drm: Micro-optimise drm_mm_for_each_node_in_range()

As we require valid start/end parameters, we can replace the initial
potential NULL with a pointer to the drm_mm.head_node and so reduce the
test on every iteration from a NULL + address comparison to just an
address comparison.

add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-26 (-26)
function                                     old     new   delta
i915_gem_evict_for_node                      719     693     -26

(No other users outside of the test harness.)

Signed-off-by: Chris Wilson <[email protected]>
Cc: Joonas Lahtinen <[email protected]>
Reviewed-by: Joonas Lahtinen <[email protected]>
Signed-off-by: Daniel Vetter <[email protected]>
Link: http://patchwork.freedesktop.org/patch/msgid/[email protected]

1 files changed, 6 insertions, 4 deletions

diff --git a/drivers/gpu/drm/selftests/test-drm_mm.c b/drivers/gpu/drm/selftests/test-drm_mm.c
index 1e71bc182ca9..2958f596081e 100644
--- a/drivers/gpu/drm/selftests/test-drm_mm.c
+++ b/drivers/gpu/drm/selftests/test-drm_mm.c
@@ -839,16 +839,18 @@ static bool assert_contiguous_in_range(struct drm_mm *mm,
 		n++;
 	}
 
-	drm_mm_for_each_node_in_range(node, mm, 0, start) {
-		if (node) {
+	if (start > 0) {
+		node = __drm_mm_interval_first(mm, 0, start - 1);
+		if (node->allocated) {
 			pr_err("node before start: node=%llx+%llu, start=%llx\n",
 			       node->start, node->size, start);
 			return false;
 		}
 	}
 
-	drm_mm_for_each_node_in_range(node, mm, end, U64_MAX) {
-		if (node) {
+	if (end < U64_MAX) {
+		node = __drm_mm_interval_first(mm, end, U64_MAX);
+		if (node->allocated) {
 			pr_err("node after end: node=%llx+%llu, end=%llx\n",
 			       node->start, node->size, end);
 			return false;