Now that Dept has already been applied to major synchronization
machanisms e.g. spinlock, wait_for_completion and the like, we can take
advantage of Dept by default if CONFIG_DEPT is on.

However, sometimes we need to manually tag wait/event on places where
Dept hasn't been applied. SDT(Single-event Dependency Tracker) would be
useful in that case to tag those. The usage is like:

1. Initialize dmap in the instance associated to the wait/event.

        sdt_map_init(dmap);

2. Add the following just before the wait.

        sdt_wait(dmap);

3. Add the following just before the event.

        sdt_event(dmap);

For better reference of SDT APIs, separated the APIs from dept.h.

Signed-off-by: Byungchul Park <[email protected]>
---
 include/linux/dept.h     | 36 --------------------------------
 include/linux/dept_sdt.h | 53 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+), 36 deletions(-)
 create mode 100644 include/linux/dept_sdt.h

diff --git a/include/linux/dept.h b/include/linux/dept.h
index 5a726bf..10ef7fc 100644
--- a/include/linux/dept.h
+++ b/include/linux/dept.h
@@ -504,32 +504,6 @@ struct dept_map_common {
  */
 extern void dept_key_init(struct dept_key *k);
 extern void dept_key_destroy(struct dept_key *k);
-
-#define DEPT_SDT_MAP_INIT(dname)       { .name = #dname }
-#define DEFINE_DEPT_SDT(x)             \
-       struct dept_map x = DEPT_SDT_MAP_INIT(x)
-
-/*
- * SDT(Single-event Dependency Tracker) APIs
- *
- * In case that one dept_map instance maps to a single event, SDT APIs
- * can be used.
- */
-#define sdt_map_init(m)                                                        
\
-       do {                                                            \
-               static struct dept_key __key;                           \
-               dept_map_init(m, &__key, 0, #m);                        \
-       } while (0)
-#define sdt_map_init_key(m, k)         dept_map_init(m, k, 0, #m)
-
-#define sdt_wait(m)                                                    \
-       do {                                                            \
-               dept_asked_event(m);                                    \
-               dept_wait(m, 1UL, _THIS_IP_, "wait", 0);                \
-       } while (0)
-#define sdt_ecxt_enter(m)              dept_ecxt_enter(m, 1UL, _THIS_IP_, 
"start", "event", 0)
-#define sdt_event(m)                   dept_event(m, 1UL, _THIS_IP_, "event")
-#define sdt_ecxt_exit(m)               dept_ecxt_exit(m, _THIS_IP_)
 #else /* !CONFIG_DEPT */
 struct dept_task { };
 struct dept_key  { };
@@ -563,15 +537,5 @@ struct dept_map_common {
 #define dept_asked_event_split_map(me, mc)             do { } while (0)
 #define dept_key_init(k)                               do { (void)(k); } while 
(0)
 #define dept_key_destroy(k)                            do { (void)(k); } while 
(0)
-
-#define DEPT_SDT_MAP_INIT(dname)
-#define DEFINE_DEPT_SDT(x)
-
-#define sdt_map_init(m)                                        do { } while (0)
-#define sdt_map_init_key(m, k)                         do { (void)(k); } while 
(0)
-#define sdt_wait(m)                                    do { } while (0)
-#define sdt_ecxt_enter(m)                              do { } while (0)
-#define sdt_event(m)                                   do { } while (0)
-#define sdt_ecxt_exit(m)                               do { } while (0)
 #endif
 #endif /* __LINUX_DEPT_H */
diff --git a/include/linux/dept_sdt.h b/include/linux/dept_sdt.h
new file mode 100644
index 0000000..32a4a9e
--- /dev/null
+++ b/include/linux/dept_sdt.h
@@ -0,0 +1,53 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Dept Single-event Dependency Tracker
+ *
+ * Started by Byungchul Park <[email protected]>:
+ *
+ *  Copyright (c) 2020 LG Electronics, Inc., Byungchul Park
+ */
+
+#ifndef __LINUX_DEPT_SDT_H
+#define __LINUX_DEPT_SDT_H
+
+#ifdef CONFIG_DEPT
+
+#include <linux/dept.h>
+
+#define DEPT_SDT_MAP_INIT(dname)       { .name = #dname }
+#define DEFINE_DEPT_SDT(x)             \
+       struct dept_map x = DEPT_SDT_MAP_INIT(x)
+
+/*
+ * SDT(Single-event Dependency Tracker) APIs
+ *
+ * In case that one dept_map instance maps to a single event, SDT APIs
+ * can be used.
+ */
+#define sdt_map_init(m)                                                        
\
+       do {                                                            \
+               static struct dept_key __key;                           \
+               dept_map_init(m, &__key, 0, #m);                        \
+       } while (0)
+#define sdt_map_init_key(m, k)         dept_map_init(m, k, 0, #m)
+
+#define sdt_wait(m)                                                    \
+       do {                                                            \
+               dept_asked_event(m);                                    \
+               dept_wait(m, 1UL, _THIS_IP_, "wait", 0);                \
+       } while (0)
+#define sdt_ecxt_enter(m)              dept_ecxt_enter(m, 1UL, _THIS_IP_, 
"start", "event", 0)
+#define sdt_event(m)                   dept_event(m, 1UL, _THIS_IP_, "event")
+#define sdt_ecxt_exit(m)               dept_ecxt_exit(m, _THIS_IP_)
+#else /* !CONFIG_DEPT */
+#define DEPT_SDT_MAP_INIT(dname)
+#define DEFINE_DEPT_SDT(x)
+
+#define sdt_map_init(m)                                        do { } while (0)
+#define sdt_map_init_key(m, k)                         do { (void)(k); } while 
(0)
+#define sdt_wait(m)                                    do { } while (0)
+#define sdt_ecxt_enter(m)                              do { } while (0)
+#define sdt_event(m)                                   do { } while (0)
+#define sdt_ecxt_exit(m)                               do { } while (0)
+#endif
+#endif /* __LINUX_DEPT_SDT_H */
-- 
1.9.1

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