[PATCH v2 0/5] rv: Clean up & simplify

[PATCH v2 0/5] rv: Clean up & simplify

[Nam Cao]

Hi,

This series removes some redundant code and simply RV.

Changes in v2:
  - drop the "nop" reactor removal patch
  - clarify commit description of reference counter removal patch

Nam Cao (5):
  rv: Remove unused field in struct rv_monitor_def
  rv: Merge struct rv_monitor_def into struct rv_monitor
  rv: Merge struct rv_reactor_def into struct rv_reactor
  rv: Remove rv_reactor's reference counter
  rv: Remove struct rv_monitor::reacting

 include/linux/rv.h            |   8 ++
 kernel/trace/rv/rv.c          | 210 +++++++++++++++-------------------
 kernel/trace/rv/rv.h          |  39 +------
 kernel/trace/rv/rv_reactors.c | 132 +++++++--------------
 4 files changed, 149 insertions(+), 240 deletions(-)

-- 
2.39.5

[PATCH v2 1/5] rv: Remove unused field in struct rv_monitor_def

[Nam Cao]

rv_monitor_def::task_monitor is not used. Delete it.

Reviewed-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Nam Cao <namcao@linutronix.de>
---
 kernel/trace/rv/rv.h | 1 -
 1 file changed, 1 deletion(-)

diff --git a/kernel/trace/rv/rv.h b/kernel/trace/rv/rv.h
index 98fca0a1adbc..873364094402 100644
--- a/kernel/trace/rv/rv.h
+++ b/kernel/trace/rv/rv.h
@@ -41,7 +41,6 @@ struct rv_monitor_def {
 	struct rv_reactor_def	*rdef;
 	bool			reacting;
 #endif
-	bool			task_monitor;
 };
 
 struct dentry *get_monitors_root(void);
-- 
2.39.5

[PATCH v2 2/5] rv: Merge struct rv_monitor_def into struct rv_monitor

[Nam Cao]

Each struct rv_monitor has a unique struct rv_monitor_def associated with
it. struct rv_monitor is statically allocated, while struct rv_monitor_def
is dynamically allocated.

This makes the code more complicated than it should be:

  - Lookup is required to get the associated rv_monitor_def from rv_monitor

  - Dynamic memory allocation is required for rv_monitor_def. This is
    harder to get right compared to static memory. For instance, there is
    an existing mistake: rv_unregister_monitor() does not free the memory
    allocated by rv_register_monitor(). This is fortunately not a real
    memory leak problem, as rv_unregister_monitor() is never called.

Simplify and merge rv_monitor_def into rv_monitor.

Reviewed-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Nam Cao <namcao@linutronix.de>
---
 include/linux/rv.h            |   8 ++
 kernel/trace/rv/rv.c          | 211 +++++++++++++++-------------------
 kernel/trace/rv/rv.h          |  27 ++---
 kernel/trace/rv/rv_reactors.c |  62 +++++-----
 4 files changed, 140 insertions(+), 168 deletions(-)

diff --git a/include/linux/rv.h b/include/linux/rv.h
index 97baf58d88b2..dba53aecdfab 100644
--- a/include/linux/rv.h
+++ b/include/linux/rv.h
@@ -7,6 +7,9 @@
 #ifndef _LINUX_RV_H
 #define _LINUX_RV_H
 
+#include <linux/types.h>
+#include <linux/list.h>
+
 #define MAX_DA_NAME_LEN	32
 
 #ifdef CONFIG_RV
@@ -98,8 +101,13 @@ struct rv_monitor {
 	void			(*disable)(void);
 	void			(*reset)(void);
 #ifdef CONFIG_RV_REACTORS
+	struct rv_reactor_def	*rdef;
 	__printf(1, 2) void	(*react)(const char *msg, ...);
+	bool			reacting;
 #endif
+	struct list_head	list;
+	struct rv_monitor	*parent;
+	struct dentry		*root_d;
 };
 
 bool rv_monitoring_on(void);
diff --git a/kernel/trace/rv/rv.c b/kernel/trace/rv/rv.c
index 108429d16ec1..6c0be2fdc52d 100644
--- a/kernel/trace/rv/rv.c
+++ b/kernel/trace/rv/rv.c
@@ -210,9 +210,9 @@ void rv_put_task_monitor_slot(int slot)
  * Monitors with a parent are nested,
  * Monitors without a parent could be standalone or containers.
  */
-bool rv_is_nested_monitor(struct rv_monitor_def *mdef)
+bool rv_is_nested_monitor(struct rv_monitor *mon)
 {
-	return mdef->parent != NULL;
+	return mon->parent != NULL;
 }
 
 /*
@@ -223,16 +223,16 @@ bool rv_is_nested_monitor(struct rv_monitor_def *mdef)
  * for enable()/disable(). Use this condition to find empty containers.
  * Keep both conditions in case we have some non-compliant containers.
  */
-bool rv_is_container_monitor(struct rv_monitor_def *mdef)
+bool rv_is_container_monitor(struct rv_monitor *mon)
 {
-	struct rv_monitor_def *next;
+	struct rv_monitor *next;
 
-	if (list_is_last(&mdef->list, &rv_monitors_list))
+	if (list_is_last(&mon->list, &rv_monitors_list))
 		return false;
 
-	next = list_next_entry(mdef, list);
+	next = list_next_entry(mon, list);
 
-	return next->parent == mdef->monitor || !mdef->monitor->enable;
+	return next->parent == mon || !mon->enable;
 }
 
 /*
@@ -241,10 +241,10 @@ bool rv_is_container_monitor(struct rv_monitor_def *mdef)
 static ssize_t monitor_enable_read_data(struct file *filp, char __user *user_buf, size_t count,
 					loff_t *ppos)
 {
-	struct rv_monitor_def *mdef = filp->private_data;
+	struct rv_monitor *mon = filp->private_data;
 	const char *buff;
 
-	buff = mdef->monitor->enabled ? "1\n" : "0\n";
+	buff = mon->enabled ? "1\n" : "0\n";
 
 	return simple_read_from_buffer(user_buf, count, ppos, buff, strlen(buff)+1);
 }
@@ -252,14 +252,14 @@ static ssize_t monitor_enable_read_data(struct file *filp, char __user *user_buf
 /*
  * __rv_disable_monitor - disabled an enabled monitor
  */
-static int __rv_disable_monitor(struct rv_monitor_def *mdef, bool sync)
+static int __rv_disable_monitor(struct rv_monitor *mon, bool sync)
 {
 	lockdep_assert_held(&rv_interface_lock);
 
-	if (mdef->monitor->enabled) {
-		mdef->monitor->enabled = 0;
-		if (mdef->monitor->disable)
-			mdef->monitor->disable();
+	if (mon->enabled) {
+		mon->enabled = 0;
+		if (mon->disable)
+			mon->disable();
 
 		/*
 		 * Wait for the execution of all events to finish.
@@ -273,90 +273,90 @@ static int __rv_disable_monitor(struct rv_monitor_def *mdef, bool sync)
 	return 0;
 }
 
