Merge remote-tracking branch 'regmap/topic/rbtree' into regmap-next

[firefly-linux-kernel-4.4.55.git] / include / linux / wait.h

diff --git a/include/linux/wait.h b/include/linux/wait.h
index 1133695eb0671d7aeb7f9140bf2b6adc3bc7483d..a67fc1635592fd34717ef559049924b1add707ca 100644 (file)
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -23,6 +23,7 @@ struct __wait_queue {
 struct wait_bit_key {
        void *flags;
        int bit_nr;
+#define WAIT_ATOMIC_T_BIT_NR -1
 };
 
 struct wait_bit_queue {
@@ -60,6 +61,9 @@ struct task_struct;
 #define __WAIT_BIT_KEY_INITIALIZER(word, bit)                          \
        { .flags = word, .bit_nr = bit, }
 
+#define __WAIT_ATOMIC_T_KEY_INITIALIZER(p)                             \
+       { .flags = p, .bit_nr = WAIT_ATOMIC_T_BIT_NR, }
+
 extern void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct lock_class_key *);
 
 #define init_waitqueue_head(q)                         \
@@ -146,8 +150,10 @@ void __wake_up_bit(wait_queue_head_t *, void *, int);
 int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
 int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
 void wake_up_bit(void *, int);
+void wake_up_atomic_t(atomic_t *);
 int out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned);
 int out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned);
+int out_of_line_wait_on_atomic_t(atomic_t *, int (*)(atomic_t *), unsigned);
 wait_queue_head_t *bit_waitqueue(void *, int);
 
 #define wake_up(x)                     __wake_up(x, TASK_NORMAL, 1, NULL)
@@ -805,6 +811,63 @@ do {                                                                       \
        __ret;                                                          \
 })
 
+#define __wait_event_interruptible_lock_irq_timeout(wq, condition,     \
+                                                   lock, ret)          \
+do {                                                                   \
+       DEFINE_WAIT(__wait);                                            \
+                                                                       \
+       for (;;) {                                                      \
+               prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
+               if (condition)                                          \
+                       break;                                          \
+               if (signal_pending(current)) {                          \
+                       ret = -ERESTARTSYS;                             \
+                       break;                                          \
+               }                                                       \
+               spin_unlock_irq(&lock);                                 \
+               ret = schedule_timeout(ret);                            \
+               spin_lock_irq(&lock);                                   \
+               if (!ret)                                               \
+                       break;                                          \
+       }                                                               \
+       finish_wait(&wq, &__wait);                                      \
+} while (0)
+
+/**
+ * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets true or a timeout elapses.
+ *             The condition is checked under the lock. This is expected
+ *             to be called with the lock taken.
+ * @wq: the waitqueue to wait on
+ * @condition: a C expression for the event to wait for
+ * @lock: a locked spinlock_t, which will be released before schedule()
+ *       and reacquired afterwards.
+ * @timeout: timeout, in jiffies
+ *
+ * The process is put to sleep (TASK_INTERRUPTIBLE) until the
+ * @condition evaluates to true or signal is received. The @condition is
+ * checked each time the waitqueue @wq is woken up.
+ *
+ * wake_up() has to be called after changing any variable that could
+ * change the result of the wait condition.
+ *
+ * This is supposed to be called while holding the lock. The lock is
+ * dropped before going to sleep and is reacquired afterwards.
+ *
+ * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
+ * was interrupted by a signal, and the remaining jiffies otherwise
+ * if the condition evaluated to true before the timeout elapsed.
+ */
+#define wait_event_interruptible_lock_irq_timeout(wq, condition, lock, \
+                                                 timeout)              \
+({                                                                     \
+       int __ret = timeout;                                            \
+                                                                       \
+       if (!(condition))                                               \
+               __wait_event_interruptible_lock_irq_timeout(            \
+                                       wq, condition, lock, __ret);    \
+       __ret;                                                          \
+})
+
 
 /*
  * These are the old interfaces to sleep waiting for an event.
@@ -902,5 +965,23 @@ static inline int wait_on_bit_lock(void *word, int bit,
                return 0;
        return out_of_line_wait_on_bit_lock(word, bit, action, mode);
 }
+
+/**
+ * wait_on_atomic_t - Wait for an atomic_t to become 0
+ * @val: The atomic value being waited on, a kernel virtual address
+ * @action: the function used to sleep, which may take special actions
+ * @mode: the task state to sleep in
+ *
+ * Wait for an atomic_t to become 0.  We abuse the bit-wait waitqueue table for
+ * the purpose of getting a waitqueue, but we set the key to a bit number
+ * outside of the target 'word'.
+ */
+static inline
+int wait_on_atomic_t(atomic_t *val, int (*action)(atomic_t *), unsigned mode)
+{
+       if (atomic_read(val) == 0)
+               return 0;
+       return out_of_line_wait_on_atomic_t(val, action, mode);
+}
        
 #endif