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maple_tree: check for MA_STATE_BULK on setting wr_rebalance

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It is possible for a bulk operation (MA_STATE_BULK is set) to enter the
new_end < mt_min_slots[type] case and set wr_rebalance as a store type. 
This is incorrect as bulk stores do not rebalance per write, but rather
after the all of the writes are done through the mas_bulk_rebalance()
path.  Therefore, add a check to make sure MA_STATE_BULK is not set before
we return wr_rebalance as the store type.

Also add a test to make sure wr_rebalance is never the store type when
doing bulk operations via mas_expected_entries()

This is a hotfix for this rc however it has no userspace effects as there
are no users of the bulk insertion mode.

Link: https://lkml.kernel.org/r/20241011214451.7286-1-sidhartha.kumar@oracle.com
Fixes: 5d659bbb52 ("maple_tree: introduce mas_wr_store_type()")
Suggested-by: Liam Howlett <liam.howlett@oracle.com>
Signed-off-by: Sidhartha <sidhartha.kumar@oracle.com>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Liam Howlett <liam.howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Sidhartha Kumar 2024-10-11 17:44:50 -04:00 committed by Andrew Morton
parent 37f0b47c51
commit a6e0ceb7bf
2 changed files with 27 additions and 1 deletions
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2
lib/maple_tree.c
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@ -4218,7 +4218,7 @@ static inline void mas_wr_store_type(struct ma_wr_state *wr_mas)
/* Potential spanning rebalance collapsing a node */
if (new_end < mt_min_slots[wr_mas->type]) {
if (!mte_is_root(mas->node)) {
if (!mte_is_root(mas->node) && !(mas->mas_flags & MA_STATE_BULK)) {
mas->store_type = wr_rebalance;
return;
}

26
tools/testing/radix-tree/maple.c
View File

@ -36317,6 +36317,28 @@ static inline int check_vma_modification(struct maple_tree *mt)
return 0;
}
/*
* test to check that bulk stores do not use wr_rebalance as the store
* type.
*/
static inline void check_bulk_rebalance(struct maple_tree *mt)
{
MA_STATE(mas, mt, ULONG_MAX, ULONG_MAX);
int max = 10;
build_full_tree(mt, 0, 2);
/* erase every entry in the tree */
do {
/* set up bulk store mode */
mas_expected_entries(&mas, max);
mas_erase(&mas);
MT_BUG_ON(mt, mas.store_type == wr_rebalance);
} while (mas_prev(&mas, 0) != NULL);
mas_destroy(&mas);
}
void farmer_tests(void)
{
struct maple_node *node;
@ -36328,6 +36350,10 @@ void farmer_tests(void)
check_vma_modification(&tree);
mtree_destroy(&tree);
mt_init(&tree);
check_bulk_rebalance(&tree);
mtree_destroy(&tree);
tree.ma_root = xa_mk_value(0);
mt_dump(&tree, mt_dump_dec);