[PATCH v19 21/40] dept: make dept able to work with an external wgen

@@ -129,6 +129,13 @@ struct dept_wait_hist {
 	unsigned int			ctxt_id;
 };
 
+/*
+ * for subsystems that requires compact use of memory e.g. struct page
+ */
+struct dept_ext_wgen {
+	unsigned int wgen;
+};
+
 void dept_on(void);
 void dept_off(void);
 void dept_init(void);

@@ -138,6 +145,7 @@ void dept_free_range(void *start, unsigned int sz);
 
 void dept_map_init(struct dept_map *m, struct dept_key *k, int sub_u, const char *n);
 void dept_map_reinit(struct dept_map *m, struct dept_key *k, int sub_u, const char *n);
+void dept_ext_wgen_init(struct dept_ext_wgen *ewg);
 void dept_map_copy(struct dept_map *to, struct dept_map *from);
 void dept_wait(struct dept_map *m, unsigned long w_f, unsigned long ip, const char *w_fn, int sub_l, long timeout);
 void dept_stage_wait(struct dept_map *m, struct dept_key *k, unsigned long ip, const char *w_fn, long timeout);

@@ -146,8 +154,8 @@ void dept_clean_stage(void);
 void dept_ttwu_stage_wait(struct task_struct *t, unsigned long ip);
 void dept_ecxt_enter(struct dept_map *m, unsigned long e_f, unsigned long ip, const char *c_fn, const char *e_fn, int sub_l);
 bool dept_ecxt_holding(struct dept_map *m, unsigned long e_f);
-void dept_request_event(struct dept_map *m);
-void dept_event(struct dept_map *m, unsigned long e_f, unsigned long ip, const char *e_fn);
+void dept_request_event(struct dept_map *m, struct dept_ext_wgen *ewg);
+void dept_event(struct dept_map *m, unsigned long e_f, unsigned long ip, const char *e_fn, struct dept_ext_wgen *ewg);
 void dept_ecxt_exit(struct dept_map *m, unsigned long e_f, unsigned long ip);
 void dept_sched_enter(void);
 void dept_sched_exit(void);

@@ -174,6 +182,7 @@ void dept_hardirqs_off(void);
 #else /* !CONFIG_DEPT */
 struct dept_key { };
 struct dept_map { };
+struct dept_ext_wgen { };
 
 #define DEPT_MAP_INITIALIZER(n, k) { }
 

@@ -186,6 +195,7 @@ struct dept_map { };
 
 #define dept_map_init(m, k, su, n)			do { (void)(n); (void)(k); } while (0)
 #define dept_map_reinit(m, k, su, n)			do { (void)(n); (void)(k); } while (0)
+#define dept_ext_wgen_init(wg)				do { } while (0)
 #define dept_map_copy(t, f)				do { } while (0)
 #define dept_wait(m, w_f, ip, w_fn, sl, t)		do { (void)(w_fn); } while (0)
 #define dept_stage_wait(m, k, ip, w_fn, t)		do { (void)(k); (void)(w_fn); } while (0)

@@ -194,8 +204,8 @@ struct dept_map { };
 #define dept_ttwu_stage_wait(t, ip)			do { } while (0)
 #define dept_ecxt_enter(m, e_f, ip, c_fn, e_fn, sl)	do { (void)(c_fn); (void)(e_fn); } while (0)
 #define dept_ecxt_holding(m, e_f)			false
-#define dept_request_event(m)				do { } while (0)
-#define dept_event(m, e_f, ip, e_fn)			do { (void)(e_fn); } while (0)
+#define dept_request_event(m, wg)			do { } while (0)
+#define dept_event(m, e_f, ip, e_fn, wg)		do { (void)(e_fn); } while (0)
 #define dept_ecxt_exit(m, e_f, ip)			do { } while (0)
 #define dept_sched_enter()				do { } while (0)
 #define dept_sched_exit()				do { } while (0)

@@ -25,7 +25,7 @@
 
 #define sdt_wait_timeout(m, t)						\
 	do {								\
-		dept_request_event(m);					\
+		dept_request_event(m, NULL);				\
 		dept_wait(m, 1UL, _THIS_IP_, __func__, 0, t);		\
 	} while (0)
 #define sdt_wait(m) sdt_wait_timeout(m, -1L)

@@ -49,9 +49,9 @@
 #define sdt_might_sleep_end()		dept_clean_stage()
 
