_lock(spinlock_t *lock)
+{
+ migrate_disable();
+ rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock);
+ spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+}
+EXPORT_SYMBOL(rt_spin_lock);
+
+void __lockfunc __rt_spin_lock(struct rt_mutex *lock)
+{
+ migrate_disable();
+ rt_spin_lock_fastlock(lock, rt_spin_lock_slowlock);
+}
+EXPORT_SYMBOL(__rt_spin_lock);
+
+void __lockfunc __rt_spin_lock__no_mg(struct rt_mutex *lock)
+{
+ rt_spin_lock_fastlock(lock, rt_spin_lock_slowlock);
+}
+EXPORT_SYMBOL(__rt_spin_lock__no_mg);
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+void __lockfunc rt_spin_lock_nested(spinlock_t *lock, int subclass)
+{
+ migrate_disable();
+ rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock);
+ spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
+}
+EXPORT_SYMBOL(rt_spin_lock_nested);
+#endif
+
+void __lockfunc rt_spin_unlock__no_mg(spinlock_t *lock)
+{
+ /* NOTE: we always pass in '1' for nested, for simplicity */
+ spin_release(&lock->dep_map, 1, _RET_IP_);
+ rt_spin_lock_fastunlock(&lock->lock, rt_spin_lock_slowunlock);
+}
+EXPORT_SYMBOL(rt_spin_unlock__no_mg);
+
+void __lockfunc rt_spin_unlock(spinlock_t *lock)
+{
+ /* NOTE: we always pass in '1' for nested, for simplicity */
+ spin_release(&lock->dep_map, 1, _RET_IP_);
+ rt_spin_lock_fastunlock(&lock->lock, rt_spin_lock_slowunlock);
+ migrate_enable();
+}
+EXPORT_SYMBOL(rt_spin_unlock);
+
+void __lockfunc __rt_spin_unlock(struct rt_mutex *lock)
+{
+ rt_spin_lock_fastunlock(lock, rt_spin_lock_slowunlock);
+}
+EXPORT_SYMBOL(__rt_spin_unlock);
+
+/*
+ * Wait for the lock to get unlocked: instead of polling for an unlock
+ * (like raw spinlocks do), we lock and unlock, to force the kernel to
+ * schedule if there's contention:
+ */
+void __lockfunc rt_spin_unlock_wait(spinlock_t *lock)
+{
+ spin_lock(lock);
+ spin_unlock(lock);
+}
+EXPORT_SYMBOL(rt_spin_unlock_wait);
+
+int __lockfunc rt_spin_trylock__no_mg(spinlock_t *lock)
+{
+ int ret;
+
+ ret = __rt_mutex_trylock(&lock->lock);
+ if (ret)
+ spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
+ return ret;
+}
+EXPORT_SYMBOL(rt_spin_trylock__no_mg);
+
+int __lockfunc rt_spin_trylock(spinlock_t *lock)
+{
+ int ret;
+
+ migrate_disable();
+ ret = __rt_mutex_trylock(&lock->lock);
+ if (ret)
+ spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
+ else
+ migrate_enable();
+ return ret;
+}
+EXPORT_SYMBOL(rt_spin_trylock);
+
+int __lockfunc rt_spin_trylock_bh(spinlock_t *lock)
+{
+ int ret;
+
+ local_bh_disable();
+ ret = __rt_mutex_trylock(&lock->lock);
+ if (ret) {
+ migrate_disable();
+ spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
+ } else
+ local_bh_enable();
+ return ret;
+}
+EXPORT_SYMBOL(rt_spin_trylock_bh);
+
+int __lockfunc rt_spin_trylock_irqsave(spinlock_t *lock, unsigned long *flags)
+{
+ int ret;
+
+ *flags = 0;
+ ret = __rt_mutex_trylock(&lock->lock);
+ if (ret) {
+ migrate_disable();
+ spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
+ }
+ return ret;
+}
+EXPORT_SYMBOL(rt_spin_trylock_irqsave);
+
+int atomic_dec_and_spin_lock(atomic_t *atomic, spinlock_t *lock)
+{
+ /* Subtract 1 from counter unless that drops it to 0 (ie. it was 1) */
+ if (atomic_add_unless(atomic, -1, 1))
+ return 0;
+ rt_spin_lock(lock);
+ if (atomic_dec_and_test(atomic))
+ return 1;
+ rt_spin_unlock(lock);
+ return 0;
+}
+EXPORT_SYMBOL(atomic_dec_and_spin_lock);
+
+ void
+__rt_spin_lock_init(spinlock_t *lock, char *name, struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ /*
+ * Make sure we are not reinitializing a held lock:
+ */
+ debug_check_no_locks_freed((void *)lock, sizeof(*lock));
+ lockdep_init_map(&lock->dep_map, name, key, 0);
+#endif
+}
+EXPORT_SYMBOL(__rt_spin_lock_init);
+
+#endif /* PREEMPT_RT_FULL */
+
+static inline int
+try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
+ struct rt_mutex_waiter *waiter)
+{
+ return __try_to_take_rt_mutex(lock, task, waiter, STEAL_NORMAL);
+}
+
/*
* Task blocks on lock.
