The patch titled
Subject: maple_tree: fix alloc node fail issue
has been added to the -mm mm-unstable branch. Its filename is
maple_tree-fix-alloc-node-fail-issue.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/maple_tree-fix-alloc-node-fail-issue.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Jiazi Li <jqqlijiazi@xxxxxxxxx>
Subject: maple_tree: fix alloc node fail issue
Date: Wed, 26 Jun 2024 12:06:30 -0400
In the following code, the second call to the mas_node_count will return
-ENOMEM:
mas_node_count(mas, MAPLE_ALLOC_SLOTS + 1);
mas_node_count(mas, MAPLE_ALLOC_SLOTS * 2 + 2);
This is because there may be some full maple_alloc node in current maple
state. Use full maple_alloc node will make max_req equal to 0. And it
leads to mt_alloc_bulk return 0. As a result, mas_node_count set mas.node
to MA_ERROR(-ENOMEM).
Find a non-full maple_alloc node, and if necessary, use this non-full node
in the next while loop.
Link: https://lkml.kernel.org/r/20240626160631.3636515-1-Liam.Howlett@xxxxxxxxxx
Fixes: 54a611b60590 ("Maple Tree: add new data structure")
Signed-off-by: Jiazi Li <jqqlijiazi@xxxxxxxxx>
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Suggested-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Reviewed-by: Wei Yang <richard.weiyang@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/maple_tree.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- a/lib/maple_tree.c~maple_tree-fix-alloc-node-fail-issue
+++ a/lib/maple_tree.c
@@ -1285,7 +1285,10 @@ static inline void mas_alloc_nodes(struc
node->node_count += count;
allocated += count;
- node = node->slot[0];
+ /* find a non-full node*/
+ do {
+ node = node->slot[0];
+ } while (unlikely(node->node_count == MAPLE_ALLOC_SLOTS));
requested -= count;
}
mas->alloc->total = allocated;
_
Patches currently in -mm which might be from jqqlijiazi@xxxxxxxxx are
maple_tree-fix-alloc-node-fail-issue.patch
maple_tree-add-some-alloc-node-test-case.patch
