sysctl.o sysctl_binary.o capability.o ptrace.o timer.o user.o \
signal.o sys.o kmod.o workqueue.o pid.o task_work.o \
extable.o params.o posix-timers.o \
- kthread.o sys_ni.o posix-cpu-timers.o mutex.o \
+ kthread.o sys_ni.o posix-cpu-timers.o \
hrtimer.o rwsem.o nsproxy.o semaphore.o \
notifier.o ksysfs.o cred.o reboot.o \
async.o range.o groups.o lglock.o smpboot.o
# Do not trace debug files and internal ftrace files
CFLAGS_REMOVE_lockdep.o = -pg
CFLAGS_REMOVE_lockdep_proc.o = -pg
-CFLAGS_REMOVE_mutex-debug.o = -pg
-CFLAGS_REMOVE_rtmutex-debug.o = -pg
CFLAGS_REMOVE_cgroup-debug.o = -pg
CFLAGS_REMOVE_irq_work.o = -pg
endif
obj-y += sched/
+obj-y += locking/
obj-y += power/
obj-y += printk/
obj-y += cpu/
obj-$(CONFIG_PROFILING) += profile.o
obj-$(CONFIG_STACKTRACE) += stacktrace.o
obj-y += time/
-obj-$(CONFIG_DEBUG_MUTEXES) += mutex-debug.o
obj-$(CONFIG_LOCKDEP) += lockdep.o
ifeq ($(CONFIG_PROC_FS),y)
obj-$(CONFIG_LOCKDEP) += lockdep_proc.o
--- /dev/null
+
+obj-y += mutex.o
+
+ifdef CONFIG_FUNCTION_TRACER
+CFLAGS_REMOVE_mutex-debug.o = -pg
+CFLAGS_REMOVE_rtmutex-debug.o = -pg
+endif
+
+obj-$(CONFIG_DEBUG_MUTEXES) += mutex-debug.o
--- /dev/null
+/*
+ * kernel/mutex-debug.c
+ *
+ * Debugging code for mutexes
+ *
+ * Started by Ingo Molnar:
+ *
+ * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *
+ * lock debugging, locking tree, deadlock detection started by:
+ *
+ * Copyright (C) 2004, LynuxWorks, Inc., Igor Manyilov, Bill Huey
+ * Released under the General Public License (GPL).
+ */
+#include <linux/mutex.h>
+#include <linux/delay.h>
+#include <linux/export.h>
+#include <linux/poison.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/kallsyms.h>
+#include <linux/interrupt.h>
+#include <linux/debug_locks.h>
+
+#include "mutex-debug.h"
+
+/*
+ * Must be called with lock->wait_lock held.
+ */
+void debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
+{
+ memset(waiter, MUTEX_DEBUG_INIT, sizeof(*waiter));
+ waiter->magic = waiter;
+ INIT_LIST_HEAD(&waiter->list);
+}
+
+void debug_mutex_wake_waiter(struct mutex *lock, struct mutex_waiter *waiter)
+{
+ SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock->wait_lock));
+ DEBUG_LOCKS_WARN_ON(list_empty(&lock->wait_list));
+ DEBUG_LOCKS_WARN_ON(waiter->magic != waiter);
+ DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));
+}
+
+void debug_mutex_free_waiter(struct mutex_waiter *waiter)
+{
+ DEBUG_LOCKS_WARN_ON(!list_empty(&waiter->list));
+ memset(waiter, MUTEX_DEBUG_FREE, sizeof(*waiter));
+}
+
+void debug_mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter,
+ struct thread_info *ti)
+{
+ SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock->wait_lock));
+
+ /* Mark the current thread as blocked on the lock: */
+ ti->task->blocked_on = waiter;
+}
+
+void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
+ struct thread_info *ti)
+{
+ DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));
+ DEBUG_LOCKS_WARN_ON(waiter->task != ti->task);
+ DEBUG_LOCKS_WARN_ON(ti->task->blocked_on != waiter);
+ ti->task->blocked_on = NULL;
+
+ list_del_init(&waiter->list);
+ waiter->task = NULL;
+}
+
+void debug_mutex_unlock(struct mutex *lock)
+{
+ if (unlikely(!debug_locks))
+ return;
+
+ DEBUG_LOCKS_WARN_ON(lock->magic != lock);
+ DEBUG_LOCKS_WARN_ON(lock->owner != current);
+ DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);
+ mutex_clear_owner(lock);
+}
+
+void debug_mutex_init(struct mutex *lock, 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 *)lock, sizeof(*lock));
+ lockdep_init_map(&lock->dep_map, name, key, 0);
+#endif
+ lock->magic = lock;
+}
+
+/***
+ * mutex_destroy - mark a mutex unusable
+ * @lock: the mutex to be destroyed
+ *
+ * This function marks the mutex uninitialized, and any subsequent
+ * use of the mutex is forbidden. The mutex must not be locked when
+ * this function is called.
+ */
+void mutex_destroy(struct mutex *lock)
+{
+ DEBUG_LOCKS_WARN_ON(mutex_is_locked(lock));
+ lock->magic = NULL;
+}
+
+EXPORT_SYMBOL_GPL(mutex_destroy);
--- /dev/null
+/*
+ * Mutexes: blocking mutual exclusion locks
+ *
+ * started by Ingo Molnar:
+ *
+ * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *
+ * This file contains mutex debugging related internal declarations,
+ * prototypes and inline functions, for the CONFIG_DEBUG_MUTEXES case.
+ * More details are in kernel/mutex-debug.c.
+ */
+
+/*
+ * This must be called with lock->wait_lock held.
+ */
+extern void debug_mutex_lock_common(struct mutex *lock,
+ struct mutex_waiter *waiter);
+extern void debug_mutex_wake_waiter(struct mutex *lock,
+ struct mutex_waiter *waiter);
+extern void debug_mutex_free_waiter(struct mutex_waiter *waiter);
+extern void debug_mutex_add_waiter(struct mutex *lock,
+ struct mutex_waiter *waiter,
+ struct thread_info *ti);
+extern void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
+ struct thread_info *ti);
+extern void debug_mutex_unlock(struct mutex *lock);
+extern void debug_mutex_init(struct mutex *lock, const char *name,
+ struct lock_class_key *key);
+
+static inline void mutex_set_owner(struct mutex *lock)
+{
+ lock->owner = current;
+}
+
+static inline void mutex_clear_owner(struct mutex *lock)
+{
+ lock->owner = NULL;
+}
+
+#define spin_lock_mutex(lock, flags) \
+ do { \
+ struct mutex *l = container_of(lock, struct mutex, wait_lock); \
+ \
+ DEBUG_LOCKS_WARN_ON(in_interrupt()); \
+ local_irq_save(flags); \
+ arch_spin_lock(&(lock)->rlock.raw_lock);\
+ DEBUG_LOCKS_WARN_ON(l->magic != l); \
+ } while (0)
+
+#define spin_unlock_mutex(lock, flags) \
+ do { \
+ arch_spin_unlock(&(lock)->rlock.raw_lock); \
+ local_irq_restore(flags); \
+ preempt_check_resched(); \
+ } while (0)
--- /dev/null
+/*
+ * kernel/mutex.c
+ *
+ * Mutexes: blocking mutual exclusion locks
+ *
+ * Started by Ingo Molnar:
+ *
+ * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *
+ * Many thanks to Arjan van de Ven, Thomas Gleixner, Steven Rostedt and
+ * David Howells for suggestions and improvements.
+ *
+ * - Adaptive spinning for mutexes by Peter Zijlstra. (Ported to mainline
+ * from the -rt tree, where it was originally implemented for rtmutexes
+ * by Steven Rostedt, based on work by Gregory Haskins, Peter Morreale
+ * and Sven Dietrich.
+ *
+ * Also see Documentation/mutex-design.txt.
+ */
+#include <linux/mutex.h>
+#include <linux/ww_mutex.h>
+#include <linux/sched.h>
+#include <linux/sched/rt.h>
+#include <linux/export.h>
+#include <linux/spinlock.h>
+#include <linux/interrupt.h>
+#include <linux/debug_locks.h>
+
+/*
+ * In the DEBUG case we are using the "NULL fastpath" for mutexes,
+ * which forces all calls into the slowpath:
+ */
+#ifdef CONFIG_DEBUG_MUTEXES
+# include "mutex-debug.h"
+# include <asm-generic/mutex-null.h>
+#else
+# include "mutex.h"
+# include <asm/mutex.h>
+#endif
+
+/*
+ * A negative mutex count indicates that waiters are sleeping waiting for the
+ * mutex.
+ */
+#define MUTEX_SHOW_NO_WAITER(mutex) (atomic_read(&(mutex)->count) >= 0)
+
+void
+__mutex_init(struct mutex *lock, const char *name, struct lock_class_key *key)
+{
+ atomic_set(&lock->count, 1);
+ spin_lock_init(&lock->wait_lock);
+ INIT_LIST_HEAD(&lock->wait_list);
+ mutex_clear_owner(lock);
+#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
+ lock->spin_mlock = NULL;
+#endif
+
+ debug_mutex_init(lock, name, key);
+}
+
+EXPORT_SYMBOL(__mutex_init);
+
+#ifndef CONFIG_DEBUG_LOCK_ALLOC
+/*
+ * We split the mutex lock/unlock logic into separate fastpath and
+ * slowpath functions, to reduce the register pressure on the fastpath.
+ * We also put the fastpath first in the kernel image, to make sure the
+ * branch is predicted by the CPU as default-untaken.
