Merge branches 'for-4.11/upstream-fixes', 'for-4.12/accutouch', 'for-4.12/cp2112...

[mirror_ubuntu-artful-kernel.git] / kernel / trace / blktrace.c

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index e33050e3ea1c32a9496c4e9317f9ac4d53f89817..b2058a7f94bd8797f5629158aeed8bf045c20e4f 100644 (file)
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -28,6 +28,8 @@
 #include <linux/uaccess.h>
 #include <linux/list.h>
 
+#include "../../block/blk.h"
+
 #include <trace/events/block.h>
 
 #include "trace_output.h"
@@ -292,9 +294,6 @@ record_it:
        local_irq_restore(flags);
 }
 
-static struct dentry *blk_tree_root;
-static DEFINE_MUTEX(blk_tree_mutex);
-
 static void blk_trace_free(struct blk_trace *bt)
 {
        debugfs_remove(bt->msg_file);
@@ -433,9 +432,9 @@ static void blk_trace_setup_lba(struct blk_trace *bt,
 /*
  * Setup everything required to start tracing
  */
-int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
-                      struct block_device *bdev,
-                      struct blk_user_trace_setup *buts)
+static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
+                             struct block_device *bdev,
+                             struct blk_user_trace_setup *buts)
 {
        struct blk_trace *bt = NULL;
        struct dentry *dir = NULL;
@@ -468,22 +467,15 @@ int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
 
        ret = -ENOENT;
 
-       mutex_lock(&blk_tree_mutex);
-       if (!blk_tree_root) {
-               blk_tree_root = debugfs_create_dir("block", NULL);
-               if (!blk_tree_root) {
-                       mutex_unlock(&blk_tree_mutex);
-                       goto err;
-               }
-       }
-       mutex_unlock(&blk_tree_mutex);
-
-       dir = debugfs_create_dir(buts->name, blk_tree_root);
+       if (!blk_debugfs_root)
+               goto err;
 
+       dir = debugfs_lookup(buts->name, blk_debugfs_root);
+       if (!dir)
+               bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);
        if (!dir)
                goto err;
 
-       bt->dir = dir;
        bt->dev = dev;
        atomic_set(&bt->dropped, 0);
        INIT_LIST_HEAD(&bt->running_list);
@@ -525,9 +517,12 @@ int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
        if (atomic_inc_return(&blk_probes_ref) == 1)
                blk_register_tracepoints();
 
-       return 0;
+       ret = 0;
 err:
-       blk_trace_free(bt);
+       if (dir && !bt->dir)
+               dput(dir);
+       if (ret)
+               blk_trace_free(bt);
        return ret;
 }