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add a helper function to test if an object is on the stack

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lib/debugobjects.c has a function to test if an object is on the stack.
The block layer and ide needs it (they need to avoid DMA from/to stack
buffers).  This patch moves the function to include/linux/sched.h so that
everyone can use it.

lib/debugobjects.c uses current->stack but this patch uses a
task_stack_page() accessor, which is a preferable way to access the stack.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Andy Whitcroft <apw@shadowen.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
FUJITA Tomonori 2008-07-23 21:26:53 -07:00 committed by Linus Torvalds
parent 68ad8df42e
commit 8b05c7e6e1
2 changed files with 8 additions and 3 deletions
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7
include/linux/sched.h
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@ -1983,6 +1983,13 @@ static inline unsigned long *end_of_stack(struct task_struct *p)
#endif
static inline int object_is_on_stack(void *obj)
{
void *stack = task_stack_page(current);
return (obj >= stack) && (obj < (stack + THREAD_SIZE));
}
extern void thread_info_cache_init(void);
/* set thread flags in other task's structures

4
lib/debugobjects.c
View file

@ -226,15 +226,13 @@ debug_object_fixup(int (*fixup)(void *addr, enum debug_obj_state state),
static void debug_object_is_on_stack(void *addr, int onstack)
{
void *stack = current->stack;
int is_on_stack;
static int limit;
if (limit > 4)
return;
is_on_stack = (addr >= stack && addr < (stack + THREAD_SIZE));
is_on_stack = object_is_on_stack(addr);
if (is_on_stack == onstack)
return;