+ */
+static __used noinline void __sched
+__mutex_lock_slowpath(atomic_t *lock_count);
+
+/**
+ * mutex_lock - acquire the mutex
+ * @lock: the mutex to be acquired
+ *
+ * Lock the mutex exclusively for this task. If the mutex is not
+ * available right now, it will sleep until it can get it.
+ *
+ * The mutex must later on be released by the same task that
+ * acquired it. Recursive locking is not allowed. The task
+ * may not exit without first unlocking the mutex. Also, kernel
+ * memory where the mutex resides mutex must not be freed with
+ * the mutex still locked. The mutex must first be initialized
+ * (or statically defined) before it can be locked. memset()-ing
+ * the mutex to 0 is not allowed.
+ *
+ * ( The CONFIG_DEBUG_MUTEXES .config option turns on debugging
+ * checks that will enforce the restrictions and will also do
+ * deadlock debugging. )
+ *
+ * This function is similar to (but not equivalent to) down().
+ */
+void __sched mutex_lock(struct mutex *lock)
+{
+ might_sleep();
+ /*
+ * The locking fastpath is the 1->0 transition from
+ * 'unlocked' into 'locked' state.
+ */
+ __mutex_fastpath_lock(&lock->count, __mutex_lock_slowpath);
+ mutex_set_owner(lock);
+}
+
+EXPORT_SYMBOL(mutex_lock);
+#endif
+
+#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
+/*
+ * In order to avoid a stampede of mutex spinners from acquiring the mutex
+ * more or less simultaneously, the spinners need to acquire a MCS lock
+ * first before spinning on the owner field.
+ *
+ * We don't inline mspin_lock() so that perf can correctly account for the
+ * time spent in this lock function.
+ */
+struct mspin_node {
+ struct mspin_node *next ;
+ int locked; /* 1 if lock acquired */
+};
+#define MLOCK(mutex) ((struct mspin_node **)&((mutex)->spin_mlock))
+
+static noinline
+void mspin_lock(struct mspin_node **lock, struct mspin_node *node)
+{
+ struct mspin_node *prev;
+
+ /* Init node */
+ node->locked = 0;
+ node->next = NULL;
+
+ prev = xchg(lock, node);
+ if (likely(prev == NULL)) {
+ /* Lock acquired */
+ node->locked = 1;
+ return;
+ }
+ ACCESS_ONCE(prev->next) = node;
+ smp_wmb();
+ /* Wait until the lock holder passes the lock down */
+ while (!ACCESS_ONCE(node->locked))
+ arch_mutex_cpu_relax();
+}
+
+static void mspin_unlock(struct mspin_node **lock, struct mspin_node *node)
+{
+ struct mspin_node *next = ACCESS_ONCE(node->next);
+
+ if (likely(!next)) {
+ /*
+ * Release the lock by setting it to NULL
+ */
+ if (cmpxchg(lock, node, NULL) == node)
+ return;
+ /* Wait until the next pointer is set */
+ while (!(next = ACCESS_ONCE(node->next)))
+ arch_mutex_cpu_relax();
+ }
+ ACCESS_ONCE(next->locked) = 1;
+ smp_wmb();
+}
+
+/*
+ * Mutex spinning code migrated from kernel/sched/core.c
+ */
+
+static inline bool owner_running(struct mutex *lock, struct task_struct *owner)
+{
+ if (lock->owner != owner)
+ return false;
+
+ /*
+ * Ensure we emit the owner->on_cpu, dereference _after_ checking
+ * lock->owner still matches owner, if that fails, owner might
+ * point to free()d memory, if it still matches, the rcu_read_lock()
+ * ensures the memory stays valid.
+ */
+ barrier();
+
+ return owner->on_cpu;
+}
+
+/*
+ * Look out! "owner" is an entirely speculative pointer
+ * access and not reliable.
+ */
+static noinline
+int mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner)
+{
+ rcu_read_lock();
+ while (owner_running(lock, owner)) {
+ if (need_resched())
+ break;
+
+ arch_mutex_cpu_relax();
+ }
+ rcu_read_unlock();
+
+ /*
+ * We break out the loop above on need_resched() and when the
+ * owner changed, which is a sign for heavy contention. Return
+ * success only when lock->owner is NULL.
+ */
+ return lock->owner == NULL;
+}
+
+/*
+ * Initial check for entering the mutex spinning loop
+ */
+static inline int mutex_can_spin_on_owner(struct mutex *lock)
+{
+ struct task_struct *owner;
+ int retval = 1;
+
+ rcu_read_lock();
+ owner = ACCESS_ONCE(lock->owner);
+ if (owner)
+ retval = owner->on_cpu;
+ rcu_read_unlock();
+ /*
+ * if lock->owner is not set, the mutex owner may have just acquired
+ * it and not set the owner yet or the mutex has been released.
+ */
+ return retval;
+}
+#endif
+
+static __used noinline void __sched __mutex_unlock_slowpath(atomic_t *lock_count);
+
+/**
+ * mutex_unlock - release the mutex
+ * @lock: the mutex to be released
+ *
+ * Unlock a mutex that has been locked by this task previously.
+ *
+ * This function must not be used in interrupt context. Unlocking
+ * of a not locked mutex is not allowed.
+ *
+ * This function is similar to (but not equivalent to) up().
+ */
+void __sched mutex_unlock(struct mutex *lock)
+{
+ /*
+ * The unlocking fastpath is the 0->1 transition from 'locked'
+ * into 'unlocked' state:
+ */
+#ifndef CONFIG_DEBUG_MUTEXES
+ /*
+ * When debugging is enabled we must not clear the owner before time,
+ * the slow path will always be taken, and that clears the owner field
+ * after verifying that it was indeed current.
+ */
+ mutex_clear_owner(lock);
+#endif
+ __mutex_fastpath_unlock(&lock->count, __mutex_unlock_slowpath);
+}
+
+EXPORT_SYMBOL(mutex_unlock);
+
+/**
+ * ww_mutex_unlock - release the w/w mutex
+ * @lock: the mutex to be released
+ *
+ * Unlock a mutex that has been locked by this task previously with any of the
+ * ww_mutex_lock* functions (with or without an acquire context). It is
+ * forbidden to release the locks after releasing the acquire context.
+ *
+ * This function must not be used in interrupt context. Unlocking
+ * of a unlocked mutex is not allowed.
+ */
+void __sched ww_mutex_unlock(struct ww_mutex *lock)
+{
+ /*
+ * The unlocking fastpath is the 0->1 transition from 'locked'
+ * into 'unlocked' state:
+ */
+ if (lock->ctx) {
+#ifdef CONFIG_DEBUG_MUTEXES
+ DEBUG_LOCKS_WARN_ON(!lock->ctx->acquired);
+#endif
+ if (lock->ctx->acquired > 0)
+ lock->ctx->acquired--;
+ lock->ctx = NULL;
+ }
+
+#ifndef CONFIG_DEBUG_MUTEXES
+ /*
+ * When debugging is enabled we must not clear the owner before time,
+ * the slow path will always be taken, and that clears the owner field
+ * after verifying that it was indeed current.
+ */
+ mutex_clear_owner(&lock->base);
+#endif
+ __mutex_fastpath_unlock(&lock->base.count, __mutex_unlock_slowpath);
+}
+EXPORT_SYMBOL(ww_mutex_unlock);
+
+static inline int __sched
+__mutex_lock_check_stamp(struct mutex *lock, struct ww_acquire_ctx *ctx)
+{
+ struct ww_mutex *ww = container_of(lock, struct ww_mutex, base);
+ struct ww_acquire_ctx *hold_ctx = ACCESS_ONCE(ww->ctx);
+
+ if (!hold_ctx)
+ return 0;
+
+ if (unlikely(ctx == hold_ctx))
+ return -EALREADY;
+
+ if (ctx->stamp - hold_ctx->stamp <= LONG_MAX &&
+ (ctx->stamp != hold_ctx->stamp || ctx > hold_ctx)) {
+#ifdef CONFIG_DEBUG_MUTEXES
+ DEBUG_LOCKS_WARN_ON(ctx->contending_lock);
+ ctx->contending_lock = ww;
+#endif
+ return -EDEADLK;
+ }
+
+ return 0;
+}
+
+static __always_inline void ww_mutex_lock_acquired(struct ww_mutex *ww,
+ struct ww_acquire_ctx *ww_ctx)
+{
+#ifdef CONFIG_DEBUG_MUTEXES
+ /*
+ * If this WARN_ON triggers, you used ww_mutex_lock to acquire,
+ * but released with a normal mutex_unlock in this call.
+ *
+ * This should never happen, always use ww_mutex_unlock.
+ */
+ DEBUG_LOCKS_WARN_ON(ww->ctx);
+
+ /*
+ * Not quite done after calling ww_acquire_done() ?
+ */
+ DEBUG_LOCKS_WARN_ON(ww_ctx->done_acquire);
+
+ if (ww_ctx->contending_lock) {
+ /*
+ * After -EDEADLK you tried to
+ * acquire a different ww_mutex? Bad!
+ */
+ DEBUG_LOCKS_WARN_ON(ww_ctx->contending_lock != ww);
+
+ /*
+ * You called ww_mutex_lock after receiving -EDEADLK,
+ * but 'forgot' to unlock everything else first?
+ */
+ DEBUG_LOCKS_WARN_ON(ww_ctx->acquired > 0);
+ ww_ctx->contending_lock = NULL;
+ }
+
+ /*
+ * Naughty, using a different class will lead to undefined behavior!
