Re: [PATCH] drm/mm: Fix search for smallest hole satisfying constraints

On Tue, Mar 18, 2014 at 09:58:14AM +0900, Michel Dänzer wrote:

From: Michel Dänzer michel.daenzer@amd.com

entry->size is the size of the node, not the size of the hole after it. So the code would actually find the hole which can satisfy the constraints and which is preceded by the smallest node, not the smallest hole satisfying the constraints.

Reported-by: "Huang, FrankR" FrankR.Huang@amd.com Signed-off-by: Michel Dänzer michel.daenzer@amd.com

But drm-next just gained my kerneldoc patch for drm_mm, so can you please respin your patch and update the docs too? While at it ... could you perhaps smash a bit of kerneldoc on top of enum drm_mm_search_flags, I seem to have missed it. With that this is

Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch

Thanks, Daniel

---

drivers/gpu/drm/drm_mm.c | 33 +++++++++++++++++---------------- 1 file changed, 17 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c index af93cc5..5d921e5 100644 --- a/drivers/gpu/drm/drm_mm.c +++ b/drivers/gpu/drm/drm_mm.c @@ -306,8 +306,8 @@ static struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm, { struct drm_mm_node *entry; struct drm_mm_node *best;

• unsigned long adj_start;
• unsigned long adj_end;

• unsigned long hole_start;

• unsigned long hole_end; unsigned long best_size;

  BUG_ON(mm->scanned_blocks);

@@ -315,7 +315,10 @@ static struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm, best = NULL; best_size = ~0UL;

• drm_mm_for_each_hole(entry, mm, adj_start, adj_end) {

• drm_mm_for_each_hole(entry, mm, hole_start, hole_end) {

• unsigned long adj_start = hole_start;
  

• unsigned long adj_end = hole_end;
  

• if (mm->color_adjust) { mm->color_adjust(entry, color, &adj_start, &adj_end); if (adj_end <= adj_start)

@@ -328,9 +331,9 @@ static struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm, if (!(flags & DRM_MM_SEARCH_BEST)) return entry;

• if (entry->size < best_size) {
  

• if ((hole_end - hole_start) < best_size) {
  best = entry;
  

• 	best_size = entry->size;
  

• 	best_size = hole_end - hole_start;
  

  } }

@@ -341,14 +344,14 @@ static struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_ unsigned long size, unsigned alignment, unsigned long color,

• 					unsigned long start,
  

• 					unsigned long end,
  

• 					unsigned long range_start,
  

• 					unsigned long range_end,
  				enum drm_mm_search_flags flags)
  

{ struct drm_mm_node *entry; struct drm_mm_node *best;

• unsigned long adj_start;
• unsigned long adj_end;

• unsigned long hole_start;

• unsigned long hole_end; unsigned long best_size;

  BUG_ON(mm->scanned_blocks);

@@ -356,11 +359,9 @@ static struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_ best = NULL; best_size = ~0UL;

• drm_mm_for_each_hole(entry, mm, adj_start, adj_end) {

• if (adj_start < start)
  

• 	adj_start = start;
  

• if (adj_end > end)
  

• 	adj_end = end;
  

• drm_mm_for_each_hole(entry, mm, hole_start, hole_end) {

• unsigned long adj_start = max(hole_start, range_start);
  

• unsigned long adj_end = min(hole_end, range_end);
  
  

  if (mm->color_adjust) { mm->color_adjust(entry, color, &adj_start, &adj_end);

@@ -374,9 +375,9 @@ static struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_ if (!(flags & DRM_MM_SEARCH_BEST)) return entry;

• if (entry->size < best_size) {
  

• if ((hole_end - hole_start) < best_size) {
  best = entry;
  

• 	best_size = entry->size;
  

• 	best_size = hole_end - hole_start;
  

  } }

-- 1.9.0

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