 #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_, __func__)
+#define sdt_event(m)			dept_event(m, 1UL, _THIS_IP_, __func__, NULL)
 #define sdt_ecxt_exit(m)		dept_ecxt_exit(m, 1UL, _THIS_IP_)
-#define sdt_request_event(m)		dept_request_event(m)
+#define sdt_request_event(m)		dept_request_event(m, NULL)
 #else /* !CONFIG_DEPT */
 #define sdt_map_init(m)			do { } while (0)
 #define sdt_map_init_key(m, k)		do { (void)(k); } while (0)

@@ -2172,6 +2172,11 @@ void dept_map_reinit(struct dept_map *m, struct dept_key *k, int sub_u,
 }
 EXPORT_SYMBOL_GPL(dept_map_reinit);
 
+void dept_ext_wgen_init(struct dept_ext_wgen *ewg)
+{
+	ewg->wgen = 0U;
+}
+
 void dept_map_copy(struct dept_map *to, struct dept_map *from)
 {
 	if (unlikely(!dept_working())) {

@@ -2355,7 +2360,7 @@ static void __dept_wait(struct dept_map *m, unsigned long w_f,
  */
 static void __dept_event(struct dept_map *m, struct dept_map *real_m,
 		unsigned long e_f, unsigned long ip, const char *e_fn,
-		bool sched_map)
+		bool sched_map, unsigned int wg)
 {
 	struct dept_class *c;
 	struct dept_key *k;

@@ -2377,7 +2382,7 @@ static void __dept_event(struct dept_map *m, struct dept_map *real_m,
 	c = check_new_class(&m->map_key, k, sub_id(m, e), m->name, sched_map);
 
 	if (c)
-		do_event(m, real_m, c, READ_ONCE(m->wgen), ip, e_fn);
+		do_event(m, real_m, c, wg, ip, e_fn);
 }
 
 void dept_wait(struct dept_map *m, unsigned long w_f,

@@ -2602,7 +2607,7 @@ void dept_ttwu_stage_wait(struct task_struct *requestor, unsigned long ip)
 	if (!m.keys)
 		goto exit;
 
-	__dept_event(&m, real_m, 1UL, ip, "try_to_wake_up", sched_map);
+	__dept_event(&m, real_m, 1UL, ip, "try_to_wake_up", sched_map, m.wgen);
 exit:
 	dept_exit(flags);
 }

@@ -2781,10 +2786,11 @@ bool dept_ecxt_holding(struct dept_map *m, unsigned long e_f)
 }
 EXPORT_SYMBOL_GPL(dept_ecxt_holding);
 
-void dept_request_event(struct dept_map *m)
+void dept_request_event(struct dept_map *m, struct dept_ext_wgen *ewg)
 {
 	unsigned long flags;
 	unsigned int wg;
+	unsigned int *wg_p;
 
 	if (unlikely(!dept_working()))
 		return;

@@ -2797,18 +2803,22 @@ void dept_request_event(struct dept_map *m)
 	 */
 	flags = dept_enter_recursive();
 
+	wg_p = ewg ? &ewg->wgen : &m->wgen;
+
 	wg = next_wgen();
-	WRITE_ONCE(m->wgen, wg);
+	WRITE_ONCE(*wg_p, wg);
 
 	dept_exit_recursive(flags);
 }
 EXPORT_SYMBOL_GPL(dept_request_event);
 
 void dept_event(struct dept_map *m, unsigned long e_f,
-		unsigned long ip, const char *e_fn)
+		unsigned long ip, const char *e_fn,
+		struct dept_ext_wgen *ewg)
 {
 	struct dept_task *dt = dept_task();
 	unsigned long flags;
+	unsigned int *wg_p;
 
 	if (unlikely(!dept_working()))
 		return;

@@ -2816,24 +2826,26 @@ void dept_event(struct dept_map *m, unsigned long e_f,
 	if (m->nocheck)
 		return;
 
+	wg_p = ewg ? &ewg->wgen : &m->wgen;
+
 	if (dt->recursive) {
 		/*
 		 * Dept won't work with this even though an event
 		 * context has been asked. Don't make it confused at
 		 * handling the event. Disable it until the next.
 		 */
-		WRITE_ONCE(m->wgen, 0U);
+		WRITE_ONCE(*wg_p, 0U);
 		return;
 	}
 
 	flags = dept_enter();
 
-	__dept_event(m, m, e_f, ip, e_fn, false);
+	__dept_event(m, m, e_f, ip, e_fn, false, READ_ONCE(*wg_p));
 
 	/*
 	 * Keep the map diabled until the next sleep.
 	 */
-	WRITE_ONCE(m->wgen, 0U);
+	WRITE_ONCE(*wg_p, 0U);
 
 	dept_exit(flags);
 }