+ */
+ DEBUG_LOCKS_WARN_ON(ww_ctx->ww_class != ww->ww_class);
+#endif
+ ww_ctx->acquired++;
+}
+
+/*
+ * after acquiring lock with fastpath or when we lost out in contested
+ * slowpath, set ctx and wake up any waiters so they can recheck.
+ *
+ * This function is never called when CONFIG_DEBUG_LOCK_ALLOC is set,
+ * as the fastpath and opportunistic spinning are disabled in that case.
+ */
+static __always_inline void
+ww_mutex_set_context_fastpath(struct ww_mutex *lock,
+ struct ww_acquire_ctx *ctx)
+{
+ unsigned long flags;
+ struct mutex_waiter *cur;
+
+ ww_mutex_lock_acquired(lock, ctx);
+
+ lock->ctx = ctx;
+
+ /*
+ * The lock->ctx update should be visible on all cores before
+ * the atomic read is done, otherwise contended waiters might be
+ * missed. The contended waiters will either see ww_ctx == NULL
+ * and keep spinning, or it will acquire wait_lock, add itself
+ * to waiter list and sleep.
+ */
+ smp_mb(); /* ^^^ */
+
+ /*
+ * Check if lock is contended, if not there is nobody to wake up
+ */
+ if (likely(atomic_read(&lock->base.count) == 0))
+ return;
+
+ /*
+ * Uh oh, we raced in fastpath, wake up everyone in this case,
+ * so they can see the new lock->ctx.
+ */
+ spin_lock_mutex(&lock->base.wait_lock, flags);
+ list_for_each_entry(cur, &lock->base.wait_list, list) {
+ debug_mutex_wake_waiter(&lock->base, cur);
+ wake_up_process(cur->task);
+ }
+ spin_unlock_mutex(&lock->base.wait_lock, flags);
+}
+
+/*
+ * Lock a mutex (possibly interruptible), slowpath:
+ */
+static __always_inline int __sched
+__mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
+ struct lockdep_map *nest_lock, unsigned long ip,
+ struct ww_acquire_ctx *ww_ctx, const bool use_ww_ctx)
+{
+ struct task_struct *task = current;
+ struct mutex_waiter waiter;
+ unsigned long flags;
+ int ret;
+
+ preempt_disable();
+ mutex_acquire_nest(&lock->dep_map, subclass, 0, nest_lock, ip);
+
+#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
+ /*
+ * Optimistic spinning.
+ *
+ * We try to spin for acquisition when we find that there are no
+ * pending waiters and the lock owner is currently running on a
+ * (different) CPU.
+ *
+ * The rationale is that if the lock owner is running, it is likely to
+ * release the lock soon.
+ *
+ * Since this needs the lock owner, and this mutex implementation
+ * doesn't track the owner atomically in the lock field, we need to
+ * track it non-atomically.
+ *
+ * We can't do this for DEBUG_MUTEXES because that relies on wait_lock
+ * to serialize everything.
+ *
+ * The mutex spinners are queued up using MCS lock so that only one
+ * spinner can compete for the mutex. However, if mutex spinning isn't
+ * going to happen, there is no point in going through the lock/unlock
+ * overhead.
+ */
+ if (!mutex_can_spin_on_owner(lock))
+ goto slowpath;
+
+ for (;;) {
+ struct task_struct *owner;
+ struct mspin_node node;
+
+ if (use_ww_ctx && ww_ctx->acquired > 0) {
+ struct ww_mutex *ww;
+
+ ww = container_of(lock, struct ww_mutex, base);
+ /*
+ * If ww->ctx is set the contents are undefined, only
+ * by acquiring wait_lock there is a guarantee that
+ * they are not invalid when reading.
+ *
+ * As such, when deadlock detection needs to be
+ * performed the optimistic spinning cannot be done.
+ */
+ if (ACCESS_ONCE(ww->ctx))
+ goto slowpath;
+ }
+
+ /*
+ * If there's an owner, wait for it to either
+ * release the lock or go to sleep.
+ */
+ mspin_lock(MLOCK(lock), &node);
+ owner = ACCESS_ONCE(lock->owner);
+ if (owner && !mutex_spin_on_owner(lock, owner)) {
+ mspin_unlock(MLOCK(lock), &node);
+ goto slowpath;
+ }
+
+ if ((atomic_read(&lock->count) == 1) &&
+ (atomic_cmpxchg(&lock->count, 1, 0) == 1)) {
+ lock_acquired(&lock->dep_map, ip);
+ if (use_ww_ctx) {
+ struct ww_mutex *ww;
+ ww = container_of(lock, struct ww_mutex, base);
+
+ ww_mutex_set_context_fastpath(ww, ww_ctx);
+ }
+
+ mutex_set_owner(lock);
+ mspin_unlock(MLOCK(lock), &node);
+ preempt_enable();
+ return 0;
+ }
+ mspin_unlock(MLOCK(lock), &node);
+
+ /*
+ * When there's no owner, we might have preempted between the
+ * owner acquiring the lock and setting the owner field. If
+ * we're an RT task that will live-lock because we won't let
+ * the owner complete.
+ */
+ if (!owner && (need_resched() || rt_task(task)))
+ goto slowpath;
+
+ /*
+ * The cpu_relax() call is a compiler barrier which forces
+ * everything in this loop to be re-loaded. We don't need
+ * memory barriers as we'll eventually observe the right
+ * values at the cost of a few extra spins.
+ */
+ arch_mutex_cpu_relax();
+ }
+slowpath:
+#endif
+ spin_lock_mutex(&lock->wait_lock, flags);
+
+ /* once more, can we acquire the lock? */
+ if (MUTEX_SHOW_NO_WAITER(lock) && (atomic_xchg(&lock->count, 0) == 1))
+ goto skip_wait;
+
+ debug_mutex_lock_common(lock, &waiter);
+ debug_mutex_add_waiter(lock, &waiter, task_thread_info(task));
+
+ /* add waiting tasks to the end of the waitqueue (FIFO): */
+ list_add_tail(&waiter.list, &lock->wait_list);
+ waiter.task = task;
+
+ lock_contended(&lock->dep_map, ip);
+
+ for (;;) {
+ /*
+ * Lets try to take the lock again - this is needed even if
+ * we get here for the first time (shortly after failing to
+ * acquire the lock), to make sure that we get a wakeup once
+ * it's unlocked. Later on, if we sleep, this is the
+ * operation that gives us the lock. We xchg it to -1, so
+ * that when we release the lock, we properly wake up the
+ * other waiters:
+ */
+ if (MUTEX_SHOW_NO_WAITER(lock) &&
+ (atomic_xchg(&lock->count, -1) == 1))
+ break;
+
+ /*
+ * got a signal? (This code gets eliminated in the
+ * TASK_UNINTERRUPTIBLE case.)
+ */
+ if (unlikely(signal_pending_state(state, task))) {
+ ret = -EINTR;
+ goto err;
+ }
+
+ if (use_ww_ctx && ww_ctx->acquired > 0) {
+ ret = __mutex_lock_check_stamp(lock, ww_ctx);
+ if (ret)
+ goto err;
+ }
+
+ __set_task_state(task, state);
+
+ /* didn't get the lock, go to sleep: */
+ spin_unlock_mutex(&lock->wait_lock, flags);
+ schedule_preempt_disabled();
+ spin_lock_mutex(&lock->wait_lock, flags);
+ }
+ mutex_remove_waiter(lock, &waiter, current_thread_info());
+ /* set it to 0 if there are no waiters left: */
+ if (likely(list_empty(&lock->wait_list)))
+ atomic_set(&lock->count, 0);
+ debug_mutex_free_waiter(&waiter);
+
+skip_wait:
+ /* got the lock - cleanup and rejoice! */
+ lock_acquired(&lock->dep_map, ip);
+ mutex_set_owner(lock);
+
+ if (use_ww_ctx) {
+ struct ww_mutex *ww = container_of(lock, struct ww_mutex, base);
+ struct mutex_waiter *cur;
+
+ /*
+ * This branch gets optimized out for the common case,
+ * and is only important for ww_mutex_lock.
+ */
+ ww_mutex_lock_acquired(ww, ww_ctx);
+ ww->ctx = ww_ctx;
+
+ /*
+ * Give any possible sleeping processes the chance to wake up,
+ * so they can recheck if they have to back off.
