dax: Use copy_from_iter_nocache

Orabug: 22913653

When userspace does a write, there's no need for the written data to
pollute the CPU cache.  This matches the original XIP code.

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
(cherry picked from commit 872eb127e3a6cddcfca1410bb808d9b9bc773dc1)
Signed-off-by: Dan Duval <dan.duval@oracle.com>

diff --git a/fs/dax.c b/fs/dax.c
index 99b5fbc38992db1f88be1a1e48dad4fda584a0c1..eaa9e0683227b7a9f6d26a11b060655cd258d4f8 100644 (file)
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -155,7 +155,7 @@ static ssize_t dax_io(struct inode *inode, struct iov_iter *iter,
                }
 
                if (iov_iter_rw(iter) == WRITE)
-                       len = copy_from_iter(addr, max - pos, iter);
+                       len = copy_from_iter_nocache(addr, max - pos, iter);
                else if (!hole)
                        len = copy_to_iter(addr, max - pos, iter);
                else