-static void rv_disable_single(struct rv_monitor_def *mdef)
+static void rv_disable_single(struct rv_monitor *mon)
 {
-	__rv_disable_monitor(mdef, true);
+	__rv_disable_monitor(mon, true);
 }
 
-static int rv_enable_single(struct rv_monitor_def *mdef)
+static int rv_enable_single(struct rv_monitor *mon)
 {
 	int retval;
 
 	lockdep_assert_held(&rv_interface_lock);
 
-	if (mdef->monitor->enabled)
+	if (mon->enabled)
 		return 0;
 
-	retval = mdef->monitor->enable();
+	retval = mon->enable();
 
 	if (!retval)
-		mdef->monitor->enabled = 1;
+		mon->enabled = 1;
 
 	return retval;
 }
 
-static void rv_disable_container(struct rv_monitor_def *mdef)
+static void rv_disable_container(struct rv_monitor *mon)
 {
-	struct rv_monitor_def *p = mdef;
+	struct rv_monitor *p = mon;
 	int enabled = 0;
 
 	list_for_each_entry_continue(p, &rv_monitors_list, list) {
-		if (p->parent != mdef->monitor)
+		if (p->parent != mon)
 			break;
 		enabled += __rv_disable_monitor(p, false);
 	}
 	if (enabled)
 		tracepoint_synchronize_unregister();
-	mdef->monitor->enabled = 0;
+	mon->enabled = 0;
 }
 
-static int rv_enable_container(struct rv_monitor_def *mdef)
+static int rv_enable_container(struct rv_monitor *mon)
 {
-	struct rv_monitor_def *p = mdef;
+	struct rv_monitor *p = mon;
 	int retval = 0;
 
 	list_for_each_entry_continue(p, &rv_monitors_list, list) {
-		if (retval || p->parent != mdef->monitor)
+		if (retval || p->parent != mon)
 			break;
 		retval = rv_enable_single(p);
 	}
 	if (retval)
-		rv_disable_container(mdef);
+		rv_disable_container(mon);
 	else
-		mdef->monitor->enabled = 1;
+		mon->enabled = 1;
 	return retval;
 }
 
 /**
  * rv_disable_monitor - disable a given runtime monitor
- * @mdef: Pointer to the monitor definition structure.
+ * @mon: Pointer to the monitor definition structure.
  *
  * Returns 0 on success.
  */
-int rv_disable_monitor(struct rv_monitor_def *mdef)
+int rv_disable_monitor(struct rv_monitor *mon)
 {
-	if (rv_is_container_monitor(mdef))
-		rv_disable_container(mdef);
+	if (rv_is_container_monitor(mon))
+		rv_disable_container(mon);
 	else
-		rv_disable_single(mdef);
+		rv_disable_single(mon);
 
 	return 0;
 }
 
 /**
  * rv_enable_monitor - enable a given runtime monitor
- * @mdef: Pointer to the monitor definition structure.
+ * @mon: Pointer to the monitor definition structure.
  *
  * Returns 0 on success, error otherwise.
  */
-int rv_enable_monitor(struct rv_monitor_def *mdef)
+int rv_enable_monitor(struct rv_monitor *mon)
 {
 	int retval;
 
-	if (rv_is_container_monitor(mdef))
-		retval = rv_enable_container(mdef);
+	if (rv_is_container_monitor(mon))
+		retval = rv_enable_container(mon);
 	else
-		retval = rv_enable_single(mdef);
+		retval = rv_enable_single(mon);
 
 	return retval;
 }
@@ -367,7 +367,7 @@ int rv_enable_monitor(struct rv_monitor_def *mdef)
 static ssize_t monitor_enable_write_data(struct file *filp, const char __user *user_buf,
 					 size_t count, loff_t *ppos)
 {
-	struct rv_monitor_def *mdef = filp->private_data;
+	struct rv_monitor *mon = filp->private_data;
 	int retval;
 	bool val;
 
@@ -378,9 +378,9 @@ static ssize_t monitor_enable_write_data(struct file *filp, const char __user *u
 	mutex_lock(&rv_interface_lock);
 
 	if (val)
-		retval = rv_enable_monitor(mdef);
+		retval = rv_enable_monitor(mon);
 	else
-		retval = rv_disable_monitor(mdef);
+		retval = rv_disable_monitor(mon);
 
 	mutex_unlock(&rv_interface_lock);
 
@@ -399,12 +399,12 @@ static const struct file_operations interface_enable_fops = {
 static ssize_t monitor_desc_read_data(struct file *filp, char __user *user_buf, size_t count,
 				      loff_t *ppos)
 {
-	struct rv_monitor_def *mdef = filp->private_data;
+	struct rv_monitor *mon = filp->private_data;
 	char buff[256];
 
 	memset(buff, 0, sizeof(buff));
 
-	snprintf(buff, sizeof(buff), "%s\n", mdef->monitor->description);
+	snprintf(buff, sizeof(buff), "%s\n", mon->description);
 
 	return simple_read_from_buffer(user_buf, count, ppos, buff, strlen(buff) + 1);
 }
@@ -419,37 +419,37 @@ static const struct file_operations interface_desc_fops = {
  * the monitor dir, where the specific options of the monitor
  * are exposed.
  */
-static int create_monitor_dir(struct rv_monitor_def *mdef, struct rv_monitor_def *parent)
+static int create_monitor_dir(struct rv_monitor *mon, struct rv_monitor *parent)
 {
 	struct dentry *root = parent ? parent->root_d : get_monitors_root();
-	const char *name = mdef->monitor->name;
+	const char *name = mon->name;
 	struct dentry *tmp;
 	int retval;
 
-	mdef->root_d = rv_create_dir(name, root);
-	if (!mdef->root_d)
+	mon->root_d = rv_create_dir(name, root);
+	if (!mon->root_d)
 		return -ENOMEM;
 
-	tmp = rv_create_file("enable", RV_MODE_WRITE, mdef->root_d, mdef, &interface_enable_fops);
+	tmp = rv_create_file("enable", RV_MODE_WRITE, mon->root_d, mon, &interface_enable_fops);
 	if (!tmp) {
 		retval = -ENOMEM;
 		goto out_remove_root;
 	}
 
-	tmp = rv_create_file("desc", RV_MODE_READ, mdef->root_d, mdef, &interface_desc_fops);
+	tmp = rv_create_file("desc", RV_MODE_READ, mon->root_d, mon, &interface_desc_fops);
 	if (!tmp) {
 		retval = -ENOMEM;
 		goto out_remove_root;
 	}
 
-	retval = reactor_populate_monitor(mdef);
+	retval = reactor_populate_monitor(mon);
 	if (retval)
 		goto out_remove_root;
 
 	return 0;
 
 out_remove_root:
-	rv_remove(mdef->root_d);
+	rv_remove(mon->root_d);
 	return retval;
 }
 
