Merge branch 'debugfs_automount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs into trace/ftrace/tracefs

Pull in Al Viro's changes to debugfs that implement the new primitive:
debugfs_create_automount(), that creates a directory in debugfs that will
safely mount another file system automatically when debugfs is mounted.

This will let tracefs automount itself on top of debugfs/tracing directory.

4 files changed, 102 insertions, 25 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 80c9d34..45e5cb1 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2497,12 +2497,14 @@ static void ftrace_run_update_code(int command)
 }
 
 static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
-				   struct ftrace_hash *old_hash)
+				   struct ftrace_ops_hash *old_hash)
 {
 	ops->flags |= FTRACE_OPS_FL_MODIFYING;
-	ops->old_hash.filter_hash = old_hash;
+	ops->old_hash.filter_hash = old_hash->filter_hash;
+	ops->old_hash.notrace_hash = old_hash->notrace_hash;
 	ftrace_run_update_code(command);
 	ops->old_hash.filter_hash = NULL;
+	ops->old_hash.notrace_hash = NULL;
 	ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
 }
 
@@ -3579,7 +3581,7 @@ static struct ftrace_ops trace_probe_ops __read_mostly =
 
 static int ftrace_probe_registered;
 
-static void __enable_ftrace_function_probe(struct ftrace_hash *old_hash)
+static void __enable_ftrace_function_probe(struct ftrace_ops_hash *old_hash)
 {
 	int ret;
 	int i;
@@ -3637,6 +3639,7 @@ int
 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 			      void *data)
 {
+	struct ftrace_ops_hash old_hash_ops;
 	struct ftrace_func_probe *entry;
 	struct ftrace_hash **orig_hash = &trace_probe_ops.func_hash->filter_hash;
 	struct ftrace_hash *old_hash = *orig_hash;
@@ -3658,6 +3661,10 @@ register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 
 	mutex_lock(&trace_probe_ops.func_hash->regex_lock);
 
+	old_hash_ops.filter_hash = old_hash;
+	/* Probes only have filters */
+	old_hash_ops.notrace_hash = NULL;
+
 	hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
 	if (!hash) {
 		count = -ENOMEM;
@@ -3718,7 +3725,7 @@ register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 
 	ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
 
-	__enable_ftrace_function_probe(old_hash);
+	__enable_ftrace_function_probe(&old_hash_ops);
 
 	if (!ret)
 		free_ftrace_hash_rcu(old_hash);
@@ -4006,10 +4013,34 @@ ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
 }
 
 static void ftrace_ops_update_code(struct ftrace_ops *ops,
-				   struct ftrace_hash *old_hash)
+				   struct ftrace_ops_hash *old_hash)
 {
-	if (ops->flags & FTRACE_OPS_FL_ENABLED && ftrace_enabled)
+	struct ftrace_ops *op;
+
+	if (!ftrace_enabled)
+		return;
+
+	if (ops->flags & FTRACE_OPS_FL_ENABLED) {
 		ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
+		return;
+	}
+
+	/*
+	 * If this is the shared global_ops filter, then we need to
+	 * check if there is another ops that shares it, is enabled.
+	 * If so, we still need to run the modify code.
+	 */
+	if (ops->func_hash != &global_ops.local_hash)
+		return;
+
+	do_for_each_ftrace_op(op, ftrace_ops_list) {
+		if (op->func_hash == &global_ops.local_hash &&
+		    op->flags & FTRACE_OPS_FL_ENABLED) {
+			ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
+			/* Only need to do this once */
+			return;
+		}
+	} while_for_each_ftrace_op(op);
 }
 
 static int
@@ -4017,6 +4048,7 @@ ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
 		unsigned long ip, int remove, int reset, int enable)
 {
 	struct ftrace_hash **orig_hash;
+	struct ftrace_ops_hash old_hash_ops;
 	struct ftrace_hash *old_hash;
 	struct ftrace_hash *hash;
 	int ret;
@@ -4053,9 +4085,11 @@ ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
 
 	mutex_lock(&ftrace_lock);
 	old_hash = *orig_hash;
+	old_hash_ops.filter_hash = ops->func_hash->filter_hash;
+	old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
 	ret = ftrace_hash_move(ops, enable, orig_hash, hash);
 	if (!ret) {
-		ftrace_ops_update_code(ops, old_hash);
+		ftrace_ops_update_code(ops, &old_hash_ops);
 		free_ftrace_hash_rcu(old_hash);
 	}
 	mutex_unlock(&ftrace_lock);
@@ -4267,6 +4301,7 @@ static void __init set_ftrace_early_filters(void)
 int ftrace_regex_release(struct inode *inode, struct file *file)
 {
 	struct seq_file *m = (struct seq_file *)file->private_data;
+	struct ftrace_ops_hash old_hash_ops;
 	struct ftrace_iterator *iter;
 	struct ftrace_hash **orig_hash;
 	struct ftrace_hash *old_hash;
@@ -4300,10 +4335,12 @@ int ftrace_regex_release(struct inode *inode, struct file *file)
 
