block_range::Delete() did not remove the block_range from the free list,

and thus, it could be used again which led to a crash.
Changed the free ranges list from a singly linked list to a doubly linked
list so that not all free ranges have to be searched for the one to be
freed anymore.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@15696 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/system/kernel/cache/block_allocator.cpp

@@ -201,8 +201,7 @@ block_range::New(block_cache *cache, block_range **_range)
 	range->base = address;
 
 	// insert into free ranges list in cache
-	range->free_next = cache->free_ranges;
+	cache->free_ranges.Add(range);
-	cache->free_ranges = range;
 
 	*_range = range;
 	return B_OK;
@@ -236,6 +235,9 @@ block_range::Delete(block_cache *cache, block_range *range)
 		vm_page_set_state(range->pages[i], PAGE_STATE_FREE);
 	}
 
+	// remove from cache free list
+	cache->free_ranges.Remove(range);
+
 	free(range);
 }
 
@@ -376,21 +378,7 @@ block_range::Allocate(block_cache *cache, block_chunk **_chunk)
 
 		if (used_mask == cache->range_mask) {
 			// range is full, remove it from the free list
-
+			cache->free_ranges.Remove(this);
-			// usually, the first entry will be ourself, but we don't count on it
-			block_range *last = NULL, *range = cache->free_ranges;
-			while (range != NULL && range != this) {
-				last = range;
-				range = range->free_next;
-			}
-			if (range == NULL) {
-				panic("block_range %p was free but not in the free list\n", this);
-			} else {
-				if (last)
-					last->free_next = free_next;
-				else
-					cache->free_ranges = free_next;
-			}
 		}
 	}
 	TRACE(("Allocate: used masks: chunk = %x, range = %lx\n", chunks[chunk].used_mask, used_mask));
@@ -409,8 +397,7 @@ block_range::Free(block_cache *cache, void *address)
 	if (chunks[chunk].used_mask == cache->chunk_mask) {
 		if (used_mask == cache->range_mask) {
 			// range was full before, add it to the free list
-			free_next = cache->free_ranges;
+			cache->free_ranges.Add(this);
-			cache->free_ranges = this;
 		}
 		// chunk was full before, propagate usage bit to range
 		used_mask &= ~(1UL << chunk);

src/system/kernel/cache/block_cache.cpp

@@ -153,8 +153,7 @@ block_cache::block_cache(int _fd, off_t numBlocks, size_t blockSize)
 	next_transaction_id(1),
 	last_transaction(NULL),
 	transaction_hash(NULL),
-	ranges_hash(NULL),
+	ranges_hash(NULL)
-	free_ranges(NULL)
 {
 	hash = hash_init(32, 0, &cached_block::Compare, &cached_block::Hash);
 	if (hash == NULL)
@@ -208,8 +207,8 @@ block_cache::InitCheck()
 block_range *
 block_cache::GetFreeRange()
 {
-	if (free_ranges != NULL)
+	if (!free_ranges.IsEmpty())
-		return free_ranges;
+		return free_ranges.First();
 
 	// we need to allocate a new range
 	block_range *range;

src/system/kernel/cache/block_cache_private.h

@@ -25,7 +25,9 @@ struct cache_transaction;
 struct cached_block;
 struct block_chunk;
 struct block_cache;
+struct block_range;
 typedef DoublyLinkedListLink<cached_block> block_link;
+typedef DoublyLinkedListLink<block_range> range_link;
 
 
 struct cached_block {
@@ -66,7 +68,7 @@ struct block_chunk {
 
 struct block_range {
 	block_range		*next;			// next in hash
-	block_range		*free_next;
+	range_link		link;
 	addr_t			base;
 	uint32			used_mask;
 	vm_page			*pages[kNumBlockRangePages];
@@ -91,6 +93,10 @@ struct block_range {
 	static uint32 Hash(void *_blockRange, const void *_address, uint32 range);
 };
 
+typedef DoublyLinkedList<block_range,
+	DoublyLinkedListMemberGetLink<block_range,
+		&block_range::link> > range_list;
+
 struct block_cache {
 	hash_table	*hash;
 	benaphore	lock;
@@ -102,7 +108,7 @@ struct block_cache {
 	hash_table	*transaction_hash;
 
 	hash_table	*ranges_hash;
-	block_range	*free_ranges;
+	range_list	free_ranges;
 	uint32		chunks_per_range;
 	size_t		chunk_size;
 	uint32		range_mask;