@@ -458,13 +458,12 @@ static int create_monitor_dir(struct rv_monitor_def *mdef, struct rv_monitor_def
  */
 static int monitors_show(struct seq_file *m, void *p)
 {
-	struct rv_monitor_def *mon_def = p;
+	struct rv_monitor *mon = p;
 
-	if (mon_def->parent)
-		seq_printf(m, "%s:%s\n", mon_def->parent->name,
-			   mon_def->monitor->name);
+	if (mon->parent)
+		seq_printf(m, "%s:%s\n", mon->parent->name, mon->name);
 	else
-		seq_printf(m, "%s\n", mon_def->monitor->name);
+		seq_printf(m, "%s\n", mon->name);
 	return 0;
 }
 
@@ -496,13 +495,13 @@ static void *available_monitors_next(struct seq_file *m, void *p, loff_t *pos)
  */
 static void *enabled_monitors_next(struct seq_file *m, void *p, loff_t *pos)
 {
-	struct rv_monitor_def *m_def = p;
+	struct rv_monitor *mon = p;
 
 	(*pos)++;
 
-	list_for_each_entry_continue(m_def, &rv_monitors_list, list) {
-		if (m_def->monitor->enabled)
-			return m_def;
+	list_for_each_entry_continue(mon, &rv_monitors_list, list) {
+		if (mon->enabled)
+			return mon;
 	}
 
 	return NULL;
@@ -510,7 +509,7 @@ static void *enabled_monitors_next(struct seq_file *m, void *p, loff_t *pos)
 
 static void *enabled_monitors_start(struct seq_file *m, loff_t *pos)
 {
-	struct rv_monitor_def *m_def;
+	struct rv_monitor *mon;
 	loff_t l;
 
 	mutex_lock(&rv_interface_lock);
@@ -518,15 +517,15 @@ static void *enabled_monitors_start(struct seq_file *m, loff_t *pos)
 	if (list_empty(&rv_monitors_list))
 		return NULL;
 
-	m_def = list_entry(&rv_monitors_list, struct rv_monitor_def, list);
+	mon = list_entry(&rv_monitors_list, struct rv_monitor, list);
 
 	for (l = 0; l <= *pos; ) {
-		m_def = enabled_monitors_next(m, m_def, &l);
-		if (!m_def)
+		mon = enabled_monitors_next(m, mon, &l);
+		if (!mon)
 			break;
 	}
 
-	return m_def;
+	return mon;
 }
 
 /*
@@ -566,13 +565,13 @@ static const struct file_operations available_monitors_ops = {
  */
 static void disable_all_monitors(void)
 {
-	struct rv_monitor_def *mdef;
+	struct rv_monitor *mon;
 	int enabled = 0;
 
 	mutex_lock(&rv_interface_lock);
 
-	list_for_each_entry(mdef, &rv_monitors_list, list)
-		enabled += __rv_disable_monitor(mdef, false);
+	list_for_each_entry(mon, &rv_monitors_list, list)
+		enabled += __rv_disable_monitor(mon, false);
 
 	if (enabled) {
 		/*
@@ -598,7 +597,7 @@ static ssize_t enabled_monitors_write(struct file *filp, const char __user *user
 				      size_t count, loff_t *ppos)
 {
 	char buff[MAX_RV_MONITOR_NAME_SIZE + 2];
-	struct rv_monitor_def *mdef;
+	struct rv_monitor *mon;
 	int retval = -EINVAL;
 	bool enable = true;
 	char *ptr, *tmp;
@@ -633,17 +632,17 @@ static ssize_t enabled_monitors_write(struct file *filp, const char __user *user
 	if (tmp)
 		ptr = tmp+1;
 
-	list_for_each_entry(mdef, &rv_monitors_list, list) {
-		if (strcmp(ptr, mdef->monitor->name) != 0)
+	list_for_each_entry(mon, &rv_monitors_list, list) {
+		if (strcmp(ptr, mon->name) != 0)
 			continue;
 
 		/*
 		 * Monitor found!
 		 */
 		if (enable)
-			retval = rv_enable_monitor(mdef);
+			retval = rv_enable_monitor(mon);
 		else
-			retval = rv_disable_monitor(mdef);
+			retval = rv_disable_monitor(mon);
 
 		if (!retval)
 			retval = count;
@@ -702,11 +701,11 @@ static void turn_monitoring_off(void)
 
 static void reset_all_monitors(void)
 {
-	struct rv_monitor_def *mdef;
+	struct rv_monitor *mon;
 
-	list_for_each_entry(mdef, &rv_monitors_list, list) {
-		if (mdef->monitor->enabled && mdef->monitor->reset)
-			mdef->monitor->reset();
+	list_for_each_entry(mon, &rv_monitors_list, list) {
+		if (mon->enabled && mon->reset)
+			mon->reset();
 	}
 }
 
@@ -768,10 +767,10 @@ static const struct file_operations monitoring_on_fops = {
 	.read   = monitoring_on_read_data,
 };
 
-static void destroy_monitor_dir(struct rv_monitor_def *mdef)
+static void destroy_monitor_dir(struct rv_monitor *mon)
 {
-	reactor_cleanup_monitor(mdef);
-	rv_remove(mdef->root_d);
+	reactor_cleanup_monitor(mon);
+	rv_remove(mon->root_d);
 }
 
 /**
@@ -783,7 +782,7 @@ static void destroy_monitor_dir(struct rv_monitor_def *mdef)
  */
 int rv_register_monitor(struct rv_monitor *monitor, struct rv_monitor *parent)
 {
-	struct rv_monitor_def *r, *p = NULL;
+	struct rv_monitor *r;
 	int retval = 0;
 
 	if (strlen(monitor->name) >= MAX_RV_MONITOR_NAME_SIZE) {
@@ -795,49 +794,31 @@ int rv_register_monitor(struct rv_monitor *monitor, struct rv_monitor *parent)
 	mutex_lock(&rv_interface_lock);
 
 	list_for_each_entry(r, &rv_monitors_list, list) {
-		if (strcmp(monitor->name, r->monitor->name) == 0) {
+		if (strcmp(monitor->name, r->name) == 0) {
 			pr_info("Monitor %s is already registered\n", monitor->name);
 			retval = -EEXIST;
 			goto out_unlock;
 		}
 	}
 
-	if (parent) {
-		list_for_each_entry(r, &rv_monitors_list, list) {
-			if (strcmp(parent->name, r->monitor->name) == 0) {
-				p = r;
-				break;
-			}
-		}
-	}
-
-	if (p && rv_is_nested_monitor(p)) {
+	if (parent && rv_is_nested_monitor(parent)) {
 		pr_info("Parent monitor %s is already nested, cannot nest further\n",
 			parent->name);
 		retval = -EINVAL;
 		goto out_unlock;
 	}
 
-	r = kzalloc(sizeof(struct rv_monitor_def), GFP_KERNEL);
-	if (!r) {
-		retval = -ENOMEM;
-		goto out_unlock;
-	}
-
-	r->monitor = monitor;
-	r->parent = parent;
+	monitor->parent = parent;
 
