Commit e777ae44 authored by Daniel Gomez's avatar Daniel Gomez Committed by Andrew Morton
Browse files

XArray: add cmpxchg order test 

XArray multi-index entries do not keep track of the order stored once the
entry is being marked as used with cmpxchg (conditionally replaced with
NULL).  Add a test to check the order is actually lost.  The test also
verifies the order and entries for all the tied indexes before and after
the NULL replacement with xa_cmpxchg.

Add another entry at 1 << order that keeps the node around and the order
information for the NULL-entry after xa_cmpxchg.

Link: https://lkml.kernel.org/r/20240131225125.1370598-3-mcgrof@kernel.org


Signed-off-by: default avatarDaniel Gomez <da.gomez@samsung.com>
Signed-off-by: default avatarLuis Chamberlain <mcgrof@kernel.org>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent a60cc288

lib/test_xarray.c

+54 −0
Original line number Diff line number Diff line
@@ -423,6 +423,59 @@ static noinline void check_cmpxchg(struct xarray *xa) 
	XA_BUG_ON(xa, !xa_empty(xa));

}



static noinline void check_cmpxchg_order(struct xarray *xa)

{

#ifdef CONFIG_XARRAY_MULTI

	void *FIVE = xa_mk_value(5);

	unsigned int i, order = 3;



	XA_BUG_ON(xa, xa_store_order(xa, 0, order, FIVE, GFP_KERNEL));



	/* Check entry FIVE has the order saved */

	XA_BUG_ON(xa, xa_get_order(xa, xa_to_value(FIVE)) != order);



	/* Check all the tied indexes have the same entry and order */

	for (i = 0; i < (1 << order); i++) {

		XA_BUG_ON(xa, xa_load(xa, i) != FIVE);

		XA_BUG_ON(xa, xa_get_order(xa, i) != order);

	}



	/* Ensure that nothing is stored at index '1 << order' */

	XA_BUG_ON(xa, xa_load(xa, 1 << order) != NULL);



	/*

	 * Additionally, keep the node information and the order at

	 * '1 << order'

	 */

	XA_BUG_ON(xa, xa_store_order(xa, 1 << order, order, FIVE, GFP_KERNEL));

	for (i = (1 << order); i < (1 << order) + (1 << order) - 1; i++) {

		XA_BUG_ON(xa, xa_load(xa, i) != FIVE);

		XA_BUG_ON(xa, xa_get_order(xa, i) != order);

	}



	/* Conditionally replace FIVE entry at index '0' with NULL */

	XA_BUG_ON(xa, xa_cmpxchg(xa, 0, FIVE, NULL, GFP_KERNEL) != FIVE);



	/* Verify the order is lost at FIVE (and old) entries */

	XA_BUG_ON(xa, xa_get_order(xa, xa_to_value(FIVE)) != 0);



	/* Verify the order and entries are lost in all the tied indexes */

	for (i = 0; i < (1 << order); i++) {

		XA_BUG_ON(xa, xa_load(xa, i) != NULL);

		XA_BUG_ON(xa, xa_get_order(xa, i) != 0);

	}



	/* Verify node and order are kept at '1 << order' */

	for (i = (1 << order); i < (1 << order) + (1 << order) - 1; i++) {

		XA_BUG_ON(xa, xa_load(xa, i) != FIVE);

		XA_BUG_ON(xa, xa_get_order(xa, i) != order);

	}



	xa_store_order(xa, 0, BITS_PER_LONG - 1, NULL, GFP_KERNEL);

	XA_BUG_ON(xa, !xa_empty(xa));

#endif

}



static noinline void check_reserve(struct xarray *xa)

{

	void *entry;
@@ -1976,6 +2029,7 @@ static int xarray_checks(void) 
	check_xas_erase(&array);

	check_insert(&array);

	check_cmpxchg(&array);

	check_cmpxchg_order(&array);

	check_reserve(&array);

	check_reserve(&xa0);

	check_multi_store(&array);