+ */
+ list_for_each_entry(cur, &lock->wait_list, list) {
+ debug_mutex_wake_waiter(lock, cur);
+ wake_up_process(cur->task);
+ }
+ }
+
+ spin_unlock_mutex(&lock->wait_lock, flags);
+ preempt_enable();
+ return 0;
+
+err:
+ mutex_remove_waiter(lock, &waiter, task_thread_info(task));
+ spin_unlock_mutex(&lock->wait_lock, flags);
+ debug_mutex_free_waiter(&waiter);
+ mutex_release(&lock->dep_map, 1, ip);
+ preempt_enable();
+ return ret;
+}
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+void __sched
+mutex_lock_nested(struct mutex *lock, unsigned int subclass)
+{
+ might_sleep();
+ __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE,
+ subclass, NULL, _RET_IP_, NULL, 0);
+}
+
+EXPORT_SYMBOL_GPL(mutex_lock_nested);
+
+void __sched
+_mutex_lock_nest_lock(struct mutex *lock, struct lockdep_map *nest)
+{
+ might_sleep();
+ __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE,
+ 0, nest, _RET_IP_, NULL, 0);
+}
+
+EXPORT_SYMBOL_GPL(_mutex_lock_nest_lock);
+
+int __sched
+mutex_lock_killable_nested(struct mutex *lock, unsigned int subclass)
+{
+ might_sleep();
+ return __mutex_lock_common(lock, TASK_KILLABLE,
+ subclass, NULL, _RET_IP_, NULL, 0);
+}
+EXPORT_SYMBOL_GPL(mutex_lock_killable_nested);
+
+int __sched
+mutex_lock_interruptible_nested(struct mutex *lock, unsigned int subclass)
+{
+ might_sleep();
+ return __mutex_lock_common(lock, TASK_INTERRUPTIBLE,
+ subclass, NULL, _RET_IP_, NULL, 0);
+}
+
+EXPORT_SYMBOL_GPL(mutex_lock_interruptible_nested);
+
+static inline int
+ww_mutex_deadlock_injection(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+#ifdef CONFIG_DEBUG_WW_MUTEX_SLOWPATH
+ unsigned tmp;
+
+ if (ctx->deadlock_inject_countdown-- == 0) {
+ tmp = ctx->deadlock_inject_interval;
+ if (tmp > UINT_MAX/4)
+ tmp = UINT_MAX;
+ else
+ tmp = tmp*2 + tmp + tmp/2;
+
+ ctx->deadlock_inject_interval = tmp;
+ ctx->deadlock_inject_countdown = tmp;
+ ctx->contending_lock = lock;
+
+ ww_mutex_unlock(lock);
+
+ return -EDEADLK;
+ }
+#endif
+
+ return 0;
+}
+
+int __sched
+__ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+ int ret;
+
+ might_sleep();
+ ret = __mutex_lock_common(&lock->base, TASK_UNINTERRUPTIBLE,
+ 0, &ctx->dep_map, _RET_IP_, ctx, 1);
+ if (!ret && ctx->acquired > 1)
+ return ww_mutex_deadlock_injection(lock, ctx);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(__ww_mutex_lock);
+
+int __sched
+__ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+ int ret;
+
+ might_sleep();
+ ret = __mutex_lock_common(&lock->base, TASK_INTERRUPTIBLE,
+ 0, &ctx->dep_map, _RET_IP_, ctx, 1);
+
+ if (!ret && ctx->acquired > 1)
+ return ww_mutex_deadlock_injection(lock, ctx);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(__ww_mutex_lock_interruptible);
+
+#endif
+
+/*
+ * Release the lock, slowpath:
+ */
+static inline void
+__mutex_unlock_common_slowpath(atomic_t *lock_count, int nested)
+{
+ struct mutex *lock = container_of(lock_count, struct mutex, count);
+ unsigned long flags;
+
+ spin_lock_mutex(&lock->wait_lock, flags);
+ mutex_release(&lock->dep_map, nested, _RET_IP_);
+ debug_mutex_unlock(lock);
+
+ /*
+ * some architectures leave the lock unlocked in the fastpath failure
+ * case, others need to leave it locked. In the later case we have to
+ * unlock it here
+ */
+ if (__mutex_slowpath_needs_to_unlock())
+ atomic_set(&lock->count, 1);
+
+ if (!list_empty(&lock->wait_list)) {
+ /* get the first entry from the wait-list: */
+ struct mutex_waiter *waiter =
+ list_entry(lock->wait_list.next,
+ struct mutex_waiter, list);
+
+ debug_mutex_wake_waiter(lock, waiter);
+
+ wake_up_process(waiter->task);
+ }
+
+ spin_unlock_mutex(&lock->wait_lock, flags);
+}
+
+/*
+ * Release the lock, slowpath:
+ */
+static __used noinline void
+__mutex_unlock_slowpath(atomic_t *lock_count)
+{
+ __mutex_unlock_common_slowpath(lock_count, 1);
+}
+
+#ifndef CONFIG_DEBUG_LOCK_ALLOC
+/*
+ * Here come the less common (and hence less performance-critical) APIs:
+ * mutex_lock_interruptible() and mutex_trylock().
+ */
+static noinline int __sched
+__mutex_lock_killable_slowpath(struct mutex *lock);
+
+static noinline int __sched
+__mutex_lock_interruptible_slowpath(struct mutex *lock);
+
+/**
+ * mutex_lock_interruptible - acquire the mutex, interruptible
+ * @lock: the mutex to be acquired
+ *
+ * Lock the mutex like mutex_lock(), and return 0 if the mutex has
+ * been acquired or sleep until the mutex becomes available. If a
+ * signal arrives while waiting for the lock then this function
+ * returns -EINTR.
+ *
+ * This function is similar to (but not equivalent to) down_interruptible().
+ */
+int __sched mutex_lock_interruptible(struct mutex *lock)
+{
+ int ret;
+
+ might_sleep();
+ ret = __mutex_fastpath_lock_retval(&lock->count);
+ if (likely(!ret)) {
+ mutex_set_owner(lock);
+ return 0;
+ } else
+ return __mutex_lock_interruptible_slowpath(lock);
+}
+
+EXPORT_SYMBOL(mutex_lock_interruptible);
+
+int __sched mutex_lock_killable(struct mutex *lock)
+{
+ int ret;
+
+ might_sleep();
+ ret = __mutex_fastpath_lock_retval(&lock->count);
+ if (likely(!ret)) {
+ mutex_set_owner(lock);
+ return 0;
+ } else
+ return __mutex_lock_killable_slowpath(lock);
+}
+EXPORT_SYMBOL(mutex_lock_killable);
+
+static __used noinline void __sched
+__mutex_lock_slowpath(atomic_t *lock_count)
+{
+ struct mutex *lock = container_of(lock_count, struct mutex, count);
+
+ __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0,
+ NULL, _RET_IP_, NULL, 0);
+}
+
+static noinline int __sched
+__mutex_lock_killable_slowpath(struct mutex *lock)
+{
+ return __mutex_lock_common(lock, TASK_KILLABLE, 0,
+ NULL, _RET_IP_, NULL, 0);
+}
+
+static noinline int __sched
+__mutex_lock_interruptible_slowpath(struct mutex *lock)
+{
+ return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, 0,
+ NULL, _RET_IP_, NULL, 0);
+}
+
+static noinline int __sched
+__ww_mutex_lock_slowpath(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+ return __mutex_lock_common(&lock->base, TASK_UNINTERRUPTIBLE, 0,
+ NULL, _RET_IP_, ctx, 1);
+}
+
+static noinline int __sched
+__ww_mutex_lock_interruptible_slowpath(struct ww_mutex *lock,
+ struct ww_acquire_ctx *ctx)
+{
+ return __mutex_lock_common(&lock->base, TASK_INTERRUPTIBLE, 0,
+ NULL, _RET_IP_, ctx, 1);
+}
+
+#endif
+
+/*
+ * Spinlock based trylock, we take the spinlock and check whether we
+ * can get the lock:
+ */
+static inline int __mutex_trylock_slowpath(atomic_t *lock_count)
+{
+ struct mutex *lock = container_of(lock_count, struct mutex, count);
+ unsigned long flags;
+ int prev;
+
+ spin_lock_mutex(&lock->wait_lock, flags);
+
+ prev = atomic_xchg(&lock->count, -1);
+ if (likely(prev == 1)) {
+ mutex_set_owner(lock);
+ mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
+ }
+
+ /* Set it back to 0 if there are no waiters: */
+ if (likely(list_empty(&lock->wait_list)))
+ atomic_set(&lock->count, 0);
+
+ spin_unlock_mutex(&lock->wait_lock, flags);
+
+ return prev == 1;
+}
+
+/**
+ * mutex_trylock - try to acquire the mutex, without waiting
+ * @lock: the mutex to be acquired
+ *
+ * Try to acquire the mutex atomically. Returns 1 if the mutex
+ * has been acquired successfully, and 0 on contention.
+ *
+ * NOTE: this function follows the spin_trylock() convention, so
+ * it is negated from the down_trylock() return values! Be careful
+ * about this when converting semaphore users to mutexes.
+ *
+ * This function must not be used in interrupt context. The
+ * mutex must be released by the same task that acquired it.
