drm/msm: Split iova purge and close

Currently these always go together, either when we purge MADV_WONTNEED
objects or when the object is freed.  But for unpin, we want to be able
to purge (unmap from iommu) the vma, while keeping the iova range
allocated (so we can remap back to the same GPU virtual address when the
object is re-pinned.
Signed-off-by: Rob Clark <robdclark@chromium.org>
Link: https://lore.kernel.org/r/20210405174532.1441497-5-robdclark@gmail.comSigned-off-by: Rob Clark <robdclark@chromium.org>

drivers/gpu/drm/msm/msm_gem.c

@@ -357,9 +357,14 @@ static void del_vma(struct msm_gem_vma *vma)
 	kfree(vma);
 }
 
-/* Called with msm_obj locked */
+/**
+ * If close is true, this also closes the VMA (releasing the allocated
+ * iova range) in addition to removing the iommu mapping.  In the eviction
+ * case (!close), we keep the iova allocated, but only remove the iommu
+ * mapping.
+ */
 static void
-put_iova_spaces(struct drm_gem_object *obj)
+put_iova_spaces(struct drm_gem_object *obj, bool close)
 {
 	struct msm_gem_object *msm_obj = to_msm_bo(obj);
 	struct msm_gem_vma *vma;
@@ -369,7 +374,8 @@ put_iova_spaces(struct drm_gem_object *obj)
 	list_for_each_entry(vma, &msm_obj->vmas, list) {
 		if (vma->aspace) {
 			msm_gem_purge_vma(vma->aspace, vma);
-			msm_gem_close_vma(vma->aspace, vma);
+			if (close)
+				msm_gem_close_vma(vma->aspace, vma);
 		}
 	}
 }
@@ -711,7 +717,8 @@ void msm_gem_purge(struct drm_gem_object *obj)
 	GEM_WARN_ON(!is_purgeable(msm_obj));
 	GEM_WARN_ON(obj->import_attach);
 
-	put_iova_spaces(obj);
+	/* Get rid of any iommu mapping(s): */
+	put_iova_spaces(obj, true);
 
 	msm_gem_vunmap(obj);
 
@@ -1013,7 +1020,7 @@ void msm_gem_free_object(struct drm_gem_object *obj)
 	/* object should not be on active list: */
 	GEM_WARN_ON(is_active(msm_obj));
 
-	put_iova_spaces(obj);
+	put_iova_spaces(obj, true);
 
 	if (obj->import_attach) {
 		GEM_WARN_ON(msm_obj->vaddr);