From: "Eric W. Biederman" <ebiederm@xmission.com>
Date: Wed, 30 Jan 2019 07:58:38 -0600
Subject: [PATCH] fs/nfs: Fix nfs_parse_devname to not modify it's argument
Git-commit: 40cc394be1aa18848b8757e03bd8ed23281f572e
Patch-mainline: v5.1
References: git-fixes

In the rare and unsupported case of a hostname list nfs_parse_devname
will modify dev_name.  There is no need to modify dev_name as the all
that is being computed is the length of the hostname, so the computed
length can just be shorted.

Fixes: dc04589827f7 ("NFS: Use common device name parsing logic for NFSv4 and NFSv2/v3")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Acked-by: NeilBrown <neilb@suse.com>

---
 fs/nfs/super.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -1932,7 +1932,7 @@ static int nfs_parse_devname(const char
 		/* kill possible hostname list: not supported */
 		comma = strchr(dev_name, ',');
 		if (comma != NULL && comma < end)
-			*comma = 0;
+			len = comma - dev_name;
 	}
 
 	if (len > maxnamlen)