blkcg: don't hold blkcg lock when deactivating policy

[mirror_ubuntu-bionic-kernel.git] / block / blk-mq-debugfs.c

diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index b56a4f35720d8a46e8a5daf3f2c63a51475308a3..54bd8c31b822d25e35c8807903bef9dffbf1277b 100644 (file)
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -703,7 +703,11 @@ static ssize_t blk_mq_debugfs_write(struct file *file, const char __user *buf,
        const struct blk_mq_debugfs_attr *attr = m->private;
        void *data = d_inode(file->f_path.dentry->d_parent)->i_private;
 
-       if (!attr->write)
+       /*
+        * Attributes that only implement .seq_ops are read-only and 'attr' is
+        * the same with 'data' in this case.
+        */
+       if (attr == data || !attr->write)
                return -EPERM;
 
        return attr->write(data, buf, count, ppos);