Commit 687149fc authored by Matthew Wilcox's avatar Matthew Wilcox
Browse files

xarray: Destroy an XArray 



This function frees all the internal memory allocated to the xarray
and reinitialises it to be empty.

Signed-off-by: default avatarMatthew Wilcox <willy@infradead.org>
parent 80a0a1a9

include/linux/xarray.h

+1 −0
Original line number Diff line number Diff line
@@ -286,6 +286,7 @@ void *xa_find_after(struct xarray *xa, unsigned long *index, 
		unsigned long max, xa_mark_t) __attribute__((nonnull(2)));

unsigned int xa_extract(struct xarray *, void **dst, unsigned long start,

		unsigned long max, unsigned int n, xa_mark_t);

void xa_destroy(struct xarray *);



/**

 * xa_init() - Initialise an empty XArray.

lib/test_xarray.c

+34 −0
Original line number Diff line number Diff line
@@ -465,6 +465,39 @@ static noinline void check_find(struct xarray *xa) 
	check_multi_find_2(xa);

}



static noinline void check_destroy(struct xarray *xa)

{

	unsigned long index;



	XA_BUG_ON(xa, !xa_empty(xa));



	/* Destroying an empty array is a no-op */

	xa_destroy(xa);

	XA_BUG_ON(xa, !xa_empty(xa));



	/* Destroying an array with a single entry */

	for (index = 0; index < 1000; index++) {

		xa_store_index(xa, index, GFP_KERNEL);

		XA_BUG_ON(xa, xa_empty(xa));

		xa_destroy(xa);

		XA_BUG_ON(xa, !xa_empty(xa));

	}



	/* Destroying an array with a single entry at ULONG_MAX */

	xa_store(xa, ULONG_MAX, xa, GFP_KERNEL);

	XA_BUG_ON(xa, xa_empty(xa));

	xa_destroy(xa);

	XA_BUG_ON(xa, !xa_empty(xa));



#ifdef CONFIG_XARRAY_MULTI

	/* Destroying an array with a multi-index entry */

	xa_store_order(xa, 1 << 11, 11, xa, GFP_KERNEL);

	XA_BUG_ON(xa, xa_empty(xa));

	xa_destroy(xa);

	XA_BUG_ON(xa, !xa_empty(xa));

#endif

}



static DEFINE_XARRAY(array);



static int xarray_checks(void)
@@ -478,6 +511,7 @@ static int xarray_checks(void) 
	check_cmpxchg(&array);

	check_multi_store(&array);

	check_find(&array);

	check_destroy(&array);



	printk("XArray: %u of %u tests passed\n", tests_passed, tests_run);

	return (tests_run == tests_passed) ? 0 : -EINVAL;

lib/xarray.c

+28 −0
Original line number Diff line number Diff line
@@ -1524,6 +1524,34 @@ unsigned int xa_extract(struct xarray *xa, void **dst, unsigned long start, 
}

EXPORT_SYMBOL(xa_extract);



/**

 * xa_destroy() - Free all internal data structures.

 * @xa: XArray.

 *

 * After calling this function, the XArray is empty and has freed all memory

 * allocated for its internal data structures.  You are responsible for

 * freeing the objects referenced by the XArray.

 *

 * Context: Any context.  Takes and releases the xa_lock, interrupt-safe.

 */

void xa_destroy(struct xarray *xa)

{

	XA_STATE(xas, xa, 0);

	unsigned long flags;

	void *entry;



	xas.xa_node = NULL;

	xas_lock_irqsave(&xas, flags);

	entry = xa_head_locked(xa);

	RCU_INIT_POINTER(xa->xa_head, NULL);

	xas_init_marks(&xas);

	/* lockdep checks we're still holding the lock in xas_free_nodes() */

	if (xa_is_node(entry))

		xas_free_nodes(&xas, xa_to_node(entry));

	xas_unlock_irqrestore(&xas, flags);

}

EXPORT_SYMBOL(xa_destroy);



#ifdef XA_DEBUG

void xa_dump_node(const struct xa_node *node)

{