sched/wait: Add wait_event_state()

Allows waiting with a custom @state.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20220822114648.989212021@infradead.org

diff --git a/include/linux/wait.h b/include/linux/wait.h
index 58cfbf8..b926eb9 100644 (file)
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -932,6 +932,34 @@ extern int do_wait_intr_irq(wait_queue_head_t *, wait_queue_entry_t *);
        __ret;                                                                  \
 })
 
+#define __wait_event_state(wq, condition, state)                               \
+       ___wait_event(wq, condition, state, 0, 0, schedule())
+
+/**
+ * wait_event_state - sleep until a condition gets true
+ * @wq_head: the waitqueue to wait on
+ * @condition: a C expression for the event to wait for
+ * @state: state to sleep in
+ *
+ * The process is put to sleep (@state) until the @condition evaluates to true
+ * or a signal is received (when allowed by @state).  The @condition is checked
+ * each time the waitqueue @wq_head is woken up.
+ *
+ * wake_up() has to be called after changing any variable that could
+ * change the result of the wait condition.
+ *
+ * The function will return -ERESTARTSYS if it was interrupted by a signal
+ * (when allowed by @state) and 0 if @condition evaluated to true.
+ */
+#define wait_event_state(wq_head, condition, state)                            \
+({                                                                             \
+       int __ret = 0;                                                          \
+       might_sleep();                                                          \
+       if (!(condition))                                                       \
+               __ret = __wait_event_state(wq_head, condition, state);          \
+       __ret;                                                                  \
+})
+
 #define __wait_event_killable_timeout(wq_head, condition, timeout)             \
        ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
                      TASK_KILLABLE, 0, timeout,                                \