*
@@ -1040,6 +1410,7 @@ static int task_blocks_on_rt_mutex(struc
* Called with lock->wait_lock held and interrupts disabled.
*/
static void mark_wakeup_next_waiter(struct wake_q_head *wake_q,
+ struct wake_q_head *wake_sleeper_q,
struct rt_mutex *lock)
{
struct rt_mutex_waiter *waiter;
@@ -1079,7 +1450,10 @@ static void mark_wakeup_next_waiter(stru
* Pairs with preempt_enable() in rt_mutex_postunlock();
*/
preempt_disable();
- wake_q_add(wake_q, waiter->task);
+ if (waiter->savestate)
+ wake_q_add(wake_sleeper_q, waiter->task);
+ else
+ wake_q_add(wake_q, waiter->task);
raw_spin_unlock(¤t->pi_lock);
}
@@ -1163,21 +1537,22 @@ void rt_mutex_adjust_pi(struct task_stru
return;
}
next_lock = waiter->lock;
- raw_spin_unlock_irqrestore(&task->pi_lock, flags);
/* gets dropped in rt_mutex_adjust_prio_chain()! */
get_task_struct(task);
+ raw_spin_unlock_irqrestore(&task->pi_lock, flags);
rt_mutex_adjust_prio_chain(task, RT_MUTEX_MIN_CHAINWALK, NULL,
next_lock, NULL, task);
}
-void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
+void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter, bool savestate)
{
debug_rt_mutex_init_waiter(waiter);
RB_CLEAR_NODE(&waiter->pi_tree_entry);
RB_CLEAR_NODE(&waiter->tree_entry);
waiter->task = NULL;
+ waiter->savestate = savestate;
}
/**
@@ -1257,7 +1632,7 @@ rt_mutex_slowlock(struct rt_mutex *lock,
unsigned long flags;
int ret = 0;
- rt_mutex_init_waiter(&waiter);
+ rt_mutex_init_waiter(&waiter, false);
/*
* Technically we could use raw_spin_[un]lock_irq() here, but this can
@@ -1359,7 +1734,8 @@ static inline int rt_mutex_slowtrylock(s
* Return whether the current task needs to call rt_mutex_postunlock().
*/
static bool __sched rt_mutex_slowunlock(struct rt_mutex *lock,
- struct wake_q_head *wake_q)
+ struct wake_q_head *wake_q,
+ struct wake_q_head *wake_sleeper_q)
{
unsigned long flags;
@@ -1413,7 +1789,7 @@ static bool __sched rt_mutex_slowunlock(
*
* Queue the next waiter for wakeup once we release the wait_lock.
*/
- mark_wakeup_next_waiter(wake_q, lock);
+ mark_wakeup_next_waiter(wake_q, wake_sleeper_q, lock);
raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
return true; /* call rt_mutex_postunlock() */
@@ -1465,9 +1841,11 @@ rt_mutex_fasttrylock(struct rt_mutex *lo
/*
* Performs the wakeup of the the top-waiter and re-enables preemption.
