Fix comments for memory allocation functions and add some extra checks.

Adapt callers.

ha/ha0ha.c

@@ -40,9 +40,13 @@ ha_create(
 		table->adaptive = FALSE;
 	}
 
+	/* Creating MEM_HEAP_BTR_SEARCH type heaps can potentially fail,
+	but in practise it never should in this case, hence the asserts. */
+	
 	if (n_mutexes == 0) {
 		if (in_btr_search) {
 			table->heap = mem_heap_create_in_btr_search(4096);
+			ut_a(table->heap);
 		} else {
 			table->heap = mem_heap_create_in_buffer(4096);
 		}
@@ -57,6 +61,7 @@ ha_create(
 	for (i = 0; i < n_mutexes; i++) {
 		if (in_btr_search) {
 			table->heaps[i] = mem_heap_create_in_btr_search(4096);
+			ut_a(table->heaps[i]);
 		} else {
 			table->heaps[i] = mem_heap_create_in_buffer(4096);
 		}

include/ha0ha.h

@@ -68,21 +68,6 @@ ha_insert_for_fold(
 				node is created! */
 	void*		data);	/* in: data, must not be NULL */
 /*****************************************************************
-Reserves the necessary hash table mutex and inserts an entry into the hash
-table. */
-UNIV_INLINE
-ibool
-ha_insert_for_fold_mutex(
-/*=====================*/
-				/* out: TRUE if succeed, FALSE if no more
-				memory could be allocated */
-	hash_table_t*	table,	/* in: hash table */
-	ulint		fold,	/* in: folded value of data; if a node with
-				the same fold value already exists, it is
-				updated to point to the same data, and no new
-				node is created! */
-	void*		data);	/* in: data, must not be NULL */
-/*****************************************************************
 Deletes an entry from a hash table. */
 
 void

include/ha0ha.ic

@@ -191,30 +191,3 @@ ha_search_and_delete_if_found(
 
 	return(FALSE);
 }
-
-/*****************************************************************
-Reserves the necessary hash table mutex and inserts an entry into the hash
-table. */
-UNIV_INLINE
-ibool
-ha_insert_for_fold_mutex(
-/*=====================*/
-				/* out: TRUE if succeed, FALSE if no more
-				memory could be allocated */
-	hash_table_t*	table,	/* in: hash table */
-	ulint		fold,	/* in: folded value of data; if a node with
-				the same fold value already exists, it is
-				updated to point to the same data, and no new
-				node is created! */
-	void*		data)	/* in: data, must not be NULL */
-{
-	ibool	ret;
-
-	hash_mutex_enter(table, fold);
-
-	ret = ha_insert_for_fold(table, fold, data);
-
-	hash_mutex_exit(table, fold);
-
-	return(ret);
-}

include/mem0mem.h

@@ -31,13 +31,18 @@ typedef mem_block_info_t	mem_block_t;
 typedef mem_block_t	mem_heap_t;
 
 /* Types of allocation for memory heaps: DYNAMIC means allocation from the
-dynamic memory pool of the C compiler, BUFFER means allocation from the index
-page buffer pool; the latter method is used for very big heaps */
+dynamic memory pool of the C compiler, BUFFER means allocation from the
+buffer pool; the latter method is used for very big heaps */
 
 #define MEM_HEAP_DYNAMIC	0	/* the most common type */
 #define MEM_HEAP_BUFFER		1
-#define MEM_HEAP_BTR_SEARCH	2	/* this flag can be ORed to the
-					previous */
+#define MEM_HEAP_BTR_SEARCH	2	/* this flag can optionally be
+					ORed to MEM_HEAP_BUFFER, in which
+					case heap->free_block is used in
+					some cases for memory allocations,
+					and if it's NULL, the memory
+					allocation functions can return
+					NULL. */
 
