[RFC PATCH v3 01/10] rcuwait: Split type definition to its own header

[Valentin Schneider]

A later commit will add a struct irq_work member to struct task_struct, which
would require <linux/sched.h> to include the definition of struct
irq_work.

Thanks to header dependency hell, incudling <linux/irq_work.h> in <linux/sched.h>
results in defining inline helpers using not-yet-defined fields (mm_struct,
task_struct, various task states...).

Break off the definition of struct rcuwait into its own header file.

Signed-off-by: Valentin Schneider <vschneid@xxxxxxxxxx>
---
 include/linux/rcuwait.h       |  9 ++-------
 include/linux/rcuwait_types.h | 16 ++++++++++++++++
 2 files changed, 18 insertions(+), 7 deletions(-)
 create mode 100644 include/linux/rcuwait_types.h

diff --git a/include/linux/rcuwait.h b/include/linux/rcuwait.h
index 27343424225cf..1f1ca7d38cdf8 100644
--- a/include/linux/rcuwait.h
+++ b/include/linux/rcuwait.h
@@ -5,17 +5,12 @@
 #include <linux/rcupdate.h>
 #include <linux/sched/signal.h>
 
+#include <linux/rcuwait_types.h>
+
 /*
  * rcuwait provides a way of blocking and waking up a single
  * task in an rcu-safe manner.
- *
- * The only time @task is non-nil is when a user is blocked (or
- * checking if it needs to) on a condition, and reset as soon as we
- * know that the condition has succeeded and are awoken.
  */
-struct rcuwait {
-	struct task_struct __rcu *task;
-};
 
 #define __RCUWAIT_INITIALIZER(name)		\
 	{ .task = NULL, }
diff --git a/include/linux/rcuwait_types.h b/include/linux/rcuwait_types.h
new file mode 100644
index 0000000000000..60a4385a2c368
--- /dev/null
+++ b/include/linux/rcuwait_types.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_RCUWAIT_TYPES_H_
+#define _LINUX_RCUWAIT_TYPES_H_
+
+#include <linux/sched.h>
+
+/*
+ * The only time @task is non-nil is when a user is blocked (or
+ * checking if it needs to) on a condition, and reset as soon as we
+ * know that the condition has succeeded and are awoken.
+ */
+struct rcuwait {
+	struct task_struct __rcu *task;
+};
+
+#endif
-- 
2.43.0