From 1c9bd1ede83cb391db2af481c73b01b63ab41e96 Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Tue, 27 Dec 2016 11:10:57 +0100 Subject: [PATCH] drm/mm: Document locking rules Drivers need to take care. Motivated by a discussion between Mark and Rob on dri-devel. Cc: Mark yao Cc: Rob Clark Reviewed-by: Chris Wilson [danvet: s/alloc|freeing/modifications/ per Chris' suggestion.] Signed-off-by: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/1482833457-29592-1-git-send-email-daniel.vetter@ffwll.ch --- drivers/gpu/drm/drm_mm.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c index 58a7e3bbe130..713f4336107f 100644 --- a/drivers/gpu/drm/drm_mm.c +++ b/drivers/gpu/drm/drm_mm.c @@ -90,6 +90,11 @@ * * Finally iteration helpers to walk all nodes and all holes are provided as are * some basic allocator dumpers for debugging. + * + * Note that this range allocator is not thread-safe, drivers need to protect + * modifications with their on locking. The idea behind this is that for a full + * memory manager additional data needs to be protected anyway, hence internal + * locking would be fully redundant. */ static struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_mm *mm, -- 2.20.1