*/
-void rt_mutex_postunlock(struct wake_q_head *wake_q)
+void rt_mutex_postunlock(struct wake_q_head *wake_q,
+ struct wake_q_head *wake_sleeper_q)
{
wake_up_q(wake_q);
+ wake_up_q_sleeper(wake_sleeper_q);
/* Pairs with preempt_disable() in rt_mutex_slowunlock() */
preempt_enable();
@@ -1476,15 +1854,30 @@ void rt_mutex_postunlock(struct wake_q_h
static inline void
rt_mutex_fastunlock(struct rt_mutex *lock,
bool (*slowfn)(struct rt_mutex *lock,
- struct wake_q_head *wqh))
+ struct wake_q_head *wqh,
+ struct wake_q_head *wq_sleeper))
{
DEFINE_WAKE_Q(wake_q);
+ DEFINE_WAKE_Q(wake_sleeper_q);
if (likely(rt_mutex_cmpxchg_release(lock, current, NULL)))
return;
- if (slowfn(lock, &wake_q))
- rt_mutex_postunlock(&wake_q);
+ if (slowfn(lock, &wake_q, &wake_sleeper_q))
+ rt_mutex_postunlock(&wake_q, &wake_sleeper_q);
+}
+
+/**
+ * __rt_mutex_lock_state - lock a rt_mutex with a given state. API use only.
+ *
+ * @lock: The rt_mutex to be locked
+ * @state: The state to set when blocking on the rt_mutex
+ */
+int __sched __rt_mutex_lock_state(struct rt_mutex *lock, int state)
+{
+ might_sleep();
+
+ return rt_mutex_fastlock(lock, state, rt_mutex_slowlock);
}
/**
@@ -1497,10 +1890,8 @@ int __sched rt_mutex_lock_state(struct r
{
int ret;
- might_sleep();
-
mutex_acquire(&lock->dep_map, 0, 0, _RET_IP_);
- ret = rt_mutex_fastlock(lock, state, rt_mutex_slowlock);
+ ret = __rt_mutex_lock_state(lock, state);
if (ret)
mutex_release(&lock->dep_map, 1, _RET_IP_);
@@ -1594,7 +1985,7 @@ rt_mutex_timed_lock(struct rt_mutex *loc
EXPORT_SYMBOL_GPL(rt_mutex_timed_lock);
/**
- * rt_mutex_trylock - try to lock a rt_mutex
+ * __rt_mutex_trylock - try to lock a rt_mutex. API use only.
*
* @lock: the rt_mutex to be locked
*
@@ -1604,10 +1995,8 @@ EXPORT_SYMBOL_GPL(rt_mutex_timed_lock);
*
* Returns 1 on success and 0 on contention
*/
-int __sched rt_mutex_trylock(struct rt_mutex *lock)
+int __sched __rt_mutex_trylock(struct rt_mutex *lock)
{
- int ret;
-
#ifdef CONFIG_PREEMPT_RT_FULL
if (WARN_ON_ONCE(in_irq() || in_nmi()))
#else
@@ -1615,7 +2004,24 @@ int __sched rt_mutex_trylock(struct rt_m
#endif
return 0;
- ret = rt_mutex_fasttrylock(lock, rt_mutex_slowtrylock);
+ return rt_mutex_fasttrylock(lock, rt_mutex_slowtrylock);
+}
+
+/**
+ * rt_mutex_trylock - try to lock a rt_mutex
+ *
+ * @lock: the rt_mutex to be locked
+ *
+ * This function can only be called in thread context. It's safe to
+ * call it from atomic regions, but not from hard interrupt or soft
+ * interrupt context.
+ *
+ * Returns 1 on success and 0 on contention
+ */
+int __sched rt_mutex_trylock(struct rt_mutex *lock)
+{
+ int ret = __rt_mutex_trylock(lock);
+
if (ret)
mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
@@ -1624,6 +2030,16 @@ int __sched rt_mutex_trylock(struct rt_m
EXPORT_SYMBOL_GPL(rt_mutex_trylock);
/**
+ * __rt_mutex_unlock - unlock a rt_mutex. API use only.
+ *
+ * @lock: the rt_mutex to be unlocked
+ */
+void __sched __rt_mutex_unlock(struct rt_mutex *lock)
+{
+ rt_mutex_fastunlock(lock, rt_mutex_slowunlock);
+}
+
+/**
* rt_mutex_unlock - unlock a rt_mutex
*
* @lock: the rt_mutex to be unlocked
@@ -1631,16 +2047,13 @@ EXPORT_SYMBOL_GPL(rt_mutex_trylock);
void __sched rt_mutex_unlock(struct rt_mutex *lock)
{
mutex_release(&lock->dep_map, 1, _RET_IP_);
- rt_mutex_fastunlock(lock, rt_mutex_slowunlock);
+ __rt_mutex_unlock(lock);
}
EXPORT_SYMBOL_GPL(rt_mutex_unlock);
-/**
- * Futex variant, that since futex variants do not use the fast-path, can be
- * simple and will not need to retry.
