[merged mm-hotfixes-stable] maple_tree-check-for-ma_state_bulk-on-setting-wr_rebalance.patch removed from -mm tree

[merged mm-hotfixes-stable] maple_tree-check-for-ma_state_bulk-on-setting-wr_rebalance.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: maple_tree: check for MA_STATE_BULK on setting wr_rebalance
has been removed from the -mm tree.  Its filename was
     maple_tree-check-for-ma_state_bulk-on-setting-wr_rebalance.patch

This patch was dropped because it was merged into the mm-hotfixes-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Subject: maple_tree: check for MA_STATE_BULK on setting wr_rebalance
Date: Fri, 11 Oct 2024 17:44:50 -0400

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: 5d659bbb52a2 ("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>
---

 lib/maple_tree.c                 |    2 +-
 tools/testing/radix-tree/maple.c |   26 ++++++++++++++++++++++++++
 2 files changed, 27 insertions(+), 1 deletion(-)

--- a/lib/maple_tree.c~maple_tree-check-for-ma_state_bulk-on-setting-wr_rebalance
+++ a/lib/maple_tree.c
@@ -4218,7 +4218,7 @@ static inline void mas_wr_store_type(str
 
 	/* 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;
 		}
--- a/tools/testing/radix-tree/maple.c~maple_tree-check-for-ma_state_bulk-on-setting-wr_rebalance
+++ a/tools/testing/radix-tree/maple.c
@@ -36317,6 +36317,28 @@ static inline int check_vma_modification
 	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);
 
_

Patches currently in -mm which might be from sidhartha.kumar@oracle.com are

maple_tree-refactor-mas_wr_store_type.patch