drm/amdkfd: Use prange->update_list head for remove_list

The remove_list head was only used for keeping track of existing ranges
that are to be removed from the svms->list. The update_list was used for
new or existing ranges that need updated attributes. These two cases are
mutually exclusive (i.e. the same range will never be on both lists).
Therefore we can use the update_list head to track the remove_list and
save another 16 bytes in the svm_range struct.
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Philip Yang <Philip.Yang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdkfd/kfd_svm.c

@@ -295,7 +295,6 @@ svm_range *svm_range_new(struct svm_range_list *svms, uint64_t start,
 	prange->last = last;
 	INIT_LIST_HEAD(&prange->list);
 	INIT_LIST_HEAD(&prange->update_list);
-	INIT_LIST_HEAD(&prange->remove_list);
 	INIT_LIST_HEAD(&prange->svm_bo_list);
 	INIT_LIST_HEAD(&prange->deferred_list);
 	INIT_LIST_HEAD(&prange->child_list);
@@ -1897,7 +1896,7 @@ svm_range_add(struct kfd_process *p, uint64_t start, uint64_t size,
 				goto out;
 			}
 
-			list_add(&old->remove_list, remove_list);
+			list_add(&old->update_list, remove_list);
 			list_add(&prange->list, insert_list);
 			list_add(&prange->update_list, update_list);
 
@@ -3243,8 +3242,7 @@ svm_range_set_attr(struct kfd_process *p, uint64_t start, uint64_t size,
 		svm_range_apply_attrs(p, prange, nattr, attrs);
 		/* TODO: unmap ranges from GPU that lost access */
 	}
-	list_for_each_entry_safe(prange, next, &remove_list,
-				remove_list) {
+	list_for_each_entry_safe(prange, next, &remove_list, update_list) {
 		pr_debug("unlink old 0x%p prange 0x%p [0x%lx 0x%lx]\n",
 			 prange->svms, prange, prange->start,
 			 prange->last);

drivers/gpu/drm/amd/amdkfd/kfd_svm.h

@@ -76,7 +76,6 @@ struct svm_work_list_item {
  *              aligned, page size is (last - start + 1)
  * @list:       link list node, used to scan all ranges of svms
  * @update_list:link list node used to add to update_list
- * @remove_list:link list node used to add to remove list
  * @mapping:    bo_va mapping structure to create and update GPU page table
  * @npages:     number of pages
  * @dma_addr:   dma mapping address on each GPU for system memory physical page
@@ -112,7 +111,6 @@ struct svm_range {
 	struct interval_tree_node	it_node;
 	struct list_head		list;
 	struct list_head		update_list;
-	struct list_head		remove_list;
 	uint64_t			npages;
 	dma_addr_t			*dma_addr[MAX_GPU_INSTANCE];
 	struct ttm_resource		*ttm_res;