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authorIngo Molnar <mingo@elte.hu>2011-07-21 09:29:14 +0200
committerIngo Molnar <mingo@elte.hu>2011-07-21 09:29:21 +0200
commit492f73a303b488ffd67097b2351d54aa6e6c7c73 (patch)
tree6e6c16fbd628bb5eb577cfc70a488ca286563e58 /kernel/trace/trace_events.c
parente08fbb78f03fe2c4f88824faf6f51ce6af185e11 (diff)
parentf7bc8b61f65726ff98f52e286b28e294499d7a08 (diff)
Merge branch 'perf/urgent' into perf/core
Merge reason: pick up the latest fixes - they won't make v3.0. Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/trace/trace_events.c')
-rw-r--r--kernel/trace/trace_events.c113
1 files changed, 95 insertions, 18 deletions
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 4d7e1498ae9..581876f9f38 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -244,6 +244,35 @@ static void ftrace_clear_events(void)
mutex_unlock(&event_mutex);
}
+static void __put_system(struct event_subsystem *system)
+{
+ struct event_filter *filter = system->filter;
+
+ WARN_ON_ONCE(system->ref_count == 0);
+ if (--system->ref_count)
+ return;
+
+ if (filter) {
+ kfree(filter->filter_string);
+ kfree(filter);
+ }
+ kfree(system->name);
+ kfree(system);
+}
+
+static void __get_system(struct event_subsystem *system)
+{
+ WARN_ON_ONCE(system->ref_count == 0);
+ system->ref_count++;
+}
+
+static void put_system(struct event_subsystem *system)
+{
+ mutex_lock(&event_mutex);
+ __put_system(system);
+ mutex_unlock(&event_mutex);
+}
+
/*
* __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
*/
@@ -519,7 +548,7 @@ system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
loff_t *ppos)
{
const char set_to_char[4] = { '?', '0', '1', 'X' };
- const char *system = filp->private_data;
+ struct event_subsystem *system = filp->private_data;
struct ftrace_event_call *call;
char buf[2];
int set = 0;
@@ -530,7 +559,7 @@ system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
if (!call->name || !call->class || !call->class->reg)
continue;
- if (system && strcmp(call->class->system, system) != 0)
+ if (system && strcmp(call->class->system, system->name) != 0)
continue;
/*
@@ -560,7 +589,8 @@ static ssize_t
system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
loff_t *ppos)
{
- const char *system = filp->private_data;
+ struct event_subsystem *system = filp->private_data;
+ const char *name = NULL;
unsigned long val;
ssize_t ret;
@@ -575,7 +605,14 @@ system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
if (val != 0 && val != 1)
return -EINVAL;
- ret = __ftrace_set_clr_event(NULL, system, NULL, val);
+ /*
+ * Opening of "enable" adds a ref count to system,
+ * so the name is safe to use.
+ */
+ if (system)
+ name = system->name;
+
+ ret = __ftrace_set_clr_event(NULL, name, NULL, val);
if (ret)
goto out;
@@ -808,6 +845,52 @@ event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
return cnt;
}
+static LIST_HEAD(event_subsystems);
+
+static int subsystem_open(struct inode *inode, struct file *filp)
+{
+ struct event_subsystem *system = NULL;
+ int ret;
+
+ if (!inode->i_private)
+ goto skip_search;
+
+ /* Make sure the system still exists */
+ mutex_lock(&event_mutex);
+ list_for_each_entry(system, &event_subsystems, list) {
+ if (system == inode->i_private) {
+ /* Don't open systems with no events */
+ if (!system->nr_events) {
+ system = NULL;
+ break;
+ }
+ __get_system(system);
+ break;
+ }
+ }
+ mutex_unlock(&event_mutex);
+
+ if (system != inode->i_private)
+ return -ENODEV;
+
+ skip_search:
+ ret = tracing_open_generic(inode, filp);
+ if (ret < 0 && system)
+ put_system(system);
+
+ return ret;
+}
+
+static int subsystem_release(struct inode *inode, struct file *file)
+{
+ struct event_subsystem *system = inode->i_private;
+
+ if (system)
+ put_system(system);
+
+ return 0;
+}
+
static ssize_t
subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
loff_t *ppos)
@@ -945,17 +1028,19 @@ static const struct file_operations ftrace_event_filter_fops = {
};
static const struct file_operations ftrace_subsystem_filter_fops = {
- .open = tracing_open_generic,
+ .open = subsystem_open,
.read = subsystem_filter_read,
.write = subsystem_filter_write,
.llseek = default_llseek,
+ .release = subsystem_release,
};
static const struct file_operations ftrace_system_enable_fops = {
- .open = tracing_open_generic,
+ .open = subsystem_open,
.read = system_enable_read,
.write = system_enable_write,
.llseek = default_llseek,
+ .release = subsystem_release,
};
static const struct file_operations ftrace_show_header_fops = {
@@ -984,8 +1069,6 @@ static struct dentry *event_trace_events_dir(void)
return d_events;
}
-static LIST_HEAD(event_subsystems);
-
static struct dentry *
event_subsystem_dir(const char *name, struct dentry *d_events)
{
@@ -995,6 +1078,7 @@ event_subsystem_dir(const char *name, struct dentry *d_events)
/* First see if we did not already create this dir */
list_for_each_entry(system, &event_subsystems, list) {
if (strcmp(system->name, name) == 0) {
+ __get_system(system);
system->nr_events++;
return system->entry;
}
@@ -1017,6 +1101,7 @@ event_subsystem_dir(const char *name, struct dentry *d_events)
}
system->nr_events = 1;
+ system->ref_count = 1;
system->name = kstrdup(name, GFP_KERNEL);
if (!system->name) {
debugfs_remove(system->entry);
@@ -1044,8 +1129,7 @@ event_subsystem_dir(const char *name, struct dentry *d_events)
"'%s/filter' entry\n", name);
}
- trace_create_file("enable", 0644, system->entry,
- (void *)system->name,
+ trace_create_file("enable", 0644, system->entry, system,
&ftrace_system_enable_fops);
return system->entry;
@@ -1166,16 +1250,9 @@ static void remove_subsystem_dir(const char *name)
list_for_each_entry(system, &event_subsystems, list) {
if (strcmp(system->name, name) == 0) {
if (!--system->nr_events) {
- struct event_filter *filter = system->filter;
-
debugfs_remove_recursive(system->entry);
list_del(&system->list);
- if (filter) {
- kfree(filter->filter_string);
- kfree(filter);
- }
- kfree(system->name);
- kfree(system);
+ __put_system(system);
}
break;
}