drm/ttm: Restore ttm prefaulting

Commit 4daa4fb ("gpu: drm: ttm: Adding new return type vm_fault_t") broke TTM prefaulting. Since vmf_insert_mixed() typically always returns VM_FAULT_NOPAGE, prefaulting stops after the second PTE. Restore (almost) the original behaviour. Unfortunately we can no longer with the new vm_fault_t return type determine whether a prefaulting PTE insertion hit an already populated PTE, and terminate the insertion loop. Instead we continue with the pre-determined number of prefaults. Fixes: 4daa4fb ("gpu: drm: ttm: Adding new return type vm_fault_t") Cc: Souptick Joarder <[email protected]> Cc: Christian König <[email protected]> Signed-off-by: Thomas Hellstrom <[email protected]> Reviewed-by: Christian König <[email protected]> Cc: [email protected] # v4.19+ Signed-off-by: Christian König <[email protected]> Link: https://patchwork.freedesktop.org/patch/330387/
wafgo · Oct 14, 2019 · 941f2f7 · 941f2f7
1 parent 73a88e4
commit 941f2f7
Showing 1 changed file with 7 additions and 9 deletions.
diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
@@ -278,15 +278,13 @@ static vm_fault_t ttm_bo_vm_fault(struct vm_fault *vmf)
 		else
 			ret = vmf_insert_pfn(&cvma, address, pfn);
 
-		/*
-		 * Somebody beat us to this PTE or prefaulting to
-		 * an already populated PTE, or prefaulting error.
-		 */
-
-		if (unlikely((ret == VM_FAULT_NOPAGE && i > 0)))
-			break;
-		else if (unlikely(ret & VM_FAULT_ERROR))
-			goto out_io_unlock;
+		/* Never error on prefaulted PTEs */
+		if (unlikely((ret & VM_FAULT_ERROR))) {
+			if (i == 0)
+				goto out_io_unlock;
+			else
+				break;
+		}
 
 		address += PAGE_SIZE;
 		if (unlikely(++page_offset >= page_last))