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Commit 75214733 authored by Daniel Vetter's avatar Daniel Vetter Committed by Dave Airlie
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drm: mm: fix range restricted allocations 

With the code cleanup in

7a6b2896 is the first bad commit
commit 7a6b2896
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.

Fixes regression bug: https://bugs.freedesktop.org/show_bug.cgi?id=29738



Reported-by-Tested-by: default avatarTill MAtthiesen <entropy@everymail.net>
Acked-by: default avatarAlex Deucher <alexdeucher@gmail.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
parent 5afda9e9

drivers/gpu/drm/drm_mm.c

+14 −10
Original line number Diff line number Diff line
@@ -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;