-	retval = create_monitor_dir(r, p);
-	if (retval) {
-		kfree(r);
-		goto out_unlock;
-	}
+	retval = create_monitor_dir(monitor, parent);
+	if (retval)
+		return retval;
 
 	/* keep children close to the parent for easier visualisation */
-	if (p)
-		list_add(&r->list, &p->list);
+	if (parent)
+		list_add(&monitor->list, &parent->list);
 	else
-		list_add_tail(&r->list, &rv_monitors_list);
+		list_add_tail(&monitor->list, &rv_monitors_list);
 
 out_unlock:
 	mutex_unlock(&rv_interface_lock);
@@ -852,17 +833,11 @@ int rv_register_monitor(struct rv_monitor *monitor, struct rv_monitor *parent)
  */
 int rv_unregister_monitor(struct rv_monitor *monitor)
 {
-	struct rv_monitor_def *ptr, *next;
-
 	mutex_lock(&rv_interface_lock);
 
-	list_for_each_entry_safe(ptr, next, &rv_monitors_list, list) {
-		if (strcmp(monitor->name, ptr->monitor->name) == 0) {
-			rv_disable_monitor(ptr);
-			list_del(&ptr->list);
-			destroy_monitor_dir(ptr);
-		}
-	}
+	rv_disable_monitor(monitor);
+	list_del(&monitor->list);
+	destroy_monitor_dir(monitor);
 
 	mutex_unlock(&rv_interface_lock);
 	return 0;
diff --git a/kernel/trace/rv/rv.h b/kernel/trace/rv/rv.h
index 873364094402..f039ec1c9156 100644
--- a/kernel/trace/rv/rv.h
+++ b/kernel/trace/rv/rv.h
@@ -32,34 +32,23 @@ struct rv_reactor_def {
 };
 #endif
 
-struct rv_monitor_def {
-	struct list_head	list;
-	struct rv_monitor	*monitor;
-	struct rv_monitor	*parent;
-	struct dentry		*root_d;
-#ifdef CONFIG_RV_REACTORS
-	struct rv_reactor_def	*rdef;
-	bool			reacting;
-#endif
-};
-
 struct dentry *get_monitors_root(void);
-int rv_disable_monitor(struct rv_monitor_def *mdef);
-int rv_enable_monitor(struct rv_monitor_def *mdef);
-bool rv_is_container_monitor(struct rv_monitor_def *mdef);
-bool rv_is_nested_monitor(struct rv_monitor_def *mdef);
+int rv_disable_monitor(struct rv_monitor *mon);
+int rv_enable_monitor(struct rv_monitor *mon);
+bool rv_is_container_monitor(struct rv_monitor *mon);
+bool rv_is_nested_monitor(struct rv_monitor *mon);
 
 #ifdef CONFIG_RV_REACTORS
-int reactor_populate_monitor(struct rv_monitor_def *mdef);
-void reactor_cleanup_monitor(struct rv_monitor_def *mdef);
+int reactor_populate_monitor(struct rv_monitor *mon);
+void reactor_cleanup_monitor(struct rv_monitor *mon);
 int init_rv_reactors(struct dentry *root_dir);
 #else
-static inline int reactor_populate_monitor(struct rv_monitor_def *mdef)
+static inline int reactor_populate_monitor(struct rv_monitor *mon)
 {
 	return 0;
 }
 
-static inline void reactor_cleanup_monitor(struct rv_monitor_def *mdef)
+static inline void reactor_cleanup_monitor(struct rv_monitor *mon)
 {
 	return;
 }
diff --git a/kernel/trace/rv/rv_reactors.c b/kernel/trace/rv/rv_reactors.c
index 740603670dd1..7cc620a1be1a 100644
--- a/kernel/trace/rv/rv_reactors.c
+++ b/kernel/trace/rv/rv_reactors.c
@@ -138,10 +138,10 @@ static const struct file_operations available_reactors_ops = {
  */
 static int monitor_reactor_show(struct seq_file *m, void *p)
 {
-	struct rv_monitor_def *mdef = m->private;
+	struct rv_monitor *mon = m->private;
 	struct rv_reactor_def *rdef = p;
 
-	if (mdef->rdef == rdef)
+	if (mon->rdef == rdef)
 		seq_printf(m, "[%s]\n", rdef->reactor->name);
 	else
 		seq_printf(m, "%s\n", rdef->reactor->name);
@@ -158,41 +158,41 @@ static const struct seq_operations monitor_reactors_seq_ops = {
 	.show	= monitor_reactor_show
 };
 
-static void monitor_swap_reactors_single(struct rv_monitor_def *mdef,
+static void monitor_swap_reactors_single(struct rv_monitor *mon,
 					 struct rv_reactor_def *rdef,
 					 bool reacting, bool nested)
 {
 	bool monitor_enabled;
 
 	/* nothing to do */
-	if (mdef->rdef == rdef)
+	if (mon->rdef == rdef)
 		return;
 
-	monitor_enabled = mdef->monitor->enabled;
+	monitor_enabled = mon->enabled;
 	if (monitor_enabled)
-		rv_disable_monitor(mdef);
+		rv_disable_monitor(mon);
 
 	/* swap reactor's usage */
-	mdef->rdef->counter--;
+	mon->rdef->counter--;
 	rdef->counter++;
 
-	mdef->rdef = rdef;
-	mdef->reacting = reacting;
-	mdef->monitor->react = rdef->reactor->react;
+	mon->rdef = rdef;
+	mon->reacting = reacting;
+	mon->react = rdef->reactor->react;
 
 	/* enable only once if iterating through a container */
 	if (monitor_enabled && !nested)
-		rv_enable_monitor(mdef);
+		rv_enable_monitor(mon);
 }
 
-static void monitor_swap_reactors(struct rv_monitor_def *mdef,
+static void monitor_swap_reactors(struct rv_monitor *mon,
 				  struct rv_reactor_def *rdef, bool reacting)
 {
-	struct rv_monitor_def *p = mdef;
+	struct rv_monitor *p = mon;
 
-	if (rv_is_container_monitor(mdef))
+	if (rv_is_container_monitor(mon))
 		list_for_each_entry_continue(p, &rv_monitors_list, list) {
-			if (p->parent != mdef->monitor)
+			if (p->parent != mon)
 				break;
 			monitor_swap_reactors_single(p, rdef, reacting, true);
 		}
@@ -202,7 +202,7 @@ static void monitor_swap_reactors(struct rv_monitor_def *mdef,
 	 * All nested monitors are enabled also if they were off, we may refine
 	 * this logic in the future.
 	 */
-	monitor_swap_reactors_single(mdef, rdef, reacting, false);
+	monitor_swap_reactors_single(mon, rdef, reacting, false);
 }
 
 static ssize_t
@@ -210,7 +210,7 @@ monitor_reactors_write(struct file *file, const char __user *user_buf,
 		      size_t count, loff_t *ppos)
 {
 	char buff[MAX_RV_REACTOR_NAME_SIZE + 2];
-	struct rv_monitor_def *mdef;
+	struct rv_monitor *mon;
 	struct rv_reactor_def *rdef;
 	struct seq_file *seq_f;
 	int retval = -EINVAL;
@@ -237,7 +237,7 @@ monitor_reactors_write(struct file *file, const char __user *user_buf,
 	 * See monitor_reactors_open()
 	 */
 	seq_f = file->private_data;
-	mdef = seq_f->private;
+	mon = seq_f->private;
 
 	mutex_lock(&rv_interface_lock);
 
