[PATCH] bdev: bd_acquire() cleanup

From: viro@parcelfarce.linux.theplanet.co.uk <viro@parcelfarce.linux.theplanet.co.uk>

bd_acquire() made static, switched to returning the block_device it had
found.  Callers updated.

fs/block_dev.c

@@ -387,26 +387,27 @@ void bdput(struct block_device *bdev)
 
 EXPORT_SYMBOL(bdput);
  
-int bd_acquire(struct inode *inode)
+static struct block_device *bd_acquire(struct inode *inode)
 {
 	struct block_device *bdev;
 	spin_lock(&bdev_lock);
-	if (inode->i_bdev && igrab(inode->i_bdev->bd_inode)) {
+	bdev = inode->i_bdev;
+	if (bdev && igrab(bdev->bd_inode)) {
 		spin_unlock(&bdev_lock);
-		return 0;
+		return bdev;
 	}
 	spin_unlock(&bdev_lock);
 	bdev = bdget(inode->i_rdev);
-	if (!bdev)
-		return -ENOMEM;
-	spin_lock(&bdev_lock);
-	if (inode->i_bdev)
-		__bd_forget(inode);
-	inode->i_bdev = bdev;
-	inode->i_mapping = bdev->bd_inode->i_mapping;
-	list_add(&inode->i_devices, &bdev->bd_inodes);
-	spin_unlock(&bdev_lock);
-	return 0;
+	if (bdev) {
+		spin_lock(&bdev_lock);
+		if (inode->i_bdev)
+			__bd_forget(inode);
+		inode->i_bdev = bdev;
+		inode->i_mapping = bdev->bd_inode->i_mapping;
+		list_add(&inode->i_devices, &bdev->bd_inodes);
+		spin_unlock(&bdev_lock);
+	}
+	return bdev;
 }
 
 /* Call when you free inode */
@@ -666,8 +667,7 @@ int blkdev_open(struct inode * inode, struct file * filp)
 	 */
 	filp->f_flags |= O_LARGEFILE;
 
-	bd_acquire(inode);
-	bdev = inode->i_bdev;
+	bdev = bd_acquire(inode);
 
 	res = do_open(bdev, filp);
 	if (res)
@@ -829,11 +829,10 @@ struct block_device *lookup_bdev(const char *path)
 	error = -EACCES;
 	if (nd.mnt->mnt_flags & MNT_NODEV)
 		goto fail;
-	error = bd_acquire(inode);
-	if (error)
+	error = -ENOMEM;
+	bdev = bd_acquire(inode);
+	if (!bdev)
 		goto fail;
-	bdev = inode->i_bdev;
-
 out:
 	path_release(&nd);
 	return bdev;

fs/devfs/base.c

@@ -1955,15 +1955,9 @@ static int devfs_notify_change (struct dentry *dentry, struct iattr *iattr)
     return 0;
 }   /*  End Function devfs_notify_change  */
 
-static void devfs_clear_inode (struct inode *inode)
-{
-    if ( S_ISBLK (inode->i_mode) ) bdput (inode->i_bdev);
-}   /*  End Function devfs_clear_inode  */
-
 static struct super_operations devfs_sops =
 { 
     .drop_inode    = generic_delete_inode,
-    .clear_inode   = devfs_clear_inode,
     .statfs        = simple_statfs,
 };
 
@@ -2015,11 +2009,7 @@ static struct inode *_devfs_get_vfs_inode (struct super_block *sb,
 	inode->i_rdev = de->u.cdev.dev;
     }
     else if ( S_ISBLK (de->mode) )
-    {
-	inode->i_rdev = de->u.bdev.dev;
-	if (bd_acquire (inode) != 0)
-		PRINTK ("(%d): no block device from bdget()\n",(int)inode->i_ino);
-    }
+	init_special_inode(inode, de->mode, de->u.bdev.dev);
     else if ( S_ISFIFO (de->mode) )
     	inode->i_fop = &def_fifo_fops;
     else if ( S_ISDIR (de->mode) )
@@ -2118,11 +2108,7 @@ static int devfs_open (struct inode *inode, struct file *file)
     if (de == NULL) return -ENODEV;
     if ( S_ISDIR (de->mode) ) return 0;
     file->private_data = de->info;
-    if ( S_ISBLK (inode->i_mode) )
-    {
-	file->f_op = &def_blk_fops;
-	err = def_blk_fops.open (inode, file); /* Module refcount unchanged */
-    } else if (S_ISCHR(inode->i_mode)) {
+    if (S_ISCHR(inode->i_mode)) {
 	ops = devfs_get_ops (de);  /*  Now have module refcount  */
 	file->f_op = ops;
 	if (file->f_op)

include/linux/fs.h

@@ -1125,7 +1125,6 @@ enum {BDEV_FILE, BDEV_SWAP, BDEV_FS, BDEV_RAW};
 extern int register_blkdev(unsigned int, const char *);
 extern int unregister_blkdev(unsigned int, const char *);
 extern struct block_device *bdget(dev_t);
-extern int bd_acquire(struct inode *inode);
 extern void bd_forget(struct inode *inode);
 extern void bdput(struct block_device *);
 extern int blkdev_open(struct inode *, struct file *);