 /* The following start size is used for the first block in the memory heap if
 the size is not specified, i.e., 0 is given as the parameter in the call of
@@ -98,13 +103,15 @@ heap freeing. */
 					  (heap), __FILE__, __LINE__)
 /*********************************************************************
 NOTE: Use the corresponding macros instead of this function. Creates a
-memory heap which allocates memory from dynamic space. For debugging
-purposes, takes also the file name and line as argument. */
+memory heap. For debugging purposes, takes also the file name and line as
+arguments. */
 UNIV_INLINE
 mem_heap_t*
 mem_heap_create_func(
 /*=================*/
-					/* out, own: memory heap */
+					/* out, own: memory heap, NULL if
+					did not succeed (only possible for
+					MEM_HEAP_BTR_SEARCH type heaps)*/
 	ulint		n,		/* in: desired start block size,
 					this means that a single user buffer
 					of size n will fit in the block, 
@@ -121,11 +128,9 @@ mem_heap_create_func(
 					block is not unintentionally erased
 					(if allocated in the stack), before
 					the memory heap is explicitly freed. */
-	ulint		type,		/* in: MEM_HEAP_DYNAMIC
-					or MEM_HEAP_BUFFER */ 
+	ulint		type,		/* in: heap type */ 
 	const char*	file_name,	/* in: file name where created */
-	ulint		line		/* in: line where created */
-	);
+	ulint		line);		/* in: line where created */
 /*********************************************************************
 NOTE: Use the corresponding macro instead of this function. Frees the space
 occupied by a memory heap. In the debug version erases the heap memory
@@ -143,8 +148,9 @@ UNIV_INLINE
 void*
 mem_heap_alloc(
 /*===========*/
-				/* out: allocated storage, NULL if
-				did not succeed */
+				/* out: allocated storage, NULL if did not
+				succeed (only possible for
+				MEM_HEAP_BTR_SEARCH type heaps) */
 	mem_heap_t*   	heap, 	/* in: memory heap */
 	ulint           n);	/* in: number of bytes; if the heap is allowed
 				to grow into the buffer pool, this must be
@@ -220,8 +226,7 @@ UNIV_INLINE
 void*
 mem_alloc_func(
 /*===========*/
-					/* out, own: free storage, NULL
-					if did not succeed */
+					/* out, own: free storage */
 	ulint		n,		/* in: desired number of bytes */
 	const char*	file_name,	/* in: file name where created */
 	ulint		line		/* in: line where created */
@@ -235,8 +240,7 @@ with mem_free. */
 void*
 mem_alloc_func_noninline(
 /*=====================*/
-					/* out, own: free storage,
-					NULL if did not succeed */
+					/* out, own: free storage */
 	ulint		n,		/* in: desired number of bytes */
 	const char*	file_name,	/* in: file name where created */
 	ulint		line		/* in: line where created */

include/mem0mem.ic

@@ -16,8 +16,9 @@ Creates a memory heap block where data can be allocated. */
 mem_block_t*
 mem_heap_create_block(
 /*==================*/
-				/* out, own: memory heap block,
-				NULL if did not succeed */
+				/* out, own: memory heap block, NULL if
+				did not succeed (only possible for
+				MEM_HEAP_BTR_SEARCH type heaps) */
 	mem_heap_t*	heap,	/* in: memory heap or NULL if first block
 				should be created */
 	ulint		n,	/* in: number of bytes needed for user data, or
@@ -50,7 +51,8 @@ mem_block_t*
 mem_heap_add_block(
 /*===============*/
 				/* out: created block, NULL if did not
-				succeed */
+				succeed (only possible for
+				MEM_HEAP_BTR_SEARCH type heaps)*/
 	mem_heap_t* 	heap,	/* in: memory heap */
 	ulint		n);	/* in: number of bytes user needs */
 
@@ -126,7 +128,9 @@ UNIV_INLINE
 void*
 mem_heap_alloc(
 /*===========*/
-				/* out: allocated storage */
+				/* out: allocated storage, NULL if did not
+				succeed (only possible for
+				MEM_HEAP_BTR_SEARCH type heaps) */
 	mem_heap_t*	heap, 	/* in: memory heap */
 	ulint           n)      /* in: number of bytes; if the heap is allowed
 				to grow into the buffer pool, this must be
@@ -370,13 +374,15 @@ mem_heap_free_top(
 
 /*********************************************************************
 NOTE: Use the corresponding macros instead of this function. Creates a
-memory heap which allocates memory from dynamic space. For debugging
-purposes, takes also the file name and line as argument. */
+memory heap. For debugging purposes, takes also the file name and line as
+argument. */
 UNIV_INLINE
 mem_heap_t*
 mem_heap_create_func(
 /*=================*/
-					/* out, own: memory heap */
+					/* out, own: memory heap, NULL if
+					did not succeed (only possible for
+					MEM_HEAP_BTR_SEARCH type heaps)*/
 	ulint		n,		/* in: desired start block size,
 					this means that a single user buffer
 					of size n will fit in the block, 
@@ -393,11 +399,9 @@ mem_heap_create_func(
 					block is not unintentionally erased
 					(if allocated in the stack), before
 					the memory heap is explicitly freed. */
-	ulint		type,		/* in: MEM_HEAP_DYNAMIC
-					or MEM_HEAP_BUFFER */ 
+	ulint		type,		/* in: heap type */ 
 	const char*	file_name,	/* in: file name where created */
-	ulint		line		/* in: line where created */
-	)
+	ulint		line)		/* in: line where created */
 {
 	mem_block_t*   block; 
 
@@ -409,8 +413,11 @@ mem_heap_create_func(
 					init_block, type, file_name, line);
 	}
 
-	ut_ad(block);
-
+	if (block == NULL) {
+		
+		return(NULL);
+	}
+	
 	UT_LIST_INIT(block->base);
 
 	/* Add the created block itself as the first block in the list */
@@ -418,11 +425,6 @@ mem_heap_create_func(
 
