From 64d3e9a9e0cc51957d243dd2b0adc5d74ff5e128 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Fri, 1 Dec 2017 00:06:52 -0500 Subject: xarray: Step through an XArray The xas_next and xas_prev functions move the xas index by one position, and adjust the rest of the iterator state to match it. This is more efficient than calling xas_set() as it keeps the iterator at the leaves of the tree instead of walking the iterator from the root each time. Signed-off-by: Matthew Wilcox --- lib/test_xarray.c | 115 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ lib/xarray.c | 74 +++++++++++++++++++++++++++++++++++ 2 files changed, 189 insertions(+) (limited to 'lib') diff --git a/lib/test_xarray.c b/lib/test_xarray.c index a96f67caa1c2..85ef1882dd3c 100644 --- a/lib/test_xarray.c +++ b/lib/test_xarray.c @@ -465,6 +465,120 @@ static noinline void check_find(struct xarray *xa) check_multi_find_2(xa); } +static noinline void check_move_small(struct xarray *xa, unsigned long idx) +{ + XA_STATE(xas, xa, 0); + unsigned long i; + + xa_store_index(xa, 0, GFP_KERNEL); + xa_store_index(xa, idx, GFP_KERNEL); + + rcu_read_lock(); + for (i = 0; i < idx * 4; i++) { + void *entry = xas_next(&xas); + if (i <= idx) + XA_BUG_ON(xa, xas.xa_node == XAS_RESTART); + XA_BUG_ON(xa, xas.xa_index != i); + if (i == 0 || i == idx) + XA_BUG_ON(xa, entry != xa_mk_value(i)); + else + XA_BUG_ON(xa, entry != NULL); + } + xas_next(&xas); + XA_BUG_ON(xa, xas.xa_index != i); + + do { + void *entry = xas_prev(&xas); + i--; + if (i <= idx) + XA_BUG_ON(xa, xas.xa_node == XAS_RESTART); + XA_BUG_ON(xa, xas.xa_index != i); + if (i == 0 || i == idx) + XA_BUG_ON(xa, entry != xa_mk_value(i)); + else + XA_BUG_ON(xa, entry != NULL); + } while (i > 0); + + xas_set(&xas, ULONG_MAX); + XA_BUG_ON(xa, xas_next(&xas) != NULL); + XA_BUG_ON(xa, xas.xa_index != ULONG_MAX); + XA_BUG_ON(xa, xas_next(&xas) != xa_mk_value(0)); + XA_BUG_ON(xa, xas.xa_index != 0); + XA_BUG_ON(xa, xas_prev(&xas) != NULL); + XA_BUG_ON(xa, xas.xa_index != ULONG_MAX); + rcu_read_unlock(); + + xa_erase_index(xa, 0); + xa_erase_index(xa, idx); + XA_BUG_ON(xa, !xa_empty(xa)); +} + +static noinline void check_move(struct xarray *xa) +{ + XA_STATE(xas, xa, (1 << 16) - 1); + unsigned long i; + + for (i = 0; i < (1 << 16); i++) + XA_BUG_ON(xa, xa_store_index(xa, i, GFP_KERNEL) != NULL); + + rcu_read_lock(); + do { + void *entry = xas_prev(&xas); + i--; + XA_BUG_ON(xa, entry != xa_mk_value(i)); + XA_BUG_ON(xa, i != xas.xa_index); + } while (i != 0); + + XA_BUG_ON(xa, xas_prev(&xas) != NULL); + XA_BUG_ON(xa, xas.xa_index != ULONG_MAX); + + do { + void *entry = xas_next(&xas); + XA_BUG_ON(xa, entry != xa_mk_value(i)); + XA_BUG_ON(xa, i != xas.xa_index); + i++; + } while (i < (1 << 16)); + rcu_read_unlock(); + + for (i = (1 << 8); i < (1 << 15); i++) + xa_erase_index(xa, i); + + i = xas.xa_index; + + rcu_read_lock(); + do { + void *entry = xas_prev(&xas); + i--; + if ((i < (1 << 8)) || (i >= (1 << 15))) + XA_BUG_ON(xa, entry != xa_mk_value(i)); + else + XA_BUG_ON(xa, entry != NULL); + XA_BUG_ON(xa, i != xas.xa_index); + } while (i != 0); + + XA_BUG_ON(xa, xas_prev(&xas) != NULL); + XA_BUG_ON(xa, xas.xa_index != ULONG_MAX); + + do { + void *entry = xas_next(&xas); + if ((i < (1 << 8)) || (i >= (1 << 15))) + XA_BUG_ON(xa, entry != xa_mk_value(i)); + else + XA_BUG_ON(xa, entry != NULL); + XA_BUG_ON(xa, i != xas.xa_index); + i++; + } while (i < (1 << 16)); + rcu_read_unlock(); + + xa_destroy(xa); + + for (i = 0; i < 16; i++) + check_move_small(xa, 1UL << i); + + for (i = 2; i < 16; i++) + check_move_small(xa, (1UL << i) - 1); +} + static noinline void check_destroy(struct xarray *xa) { unsigned long index; @@ -512,6 +626,7 @@ static int xarray_checks(void) check_multi_store(&array); check_find(&array); check_destroy(&array); + check_move(&array); printk("XArray: %u of %u tests passed\n", tests_passed, tests_run); return (tests_run == tests_passed) ? 0 : -EINVAL; diff --git a/lib/xarray.c b/lib/xarray.c index 057dbe0d3bf6..303c46579598 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -876,6 +876,80 @@ void xas_pause(struct xa_state *xas) } EXPORT_SYMBOL_GPL(xas_pause); +/* + * __xas_prev() - Find the previous entry in the XArray. + * @xas: XArray operation state. + * + * Helper function for xas_prev() which handles all the complex cases + * out of line. + */ +void *__xas_prev(struct xa_state *xas) +{ + void *entry; + + if (!xas_frozen(xas->xa_node)) + xas->xa_index--; + if (xas_not_node(xas->xa_node)) + return xas_load(xas); + + if (xas->xa_offset != get_offset(xas->xa_index, xas->xa_node)) + xas->xa_offset--; + + while (xas->xa_offset == 255) { + xas->xa_offset = xas->xa_node->offset - 1; + xas->xa_node = xa_parent(xas->xa, xas->xa_node); + if (!xas->xa_node) + return set_bounds(xas); + } + + for (;;) { + entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset); + if (!xa_is_node(entry)) + return entry; + + xas->xa_node = xa_to_node(entry); + xas_set_offset(xas); + } +} +EXPORT_SYMBOL_GPL(__xas_prev); + +/* + * __xas_next() - Find the next entry in the XArray. + * @xas: XArray operation state. + * + * Helper function for xas_next() which handles all the complex cases + * out of line. + */ +void *__xas_next(struct xa_state *xas) +{ + void *entry; + + if (!xas_frozen(xas->xa_node)) + xas->xa_index++; + if (xas_not_node(xas->xa_node)) + return xas_load(xas); + + if (xas->xa_offset != get_offset(xas->xa_index, xas->xa_node)) + xas->xa_offset++; + + while (xas->xa_offset == XA_CHUNK_SIZE) { + xas->xa_offset = xas->xa_node->offset + 1; + xas->xa_node = xa_parent(xas->xa, xas->xa_node); + if (!xas->xa_node) + return set_bounds(xas); + } + + for (;;) { + entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset); + if (!xa_is_node(entry)) + return entry; + + xas->xa_node = xa_to_node(entry); + xas_set_offset(xas); + } +} +EXPORT_SYMBOL_GPL(__xas_next); + /** * xas_find() - Find the next present entry in the XArray. * @xas: XArray operation state. -- cgit v1.2.3