 		mutex_lock(&ftrace_lock);
 		old_hash = *orig_hash;
+		old_hash_ops.filter_hash = iter->ops->func_hash->filter_hash;
+		old_hash_ops.notrace_hash = iter->ops->func_hash->notrace_hash;
 		ret = ftrace_hash_move(iter->ops, filter_hash,
 				       orig_hash, iter->hash);
 		if (!ret) {
-			ftrace_ops_update_code(iter->ops, old_hash);
+			ftrace_ops_update_code(iter->ops, &old_hash_ops);
 			free_ftrace_hash_rcu(old_hash);
 		}
 		mutex_unlock(&ftrace_lock);
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 5afce60..38c613e 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -6888,7 +6888,6 @@ void __init trace_init(void)
 			tracepoint_printk = 0;
 	}
 	tracer_alloc_buffers();
-	init_ftrace_syscalls();
 	trace_event_init();	
 }
 
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 4ff8c13..db54dda 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -2429,12 +2429,39 @@ static __init int event_trace_memsetup(void)
 	return 0;
 }
 
+static __init void
+early_enable_events(struct trace_array *tr, bool disable_first)
+{
+	char *buf = bootup_event_buf;
+	char *token;
+	int ret;
+
+	while (true) {
+		token = strsep(&buf, ",");
+
+		if (!token)
+			break;
+		if (!*token)
+			continue;
+
+		/* Restarting syscalls requires that we stop them first */
+		if (disable_first)
+			ftrace_set_clr_event(tr, token, 0);
+
+		ret = ftrace_set_clr_event(tr, token, 1);
+		if (ret)
+			pr_warn("Failed to enable trace event: %s\n", token);
+
+		/* Put back the comma to allow this to be called again */
+		if (buf)
+			*(buf - 1) = ',';
+	}
+}
+
 static __init int event_trace_enable(void)
 {
 	struct trace_array *tr = top_trace_array();
 	struct ftrace_event_call **iter, *call;
-	char *buf = bootup_event_buf;
-	char *token;
 	int ret;
 
 	if (!tr)
@@ -2456,18 +2483,7 @@ static __init int event_trace_enable(void)
 	 */
 	__trace_early_add_events(tr);
 
-	while (true) {
-		token = strsep(&buf, ",");
-
-		if (!token)
-			break;
-		if (!*token)
-			continue;
-
-		ret = ftrace_set_clr_event(tr, token, 1);
-		if (ret)
-			pr_warn("Failed to enable trace event: %s\n", token);
-	}
+	early_enable_events(tr, false);
 
 	trace_printk_start_comm();
 
@@ -2478,6 +2494,31 @@ static __init int event_trace_enable(void)
 	return 0;
 }
 
+/*
+ * event_trace_enable() is called from trace_event_init() first to
+ * initialize events and perhaps start any events that are on the
+ * command line. Unfortunately, there are some events that will not
+ * start this early, like the system call tracepoints that need
+ * to set the TIF_SYSCALL_TRACEPOINT flag of pid 1. But event_trace_enable()
+ * is called before pid 1 starts, and this flag is never set, making
+ * the syscall tracepoint never get reached, but the event is enabled
+ * regardless (and not doing anything).
+ */
+static __init int event_trace_enable_again(void)
+{
+	struct trace_array *tr;
+
+	tr = top_trace_array();
+	if (!tr)
+		return -ENODEV;
+
+	early_enable_events(tr, true);
+
+	return 0;
+}
+
+early_initcall(event_trace_enable_again);
+
 static __init int event_trace_init(void)
 {
 	struct trace_array *tr;
diff --git a/kernel/trace/trace_kdb.c b/kernel/trace/trace_kdb.c
index b0b1c44..3ccf5c2 100644
--- a/kernel/trace/trace_kdb.c
+++ b/kernel/trace/trace_kdb.c
@@ -132,8 +132,8 @@ static int kdb_ftdump(int argc, const char **argv)
 
 static __init int kdb_ftrace_register(void)
 {
-	kdb_register_repeat("ftdump", kdb_ftdump, "[skip_#lines] [cpu]",
-			    "Dump ftrace log", 0, KDB_REPEAT_NONE);
+	kdb_register_flags("ftdump", kdb_ftdump, "[skip_#lines] [cpu]",
+			    "Dump ftrace log", 0, KDB_ENABLE_ALWAYS_SAFE);
 	return 0;
 }