@@ -252,7 +252,7 @@ monitor_reactors_write(struct file *file, const char __user *user_buf,
 		else
 			enable = true;
 
-		monitor_swap_reactors(mdef, rdef, enable);
+		monitor_swap_reactors(mon, rdef, enable);
 
 		retval = count;
 		break;
@@ -268,7 +268,7 @@ monitor_reactors_write(struct file *file, const char __user *user_buf,
  */
 static int monitor_reactors_open(struct inode *inode, struct file *file)
 {
-	struct rv_monitor_def *mdef = inode->i_private;
+	struct rv_monitor *mon = inode->i_private;
 	struct seq_file *seq_f;
 	int ret;
 
@@ -284,7 +284,7 @@ static int monitor_reactors_open(struct inode *inode, struct file *file)
 	/*
 	 * Copy the create file "private" data to the seq_file private data.
 	 */
-	seq_f->private = mdef;
+	seq_f->private = mon;
 
 	return 0;
 };
@@ -454,37 +454,37 @@ static const struct file_operations reacting_on_fops = {
 
 /**
  * reactor_populate_monitor - creates per monitor reactors file
- * @mdef:	monitor's definition.
+ * @mon:	The monitor.
  *
  * Returns 0 if successful, error otherwise.
  */
-int reactor_populate_monitor(struct rv_monitor_def *mdef)
+int reactor_populate_monitor(struct rv_monitor *mon)
 {
 	struct dentry *tmp;
 
-	tmp = rv_create_file("reactors", RV_MODE_WRITE, mdef->root_d, mdef, &monitor_reactors_ops);
+	tmp = rv_create_file("reactors", RV_MODE_WRITE, mon->root_d, mon, &monitor_reactors_ops);
 	if (!tmp)
 		return -ENOMEM;
 
 	/*
 	 * Configure as the rv_nop reactor.
 	 */
-	mdef->rdef = get_reactor_rdef_by_name("nop");
-	mdef->rdef->counter++;
-	mdef->reacting = false;
+	mon->rdef = get_reactor_rdef_by_name("nop");
+	mon->rdef->counter++;
+	mon->reacting = false;
 
 	return 0;
 }
 
 /**
  * reactor_cleanup_monitor - cleanup a monitor reference
- * @mdef:       monitor's definition.
+ * @mon:       the monitor.
  */
-void reactor_cleanup_monitor(struct rv_monitor_def *mdef)
+void reactor_cleanup_monitor(struct rv_monitor *mon)
 {
 	lockdep_assert_held(&rv_interface_lock);
-	mdef->rdef->counter--;
-	WARN_ON_ONCE(mdef->rdef->counter < 0);
+	mon->rdef->counter--;
+	WARN_ON_ONCE(mon->rdef->counter < 0);
 }
 
 /*
-- 
2.39.5

[PATCH v2 3/5] rv: Merge struct rv_reactor_def into struct rv_reactor

[Nam Cao]

Each struct rv_reactor has a unique struct rv_reactor_def associated with
it. struct rv_reactor is statically allocated, while struct rv_reactor_def
is dynamically allocated.

This makes the code more complicated than it should be:

  - Lookup is required to get the associated rv_reactor_def from rv_reactor

  - Dynamic memory allocation is required for rv_reactor_def. This is
    harder to get right compared to static memory. For instance, there is
    an existing mistake: rv_unregister_reactor() does not free the memory
    allocated by rv_register_reactor(). This is fortunately not a real
    memory leak problem as rv_unregister_reactor() is never called.

Simplify and merge rv_reactor_def into rv_reactor.

Reviewed-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Nam Cao <namcao@linutronix.de>
---
 include/linux/rv.h            |  5 +-
 kernel/trace/rv/rv.h          |  9 ----
 kernel/trace/rv/rv_reactors.c | 92 +++++++++++++++--------------------
 3 files changed, 43 insertions(+), 63 deletions(-)

diff --git a/include/linux/rv.h b/include/linux/rv.h
index dba53aecdfab..c22c9b8c1567 100644
--- a/include/linux/rv.h
+++ b/include/linux/rv.h
@@ -90,6 +90,9 @@ struct rv_reactor {
 	const char		*name;
 	const char		*description;
 	__printf(1, 2) void	(*react)(const char *msg, ...);
+	struct list_head	list;
+	/* protected by the monitor interface lock */
+	int			counter;
 };
 #endif
 
@@ -101,7 +104,7 @@ struct rv_monitor {
 	void			(*disable)(void);
 	void			(*reset)(void);
 #ifdef CONFIG_RV_REACTORS
-	struct rv_reactor_def	*rdef;
+	struct rv_reactor	*reactor;
 	__printf(1, 2) void	(*react)(const char *msg, ...);
 	bool			reacting;
 #endif
diff --git a/kernel/trace/rv/rv.h b/kernel/trace/rv/rv.h
index f039ec1c9156..8c38f9dd41bc 100644
--- a/kernel/trace/rv/rv.h
+++ b/kernel/trace/rv/rv.h
@@ -23,15 +23,6 @@ struct rv_interface {
 extern struct mutex rv_interface_lock;
 extern struct list_head rv_monitors_list;
 
-#ifdef CONFIG_RV_REACTORS
-struct rv_reactor_def {
-	struct list_head	list;
-	struct rv_reactor	*reactor;
-	/* protected by the monitor interface lock */
-	int			counter;
-};
-#endif
-
 struct dentry *get_monitors_root(void);
 int rv_disable_monitor(struct rv_monitor *mon);
 int rv_enable_monitor(struct rv_monitor *mon);
diff --git a/kernel/trace/rv/rv_reactors.c b/kernel/trace/rv/rv_reactors.c
index 7cc620a1be1a..2c7909e6d0e7 100644
--- a/kernel/trace/rv/rv_reactors.c
+++ b/kernel/trace/rv/rv_reactors.c
@@ -70,12 +70,12 @@
  */
 static LIST_HEAD(rv_reactors_list);
 