- */
-bool __sched __rt_mutex_futex_unlock(struct rt_mutex *lock,
- struct wake_q_head *wake_q)
+static bool __sched __rt_mutex_unlock_common(struct rt_mutex *lock,
+ struct wake_q_head *wake_q,
+ struct wake_q_head *wq_sleeper)
{
lockdep_assert_held(&lock->wait_lock);
@@ -1657,22 +2070,34 @@ bool __sched __rt_mutex_futex_unlock(str
* avoid inversion prior to the wakeup. preempt_disable()
* therein pairs with rt_mutex_postunlock().
*/
- mark_wakeup_next_waiter(wake_q, lock);
+ mark_wakeup_next_waiter(wake_q, wq_sleeper, lock);
return true; /* call postunlock() */
}
+/**
+ * Futex variant, that since futex variants do not use the fast-path, can be
+ * simple and will not need to retry.
+ */
+bool __sched __rt_mutex_futex_unlock(struct rt_mutex *lock,
+ struct wake_q_head *wake_q,
+ struct wake_q_head *wq_sleeper)
+{
+ return __rt_mutex_unlock_common(lock, wake_q, wq_sleeper);
+}
+
void __sched rt_mutex_futex_unlock(struct rt_mutex *lock)
{
DEFINE_WAKE_Q(wake_q);
+ DEFINE_WAKE_Q(wake_sleeper_q);
bool postunlock;
raw_spin_lock_irq(&lock->wait_lock);
- postunlock = __rt_mutex_futex_unlock(lock, &wake_q);
+ postunlock = __rt_mutex_futex_unlock(lock, &wake_q, &wake_sleeper_q);
raw_spin_unlock_irq(&lock->wait_lock);
if (postunlock)
- rt_mutex_postunlock(&wake_q);
+ rt_mutex_postunlock(&wake_q, &wake_sleeper_q);
}
/**
@@ -1705,13 +2130,12 @@ void __rt_mutex_init(struct rt_mutex *lo
struct lock_class_key *key)
{
lock->owner = NULL;
- raw_spin_lock_init(&lock->wait_lock);
lock->waiters = RB_ROOT_CACHED;
if (name && key)
debug_rt_mutex_init(lock, name, key);
}
-EXPORT_SYMBOL_GPL(__rt_mutex_init);
+EXPORT_SYMBOL(__rt_mutex_init);
/**
* rt_mutex_init_proxy_locked - initialize and lock a rt_mutex on behalf of a
@@ -1730,7 +2154,7 @@ EXPORT_SYMBOL_GPL(__rt_mutex_init);
void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
struct task_struct *proxy_owner)
{
- __rt_mutex_init(lock, NULL, NULL);
+ rt_mutex_init(lock);
debug_rt_mutex_proxy_lock(lock, proxy_owner);
rt_mutex_set_owner(lock, proxy_owner);
}
@@ -1978,3 +2402,25 @@ bool rt_mutex_cleanup_proxy_lock(struct
return cleanup;
}
+
+#ifdef CONFIG_PREEMPT_RT_FULL
+struct ww_mutex {
+};
+struct ww_acquire_ctx {
+};
+int __ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ww_ctx)
+{
+ BUG();
+}
+EXPORT_SYMBOL_GPL(__ww_mutex_lock);
+int __ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ww_ctx)
+{
+ BUG();
+}
+EXPORT_SYMBOL_GPL(__ww_mutex_lock_interruptible);
+void __sched ww_mutex_unlock(struct ww_mutex *lock)
+{
+ BUG();
+}
+EXPORT_SYMBOL_GPL(ww_mutex_unlock);
+#endif
--- a/kernel/locking/rtmutex_common.h
+++ b/kernel/locking/rtmutex_common.h
@@ -14,6 +14,7 @@
#include <linux/rtmutex.h>
#include <linux/sched/wake_q.h>
+#include <linux/sched/debug.h>
/*
* This is the control structure for tasks blocked on a rt_mutex,
@@ -28,6 +29,7 @@ struct rt_mutex_waiter {
struct rb_node pi_tree_entry;
struct task_struct *task;
struct rt_mutex *lock;
+ bool savestate;
#ifdef CONFIG_DEBUG_RT_MUTEXES
unsigned long ip;
struct pid *deadlock_task_pid;
@@ -106,7 +108,7 @@ extern struct task_struct *rt_mutex_next
extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
struct task_struct *proxy_owner);
extern void rt_mutex_proxy_unlock(struct rt_mutex *lock);
-extern void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter);
+extern void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter, bool savetate);
extern int __rt_mutex_start_proxy_lock(struct rt_mutex *lock,
struct rt_mutex_waiter *waiter,
struct task_struct *task);
@@ -124,9 +126,11 @@ extern int __rt_mutex_futex_trylock(stru
extern void rt_mutex_futex_unlock(struct rt_mutex *lock);
extern bool __rt_mutex_futex_unlock(struct rt_mutex *lock,
- struct wake_q_head *wqh);
+ struct wake_q_head *wqh,
+ struct wake_q_head *wq_sleeper);
-extern void rt_mutex_postunlock(struct wake_q_head *wake_q);
+extern void rt_mutex_postunlock(struct wake_q_head *wake_q,
+ struct wake_q_head *wake_sleeper_q);
#ifdef CONFIG_DEBUG_RT_MUTEXES
# include "rtmutex-debug.h"
--- a/kernel/locking/spinlock.c
+++ b/kernel/locking/spinlock.c
@@ -124,8 +124,11 @@ void __lockfunc __raw_##op##_lock_bh(loc
* __[spin|read|write]_lock_bh()
*/
BUILD_LOCK_OPS(spin, raw_spinlock);
+
+#ifndef CONFIG_PREEMPT_RT_FULL
BUILD_LOCK_OPS(read, rwlock);
BUILD_LOCK_OPS(write, rwlock);
+#endif
#endif
@@ -209,6 +212,8 @@ void __lockfunc _raw_spin_unlock_bh(raw_
EXPORT_SYMBOL(_raw_spin_unlock_bh);
#endif
+#ifndef CONFIG_PREEMPT_RT_FULL
+
#ifndef CONFIG_INLINE_READ_TRYLOCK
int __lockfunc _raw_read_trylock(rwlock_t *lock)
{
@@ -353,6 +358,8 @@ void __lockfunc _raw_write_unlock_bh(rwl
EXPORT_SYMBOL(_raw_write_unlock_bh);
#endif
+#endif /* !PREEMPT_RT_FULL */
+
#ifdef CONFIG_DEBUG_LOCK_ALLOC
void __lockfunc _raw_spin_lock_nested(raw_spinlock_t *lock, int subclass)
--- a/kernel/locking/spinlock_debug.c
+++ b/kernel/locking/spinlock_debug.c
@@ -31,6 +31,7 @@ void __raw_spin_lock_init(raw_spinlock_t
EXPORT_SYMBOL(__raw_spin_lock_init);
+#ifndef CONFIG_PREEMPT_RT_FULL
void __rwlock_init(rwlock_t *lock, const char *name,
struct lock_class_key *key)
{
@@ -48,6 +49,7 @@ void __rwlock_init(rwlock_t *lock, const
}
EXPORT_SYMBOL(__rwlock_init);
+#endif
static void spin_dump(raw_spinlock_t *lock, const char *msg)
{
@@ -135,6 +137,7 @@ void do_raw_spin_unlock(raw_spinlock_t *
arch_spin_unlock(&lock->raw_lock);
}
+#ifndef CONFIG_PREEMPT_RT_FULL
static void rwlock_bug(rwlock_t *lock, const char *msg)
{
if (!debug_locks_off())
@@ -224,3 +227,5 @@ void do_raw_write_unlock(rwlock_t *lock)
debug_write_unlock(lock);
arch_write_unlock(&lock->raw_lock);
}
+
+#endif
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -492,7 +492,7 @@ void wake_q_add_safe(struct wake_q_head
put_task_struct(task);
}
-void wake_up_q(struct wake_q_head *head)
+void __wake_up_q(struct wake_q_head *head, bool sleeper)
{
struct wake_q_node *node = head->first;
@@ -509,7 +509,10 @@ void wake_up_q(struct wake_q_head *head)
* wake_up_process() implies a wmb() to pair with the queueing
* in wake_q_add() so as not to miss wakeups.
*/
- wake_up_process(task);
+ if (sleeper)
+ wake_up_lock_sleeper(task);
+ else
+ wake_up_process(task);
put_task_struct(task);
}
}