From aada54f9800497cc8249c99ffcb1431c6d8e98e7 Mon Sep 17 00:00:00 2001
From: Ross Zwisler <ross.zwisler@linux.intel.com>
Date: Tue, 8 Nov 2016 11:32:00 +1100
Subject: [PATCH] dax: remove the last BUG_ON() from fs/dax.c

Don't take down the kernel if we get an invalid 'from' and 'length'
argument pair.  Just warn once and return an error.

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dave Chinner <david@fromorbit.com>
---
 fs/dax.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/dax.c b/fs/dax.c
index e52e7543c351..219fa2bd676a 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -1194,7 +1194,8 @@ int dax_zero_page_range(struct inode *inode, loff_t from, unsigned length,
 	/* Block boundary? Nothing to do */
 	if (!length)
 		return 0;
-	BUG_ON((offset + length) > PAGE_SIZE);
+	if (WARN_ON_ONCE((offset + length) > PAGE_SIZE))
+		return -EINVAL;
 
 	memset(&bh, 0, sizeof(bh));
 	bh.b_bdev = inode->i_sb->s_bdev;