Attachment 38195 Details for Bug 29738 – fix range restriction checks in drm_mm

[patch] fix range restriction checks in drm_mm

0001-drm-mm-fix-range-restricted-allocations.patch (text/plain), 3.02 KB, created by Daniel Vetter on 2010-08-26 12:37:10 UTC

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Creator: Daniel Vetter

Created: 2010-08-26 12:37:10 UTC

Size: 3.02 KB

patch

obsolete

>From 6f64e64166af7a4f3c48141a2a20336fb805cbb3 Mon Sep 17 00:00:00 2001
>From: Daniel Vetter <daniel.vetter@ffwll.ch>
>Date: Thu, 26 Aug 2010 21:37:48 +0200
>Subject: [PATCH] drm: mm: fix range restricted allocations
>
>With the code cleanup in
>
>7a6b2896f261894dde287d3faefa4b432cddca53 is the first bad commit
>commit 7a6b2896f261894dde287d3faefa4b432cddca53
>Author: Daniel Vetter <daniel.vetter@ffwll.ch>
>Date:   Fri Jul 2 15:02:15 2010 +0100
>
>    drm_mm: extract check_free_mm_node
>
>I've botched up the range-restriction checks. The result is usually
>an X server dying with SIGBUS in libpixman (software fallback rendering).
>Change the code to adjust the start and end for range restricted
>allocations. IMHO this even makes the code a bit clearer.
>
>Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
>---
> drivers/gpu/drm/drm_mm.c |   24 ++++++++++++++----------
> 1 files changed, 14 insertions(+), 10 deletions(-)
>
>diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c
>index da99edc..a6bfc30 100644
>--- a/drivers/gpu/drm/drm_mm.c
>+++ b/drivers/gpu/drm/drm_mm.c
>@@ -285,21 +285,21 @@ void drm_mm_put_block(struct drm_mm_node *cur)
> 
> EXPORT_SYMBOL(drm_mm_put_block);
> 
>-static int check_free_mm_node(struct drm_mm_node *entry, unsigned long size,
>-			      unsigned alignment)
>+static int check_free_hole(unsigned long start, unsigned long end,
>+			   unsigned long size, unsigned alignment)
> {
> 	unsigned wasted = 0;
> 
>-	if (entry->size < size)
>+	if (end - start < size)
> 		return 0;
> 
> 	if (alignment) {
>-		register unsigned tmp = entry->start % alignment;
>+		unsigned tmp = start % alignment;
> 		if (tmp)
> 			wasted = alignment - tmp;
> 	}
> 
>-	if (entry->size >= size + wasted) {
>+	if (end >= start + size + wasted) {
> 		return 1;
> 	}
> 
>@@ -320,7 +320,8 @@ struct drm_mm_node *drm_mm_search_free(const struct drm_mm *mm,
> 	best_size = ~0UL;
> 
> 	list_for_each_entry(entry, &mm->free_stack, free_stack) {
>-		if (!check_free_mm_node(entry, size, alignment))
>+		if (!check_free_hole(entry->start, entry->start + entry->size,
>+				     size, alignment))
> 			continue;
> 
> 		if (!best_match)
>@@ -353,10 +354,12 @@ struct drm_mm_node *drm_mm_search_free_in_range(const struct drm_mm *mm,
> 	best_size = ~0UL;
> 
> 	list_for_each_entry(entry, &mm->free_stack, free_stack) {
>-		if (entry->start > end || (entry->start+entry->size) < start)
>-			continue;
>+		unsigned long adj_start = entry->start < start ?
>+			start : entry->start;
>+		unsigned long adj_end = entry->start + entry->size > end ?
>+			end : entry->start + entry->size;
> 
>-		if (!check_free_mm_node(entry, size, alignment))
>+		if (!check_free_hole(adj_start, adj_end, size, alignment))
> 			continue;
> 
> 		if (!best_match)
>@@ -449,7 +452,8 @@ int drm_mm_scan_add_block(struct drm_mm_node *node)
> 	node->free_stack.prev = prev_free;
> 	node->free_stack.next = next_free;
> 
>-	if (check_free_mm_node(node, mm->scan_size, mm->scan_alignment)) {
>+	if (check_free_hole(node->start, node->start + node->size,
>+			    mm->scan_size, mm->scan_alignment)) {
> 		mm->scan_hit_start = node->start;
> 		mm->scan_hit_size = node->size;
> 
>-- 
>1.7.1
>

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