+ maple-tree-add-new-data-structure-fix.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: maple_tree: Fix expanding null off the end of the data.
has been added to the -mm mm-unstable branch.  Its filename is
     maple-tree-add-new-data-structure-fix.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/maple-tree-add-new-data-structure-fix.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: Liam Howlett <liam.howlett@oracle.com>
Subject: maple_tree: Fix expanding null off the end of the data.

When expanding a write of null to another null, the metadata for the end
of the node may be off by one.  Fix this issue by setting the write end
pivot (wr_mas->end_piv) in mas_wr_extend_null().  Also use the saved value
for the end pivot during node stores instead of looking up the same entry
again.

There is also unnecessary code in mas_wr_extend_null() that can be
dropped.

Link: https://lkml.kernel.org/r/20220511144304.1430851-2-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 lib/maple_tree.c |    8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

--- a/lib/maple_tree.c~maple-tree-add-new-data-structure-fix
+++ a/lib/maple_tree.c
@@ -3981,8 +3981,7 @@ static inline bool mas_wr_node_store(str
 
 		new_end++;
 	} else {
-		if (mas_safe_pivot(mas, wr_mas->pivots, wr_mas->offset_end,
-				   wr_mas->type) == mas->last)
+		if (wr_mas->end_piv == mas->last)
 			wr_mas->offset_end++;
 
 		new_end -= wr_mas->offset_end - offset - 1;
@@ -4146,10 +4145,7 @@ static inline void mas_wr_extend_null(st
 			mas->last = mas->max;
 		else
 			mas->last = wr_mas->pivots[wr_mas->offset_end];
-	} else if ((mas->last > wr_mas->end_piv) &&
-		   !wr_mas->slots[wr_mas->offset_end]) {
-		mas->last = wr_mas->end_piv;
-		wr_mas->offset_end++;
+		wr_mas->end_piv = mas->last;
 	}
 
 	if (!wr_mas->content) {
_

Patches currently in -mm which might be from liam.howlett@oracle.com are

maple-tree-add-new-data-structure-fix.patch