+ */
+int __sched mutex_trylock(struct mutex *lock)
+{
+ int ret;
+
+ ret = __mutex_fastpath_trylock(&lock->count, __mutex_trylock_slowpath);
+ if (ret)
+ mutex_set_owner(lock);
+
+ return ret;
+}
+EXPORT_SYMBOL(mutex_trylock);
+
+#ifndef CONFIG_DEBUG_LOCK_ALLOC
+int __sched
+__ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+ int ret;
+
+ might_sleep();
+
+ ret = __mutex_fastpath_lock_retval(&lock->base.count);
+
+ if (likely(!ret)) {
+ ww_mutex_set_context_fastpath(lock, ctx);
+ mutex_set_owner(&lock->base);
+ } else
+ ret = __ww_mutex_lock_slowpath(lock, ctx);
+ return ret;
+}
+EXPORT_SYMBOL(__ww_mutex_lock);
+
+int __sched
+__ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+ int ret;
+
+ might_sleep();
+
+ ret = __mutex_fastpath_lock_retval(&lock->base.count);
+
+ if (likely(!ret)) {
+ ww_mutex_set_context_fastpath(lock, ctx);
+ mutex_set_owner(&lock->base);
+ } else
+ ret = __ww_mutex_lock_interruptible_slowpath(lock, ctx);
+ return ret;
+}
+EXPORT_SYMBOL(__ww_mutex_lock_interruptible);
+
+#endif
+
+/**
+ * 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);
--- /dev/null
+/*
+ * Mutexes: blocking mutual exclusion locks
+ *
+ * started by Ingo Molnar:
+ *
+ * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *
+ * This file contains mutex debugging related internal prototypes, for the
+ * !CONFIG_DEBUG_MUTEXES case. Most of them are NOPs:
+ */
+
+#define spin_lock_mutex(lock, flags) \
+ do { spin_lock(lock); (void)(flags); } while (0)
+#define spin_unlock_mutex(lock, flags) \
+ do { spin_unlock(lock); (void)(flags); } while (0)
+#define mutex_remove_waiter(lock, waiter, ti) \
+ __list_del((waiter)->list.prev, (waiter)->list.next)
+
+#ifdef CONFIG_SMP
+static inline void mutex_set_owner(struct mutex *lock)
+{
+ lock->owner = current;
+}
+
+static inline void mutex_clear_owner(struct mutex *lock)
+{
+ lock->owner = NULL;
+}
+#else
+static inline void mutex_set_owner(struct mutex *lock)
+{
+}
+
+static inline void mutex_clear_owner(struct mutex *lock)
+{
+}
+#endif
+
+#define debug_mutex_wake_waiter(lock, waiter) do { } while (0)
+#define debug_mutex_free_waiter(waiter) do { } while (0)
+#define debug_mutex_add_waiter(lock, waiter, ti) do { } while (0)
+#define debug_mutex_unlock(lock) do { } while (0)
+#define debug_mutex_init(lock, name, key) do { } while (0)
+
+static inline void
+debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
+{
+}
+++ /dev/null
-/*
- * kernel/mutex-debug.c
- *
- * Debugging code for mutexes
- *
- * Started by Ingo Molnar:
- *
- * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
- *
- * lock debugging, locking tree, deadlock detection started by:
- *
- * Copyright (C) 2004, LynuxWorks, Inc., Igor Manyilov, Bill Huey
- * Released under the General Public License (GPL).
- */
-#include <linux/mutex.h>
-#include <linux/delay.h>
-#include <linux/export.h>
-#include <linux/poison.h>
-#include <linux/sched.h>
-#include <linux/spinlock.h>
-#include <linux/kallsyms.h>
-#include <linux/interrupt.h>
-#include <linux/debug_locks.h>
-
-#include "mutex-debug.h"
-
-/*
- * Must be called with lock->wait_lock held.
- */
-void debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
-{
- memset(waiter, MUTEX_DEBUG_INIT, sizeof(*waiter));
- waiter->magic = waiter;
- INIT_LIST_HEAD(&waiter->list);
-}
-
-void debug_mutex_wake_waiter(struct mutex *lock, struct mutex_waiter *waiter)
-{
- SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock->wait_lock));
- DEBUG_LOCKS_WARN_ON(list_empty(&lock->wait_list));
- DEBUG_LOCKS_WARN_ON(waiter->magic != waiter);
- DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));
-}
-
-void debug_mutex_free_waiter(struct mutex_waiter *waiter)
-{
- DEBUG_LOCKS_WARN_ON(!list_empty(&waiter->list));
- memset(waiter, MUTEX_DEBUG_FREE, sizeof(*waiter));
-}
-
-void debug_mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter,
- struct thread_info *ti)
-{
- SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock->wait_lock));
-
- /* Mark the current thread as blocked on the lock: */
- ti->task->blocked_on = waiter;
-}
-
-void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
- struct thread_info *ti)
-{
- DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));
- DEBUG_LOCKS_WARN_ON(waiter->task != ti->task);
- DEBUG_LOCKS_WARN_ON(ti->task->blocked_on != waiter);
- ti->task->blocked_on = NULL;
-
- list_del_init(&waiter->list);
- waiter->task = NULL;
-}
-
-void debug_mutex_unlock(struct mutex *lock)
-{
- if (unlikely(!debug_locks))
- return;
-
- DEBUG_LOCKS_WARN_ON(lock->magic != lock);
- DEBUG_LOCKS_WARN_ON(lock->owner != current);
- DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);
- mutex_clear_owner(lock);
-}
-
-void debug_mutex_init(struct mutex *lock, 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 *)lock, sizeof(*lock));
- lockdep_init_map(&lock->dep_map, name, key, 0);
-#endif
- lock->magic = lock;
-}
-
-/***
- * mutex_destroy - mark a mutex unusable
- * @lock: the mutex to be destroyed
- *
- * This function marks the mutex uninitialized, and any subsequent
- * use of the mutex is forbidden. The mutex must not be locked when
- * this function is called.
- */
-void mutex_destroy(struct mutex *lock)
-{
- DEBUG_LOCKS_WARN_ON(mutex_is_locked(lock));
- lock->magic = NULL;
-}
-
-EXPORT_SYMBOL_GPL(mutex_destroy);
+++ /dev/null
-/*
- * Mutexes: blocking mutual exclusion locks
- *
- * started by Ingo Molnar:
- *
- * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
- *
- * This file contains mutex debugging related internal declarations,
- * prototypes and inline functions, for the CONFIG_DEBUG_MUTEXES case.
- * More details are in kernel/mutex-debug.c.
- */
-
-/*
- * This must be called with lock->wait_lock held.
- */
-extern void debug_mutex_lock_common(struct mutex *lock,
- struct mutex_waiter *waiter);
-extern void debug_mutex_wake_waiter(struct mutex *lock,
- struct mutex_waiter *waiter);
-extern void debug_mutex_free_waiter(struct mutex_waiter *waiter);
-extern void debug_mutex_add_waiter(struct mutex *lock,
- struct mutex_waiter *waiter,
- struct thread_info *ti);
-extern void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
- struct thread_info *ti);
-extern void debug_mutex_unlock(struct mutex *lock);
-extern void debug_mutex_init(struct mutex *lock, const char *name,
- struct lock_class_key *key);
-
-static inline void mutex_set_owner(struct mutex *lock)
-{
- lock->owner = current;
-}
-
-static inline void mutex_clear_owner(struct mutex *lock)
-{
- lock->owner = NULL;
-}
-
-#define spin_lock_mutex(lock, flags) \
- do { \
- struct mutex *l = container_of(lock, struct mutex, wait_lock); \
- \
- DEBUG_LOCKS_WARN_ON(in_interrupt()); \
- local_irq_save(flags); \
- arch_spin_lock(&(lock)->rlock.raw_lock);\
- DEBUG_LOCKS_WARN_ON(l->magic != l); \
- } while (0)
-
-#define spin_unlock_mutex(lock, flags) \
- do { \
- arch_spin_unlock(&(lock)->rlock.raw_lock); \
- local_irq_restore(flags); \
- preempt_check_resched(); \
- } while (0)
+++ /dev/null
-/*
- * kernel/mutex.c
- *
- * Mutexes: blocking mutual exclusion locks
- *
- * Started by Ingo Molnar:
- *
- * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
- *
- * Many thanks to Arjan van de Ven, Thomas Gleixner, Steven Rostedt and
- * David Howells for suggestions and improvements.
- *
- * - Adaptive spinning for mutexes by Peter Zijlstra. (Ported to mainline
- * from the -rt tree, where it was originally implemented for rtmutexes
- * by Steven Rostedt, based on work by Gregory Haskins, Peter Morreale
- * and Sven Dietrich.
- *
- * Also see Documentation/mutex-design.txt.
- */
-#include <linux/mutex.h>
-#include <linux/ww_mutex.h>
-#include <linux/sched.h>
-#include <linux/sched/rt.h>
-#include <linux/export.h>
-#include <linux/spinlock.h>
-#include <linux/interrupt.h>
-#include <linux/debug_locks.h>
-
-/*
- * In the DEBUG case we are using the "NULL fastpath" for mutexes,
- * which forces all calls into the slowpath:
- */
-#ifdef CONFIG_DEBUG_MUTEXES
-# include "mutex-debug.h"
-# include <asm-generic/mutex-null.h>
-#else
-# include "mutex.h"
-# include <asm/mutex.h>
-#endif
-
-/*
- * A negative mutex count indicates that waiters are sleeping waiting for the
- * mutex.
- */
-#define MUTEX_SHOW_NO_WAITER(mutex) (atomic_read(&(mutex)->count) >= 0)
-
-void
-__mutex_init(struct mutex *lock, const char *name, struct lock_class_key *key)
-{
- atomic_set(&lock->count, 1);
- spin_lock_init(&lock->wait_lock);
- INIT_LIST_HEAD(&lock->wait_list);
- mutex_clear_owner(lock);
-#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
- lock->spin_mlock = NULL;
-#endif
-
- debug_mutex_init(lock, name, key);
-}
-
-EXPORT_SYMBOL(__mutex_init);
-
-#ifndef CONFIG_DEBUG_LOCK_ALLOC
-/*
- * We split the mutex lock/unlock logic into separate fastpath and
- * slowpath functions, to reduce the register pressure on the fastpath.
- * We also put the fastpath first in the kernel image, to make sure the
- * branch is predicted by the CPU as default-untaken.
- */
-static __used noinline void __sched
-__mutex_lock_slowpath(atomic_t *lock_count);
-
-/**
- * mutex_lock - acquire the mutex
- * @lock: the mutex to be acquired
- *
- * Lock the mutex exclusively for this task. If the mutex is not
- * available right now, it will sleep until it can get it.
