From: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Date: Tue, 3 Apr 2012 17:05:47 +0000 (+0100)
Subject: xen/gntdev: do not set VM_PFNMAP
X-Git-Tag: v3.3.4~77
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f03ee5fccf5b1696f355ee978aec00e638dc9bd7;p=thirdparty%2Fkernel%2Fstable.git

xen/gntdev: do not set VM_PFNMAP

commit e8e937be971d706061dc56220ff3605ab77622a7 upstream.

Since we are using the m2p_override we do have struct pages
corresponding to the user vma mmap'ed by gntdev.

Removing the VM_PFNMAP flag makes get_user_pages work on that vma.
An example test case would be using a Xen userspace block backend
(QDISK) on a file on NFS using O_DIRECT.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index 99d8151c824ad..1ffd03bf8e10d 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -722,7 +722,7 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
 	vma->vm_flags |= VM_RESERVED|VM_DONTEXPAND;
 
 	if (use_ptemod)
-		vma->vm_flags |= VM_DONTCOPY|VM_PFNMAP;
+		vma->vm_flags |= VM_DONTCOPY;
 
 	vma->vm_private_data = map;