-static struct rv_reactor_def *get_reactor_rdef_by_name(char *name)
+static struct rv_reactor *get_reactor_rdef_by_name(char *name)
 {
-	struct rv_reactor_def *r;
+	struct rv_reactor *r;
 
 	list_for_each_entry(r, &rv_reactors_list, list) {
-		if (strcmp(name, r->reactor->name) == 0)
+		if (strcmp(name, r->name) == 0)
 			return r;
 	}
 	return NULL;
@@ -86,9 +86,9 @@ static struct rv_reactor_def *get_reactor_rdef_by_name(char *name)
  */
 static int reactors_show(struct seq_file *m, void *p)
 {
-	struct rv_reactor_def *rea_def = p;
+	struct rv_reactor *reactor = p;
 
-	seq_printf(m, "%s\n", rea_def->reactor->name);
+	seq_printf(m, "%s\n", reactor->name);
 	return 0;
 }
 
@@ -139,12 +139,12 @@ static const struct file_operations available_reactors_ops = {
 static int monitor_reactor_show(struct seq_file *m, void *p)
 {
 	struct rv_monitor *mon = m->private;
-	struct rv_reactor_def *rdef = p;
+	struct rv_reactor *reactor = p;
 
-	if (mon->rdef == rdef)
-		seq_printf(m, "[%s]\n", rdef->reactor->name);
+	if (mon->reactor == reactor)
+		seq_printf(m, "[%s]\n", reactor->name);
 	else
-		seq_printf(m, "%s\n", rdef->reactor->name);
+		seq_printf(m, "%s\n", reactor->name);
 	return 0;
 }
 
@@ -159,13 +159,13 @@ static const struct seq_operations monitor_reactors_seq_ops = {
 };
 
 static void monitor_swap_reactors_single(struct rv_monitor *mon,
-					 struct rv_reactor_def *rdef,
+					 struct rv_reactor *reactor,
 					 bool reacting, bool nested)
 {
 	bool monitor_enabled;
 
 	/* nothing to do */
-	if (mon->rdef == rdef)
+	if (mon->reactor == reactor)
 		return;
 
 	monitor_enabled = mon->enabled;
@@ -173,12 +173,12 @@ static void monitor_swap_reactors_single(struct rv_monitor *mon,
 		rv_disable_monitor(mon);
 
 	/* swap reactor's usage */
-	mon->rdef->counter--;
-	rdef->counter++;
+	mon->reactor->counter--;
+	reactor->counter++;
 
-	mon->rdef = rdef;
+	mon->reactor = reactor;
 	mon->reacting = reacting;
-	mon->react = rdef->reactor->react;
+	mon->react = reactor->react;
 
 	/* enable only once if iterating through a container */
 	if (monitor_enabled && !nested)
@@ -186,7 +186,7 @@ static void monitor_swap_reactors_single(struct rv_monitor *mon,
 }
 
 static void monitor_swap_reactors(struct rv_monitor *mon,
-				  struct rv_reactor_def *rdef, bool reacting)
+				  struct rv_reactor *reactor, bool reacting)
 {
 	struct rv_monitor *p = mon;
 
@@ -194,7 +194,7 @@ static void monitor_swap_reactors(struct rv_monitor *mon,
 		list_for_each_entry_continue(p, &rv_monitors_list, list) {
 			if (p->parent != mon)
 				break;
-			monitor_swap_reactors_single(p, rdef, reacting, true);
+			monitor_swap_reactors_single(p, reactor, reacting, true);
 		}
 	/*
 	 * This call enables and disables the monitor if they were active.
@@ -202,7 +202,7 @@ static void monitor_swap_reactors(struct rv_monitor *mon,
 	 * All nested monitors are enabled also if they were off, we may refine
 	 * this logic in the future.
 	 */
-	monitor_swap_reactors_single(mon, rdef, reacting, false);
+	monitor_swap_reactors_single(mon, reactor, reacting, false);
 }
 
 static ssize_t
@@ -211,7 +211,7 @@ monitor_reactors_write(struct file *file, const char __user *user_buf,
 {
 	char buff[MAX_RV_REACTOR_NAME_SIZE + 2];
 	struct rv_monitor *mon;
-	struct rv_reactor_def *rdef;
+	struct rv_reactor *reactor;
 	struct seq_file *seq_f;
 	int retval = -EINVAL;
 	bool enable;
@@ -243,16 +243,16 @@ monitor_reactors_write(struct file *file, const char __user *user_buf,
 
 	retval = -EINVAL;
 
-	list_for_each_entry(rdef, &rv_reactors_list, list) {
-		if (strcmp(ptr, rdef->reactor->name) != 0)
+	list_for_each_entry(reactor, &rv_reactors_list, list) {
+		if (strcmp(ptr, reactor->name) != 0)
 			continue;
 
-		if (rdef == get_reactor_rdef_by_name("nop"))
+		if (strcmp(reactor->name, "nop"))
 			enable = false;
 		else
 			enable = true;
 
-		monitor_swap_reactors(mon, rdef, enable);
+		monitor_swap_reactors(mon, reactor, enable);
 
 		retval = count;
 		break;
@@ -299,23 +299,16 @@ static const struct file_operations monitor_reactors_ops = {
 
 static int __rv_register_reactor(struct rv_reactor *reactor)
 {
-	struct rv_reactor_def *r;
+	struct rv_reactor *r;
 
 	list_for_each_entry(r, &rv_reactors_list, list) {
-		if (strcmp(reactor->name, r->reactor->name) == 0) {
+		if (strcmp(reactor->name, r->name) == 0) {
 			pr_info("Reactor %s is already registered\n", reactor->name);
 			return -EINVAL;
 		}
 	}
 
-	r = kzalloc(sizeof(struct rv_reactor_def), GFP_KERNEL);
-	if (!r)
-		return -ENOMEM;
-
-	r->reactor = reactor;
-	r->counter = 0;
-
-	list_add_tail(&r->list, &rv_reactors_list);
+	list_add_tail(&reactor->list, &rv_reactors_list);
 
 	return 0;
 }
@@ -350,26 +343,19 @@ int rv_register_reactor(struct rv_reactor *reactor)
  */
 int rv_unregister_reactor(struct rv_reactor *reactor)
 {
-	struct rv_reactor_def *ptr, *next;
 	int ret = 0;
 
 	mutex_lock(&rv_interface_lock);
 
