fb-defio: If FBINFO_VIRTFB is defined, do not set VM_IO flag.

Most users (except sh_mobile_lcdcfb.c) get their framebuffer from
vmalloc. Setting VM_IO is not necessary as the memory obtained
from vmalloc is System RAM type and is not susceptible to PCI memory
constraints.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: NJaya Kumar <jayakumar.lkml@gmail.com>

drivers/video/fb_defio.c

@@ -144,7 +144,9 @@ static const struct address_space_operations fb_deferred_io_aops = {
 static int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma)
 {
 	vma->vm_ops = &fb_deferred_io_vm_ops;
-	vma->vm_flags |= ( VM_IO | VM_RESERVED | VM_DONTEXPAND );
+	vma->vm_flags |= ( VM_RESERVED | VM_DONTEXPAND );
+	if (!(info->flags & FBINFO_VIRTFB))
+		vma->vm_flags |= VM_IO;
 	vma->vm_private_data = info;
 	return 0;
 }

include/linux/fb.h

@@ -768,6 +768,7 @@ struct fb_tile_ops {
 	 *  takes over; acceleration engine should be in a quiescent state */
 
 /* hints */
+#define FBINFO_VIRTFB		0x0004 /* FB is System RAM, not device. */
 #define FBINFO_PARTIAL_PAN_OK	0x0040 /* otw use pan only for double-buffering */
 #define FBINFO_READS_FAST	0x0080 /* soft-copy faster than rendering */