- *
- * The mutex must later on be released by the same task that
- * acquired it. Recursive locking is not allowed. The task
- * may not exit without first unlocking the mutex. Also, kernel
- * memory where the mutex resides mutex must not be freed with
- * the mutex still locked. The mutex must first be initialized
- * (or statically defined) before it can be locked. memset()-ing
- * the mutex to 0 is not allowed.
- *
- * ( The CONFIG_DEBUG_MUTEXES .config option turns on debugging
- * checks that will enforce the restrictions and will also do
- * deadlock debugging. )
- *
- * This function is similar to (but not equivalent to) down().
- */
-void __sched mutex_lock(struct mutex *lock)
-{
- might_sleep();
- /*
- * The locking fastpath is the 1->0 transition from
- * 'unlocked' into 'locked' state.
- */
- __mutex_fastpath_lock(&lock->count, __mutex_lock_slowpath);
- mutex_set_owner(lock);
-}
-
-EXPORT_SYMBOL(mutex_lock);
-#endif
-
-#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
-/*
- * In order to avoid a stampede of mutex spinners from acquiring the mutex
- * more or less simultaneously, the spinners need to acquire a MCS lock
- * first before spinning on the owner field.
- *
- * We don't inline mspin_lock() so that perf can correctly account for the
- * time spent in this lock function.
- */
-struct mspin_node {
- struct mspin_node *next ;
- int locked; /* 1 if lock acquired */
-};
-#define MLOCK(mutex) ((struct mspin_node **)&((mutex)->spin_mlock))
-
-static noinline
-void mspin_lock(struct mspin_node **lock, struct mspin_node *node)
-{
- struct mspin_node *prev;
-
- /* Init node */
- node->locked = 0;
- node->next = NULL;
-
- prev = xchg(lock, node);
- if (likely(prev == NULL)) {
- /* Lock acquired */
- node->locked = 1;
- return;
- }
- ACCESS_ONCE(prev->next) = node;
- smp_wmb();
- /* Wait until the lock holder passes the lock down */
- while (!ACCESS_ONCE(node->locked))
- arch_mutex_cpu_relax();
-}
-
-static void mspin_unlock(struct mspin_node **lock, struct mspin_node *node)
-{
- struct mspin_node *next = ACCESS_ONCE(node->next);
-
- if (likely(!next)) {
- /*
- * Release the lock by setting it to NULL
- */
- if (cmpxchg(lock, node, NULL) == node)
- return;
- /* Wait until the next pointer is set */
- while (!(next = ACCESS_ONCE(node->next)))
- arch_mutex_cpu_relax();
- }
- ACCESS_ONCE(next->locked) = 1;
- smp_wmb();
-}
-
-/*
- * Mutex spinning code migrated from kernel/sched/core.c
- */
-
-static inline bool owner_running(struct mutex *lock, struct task_struct *owner)
-{
- if (lock->owner != owner)
- return false;
-
- /*
- * Ensure we emit the owner->on_cpu, dereference _after_ checking
- * lock->owner still matches owner, if that fails, owner might
- * point to free()d memory, if it still matches, the rcu_read_lock()
- * ensures the memory stays valid.
- */
- barrier();
-
- return owner->on_cpu;
-}
-
-/*
- * Look out! "owner" is an entirely speculative pointer
- * access and not reliable.
- */
-static noinline
-int mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner)
-{
- rcu_read_lock();
- while (owner_running(lock, owner)) {
- if (need_resched())
- break;
-
- arch_mutex_cpu_relax();
- }
- rcu_read_unlock();
-
- /*
- * We break out the loop above on need_resched() and when the
- * owner changed, which is a sign for heavy contention. Return
- * success only when lock->owner is NULL.
- */
- return lock->owner == NULL;
-}
-
-/*
- * Initial check for entering the mutex spinning loop
- */
-static inline int mutex_can_spin_on_owner(struct mutex *lock)
-{
- struct task_struct *owner;
- int retval = 1;
-
- rcu_read_lock();
- owner = ACCESS_ONCE(lock->owner);
- if (owner)
- retval = owner->on_cpu;
- rcu_read_unlock();
- /*
- * if lock->owner is not set, the mutex owner may have just acquired
- * it and not set the owner yet or the mutex has been released.
- */
- return retval;
-}
-#endif
-
-static __used noinline void __sched __mutex_unlock_slowpath(atomic_t *lock_count);
-
-/**
- * mutex_unlock - release the mutex
- * @lock: the mutex to be released
- *
- * Unlock a mutex that has been locked by this task previously.
- *
- * This function must not be used in interrupt context. Unlocking
- * of a not locked mutex is not allowed.
- *
- * This function is similar to (but not equivalent to) up().
- */
-void __sched mutex_unlock(struct mutex *lock)
-{
- /*
- * The unlocking fastpath is the 0->1 transition from 'locked'
- * into 'unlocked' state:
- */
-#ifndef CONFIG_DEBUG_MUTEXES
- /*
- * When debugging is enabled we must not clear the owner before time,
- * the slow path will always be taken, and that clears the owner field
- * after verifying that it was indeed current.
- */
- mutex_clear_owner(lock);
-#endif
- __mutex_fastpath_unlock(&lock->count, __mutex_unlock_slowpath);
-}
-
-EXPORT_SYMBOL(mutex_unlock);
-
-/**
- * ww_mutex_unlock - release the w/w mutex
- * @lock: the mutex to be released
- *
- * Unlock a mutex that has been locked by this task previously with any of the
- * ww_mutex_lock* functions (with or without an acquire context). It is
- * forbidden to release the locks after releasing the acquire context.
- *
- * This function must not be used in interrupt context. Unlocking
- * of a unlocked mutex is not allowed.
- */
-void __sched ww_mutex_unlock(struct ww_mutex *lock)
-{
- /*
- * The unlocking fastpath is the 0->1 transition from 'locked'
- * into 'unlocked' state:
- */
- if (lock->ctx) {
-#ifdef CONFIG_DEBUG_MUTEXES
- DEBUG_LOCKS_WARN_ON(!lock->ctx->acquired);
-#endif
- if (lock->ctx->acquired > 0)
- lock->ctx->acquired--;
- lock->ctx = NULL;
- }
-
-#ifndef CONFIG_DEBUG_MUTEXES
- /*
- * When debugging is enabled we must not clear the owner before time,
- * the slow path will always be taken, and that clears the owner field
- * after verifying that it was indeed current.
- */
- mutex_clear_owner(&lock->base);
-#endif
- __mutex_fastpath_unlock(&lock->base.count, __mutex_unlock_slowpath);
-}
-EXPORT_SYMBOL(ww_mutex_unlock);
-
-static inline int __sched
-__mutex_lock_check_stamp(struct mutex *lock, struct ww_acquire_ctx *ctx)
-{
- struct ww_mutex *ww = container_of(lock, struct ww_mutex, base);
- struct ww_acquire_ctx *hold_ctx = ACCESS_ONCE(ww->ctx);
-
- if (!hold_ctx)
- return 0;
-
- if (unlikely(ctx == hold_ctx))
- return -EALREADY;
-
- if (ctx->stamp - hold_ctx->stamp <= LONG_MAX &&
- (ctx->stamp != hold_ctx->stamp || ctx > hold_ctx)) {
-#ifdef CONFIG_DEBUG_MUTEXES
- DEBUG_LOCKS_WARN_ON(ctx->contending_lock);
- ctx->contending_lock = ww;
-#endif
- return -EDEADLK;
- }
-
- return 0;
-}
-
-static __always_inline void ww_mutex_lock_acquired(struct ww_mutex *ww,
- struct ww_acquire_ctx *ww_ctx)
-{
-#ifdef CONFIG_DEBUG_MUTEXES
- /*
- * If this WARN_ON triggers, you used ww_mutex_lock to acquire,
- * but released with a normal mutex_unlock in this call.
- *
- * This should never happen, always use ww_mutex_unlock.
- */
- DEBUG_LOCKS_WARN_ON(ww->ctx);
-
- /*
- * Not quite done after calling ww_acquire_done() ?
- */
- DEBUG_LOCKS_WARN_ON(ww_ctx->done_acquire);
-
- if (ww_ctx->contending_lock) {
- /*
- * After -EDEADLK you tried to
- * acquire a different ww_mutex? Bad!
- */
- DEBUG_LOCKS_WARN_ON(ww_ctx->contending_lock != ww);
-
- /*
- * You called ww_mutex_lock after receiving -EDEADLK,
- * but 'forgot' to unlock everything else first?
- */
- DEBUG_LOCKS_WARN_ON(ww_ctx->acquired > 0);
- ww_ctx->contending_lock = NULL;
- }
-
- /*
- * Naughty, using a different class will lead to undefined behavior!
- */
- DEBUG_LOCKS_WARN_ON(ww_ctx->ww_class != ww->ww_class);
-#endif
- ww_ctx->acquired++;
-}
-
-/*
- * after acquiring lock with fastpath or when we lost out in contested
- * slowpath, set ctx and wake up any waiters so they can recheck.
- *
- * This function is never called when CONFIG_DEBUG_LOCK_ALLOC is set,
- * as the fastpath and opportunistic spinning are disabled in that case.
- */
-static __always_inline void
-ww_mutex_set_context_fastpath(struct ww_mutex *lock,
- struct ww_acquire_ctx *ctx)
-{
- unsigned long flags;
- struct mutex_waiter *cur;
-
- ww_mutex_lock_acquired(lock, ctx);
-
- lock->ctx = ctx;
-
- /*
- * The lock->ctx update should be visible on all cores before
- * the atomic read is done, otherwise contended waiters might be
- * missed. The contended waiters will either see ww_ctx == NULL
- * and keep spinning, or it will acquire wait_lock, add itself
- * to waiter list and sleep.
