[PATCH] fix/simplify mutex debugging code

Let's switch mutex_debug_check_no_locks_freed() to take (addr, len) as
arguments instead, since all its callers were just calculating the 'to'
address for themselves anyway... (and sometimes doing so badly).
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/i386/mm/pageattr.c

@@ -224,7 +224,7 @@ void kernel_map_pages(struct page *page, int numpages, int enable)
 		return;
 	if (!enable)
 		mutex_debug_check_no_locks_freed(page_address(page),
-						 page_address(page+numpages));
+						 numpages * PAGE_SIZE);
 
 	/* the return value is ignored - the calls cannot fail,
 	 * large pages are disabled at boot time.

include/linux/mm.h

@@ -1027,7 +1027,7 @@ kernel_map_pages(struct page *page, int numpages, int enable)
 {
 	if (!PageHighMem(page) && !enable)
 		mutex_debug_check_no_locks_freed(page_address(page),
-						 page_address(page + numpages));
+						 numpages * PAGE_SIZE);
 }
 #endif
 

include/linux/mutex-debug.h

@@ -18,6 +18,6 @@ extern void FASTCALL(mutex_destroy(struct mutex *lock));
 extern void mutex_debug_show_all_locks(void);
 extern void mutex_debug_show_held_locks(struct task_struct *filter);
 extern void mutex_debug_check_no_locks_held(struct task_struct *task);
-extern void mutex_debug_check_no_locks_freed(const void *from, const void *to);
+extern void mutex_debug_check_no_locks_freed(const void *from, unsigned long len);
 
 #endif

include/linux/mutex.h

@@ -79,7 +79,7 @@ struct mutex_waiter {
 # define mutex_debug_show_all_locks()			do { } while (0)
 # define mutex_debug_show_held_locks(p)			do { } while (0)
 # define mutex_debug_check_no_locks_held(task)		do { } while (0)
-# define mutex_debug_check_no_locks_freed(from, to)	do { } while (0)
+# define mutex_debug_check_no_locks_freed(from, len)	do { } while (0)
 #endif
 
 #define __MUTEX_INITIALIZER(lockname) \

kernel/mutex-debug.c

@@ -333,9 +333,10 @@ void mutex_debug_check_no_locks_held(struct task_struct *task)
  * is destroyed or reinitialized - this code checks whether there is
  * any held lock in the memory range of <from> to <to>:
  */
-void mutex_debug_check_no_locks_freed(const void *from, const void *to)
+void mutex_debug_check_no_locks_freed(const void *from, unsigned long len)
 {
 	struct list_head *curr, *next;
+	const void *to = from + len;
 	unsigned long flags;
 	struct mutex *lock;
 	void *lock_addr;
@@ -437,7 +438,7 @@ void debug_mutex_init(struct mutex *lock, const char *name)
 	/*
 	 * Make sure we are not reinitializing a held lock:
 	 */
-	mutex_debug_check_no_locks_freed((void *)lock, (void *)(lock + 1));
+	mutex_debug_check_no_locks_freed((void *)lock, sizeof(*lock));
 	lock->owner = NULL;
 	INIT_LIST_HEAD(&lock->held_list);
 	lock->name = name;

mm/page_alloc.c

@@ -417,7 +417,7 @@ static void __free_pages_ok(struct page *page, unsigned int order)
 	arch_free_page(page, order);
 	if (!PageHighMem(page))
 		mutex_debug_check_no_locks_freed(page_address(page),
-			page_address(page+(1<<order)));
+						 PAGE_SIZE<<order);
 
 #ifndef CONFIG_MMU
 	for (i = 1 ; i < (1 << order) ; ++i)

mm/slab.c

@@ -3071,7 +3071,7 @@ void kfree(const void *objp)
 	local_irq_save(flags);
 	kfree_debugcheck(objp);
 	c = page_get_cache(virt_to_page(objp));
-	mutex_debug_check_no_locks_freed(objp, objp+obj_reallen(c));
+	mutex_debug_check_no_locks_freed(objp, obj_reallen(c));
 	__cache_free(c, (void *)objp);
 	local_irq_restore(flags);
 }