-	list_for_each_entry_safe(ptr, next, &rv_reactors_list, list) {
-		if (strcmp(reactor->name, ptr->reactor->name) == 0) {
-
-			if (!ptr->counter) {
-				list_del(&ptr->list);
-			} else {
-				printk(KERN_WARNING
-				       "rv: the rv_reactor %s is in use by %d monitor(s)\n",
-				       ptr->reactor->name, ptr->counter);
-				printk(KERN_WARNING "rv: the rv_reactor %s cannot be removed\n",
-				       ptr->reactor->name);
-				ret = -EBUSY;
-				break;
-			}
-		}
+	if (!reactor->counter) {
+		list_del(&reactor->list);
+	} else {
+		printk(KERN_WARNING
+		       "rv: the rv_reactor %s is in use by %d monitor(s)\n",
+		       reactor->name, reactor->counter);
+		printk(KERN_WARNING "rv: the rv_reactor %s cannot be removed\n",
+		       reactor->name);
+		ret = -EBUSY;
 	}
 
 	mutex_unlock(&rv_interface_lock);
@@ -469,8 +455,8 @@ int reactor_populate_monitor(struct rv_monitor *mon)
 	/*
 	 * Configure as the rv_nop reactor.
 	 */
-	mon->rdef = get_reactor_rdef_by_name("nop");
-	mon->rdef->counter++;
+	mon->reactor = get_reactor_rdef_by_name("nop");
+	mon->reactor->counter++;
 	mon->reacting = false;
 
 	return 0;
@@ -483,8 +469,8 @@ int reactor_populate_monitor(struct rv_monitor *mon)
 void reactor_cleanup_monitor(struct rv_monitor *mon)
 {
 	lockdep_assert_held(&rv_interface_lock);
-	mon->rdef->counter--;
-	WARN_ON_ONCE(mon->rdef->counter < 0);
+	mon->reactor->counter--;
+	WARN_ON_ONCE(mon->reactor->counter < 0);
 }
 
 /*
-- 
2.39.5

[PATCH v2 4/5] rv: Remove rv_reactor's reference counter

[Nam Cao]

rv_reactor has a reference counter to ensure it is not removed while
monitors are still using it.

However, this is futile, as __exit functions are not expected to fail and
will proceed normally despite rv_unregister_reactor() returning an error.

At the moment, reactors do not support being built as modules, therefore
they are never removed and the reference counters are not necessary.

If we support building RV reactors as modules in the future, kernel
module's centralized facilities such as try_module_get(), module_put() or
MODULE_SOFTDEP should be used instead of this custom implementation.

Remove this reference counter.

Reviewed-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Nam Cao <namcao@linutronix.de>
---
 include/linux/rv.h            |  2 --
 kernel/trace/rv/rv.c          |  1 -
 kernel/trace/rv/rv.h          |  6 ------
 kernel/trace/rv/rv_reactors.c | 33 ++-------------------------------
 4 files changed, 2 insertions(+), 40 deletions(-)

diff --git a/include/linux/rv.h b/include/linux/rv.h
index c22c9b8c1567..2f867d6f72ba 100644
--- a/include/linux/rv.h
+++ b/include/linux/rv.h
@@ -91,8 +91,6 @@ struct rv_reactor {
 	const char		*description;
 	__printf(1, 2) void	(*react)(const char *msg, ...);
 	struct list_head	list;
-	/* protected by the monitor interface lock */
-	int			counter;
 };
 #endif
 
diff --git a/kernel/trace/rv/rv.c b/kernel/trace/rv/rv.c
index 6c0be2fdc52d..6c8498743b98 100644
--- a/kernel/trace/rv/rv.c
+++ b/kernel/trace/rv/rv.c
@@ -769,7 +769,6 @@ static const struct file_operations monitoring_on_fops = {
 
 static void destroy_monitor_dir(struct rv_monitor *mon)
 {
-	reactor_cleanup_monitor(mon);
 	rv_remove(mon->root_d);
 }
 
diff --git a/kernel/trace/rv/rv.h b/kernel/trace/rv/rv.h
index 8c38f9dd41bc..1485a70c1bf4 100644
--- a/kernel/trace/rv/rv.h
+++ b/kernel/trace/rv/rv.h
@@ -31,7 +31,6 @@ bool rv_is_nested_monitor(struct rv_monitor *mon);
 
 #ifdef CONFIG_RV_REACTORS
 int reactor_populate_monitor(struct rv_monitor *mon);
-void reactor_cleanup_monitor(struct rv_monitor *mon);
 int init_rv_reactors(struct dentry *root_dir);
 #else
 static inline int reactor_populate_monitor(struct rv_monitor *mon)
@@ -39,11 +38,6 @@ static inline int reactor_populate_monitor(struct rv_monitor *mon)
 	return 0;
 }
 
-static inline void reactor_cleanup_monitor(struct rv_monitor *mon)
-{
-	return;
-}
-
 static inline int init_rv_reactors(struct dentry *root_dir)
 {
 	return 0;
diff --git a/kernel/trace/rv/rv_reactors.c b/kernel/trace/rv/rv_reactors.c
index 2c7909e6d0e7..a8e849e6cd85 100644
--- a/kernel/trace/rv/rv_reactors.c
+++ b/kernel/trace/rv/rv_reactors.c
@@ -172,10 +172,6 @@ static void monitor_swap_reactors_single(struct rv_monitor *mon,
 	if (monitor_enabled)
 		rv_disable_monitor(mon);
 
-	/* swap reactor's usage */
-	mon->reactor->counter--;
-	reactor->counter++;
-
 	mon->reactor = reactor;
 	mon->reacting = reacting;
 	mon->react = reactor->react;
@@ -343,23 +339,10 @@ int rv_register_reactor(struct rv_reactor *reactor)
  */
 int rv_unregister_reactor(struct rv_reactor *reactor)
 {
-	int ret = 0;
-
 	mutex_lock(&rv_interface_lock);
-
-	if (!reactor->counter) {
-		list_del(&reactor->list);
-	} else {
-		printk(KERN_WARNING
-		       "rv: the rv_reactor %s is in use by %d monitor(s)\n",
-		       reactor->name, reactor->counter);
-		printk(KERN_WARNING "rv: the rv_reactor %s cannot be removed\n",
-		       reactor->name);
-		ret = -EBUSY;
-	}
-
+	list_del(&reactor->list);
 	mutex_unlock(&rv_interface_lock);
-	return ret;
+	return 0;
 }
 
 /*
@@ -456,23 +439,11 @@ int reactor_populate_monitor(struct rv_monitor *mon)
 	 * Configure as the rv_nop reactor.
 	 */
 	mon->reactor = get_reactor_rdef_by_name("nop");
-	mon->reactor->counter++;
 	mon->reacting = false;
 
 	return 0;
 }
 
-/**
- * reactor_cleanup_monitor - cleanup a monitor reference
- * @mon:       the monitor.
- */
-void reactor_cleanup_monitor(struct rv_monitor *mon)
-{
-	lockdep_assert_held(&rv_interface_lock);
-	mon->reactor->counter--;
-	WARN_ON_ONCE(mon->reactor->counter < 0);
-}
-
 /*
  * Nop reactor register
  */
-- 
2.39.5

[PATCH v2 5/5] rv: Remove struct rv_monitor::reacting

[Nam Cao]

The field 'reacting' in struct rv_monitor is set but never used. Delete it.

