UPSTREAM: binder: Make transaction_log available in binderfs

Currently, the binder transaction log files 'transaction_log'
and 'failed_transaction_log' live in debugfs at the following locations:

/sys/kernel/debug/binder/failed_transaction_log
/sys/kernel/debug/binder/transaction_log

This patch makes these files also available in a binderfs instance
mounted with the mount option "stats=global".
It does not affect the presence of these files in debugfs.
If a binderfs instance is mounted at path /dev/binderfs, the location of
these files will be as follows:

/dev/binderfs/binder_logs/failed_transaction_log
/dev/binderfs/binder_logs/transaction_log

This change provides an alternate option to access these files when
debugfs is not mounted.

Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Hridya Valsaraju <hridya@google.com>
Link: https://lore.kernel.org/r/20190903161655.107408-4-hridya@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Bug: 136497735
(cherry picked from commit c31e73121f4c1ec41143423ac6ce3ce6dafdcec1)
Change-Id: I20d9e6c4c7115297f9740cc42a516c315b3a209e
diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index f85cbd6..e3b5d61 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -201,30 +201,8 @@
 	atomic_inc(&binder_stats.obj_created[type]);
 }
 
-struct binder_transaction_log_entry {
-	int debug_id;
-	int debug_id_done;
-	int call_type;
-	int from_proc;
-	int from_thread;
-	int target_handle;
-	int to_proc;
-	int to_thread;
-	int to_node;
-	int data_size;
-	int offsets_size;
-	int return_error_line;
-	uint32_t return_error;
-	uint32_t return_error_param;
-	const char *context_name;
-};
-struct binder_transaction_log {
-	atomic_t cur;
-	bool full;
-	struct binder_transaction_log_entry entry[32];
-};
-static struct binder_transaction_log binder_transaction_log;
-static struct binder_transaction_log binder_transaction_log_failed;
+struct binder_transaction_log binder_transaction_log;
+struct binder_transaction_log binder_transaction_log_failed;
 
 static struct binder_transaction_log_entry *binder_transaction_log_add(
 	struct binder_transaction_log *log)
@@ -5993,7 +5971,7 @@
 			"\n" : " (incomplete)\n");
 }
 
-static int transaction_log_show(struct seq_file *m, void *unused)
+int binder_transaction_log_show(struct seq_file *m, void *unused)
 {
 	struct binder_transaction_log *log = m->private;
 	unsigned int log_cur = atomic_read(&log->cur);
@@ -6025,8 +6003,6 @@
 	.release = binder_release,
 };
 
-DEFINE_SHOW_ATTRIBUTE(transaction_log);
-
 static int __init init_binder_device(const char *name)
 {
 	int ret;
@@ -6095,12 +6071,12 @@
 				    0444,
 				    binder_debugfs_dir_entry_root,
 				    &binder_transaction_log,
-				    &transaction_log_fops);
+				    &binder_transaction_log_fops);
 		debugfs_create_file("failed_transaction_log",
 				    0444,
 				    binder_debugfs_dir_entry_root,
 				    &binder_transaction_log_failed,
-				    &transaction_log_fops);
+				    &binder_transaction_log_fops);
 	}
 
 	if (!IS_ENABLED(CONFIG_ANDROID_BINDERFS) &&