ext2: cleanup the dax handling in ext2_fill_super

Only call fs_dax_get_by_bdev once the sbi has been allocated and remove
the need for the dax_dev local variable.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-20-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

fs/ext2/super.c

@@ -802,7 +802,6 @@ static unsigned long descriptor_loc(struct super_block *sb,
 
 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 {
-	struct dax_device *dax_dev = fs_dax_get_by_bdev(sb->s_bdev);
 	struct buffer_head * bh;
 	struct ext2_sb_info * sbi;
 	struct ext2_super_block * es;
@@ -822,17 +821,17 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 
 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 	if (!sbi)
-		goto failed;
+		return -ENOMEM;
 
 	sbi->s_blockgroup_lock =
 		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
 	if (!sbi->s_blockgroup_lock) {
 		kfree(sbi);
-		goto failed;
+		return -ENOMEM;
 	}
 	sb->s_fs_info = sbi;
 	sbi->s_sb_block = sb_block;
-	sbi->s_daxdev = dax_dev;
+	sbi->s_daxdev = fs_dax_get_by_bdev(sb->s_bdev);
 
 	spin_lock_init(&sbi->s_lock);
 	ret = -EINVAL;
@@ -946,7 +945,7 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 	blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
 
 	if (test_opt(sb, DAX)) {
-		if (!dax_dev) {
+		if (!sbi->s_daxdev) {
 			ext2_msg(sb, KERN_ERR,
 				"DAX unsupported by block device. Turning off DAX.");
 			clear_opt(sbi->s_mount_opt, DAX);
@@ -1201,11 +1200,10 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 failed_mount:
 	brelse(bh);
 failed_sbi:
+	fs_put_dax(sbi->s_daxdev);
 	sb->s_fs_info = NULL;
 	kfree(sbi->s_blockgroup_lock);
 	kfree(sbi);
-failed:
-	fs_put_dax(dax_dev);
 	return ret;
 }