 #ifdef UNIV_MEM_DEBUG
 
-	if (block == NULL) {
-
-		return(block);
-	}
-
 	mem_hash_insert(block, file_name, line);
 
 #endif
@@ -484,8 +486,7 @@ UNIV_INLINE
 void*
 mem_alloc_func(
 /*===========*/
-					/* out, own: free storage, NULL
-					if did not succeed */
+					/* out, own: free storage */
 	ulint		n,		/* in: desired number of bytes */
 	const char*	file_name,	/* in: file name where created */
 	ulint		line		/* in: line where created */
@@ -496,11 +497,7 @@ mem_alloc_func(
 
 	heap = mem_heap_create_func(n, NULL, MEM_HEAP_DYNAMIC, file_name,
 									line);
-	if (heap == NULL) {
 
-		return(NULL);
-	}
-	
 	/* Note that as we created the first block in the heap big enough
 	for the buffer requested by the caller, the buffer will be in the
 	first block and thus we can calculate the pointer to the heap from

lock/lock0lock.c

@@ -1705,7 +1705,7 @@ static
 lock_t*
 lock_rec_create(
 /*============*/
-				/* out: created lock, NULL if out of memory */
+				/* out: created lock */
 	ulint		type_mode,/* in: lock mode and wait flag, type is
 				ignored and replaced by LOCK_REC */
 	rec_t*		rec,	/* in: record on page */
@@ -1746,11 +1746,6 @@ lock_rec_create(
 	n_bytes = 1 + n_bits / 8;
 
 	lock = mem_heap_alloc(trx->lock_heap, sizeof(lock_t) + n_bytes);
-	
-	if (UNIV_UNLIKELY(lock == NULL)) {
-
-		return(NULL);
-	}
 
 	UT_LIST_ADD_LAST(trx_locks, trx->trx_locks, lock);
 
@@ -1886,8 +1881,7 @@ static
 lock_t*
 lock_rec_add_to_queue(
 /*==================*/
-				/* out: lock where the bit was set, NULL if out
-				of memory */
+				/* out: lock where the bit was set */
 	ulint		type_mode,/* in: lock mode, wait, gap etc. flags;
 				type is ignored and replaced by LOCK_REC */
 	rec_t*		rec,	/* in: record on page */
@@ -3405,8 +3399,7 @@ UNIV_INLINE
 lock_t*
 lock_table_create(
 /*==============*/
-				/* out, own: new lock object, or NULL if
-				out of memory */
+				/* out, own: new lock object */
 	dict_table_t*	table,	/* in: database table in dictionary cache */
 	ulint		type_mode,/* in: lock mode possibly ORed with
 				LOCK_WAIT */
@@ -3432,11 +3425,6 @@ lock_table_create(
 		lock = mem_heap_alloc(trx->lock_heap, sizeof(lock_t));
 	}
 
-	if (lock == NULL) {
-
-		return(NULL);
-	}
-
 	UT_LIST_ADD_LAST(trx_locks, trx->trx_locks, lock);
 
 	lock->type_mode = type_mode | LOCK_TABLE;

mem/mem0mem.c

@@ -92,12 +92,10 @@ with mem_free. */
 void*
 mem_alloc_func_noninline(
 /*=====================*/
-					/* out, own: free storage,
-					NULL if did not succeed */
+					/* out, own: free storage */
 	ulint		n,		/* in: desired number of bytes */
 	const char*	file_name,	/* in: file name where created */
-	ulint		line		/* in: line where created */
-	)
+	ulint		line)		/* in: line where created */
 {
 	return(mem_alloc_func(n, file_name, line));	
 }
@@ -122,8 +120,9 @@ Creates a memory heap block where data can be allocated. */
 mem_block_t*
 mem_heap_create_block(
 /*==================*/
-				/* out, own: memory heap block,
-				NULL if did not succeed */
+				/* out, own: memory heap block, NULL if
+				did not succeed (only possible for
+				MEM_HEAP_BTR_SEARCH type heaps) */
 	mem_heap_t*	heap,	/* in: memory heap or NULL if first block
 				should be created */
 	ulint		n,	/* in: number of bytes needed for user data, or
@@ -182,6 +181,8 @@ mem_heap_create_block(
 	}
 
 	if (block == NULL) {
+		/* Only MEM_HEAP_BTR_SEARCH allocation should ever fail. */
+		ut_a(type & MEM_HEAP_BTR_SEARCH);
 
 		return(NULL);
 	}
@@ -222,7 +223,8 @@ mem_block_t*
 mem_heap_add_block(
 /*===============*/
 				/* out: created block, NULL if did not
-				succeed */
+				succeed (only possible for
+				MEM_HEAP_BTR_SEARCH type heaps)*/
 	mem_heap_t* 	heap,	/* in: memory heap */
 	ulint		n)	/* in: number of bytes user needs */
 {