Thread (37 messages) 37 messages, 4 authors, 2026-06-13
COLD39d

[PATCH v2 06/14] drm/ttm: Open-code reservation list walk

From: Kaitao Cheng <hidden>
Date: 2026-06-09 06:27:41
Also in: dri-devel, intel-gfx, linux-sound, linux-spi, linux-tegra, lkml
Subsystem: drm drivers, drm drivers and misc gpu patches, drm ttm subsystem, the rest · Maintainers: David Airlie, Simona Vetter, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, Christian Koenig, Huang Rui, Linus Torvalds

From: Kaitao Cheng <redacted>

A later change will make list_for_each_entry() cache the next element
before entering the loop body. ttm_eu_reserve_buffers() may move the
current validation buffer to the duplicates list and then rewinds the
cursor before continuing.

Keep the reservation walk open-coded so the loop step uses the cursor
selected by that duplicate handling. This preserves the existing
traversal semantics and prepares the code for the list iterator update.

Signed-off-by: Kaitao Cheng <redacted>
---
 drivers/gpu/drm/ttm/ttm_execbuf_util.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/ttm/ttm_execbuf_util.c b/drivers/gpu/drm/ttm/ttm_execbuf_util.c
index bc7a83a9fe44..8072f07d5557 100644
--- a/drivers/gpu/drm/ttm/ttm_execbuf_util.c
+++ b/drivers/gpu/drm/ttm/ttm_execbuf_util.c
@@ -86,7 +86,9 @@ int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket,
 	if (ticket)
 		ww_acquire_init(ticket, &reservation_ww_class);
 
-	list_for_each_entry(entry, list, head) {
+	for (entry = list_first_entry(list, typeof(*entry), head);
+	     !list_entry_is_head(entry, list, head);
+	     entry = list_next_entry(entry, head)) {
 		struct ttm_buffer_object *bo = entry->bo;
 		unsigned int num_fences;
 
-- 
2.43.0
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