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XArray: Fix splitting to non-zero orders

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Splitting an order-4 entry into order-2 entries would leave the array
containing pointers to 000040008000c000 instead of 000044448888cccc.
This is a one-character fix, but enhance the test suite to check this
case.

Reported-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
This commit is contained in:
Matthew Wilcox (Oracle) 2020-11-19 08:32:31 -05:00
parent 12efebab09
commit 3012110d71
2 changed files with 16 additions and 14 deletions
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26
lib/test_xarray.c
View File

@ -1530,24 +1530,24 @@ static noinline void check_store_range(struct xarray *xa)
#ifdef CONFIG_XARRAY_MULTI #ifdef CONFIG_XARRAY_MULTI
static void check_split_1(struct xarray *xa, unsigned long index, static void check_split_1(struct xarray *xa, unsigned long index,
unsigned int order) unsigned int order, unsigned int new_order)
{ {
XA_STATE(xas, xa, index); XA_STATE_ORDER(xas, xa, index, new_order);
void *entry; unsigned int i;
unsigned int i = 0;
xa_store_order(xa, index, order, xa, GFP_KERNEL); xa_store_order(xa, index, order, xa, GFP_KERNEL);
xas_split_alloc(&xas, xa, order, GFP_KERNEL); xas_split_alloc(&xas, xa, order, GFP_KERNEL);
xas_lock(&xas); xas_lock(&xas);
xas_split(&xas, xa, order); xas_split(&xas, xa, order);
for (i = 0; i < (1 << order); i += (1 << new_order))
__xa_store(xa, index + i, xa_mk_index(index + i), 0);
xas_unlock(&xas); xas_unlock(&xas);
xa_for_each(xa, index, entry) { for (i = 0; i < (1 << order); i++) {
XA_BUG_ON(xa, entry != xa); unsigned int val = index + (i & ~((1 << new_order) - 1));
i++; XA_BUG_ON(xa, xa_load(xa, index + i) != xa_mk_index(val));
} }
XA_BUG_ON(xa, i != 1 << order);
xa_set_mark(xa, index, XA_MARK_0); xa_set_mark(xa, index, XA_MARK_0);
XA_BUG_ON(xa, !xa_get_mark(xa, index, XA_MARK_0)); XA_BUG_ON(xa, !xa_get_mark(xa, index, XA_MARK_0));
@ -1557,14 +1557,16 @@ static void check_split_1(struct xarray *xa, unsigned long index,
static noinline void check_split(struct xarray *xa) static noinline void check_split(struct xarray *xa)
{ {
unsigned int order; unsigned int order, new_order;
XA_BUG_ON(xa, !xa_empty(xa)); XA_BUG_ON(xa, !xa_empty(xa));
for (order = 1; order < 2 * XA_CHUNK_SHIFT; order++) { for (order = 1; order < 2 * XA_CHUNK_SHIFT; order++) {
check_split_1(xa, 0, order); for (new_order = 0; new_order < order; new_order++) {
check_split_1(xa, 1UL << order, order); check_split_1(xa, 0, order, new_order);
check_split_1(xa, 3UL << order, order); check_split_1(xa, 1UL << order, order, new_order);
check_split_1(xa, 3UL << order, order, new_order);
}
} }
} }
#else #else

4
lib/xarray.c
View File

@ -1011,7 +1011,7 @@ void xas_split_alloc(struct xa_state *xas, void *entry, unsigned int order,
do { do {
unsigned int i; unsigned int i;
void *sibling; void *sibling = NULL;
struct xa_node *node; struct xa_node *node;
node = kmem_cache_alloc(radix_tree_node_cachep, gfp); node = kmem_cache_alloc(radix_tree_node_cachep, gfp);
@ -1021,7 +1021,7 @@ void xas_split_alloc(struct xa_state *xas, void *entry, unsigned int order,
for (i = 0; i < XA_CHUNK_SIZE; i++) { for (i = 0; i < XA_CHUNK_SIZE; i++) {
if ((i & mask) == 0) { if ((i & mask) == 0) {
RCU_INIT_POINTER(node->slots[i], entry); RCU_INIT_POINTER(node->slots[i], entry);
sibling = xa_mk_sibling(0); sibling = xa_mk_sibling(i);
} else { } else {
RCU_INIT_POINTER(node->slots[i], sibling); RCU_INIT_POINTER(node->slots[i], sibling);
} }