Avoid clobbering adjacent blocks if they happen to expire earlier and
amalgamate together to form the requested hole.
In passing this fixes a regression from
commit ea7b1dd44867e9cd6bac67e7c9fc3f128b5b255c
Author: Daniel Vetter <daniel.vet...@ffwll.ch>
Date: Fri Feb 18 17:59:12 2011 +0100
drm: mm: track free areas implicitly
which swaps the end address for size (with a potential overflow) and
effectively causes the eviction code to clobber almost all earlier
buffers above the evictee.
Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vet...@ffwll.ch>
---
drivers/gpu/drm/drm_mm.c | 58 +++++++++++++++++++++++++---------------------
include/drm/drm_mm.h | 2 +-
2 files changed, 33 insertions(+), 27 deletions(-)
diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c
index 7103aa3..c93729c 100644
--- a/drivers/gpu/drm/drm_mm.c
+++ b/drivers/gpu/drm/drm_mm.c
@@ -421,6 +421,25 @@ static int check_free_hole(unsigned long start, unsigned
long end,
return end >= start + size;
}
+static int adjust_free_hole(unsigned long *start, unsigned long *end,
+ unsigned long size, unsigned alignment)
+{
+ if (*end - *start < size)
+ return 0;
+
+ if (alignment) {
+ unsigned tmp = *start % alignment;
+ if (tmp)
+ *start += alignment - tmp;
+ }
+
+ if (*end - *start < size)
+ return 0;
+
+ *end = *start + size;
+ return 1;
+}
+
struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm,
unsigned long size,
unsigned alignment,
@@ -545,7 +564,7 @@ void drm_mm_init_scan(struct drm_mm *mm,
mm->scan_size = size;
mm->scanned_blocks = 0;
mm->scan_hit_start = 0;
- mm->scan_hit_size = 0;
+ mm->scan_hit_end = 0;
mm->scan_check_range = 0;
mm->prev_scanned_node = NULL;
}
@@ -572,7 +591,7 @@ void drm_mm_init_scan_with_range(struct drm_mm *mm,
mm->scan_size = size;
mm->scanned_blocks = 0;
mm->scan_hit_start = 0;
- mm->scan_hit_size = 0;
+ mm->scan_hit_end = 0;
mm->scan_start = start;
mm->scan_end = end;
mm->scan_check_range = 1;
@@ -591,8 +610,6 @@ int drm_mm_scan_add_block(struct drm_mm_node *node)
struct drm_mm *mm = node->mm;
struct drm_mm_node *prev_node;
unsigned long hole_start, hole_end;
- unsigned long adj_start;
- unsigned long adj_end;
mm->scanned_blocks++;
@@ -612,24 +629,21 @@ int drm_mm_scan_add_block(struct drm_mm_node *node)
hole_start = drm_mm_hole_node_start(prev_node);
hole_end = drm_mm_hole_node_end(prev_node);
- adj_start = hole_start;
- adj_end = hole_end;
-
if (mm->color_adjust)
- mm->color_adjust(prev_node, mm->scan_color, &adj_start,
&adj_end);
+ mm->color_adjust(prev_node, mm->scan_color,
+ &hole_start, &hole_end);
if (mm->scan_check_range) {
- if (adj_start < mm->scan_start)
- adj_start = mm->scan_start;
- if (adj_end > mm->scan_end)
- adj_end = mm->scan_end;
+ if (hole_start < mm->scan_start)
+ hole_start = mm->scan_start;
+ if (hole_end > mm->scan_end)
+ hole_end = mm->scan_end;
}
- if (check_free_hole(adj_start, adj_end,
- mm->scan_size, mm->scan_alignment)) {
+ if (adjust_free_hole(&hole_start, &hole_end,
+ mm->scan_size, mm->scan_alignment)) {
mm->scan_hit_start = hole_start;
- mm->scan_hit_size = hole_end;
-
+ mm->scan_hit_end = hole_end;
return 1;
}
@@ -668,16 +682,8 @@ int drm_mm_scan_remove_block(struct drm_mm_node *node)
INIT_LIST_HEAD(&node->node_list);
list_add(&node->node_list, &prev_node->node_list);
- /* Only need to check for containement because start&size for the
- * complete resulting free block (not just the desired part) is
- * stored. */
- if (node->start >= mm->scan_hit_start &&
- node->start + node->size
- <= mm->scan_hit_start + mm->scan_hit_size) {
- return 1;
- }
-
- return 0;
+ return (node->start + node->size >= mm->scan_hit_start &&
+ node->start <= mm->scan_hit_end);
}
EXPORT_SYMBOL(drm_mm_scan_remove_block);
diff --git a/include/drm/drm_mm.h b/include/drm/drm_mm.h
index 9a08a45..9e06ca1 100644
--- a/include/drm/drm_mm.h
+++ b/include/drm/drm_mm.h
@@ -70,7 +70,7 @@ struct drm_mm {
unsigned long scan_color;
unsigned long scan_size;
unsigned long scan_hit_start;
- unsigned scan_hit_size;
+ unsigned long scan_hit_end;
unsigned scanned_blocks;
unsigned long scan_start;
unsigned long scan_end;
--
1.7.10.4
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