Reviewed-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Nam Cao <namcao@linutronix.de>
---
 include/linux/rv.h            |  1 -
 kernel/trace/rv/rv_reactors.c | 13 +++++--------
 2 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/include/linux/rv.h b/include/linux/rv.h
index 2f867d6f72ba..80731242fe60 100644
--- a/include/linux/rv.h
+++ b/include/linux/rv.h
@@ -104,7 +104,6 @@ struct rv_monitor {
 #ifdef CONFIG_RV_REACTORS
 	struct rv_reactor	*reactor;
 	__printf(1, 2) void	(*react)(const char *msg, ...);
-	bool			reacting;
 #endif
 	struct list_head	list;
 	struct rv_monitor	*parent;
diff --git a/kernel/trace/rv/rv_reactors.c b/kernel/trace/rv/rv_reactors.c
index a8e849e6cd85..5e52886b4511 100644
--- a/kernel/trace/rv/rv_reactors.c
+++ b/kernel/trace/rv/rv_reactors.c
@@ -160,7 +160,7 @@ static const struct seq_operations monitor_reactors_seq_ops = {
 
 static void monitor_swap_reactors_single(struct rv_monitor *mon,
 					 struct rv_reactor *reactor,
-					 bool reacting, bool nested)
+					 bool nested)
 {
 	bool monitor_enabled;
 
@@ -173,7 +173,6 @@ static void monitor_swap_reactors_single(struct rv_monitor *mon,
 		rv_disable_monitor(mon);
 
 	mon->reactor = reactor;
-	mon->reacting = reacting;
 	mon->react = reactor->react;
 
 	/* enable only once if iterating through a container */
@@ -181,8 +180,7 @@ static void monitor_swap_reactors_single(struct rv_monitor *mon,
 		rv_enable_monitor(mon);
 }
 
-static void monitor_swap_reactors(struct rv_monitor *mon,
-				  struct rv_reactor *reactor, bool reacting)
+static void monitor_swap_reactors(struct rv_monitor *mon, struct rv_reactor *reactor)
 {
 	struct rv_monitor *p = mon;
 
@@ -190,7 +188,7 @@ static void monitor_swap_reactors(struct rv_monitor *mon,
 		list_for_each_entry_continue(p, &rv_monitors_list, list) {
 			if (p->parent != mon)
 				break;
-			monitor_swap_reactors_single(p, reactor, reacting, true);
+			monitor_swap_reactors_single(p, reactor, true);
 		}
 	/*
 	 * This call enables and disables the monitor if they were active.
@@ -198,7 +196,7 @@ static void monitor_swap_reactors(struct rv_monitor *mon,
 	 * All nested monitors are enabled also if they were off, we may refine
 	 * this logic in the future.
 	 */
-	monitor_swap_reactors_single(mon, reactor, reacting, false);
+	monitor_swap_reactors_single(mon, reactor, false);
 }
 
 static ssize_t
@@ -248,7 +246,7 @@ monitor_reactors_write(struct file *file, const char __user *user_buf,
 		else
 			enable = true;
 
-		monitor_swap_reactors(mon, reactor, enable);
+		monitor_swap_reactors(mon, reactor);
 
 		retval = count;
 		break;
@@ -439,7 +437,6 @@ int reactor_populate_monitor(struct rv_monitor *mon)
 	 * Configure as the rv_nop reactor.
 	 */
 	mon->reactor = get_reactor_rdef_by_name("nop");
-	mon->reacting = false;
 
 	return 0;
 }
-- 
2.39.5

Re: [PATCH v2 5/5] rv: Remove struct rv_monitor::reacting

[kernel test robot]

Hi Nam,

kernel test robot noticed the following build warnings:

[auto build test WARNING on trace/for-next]
[also build test WARNING on next-20250723]
[cannot apply to linus/master v6.16-rc7]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Nam-Cao/rv-Remove-unused-field-in-struct-rv_monitor_def/20250723-144825
base:   https://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace for-next
patch link:    https://lore.kernel.org/r/58c63faec76ffb36552fcd1fdcc4b9dd841efd94.1753252872.git.namcao%40linutronix.de
patch subject: [PATCH v2 5/5] rv: Remove struct rv_monitor::reacting
config: arc-randconfig-002-20250724 (https://download.01.org/0day-ci/archive/20250724/202507241015.Qun68uPH-lkp@intel.com/config)
compiler: arc-linux-gcc (GCC) 15.1.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250724/202507241015.Qun68uPH-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202507241015.Qun68uPH-lkp@intel.com/

All warnings (new ones prefixed by >>):

   kernel/trace/rv/rv_reactors.c: In function 'monitor_reactors_write':
>> kernel/trace/rv/rv_reactors.c:211:14: warning: variable 'enable' set but not used [-Wunused-but-set-variable]
     211 |         bool enable;
         |              ^~~~~~


vim +/enable +211 kernel/trace/rv/rv_reactors.c

cb85c660fcd4b3a Gabriele Monaco            2025-03-05  201  
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  202  static ssize_t
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  203  monitor_reactors_write(struct file *file, const char __user *user_buf,
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  204  		      size_t count, loff_t *ppos)
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  205  {
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  206  	char buff[MAX_RV_REACTOR_NAME_SIZE + 2];
98b2531fbe93031 Nam Cao                    2025-07-23  207  	struct rv_monitor *mon;
aef8790cfb7b07f Nam Cao                    2025-07-23  208  	struct rv_reactor *reactor;
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  209  	struct seq_file *seq_f;
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  210  	int retval = -EINVAL;
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29 @211  	bool enable;
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  212  	char *ptr;
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  213  	int len;
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  214  
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  215  	if (count < 1 || count > MAX_RV_REACTOR_NAME_SIZE + 1)
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  216  		return -EINVAL;
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  217  
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  218  	memset(buff, 0, sizeof(buff));
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  219  
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  220  	retval = simple_write_to_buffer(buff, sizeof(buff) - 1, ppos, user_buf, count);
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  221  	if (retval < 0)
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  222  		return -EFAULT;
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  223  
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  224  	ptr = strim(buff);
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  225  
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  226  	len = strlen(ptr);
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  227  	if (!len)
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  228  		return count;
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  229  
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  230  	/*
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  231  	 * See monitor_reactors_open()
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  232  	 */
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  233  	seq_f = file->private_data;
98b2531fbe93031 Nam Cao                    2025-07-23  234  	mon = seq_f->private;
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  235  
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  236  	mutex_lock(&rv_interface_lock);
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  237  
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  238  	retval = -EINVAL;
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  239  
aef8790cfb7b07f Nam Cao                    2025-07-23  240  	list_for_each_entry(reactor, &rv_reactors_list, list) {
aef8790cfb7b07f Nam Cao                    2025-07-23  241  		if (strcmp(ptr, reactor->name) != 0)
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  242  			continue;
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  243  
aef8790cfb7b07f Nam Cao                    2025-07-23  244  		if (strcmp(reactor->name, "nop"))
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  245  			enable = false;
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  246  		else
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  247  			enable = true;
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  248  
a96356e99938184 Nam Cao                    2025-07-23  249  		monitor_swap_reactors(mon, reactor);
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  250  
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  251  		retval = count;
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  252  		break;
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  253  	}
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  254  
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  255  	mutex_unlock(&rv_interface_lock);
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  256  
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  257  	return retval;
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  258  }
04acadcb4453cf8 Daniel Bristot de Oliveira 2022-07-29  259  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki