nfs: add kmalloc return value check in decode_and_add_ds

add kmalloc return value check in decode_and_add_ds

Signed-off-by: Stanislav Fomichev <kernel@fomichev.me>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/nfs4filelayoutdev.c b/fs/nfs/nfs4filelayoutdev.c
index f5c9b12..b73c343 100644
--- a/fs/nfs/nfs4filelayoutdev.c
+++ b/fs/nfs/nfs4filelayoutdev.c
@@ -219,6 +219,10 @@
 		goto out_err;
 	}
 	buf = kmalloc(rlen + 1, GFP_KERNEL);
+	if (!buf) {
+		dprintk("%s: Not enough memory\n", __func__);
+		goto out_err;
+	}
 	buf[rlen] = '\0';
 	memcpy(buf, r_addr, rlen);