lib/xarray: introduce a new helper xas_get_order

commit a4864671ca0bf51c8e78242951741df52c06766f upstream.

It can be used after xas_load to check the order of loaded entries.
Compared to xa_get_order, it saves an XA_STATE and avoid a rewalk.

Added new test for xas_get_order, to make the test work, we have to export
xas_get_order with EXPORT_SYMBOL_GPL.

Also fix a sparse warning by checking the slot value with xa_entry instead
of accessing it directly, as suggested by Matthew Wilcox.

[kasong@tencent.com: simplify comment, sparse warning fix, per Matthew Wilcox]
  Link: https://lkml.kernel.org/r/20240416071722.45997-4-ryncsn@gmail.com
Link: https://lkml.kernel.org/r/20240415171857.19244-4-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: 6758c1128ceb ("mm/filemap: optimize filemap folio adding")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Kairui Song
2024-10-02 05:06:24 +08:00
committed by Greg Kroah-Hartman
parent ff3c557fa9
commit 734594d41c
3 changed files with 73 additions and 20 deletions

View File

@@ -1756,6 +1756,39 @@ static noinline void check_get_order(struct xarray *xa)
}
}
static noinline void check_xas_get_order(struct xarray *xa)
{
XA_STATE(xas, xa, 0);
unsigned int max_order = IS_ENABLED(CONFIG_XARRAY_MULTI) ? 20 : 1;
unsigned int order;
unsigned long i, j;
for (order = 0; order < max_order; order++) {
for (i = 0; i < 10; i++) {
xas_set_order(&xas, i << order, order);
do {
xas_lock(&xas);
xas_store(&xas, xa_mk_value(i));
xas_unlock(&xas);
} while (xas_nomem(&xas, GFP_KERNEL));
for (j = i << order; j < (i + 1) << order; j++) {
xas_set_order(&xas, j, 0);
rcu_read_lock();
xas_load(&xas);
XA_BUG_ON(xa, xas_get_order(&xas) != order);
rcu_read_unlock();
}
xas_lock(&xas);
xas_set_order(&xas, i << order, order);
xas_store(&xas, NULL);
xas_unlock(&xas);
}
}
}
static noinline void check_destroy(struct xarray *xa)
{
unsigned long index;
@@ -1805,6 +1838,7 @@ static int xarray_checks(void)
check_reserve(&xa0);
check_multi_store(&array);
check_get_order(&array);
check_xas_get_order(&array);
check_xa_alloc();
check_find(&array);
check_find_entry(&array);