[PATCH] drm/ttm: Correctly set page mapping and -index members

[Thomas Hellstrom]

Needed for some vm operations; most notably unmap_mapping_range() with
even_cows = 0.

Signed-off-by: Thomas Hellstrom <thellstrom at vmware.com>
Reviewed-by: Brian Paul <brianp at vmware.com>
---
 drivers/gpu/drm/ttm/ttm_bo_vm.c |    5 +++++
 drivers/gpu/drm/ttm/ttm_tt.c    |   27 +++++++++++++++++++++++----
 include/drm/ttm/ttm_bo_driver.h |    9 +++++++++
 3 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
index 12d7f53..cfcdf5b 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
@@ -226,6 +226,9 @@ static int ttm_bo_vm_fault(struct vm_area_struct *vma, 
struct vm_fault *vmf)
                        } else if (unlikely(!page)) {
                                break;
                        }
+                       page->mapping = vma->vm_file->f_mapping;
+                       page->index = drm_vma_node_start(&bo->vma_node) +
+                               page_offset;
                        pfn = page_to_pfn(page);
                }

@@ -263,6 +266,8 @@ static void ttm_bo_vm_open(struct vm_area_struct *vma)
        struct ttm_buffer_object *bo =
            (struct ttm_buffer_object *)vma->vm_private_data;

+       WARN_ON(bo->bdev->dev_mapping != vma->vm_file->f_mapping);
+
        (void)ttm_bo_reference(bo);
 }

diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c
index 210d503..9af9908 100644
--- a/drivers/gpu/drm/ttm/ttm_tt.c
+++ b/drivers/gpu/drm/ttm/ttm_tt.c
@@ -170,9 +170,8 @@ void ttm_tt_destroy(struct ttm_tt *ttm)
                ttm_tt_unbind(ttm);
        }

-       if (ttm->state == tt_unbound) {
-               ttm->bdev->driver->ttm_tt_unpopulate(ttm);
-       }
+       if (ttm->state == tt_unbound)
+               ttm_tt_unpopulate(ttm);

        if (!(ttm->page_flags & TTM_PAGE_FLAG_PERSISTENT_SWAP) &&
            ttm->swap_storage)
@@ -362,7 +361,7 @@ int ttm_tt_swapout(struct ttm_tt *ttm, struct file 
*persistent_swap_storage)
                page_cache_release(to_page);
        }

-       ttm->bdev->driver->ttm_tt_unpopulate(ttm);
+       ttm_tt_unpopulate(ttm);
        ttm->swap_storage = swap_storage;
        ttm->page_flags |= TTM_PAGE_FLAG_SWAPPED;
        if (persistent_swap_storage)
@@ -375,3 +374,23 @@ out_err:

        return ret;
 }
+
+static void ttm_tt_clear_mapping(struct ttm_tt *ttm)
+{
+       pgoff_t i;
+       struct page **page = ttm->pages;
+
+       for (i = 0; i < ttm->num_pages; ++i) {
+               (*page)->mapping = NULL;
+               (*page++)->index = 0;
+       }
+}
+
+void ttm_tt_unpopulate(struct ttm_tt *ttm)
+{
+       if (ttm->state == tt_unpopulated)
+               return;
+
+       ttm_tt_clear_mapping(ttm);
+       ttm->bdev->driver->ttm_tt_unpopulate(ttm);
+}
diff --git a/include/drm/ttm/ttm_bo_driver.h b/include/drm/ttm/ttm_bo_driver.h
index 8639c85..32d34eb 100644
--- a/include/drm/ttm/ttm_bo_driver.h
+++ b/include/drm/ttm/ttm_bo_driver.h
@@ -681,6 +681,15 @@ extern int ttm_tt_set_placement_caching(struct ttm_tt 
*ttm, uint32_t placement);
 extern int ttm_tt_swapout(struct ttm_tt *ttm,
                          struct file *persistent_swap_storage);

+/**
+ * ttm_tt_unpopulate - free pages from a ttm
+ *
+ * @ttm: Pointer to the ttm_tt structure
+ *
+ * Calls the driver method to free all pages from a ttm
+ */
+extern void ttm_tt_unpopulate(struct ttm_tt *ttm);
+
 /*
  * ttm_bo.c
  */
-- 
1.7.10.4