From 970c941acb9fc2556ea5b7c5a8225a7935692652 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jean-S=C3=A9bastien=20P=C3=A9dron?= <dumbbell@FreeBSD.org>
Date: Sun, 25 Aug 2013 15:15:55 +0000
Subject: [PATCH] drm/ttm: Fix unmap of buffer object

Add a new ttm_bo_release_mmap() function to unmap pages in a
vm_object_t. Pages are freed when the buffer object is later released.

This function is called in ttm_bo_unmap_virtual_locked(), replacing
Linux' unmap_mapping_range(). In particular this is called when a buffer
object is about to be moved, so that its mapping is invalidated.

However, we don't use this function in ttm_bo_vm_dtor(), because the
vm_object_t is already marked as OBJ_DEAD and the pages will be
unmapped.

Approved by:	kib@
---
 sys/dev/drm2/ttm/ttm_bo.c    |  7 +------
 sys/dev/drm2/ttm/ttm_bo_vm.c | 27 +++++++++++++++++++++++++++
 2 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/sys/dev/drm2/ttm/ttm_bo.c b/sys/dev/drm2/ttm/ttm_bo.c
index 8bd8af930963..d7b1d3066b21 100644
--- a/sys/dev/drm2/ttm/ttm_bo.c
+++ b/sys/dev/drm2/ttm/ttm_bo.c
@@ -1634,13 +1634,8 @@ bool ttm_mem_reg_is_pci(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem)
 
 void ttm_bo_unmap_virtual_locked(struct ttm_buffer_object *bo)
 {
-	struct ttm_bo_device *bdev = bo->bdev;
-	/* off_t offset = (off_t)bo->addr_space_offset;XXXKIB */
-	/* off_t holelen = ((off_t)bo->mem.num_pages) << PAGE_SHIFT;XXXKIB */
 
-	if (!bdev->dev_mapping)
-		return;
-	/* unmap_mapping_range(bdev->dev_mapping, offset, holelen, 1); XXXKIB */
+	ttm_bo_release_mmap(bo);
 	ttm_mem_io_free_vm(bo);
 }
 
diff --git a/sys/dev/drm2/ttm/ttm_bo_vm.c b/sys/dev/drm2/ttm/ttm_bo_vm.c
index f420fd5b93aa..8674551f7f70 100644
--- a/sys/dev/drm2/ttm/ttm_bo_vm.c
+++ b/sys/dev/drm2/ttm/ttm_bo_vm.c
@@ -361,6 +361,33 @@ out_unref:
 	return ret;
 }
 
+void
+ttm_bo_release_mmap(struct ttm_buffer_object *bo)
+{
+	vm_object_t vm_obj;
+	vm_page_t m;
+	int i;
+
+	vm_obj = cdev_pager_lookup(bo);
+	if (vm_obj == NULL) {
+		return;
+	}
+
+	VM_OBJECT_WLOCK(vm_obj);
+retry:
+	for (i = 0; i < bo->num_pages; i++) {
+		m = vm_page_lookup(vm_obj, i);
+		if (m == NULL)
+			continue;
+		if (vm_page_sleep_if_busy(m, "ttm_unm"))
+			goto retry;
+		cdev_pager_free_page(vm_obj, m);
+	}
+	VM_OBJECT_WUNLOCK(vm_obj);
+
+	vm_object_deallocate(vm_obj);
+}
+
 #if 0
 int ttm_fbdev_mmap(struct vm_area_struct *vma, struct ttm_buffer_object *bo)
 {