It is not currently possible to wait wait_var_event for an io_schedule()
style wait. This patch adds wait_var_event_io() for that purpose.
Signed-off-by: NeilBrown <neilb@suse.de>
---
include/linux/wait_bit.h | 31 +++++++++++++++++++++++++++++++
1 file changed, 31 insertions(+)
diff --git a/include/linux/wait_bit.h b/include/linux/wait_bit.h
index 6aea10efca3d..6346e26fbfd1 100644
--- a/include/linux/wait_bit.h
+++ b/include/linux/wait_bit.h
@@ -281,6 +281,9 @@ __out: __ret; \
#define __wait_var_event(var, condition) \
___wait_var_event(var, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
schedule())
+#define __wait_var_event_io(var, condition) \
+ ___wait_var_event(var, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
+ io_schedule())
/**
* wait_var_event - wait for a variable to be updated and notified
@@ -306,6 +309,34 @@ do { \
__wait_var_event(var, condition); \
} while (0)
+/**
+ * wait_var_event_io - wait for a variable to be updated and notified
+ * @var: the address of variable being waited on
+ * @condition: the condition to wait for
+ *
+ * Wait for an IO related @condition to be true, only re-checking when a
+ * wake up is received for the given @var (an arbitrary kernel address
+ * which need not be directly related to the given condition, but
+ * usually is).
+ *
+ * The process will wait on a waitqueue selected by hash from a shared
+ * pool. It will only be woken on a wake_up for the given address.
+ *
+ * This is similar to wait_var_event(), but calls io_schedule() instead
+ * of schedule().
+ *
+ * The condition should normally use smp_load_acquire() or a similarly
+ * ordered access to ensure that any changes to memory made before the
+ * condition became true will be visible after the wait completes.
+ */
+#define wait_var_event_io(var, condition) \
+do { \
+ might_sleep(); \
+ if (condition) \
+ break; \
+ __wait_var_event_io(var, condition); \
+} while (0)
+
#define __wait_var_event_killable(var, condition) \
___wait_var_event(var, condition, TASK_KILLABLE, 0, 0, \
schedule())
--
2.46.0