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Subject[PATCH 13/32] wait: Add wait_event_hrtimeout()
Date
Analagous to wait_event_timeout() and friends, this adds
wait_event_hrtimeout() and wait_event_interruptible_hrtimeout().

Note that unlike the versions that use regular timers, these don't
return the amount of time remaining when they return - instead, they
return 0 or -ETIME if they timed out.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
---
include/linux/wait.h | 86 ++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 86 insertions(+)

diff --git a/include/linux/wait.h b/include/linux/wait.h
index 168dfe1..3088723 100644
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -330,6 +330,92 @@ do { \
__ret; \
})

+#define __wait_event_hrtimeout(wq, condition, timeout, state) \
+({ \
+ int __ret = 0; \
+ DEFINE_WAIT(__wait); \
+ struct hrtimer_sleeper __t; \
+ \
+ hrtimer_init_on_stack(&__t.timer, CLOCK_MONOTONIC, \
+ HRTIMER_MODE_REL); \
+ hrtimer_init_sleeper(&__t, current); \
+ if ((timeout).tv64 != KTIME_MAX) \
+ hrtimer_start_range_ns(&__t.timer, timeout, \
+ current->timer_slack_ns, \
+ HRTIMER_MODE_REL); \
+ \
+ for (;;) { \
+ prepare_to_wait(&wq, &__wait, state); \
+ if (condition) \
+ break; \
+ if (state == TASK_INTERRUPTIBLE && \
+ signal_pending(current)) { \
+ __ret = -ERESTARTSYS; \
+ break; \
+ } \
+ if (!__t.task) { \
+ __ret = -ETIME; \
+ break; \
+ } \
+ schedule(); \
+ } \
+ \
+ hrtimer_cancel(&__t.timer); \
+ destroy_hrtimer_on_stack(&__t.timer); \
+ finish_wait(&wq, &__wait); \
+ __ret; \
+})
+
+/**
+ * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
+ * @wq: the waitqueue to wait on
+ * @condition: a C expression for the event to wait for
+ * @timeout: timeout, in jiffies
+ *
+ * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
+ * @condition evaluates to true or a 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.
+ *
+ * The function returns 0 if @condition became true, or -ETIME if the timeout
+ * elapsed.
+ */
+#define wait_event_hrtimeout(wq, condition, timeout) \
+({ \
+ int __ret = 0; \
+ if (!(condition)) \
+ __ret = __wait_event_hrtimeout(wq, condition, timeout, \
+ TASK_UNINTERRUPTIBLE); \
+ __ret; \
+})
+
+/**
+ * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
+ * @wq: the waitqueue to wait on
+ * @condition: a C expression for the event to wait for
+ * @timeout: timeout, in jiffies
+ *
+ * The process is put to sleep (TASK_INTERRUPTIBLE) until the
+ * @condition evaluates to true or a 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.
+ *
+ * The function returns 0 if @condition became true, -ERESTARTSYS if it was
+ * interrupted by a signal, or -ETIME if the timeout elapsed.
+ */
+#define wait_event_interruptible_hrtimeout(wq, condition, timeout) \
+({ \
+ long __ret = 0; \
+ if (!(condition)) \
+ __ret = __wait_event_hrtimeout(wq, condition, timeout, \
+ TASK_INTERRUPTIBLE); \
+ __ret; \
+})
+
#define __wait_event_interruptible_exclusive(wq, condition, ret) \
do { \
DEFINE_WAIT(__wait); \
--
1.7.12


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