- */
- smp_mb(); /* ^^^ */
-
- /*
- * Check if lock is contended, if not there is nobody to wake up
- */
- if (likely(atomic_read(&lock->base.count) == 0))
- return;
-
- /*
- * Uh oh, we raced in fastpath, wake up everyone in this case,
- * so they can see the new lock->ctx.
- */
- spin_lock_mutex(&lock->base.wait_lock, flags);
- list_for_each_entry(cur, &lock->base.wait_list, list) {
- debug_mutex_wake_waiter(&lock->base, cur);
- wake_up_process(cur->task);
- }
- spin_unlock_mutex(&lock->base.wait_lock, flags);
-}
-
-/*
- * Lock a mutex (possibly interruptible), slowpath:
- */
-static __always_inline int __sched
-__mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
- struct lockdep_map *nest_lock, unsigned long ip,
- struct ww_acquire_ctx *ww_ctx, const bool use_ww_ctx)
-{
- struct task_struct *task = current;
- struct mutex_waiter waiter;
- unsigned long flags;
- int ret;
-
- preempt_disable();
- mutex_acquire_nest(&lock->dep_map, subclass, 0, nest_lock, ip);
-
-#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
- /*
- * Optimistic spinning.
- *
- * We try to spin for acquisition when we find that there are no
- * pending waiters and the lock owner is currently running on a
- * (different) CPU.
- *
- * The rationale is that if the lock owner is running, it is likely to
- * release the lock soon.
- *
- * Since this needs the lock owner, and this mutex implementation
- * doesn't track the owner atomically in the lock field, we need to
- * track it non-atomically.
- *
- * We can't do this for DEBUG_MUTEXES because that relies on wait_lock
- * to serialize everything.
- *
- * The mutex spinners are queued up using MCS lock so that only one
- * spinner can compete for the mutex. However, if mutex spinning isn't
- * going to happen, there is no point in going through the lock/unlock
- * overhead.
- */
- if (!mutex_can_spin_on_owner(lock))
- goto slowpath;
-
- for (;;) {
- struct task_struct *owner;
- struct mspin_node node;
-
- if (use_ww_ctx && ww_ctx->acquired > 0) {
- struct ww_mutex *ww;
-
- ww = container_of(lock, struct ww_mutex, base);
- /*
- * If ww->ctx is set the contents are undefined, only
- * by acquiring wait_lock there is a guarantee that
- * they are not invalid when reading.
- *
- * As such, when deadlock detection needs to be
- * performed the optimistic spinning cannot be done.
- */
- if (ACCESS_ONCE(ww->ctx))
- goto slowpath;
- }
-
- /*
- * If there's an owner, wait for it to either
- * release the lock or go to sleep.
- */
- mspin_lock(MLOCK(lock), &node);
- owner = ACCESS_ONCE(lock->owner);
- if (owner && !mutex_spin_on_owner(lock, owner)) {
- mspin_unlock(MLOCK(lock), &node);
- goto slowpath;
- }
-
- if ((atomic_read(&lock->count) == 1) &&
- (atomic_cmpxchg(&lock->count, 1, 0) == 1)) {
- lock_acquired(&lock->dep_map, ip);
- if (use_ww_ctx) {
- struct ww_mutex *ww;
- ww = container_of(lock, struct ww_mutex, base);
-
- ww_mutex_set_context_fastpath(ww, ww_ctx);
- }
-
- mutex_set_owner(lock);
- mspin_unlock(MLOCK(lock), &node);
- preempt_enable();
- return 0;
- }
- mspin_unlock(MLOCK(lock), &node);
-
- /*
- * When there's no owner, we might have preempted between the
- * owner acquiring the lock and setting the owner field. If
- * we're an RT task that will live-lock because we won't let
- * the owner complete.
- */
- if (!owner && (need_resched() || rt_task(task)))
- goto slowpath;
-
- /*
- * The cpu_relax() call is a compiler barrier which forces
- * everything in this loop to be re-loaded. We don't need
- * memory barriers as we'll eventually observe the right
- * values at the cost of a few extra spins.
- */
- arch_mutex_cpu_relax();
- }
-slowpath:
-#endif
- spin_lock_mutex(&lock->wait_lock, flags);
-
- /* once more, can we acquire the lock? */
- if (MUTEX_SHOW_NO_WAITER(lock) && (atomic_xchg(&lock->count, 0) == 1))
- goto skip_wait;
-
- debug_mutex_lock_common(lock, &waiter);
- debug_mutex_add_waiter(lock, &waiter, task_thread_info(task));
-
- /* add waiting tasks to the end of the waitqueue (FIFO): */
- list_add_tail(&waiter.list, &lock->wait_list);
- waiter.task = task;
-
- lock_contended(&lock->dep_map, ip);
-
- for (;;) {
- /*
- * Lets try to take the lock again - this is needed even if
- * we get here for the first time (shortly after failing to
- * acquire the lock), to make sure that we get a wakeup once
- * it's unlocked. Later on, if we sleep, this is the
- * operation that gives us the lock. We xchg it to -1, so
- * that when we release the lock, we properly wake up the
- * other waiters:
- */
- if (MUTEX_SHOW_NO_WAITER(lock) &&
- (atomic_xchg(&lock->count, -1) == 1))
- break;
-
- /*
- * got a signal? (This code gets eliminated in the
- * TASK_UNINTERRUPTIBLE case.)
- */
- if (unlikely(signal_pending_state(state, task))) {
- ret = -EINTR;
- goto err;
- }
-
- if (use_ww_ctx && ww_ctx->acquired > 0) {
- ret = __mutex_lock_check_stamp(lock, ww_ctx);
- if (ret)
- goto err;
- }
-
- __set_task_state(task, state);
-
- /* didn't get the lock, go to sleep: */
- spin_unlock_mutex(&lock->wait_lock, flags);
- schedule_preempt_disabled();
- spin_lock_mutex(&lock->wait_lock, flags);
- }
- mutex_remove_waiter(lock, &waiter, current_thread_info());
- /* set it to 0 if there are no waiters left: */
- if (likely(list_empty(&lock->wait_list)))
- atomic_set(&lock->count, 0);
- debug_mutex_free_waiter(&waiter);
-
-skip_wait:
- /* got the lock - cleanup and rejoice! */
- lock_acquired(&lock->dep_map, ip);
- mutex_set_owner(lock);
-
- if (use_ww_ctx) {
- struct ww_mutex *ww = container_of(lock, struct ww_mutex, base);
- struct mutex_waiter *cur;
-
- /*
- * This branch gets optimized out for the common case,
- * and is only important for ww_mutex_lock.
- */
- ww_mutex_lock_acquired(ww, ww_ctx);
- ww->ctx = ww_ctx;
-
- /*
- * Give any possible sleeping processes the chance to wake up,
- * so they can recheck if they have to back off.
