From d5686b444ff3f72808d2b3fbd58672a86cdf38e7 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Fri, 1 Aug 2008 05:00:11 -0400
Subject: [PATCH] [PATCH] switch mtd and dm-table to lookup_bdev()

No need to open-code it...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 drivers/md/dm-table.c  | 29 ++++++-----------------------
 drivers/mtd/mtdsuper.c | 33 +++++++++++----------------------
 fs/block_dev.c         |  1 +
 3 files changed, 18 insertions(+), 45 deletions(-)

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 798e468103b..61f44140923 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -316,29 +316,12 @@ static inline int check_space(struct dm_table *t)
  */
 static int lookup_device(const char *path, dev_t *dev)
 {
-	int r;
-	struct nameidata nd;
-	struct inode *inode;
-
-	if ((r = path_lookup(path, LOOKUP_FOLLOW, &nd)))
-		return r;
-
-	inode = nd.path.dentry->d_inode;
-	if (!inode) {
-		r = -ENOENT;
-		goto out;
-	}
-
-	if (!S_ISBLK(inode->i_mode)) {
-		r = -ENOTBLK;
-		goto out;
-	}
-
-	*dev = inode->i_rdev;
-
- out:
-	path_put(&nd.path);
-	return r;
+	struct block_device *bdev = lookup_bdev(path);
+	if (IS_ERR(bdev))
+		return PTR_ERR(bdev);
+	*dev = bdev->bd_dev;
+	bdput(bdev);
+	return 0;
 }
 
 /*
diff --git a/drivers/mtd/mtdsuper.c b/drivers/mtd/mtdsuper.c
index 28cc6787a80..9b6af7e74a6 100644
--- a/drivers/mtd/mtdsuper.c
+++ b/drivers/mtd/mtdsuper.c
@@ -125,7 +125,7 @@ int get_sb_mtd(struct file_system_type *fs_type, int flags,
 	       int (*fill_super)(struct super_block *, void *, int),
 	       struct vfsmount *mnt)
 {
-	struct nameidata nd;
+	struct block_device *bdev;
 	int mtdnr, ret;
 
 	if (!dev_name)
@@ -181,29 +181,20 @@ int get_sb_mtd(struct file_system_type *fs_type, int flags,
 	/* try the old way - the hack where we allowed users to mount
 	 * /dev/mtdblock$(n) but didn't actually _use_ the blockdev
 	 */
-	ret = path_lookup(dev_name, LOOKUP_FOLLOW, &nd);
-
-	DEBUG(1, "MTDSB: path_lookup() returned %d, inode %p\n",
-	      ret, nd.path.dentry ? nd.path.dentry->d_inode : NULL);
-
-	if (ret)
+	bdev = lookup_bdev(dev_name);
+	if (IS_ERR(bdev)) {
+		ret = PTR_ERR(bdev);
+		DEBUG(1, "MTDSB: lookup_bdev() returned %d\n", ret);
 		return ret;
-
-	ret = -EINVAL;
-
-	if (!S_ISBLK(nd.path.dentry->d_inode->i_mode))
-		goto out;
-
-	if (nd.path.mnt->mnt_flags & MNT_NODEV) {
-		ret = -EACCES;
-		goto out;
 	}
+	DEBUG(1, "MTDSB: lookup_bdev() returned 0\n");
 
-	if (imajor(nd.path.dentry->d_inode) != MTD_BLOCK_MAJOR)
+	ret = -EINVAL;
+	if (MAJOR(bdev->bd_dev) != MTD_BLOCK_MAJOR)
 		goto not_an_MTD_device;
 
-	mtdnr = iminor(nd.path.dentry->d_inode);
-	path_put(&nd.path);
+	mtdnr = MINOR(bdev->bd_dev);
+	bdput(bdev);
 
 	return get_sb_mtd_nr(fs_type, flags, dev_name, data, mtdnr, fill_super,
 			     mnt);
@@ -213,10 +204,8 @@ not_an_MTD_device:
 		printk(KERN_NOTICE
 		       "MTD: Attempt to mount non-MTD device \"%s\"\n",
 		       dev_name);
-out:
-	path_put(&nd.path);
+	bdput(bdev);
 	return ret;
-
 }
 
 EXPORT_SYMBOL_GPL(get_sb_mtd);
diff --git a/fs/block_dev.c b/fs/block_dev.c
index e664b0b7048..aff54219e04 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1236,6 +1236,7 @@ fail:
 	bdev = ERR_PTR(error);
 	goto out;
 }
+EXPORT_SYMBOL(lookup_bdev);
 
 /**
  * open_bdev_excl  -  open a block device by name and set it up for use
-- 
2.41.0