- */
- list_for_each_entry(cur, &lock->wait_list, list) {
- debug_mutex_wake_waiter(lock, cur);
- wake_up_process(cur->task);
- }
- }
-
- spin_unlock_mutex(&lock->wait_lock, flags);
- preempt_enable();
- return 0;
-
-err:
- mutex_remove_waiter(lock, &waiter, task_thread_info(task));
- spin_unlock_mutex(&lock->wait_lock, flags);
- debug_mutex_free_waiter(&waiter);
- mutex_release(&lock->dep_map, 1, ip);
- preempt_enable();
- return ret;
-}
-
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-void __sched
-mutex_lock_nested(struct mutex *lock, unsigned int subclass)
-{
- might_sleep();
- __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE,
- subclass, NULL, _RET_IP_, NULL, 0);
-}
-
-EXPORT_SYMBOL_GPL(mutex_lock_nested);
-
-void __sched
-_mutex_lock_nest_lock(struct mutex *lock, struct lockdep_map *nest)
-{
- might_sleep();
- __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE,
- 0, nest, _RET_IP_, NULL, 0);
-}
-
-EXPORT_SYMBOL_GPL(_mutex_lock_nest_lock);
-
-int __sched
-mutex_lock_killable_nested(struct mutex *lock, unsigned int subclass)
-{
- might_sleep();
- return __mutex_lock_common(lock, TASK_KILLABLE,
- subclass, NULL, _RET_IP_, NULL, 0);
-}
-EXPORT_SYMBOL_GPL(mutex_lock_killable_nested);
-
-int __sched
-mutex_lock_interruptible_nested(struct mutex *lock, unsigned int subclass)
-{
- might_sleep();
- return __mutex_lock_common(lock, TASK_INTERRUPTIBLE,
- subclass, NULL, _RET_IP_, NULL, 0);
-}
-
-EXPORT_SYMBOL_GPL(mutex_lock_interruptible_nested);
-
-static inline int
-ww_mutex_deadlock_injection(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
-{
-#ifdef CONFIG_DEBUG_WW_MUTEX_SLOWPATH
- unsigned tmp;
-
- if (ctx->deadlock_inject_countdown-- == 0) {
- tmp = ctx->deadlock_inject_interval;
- if (tmp > UINT_MAX/4)
- tmp = UINT_MAX;
- else
- tmp = tmp*2 + tmp + tmp/2;
-
- ctx->deadlock_inject_interval = tmp;
- ctx->deadlock_inject_countdown = tmp;
- ctx->contending_lock = lock;
-
- ww_mutex_unlock(lock);
-
- return -EDEADLK;
- }
-#endif
-
- return 0;
-}
-
-int __sched
-__ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
-{
- int ret;
-
- might_sleep();
- ret = __mutex_lock_common(&lock->base, TASK_UNINTERRUPTIBLE,
- 0, &ctx->dep_map, _RET_IP_, ctx, 1);
- if (!ret && ctx->acquired > 1)
- return ww_mutex_deadlock_injection(lock, ctx);
-
- return ret;
-}
-EXPORT_SYMBOL_GPL(__ww_mutex_lock);
-
-int __sched
-__ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
-{
- int ret;
-
- might_sleep();
- ret = __mutex_lock_common(&lock->base, TASK_INTERRUPTIBLE,
- 0, &ctx->dep_map, _RET_IP_, ctx, 1);
-
- if (!ret && ctx->acquired > 1)
- return ww_mutex_deadlock_injection(lock, ctx);
-
- return ret;
-}
-EXPORT_SYMBOL_GPL(__ww_mutex_lock_interruptible);
-
-#endif
-
-/*
- * Release the lock, slowpath:
- */
-static inline void
-__mutex_unlock_common_slowpath(atomic_t *lock_count, int nested)
-{
- struct mutex *lock = container_of(lock_count, struct mutex, count);
- unsigned long flags;
-
- spin_lock_mutex(&lock->wait_lock, flags);
- mutex_release(&lock->dep_map, nested, _RET_IP_);
- debug_mutex_unlock(lock);
-
- /*
- * some architectures leave the lock unlocked in the fastpath failure
- * case, others need to leave it locked. In the later case we have to
- * unlock it here
- */
- if (__mutex_slowpath_needs_to_unlock())
- atomic_set(&lock->count, 1);
-
- if (!list_empty(&lock->wait_list)) {
- /* get the first entry from the wait-list: */
- struct mutex_waiter *waiter =
- list_entry(lock->wait_list.next,
- struct mutex_waiter, list);
-
- debug_mutex_wake_waiter(lock, waiter);
-
- wake_up_process(waiter->task);
- }
-
- spin_unlock_mutex(&lock->wait_lock, flags);
-}
-
-/*
- * Release the lock, slowpath:
- */
-static __used noinline void
-__mutex_unlock_slowpath(atomic_t *lock_count)
-{
- __mutex_unlock_common_slowpath(lock_count, 1);
-}
-
-#ifndef CONFIG_DEBUG_LOCK_ALLOC
-/*
- * Here come the less common (and hence less performance-critical) APIs:
- * mutex_lock_interruptible() and mutex_trylock().
- */
-static noinline int __sched
-__mutex_lock_killable_slowpath(struct mutex *lock);
-
-static noinline int __sched
-__mutex_lock_interruptible_slowpath(struct mutex *lock);
-
-/**
- * mutex_lock_interruptible - acquire the mutex, interruptible
- * @lock: the mutex to be acquired
- *
- * Lock the mutex like mutex_lock(), and return 0 if the mutex has
- * been acquired or sleep until the mutex becomes available. If a
- * signal arrives while waiting for the lock then this function
- * returns -EINTR.
- *
- * This function is similar to (but not equivalent to) down_interruptible().
- */
-int __sched mutex_lock_interruptible(struct mutex *lock)
-{
- int ret;
-
- might_sleep();
- ret = __mutex_fastpath_lock_retval(&lock->count);
- if (likely(!ret)) {
- mutex_set_owner(lock);
- return 0;
- } else
- return __mutex_lock_interruptible_slowpath(lock);
-}
-
-EXPORT_SYMBOL(mutex_lock_interruptible);
-
-int __sched mutex_lock_killable(struct mutex *lock)
-{
- int ret;
-
- might_sleep();
- ret = __mutex_fastpath_lock_retval(&lock->count);
- if (likely(!ret)) {
- mutex_set_owner(lock);
- return 0;
- } else
- return __mutex_lock_killable_slowpath(lock);
-}
-EXPORT_SYMBOL(mutex_lock_killable);
-
-static __used noinline void __sched
-__mutex_lock_slowpath(atomic_t *lock_count)
-{
- struct mutex *lock = container_of(lock_count, struct mutex, count);
-
- __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0,
- NULL, _RET_IP_, NULL, 0);
-}
-
-static noinline int __sched
-__mutex_lock_killable_slowpath(struct mutex *lock)
-{
- return __mutex_lock_common(lock, TASK_KILLABLE, 0,
- NULL, _RET_IP_, NULL, 0);
-}
-
-static noinline int __sched
-__mutex_lock_interruptible_slowpath(struct mutex *lock)
-{
- return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, 0,
- NULL, _RET_IP_, NULL, 0);
-}
-
-static noinline int __sched
-__ww_mutex_lock_slowpath(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
-{
- return __mutex_lock_common(&lock->base, TASK_UNINTERRUPTIBLE, 0,
- NULL, _RET_IP_, ctx, 1);
-}
-
-static noinline int __sched
-__ww_mutex_lock_interruptible_slowpath(struct ww_mutex *lock,
- struct ww_acquire_ctx *ctx)
-{
- return __mutex_lock_common(&lock->base, TASK_INTERRUPTIBLE, 0,
- NULL, _RET_IP_, ctx, 1);
-}
-
-#endif
-
-/*
- * Spinlock based trylock, we take the spinlock and check whether we
- * can get the lock:
- */
-static inline int __mutex_trylock_slowpath(atomic_t *lock_count)
-{
- struct mutex *lock = container_of(lock_count, struct mutex, count);
- unsigned long flags;
- int prev;
-
- spin_lock_mutex(&lock->wait_lock, flags);
-
- prev = atomic_xchg(&lock->count, -1);
- if (likely(prev == 1)) {
- mutex_set_owner(lock);
- mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
- }
-
- /* Set it back to 0 if there are no waiters: */
- if (likely(list_empty(&lock->wait_list)))
- atomic_set(&lock->count, 0);
-
- spin_unlock_mutex(&lock->wait_lock, flags);
-
- return prev == 1;
-}
-
-/**
- * mutex_trylock - try to acquire the mutex, without waiting
- * @lock: the mutex to be acquired
- *
- * Try to acquire the mutex atomically. Returns 1 if the mutex
- * has been acquired successfully, and 0 on contention.
- *
- * NOTE: this function follows the spin_trylock() convention, so
- * it is negated from the down_trylock() return values! Be careful
- * about this when converting semaphore users to mutexes.
- *
- * This function must not be used in interrupt context. The
- * mutex must be released by the same task that acquired it.
- */
-int __sched mutex_trylock(struct mutex *lock)
-{
- int ret;
-
- ret = __mutex_fastpath_trylock(&lock->count, __mutex_trylock_slowpath);
- if (ret)
- mutex_set_owner(lock);
-
- return ret;
-}
-EXPORT_SYMBOL(mutex_trylock);
-
-#ifndef CONFIG_DEBUG_LOCK_ALLOC
-int __sched
-__ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
-{
- int ret;
-
- might_sleep();
-
- ret = __mutex_fastpath_lock_retval(&lock->base.count);
-
- if (likely(!ret)) {
- ww_mutex_set_context_fastpath(lock, ctx);
- mutex_set_owner(&lock->base);
- } else
- ret = __ww_mutex_lock_slowpath(lock, ctx);
- return ret;
-}
-EXPORT_SYMBOL(__ww_mutex_lock);
-
-int __sched
-__ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
-{
- int ret;
-
- might_sleep();
-
- ret = __mutex_fastpath_lock_retval(&lock->base.count);
-
- if (likely(!ret)) {
- ww_mutex_set_context_fastpath(lock, ctx);
- mutex_set_owner(&lock->base);
- } else
- ret = __ww_mutex_lock_interruptible_slowpath(lock, ctx);
- return ret;
-}
-EXPORT_SYMBOL(__ww_mutex_lock_interruptible);
-
-#endif
-
-/**
- * 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);
+++ /dev/null
-/*
- * Mutexes: blocking mutual exclusion locks
- *
- * started by Ingo Molnar:
- *
- * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
- *
- * This file contains mutex debugging related internal prototypes, for the
- * !CONFIG_DEBUG_MUTEXES case. Most of them are NOPs:
- */
-
-#define spin_lock_mutex(lock, flags) \
- do { spin_lock(lock); (void)(flags); } while (0)
-#define spin_unlock_mutex(lock, flags) \
- do { spin_unlock(lock); (void)(flags); } while (0)
-#define mutex_remove_waiter(lock, waiter, ti) \
- __list_del((waiter)->list.prev, (waiter)->list.next)
-
-#ifdef CONFIG_SMP
-static inline void mutex_set_owner(struct mutex *lock)
-{
- lock->owner = current;
-}
-
-static inline void mutex_clear_owner(struct mutex *lock)
-{
- lock->owner = NULL;
-}
-#else
-static inline void mutex_set_owner(struct mutex *lock)
-{
-}
-
-static inline void mutex_clear_owner(struct mutex *lock)
-{
-}
-#endif
-
-#define debug_mutex_wake_waiter(lock, waiter) do { } while (0)
-#define debug_mutex_free_waiter(waiter) do { } while (0)
-#define debug_mutex_add_waiter(lock, waiter, ti) do { } while (0)
-#define debug_mutex_unlock(lock) do { } while (0)
-#define debug_mutex_init(lock, name, key) do { } while (0)
-
-static inline void
-debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
-{
-}
projects / openwrt / staging / blogic.git / commitdiff