The patch titled
Subject: maple_tree: make maple state reusable after mas_empty_area_rev()
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
maple_tree-make-maple-state-reusable-after-mas_empty_area_rev.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/maple_tree-make-maple-state-reusable-after-mas_empty_area_rev.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>
Subject: maple_tree: make maple state reusable after mas_empty_area_rev()
Date: Fri, 14 Apr 2023 10:57:26 -0400
Stop using maple state min/max for the range by passing through pointers
for those values. This will allow the maple state to be reused without
resetting.
Also add some logic to fail out early on searching with invalid
arguments.
Link: https://lkml.kernel.org/r/20230414145728.4067069-1-Liam.Howlett@xxxxxxxxxx
Fixes: 54a611b60590 ("Maple Tree: add new data structure")
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Reported-by: Rick Edgecombe <rick.p.edgecombe@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/maple_tree.c | 27 +++++++++++++--------------
1 file changed, 13 insertions(+), 14 deletions(-)
--- a/lib/maple_tree.c~maple_tree-make-maple-state-reusable-after-mas_empty_area_rev
+++ a/lib/maple_tree.c
@@ -4965,7 +4965,8 @@ not_found:
* Return: True if found in a leaf, false otherwise.
*
*/
-static bool mas_rev_awalk(struct ma_state *mas, unsigned long size)
+static bool mas_rev_awalk(struct ma_state *mas, unsigned long size,
+ unsigned long *gap_min, unsigned long *gap_max)
{
enum maple_type type = mte_node_type(mas->node);
struct maple_node *node = mas_mn(mas);
@@ -5030,8 +5031,8 @@ static bool mas_rev_awalk(struct ma_stat
if (unlikely(ma_is_leaf(type))) {
mas->offset = offset;
- mas->min = min;
- mas->max = min + gap - 1;
+ *gap_min = min;
+ *gap_max = min + gap - 1;
return true;
}
@@ -5307,6 +5308,9 @@ int mas_empty_area(struct ma_state *mas,
unsigned long *pivots;
enum maple_type mt;
+ if (min >= max)
+ return -EINVAL;
+
if (mas_is_start(mas))
mas_start(mas);
else if (mas->offset >= 2)
@@ -5361,6 +5365,9 @@ int mas_empty_area_rev(struct ma_state *
{
struct maple_enode *last = mas->node;
+ if (min >= max)
+ return -EINVAL;
+
if (mas_is_start(mas)) {
mas_start(mas);
mas->offset = mas_data_end(mas);
@@ -5380,7 +5387,7 @@ int mas_empty_area_rev(struct ma_state *
mas->index = min;
mas->last = max;
- while (!mas_rev_awalk(mas, size)) {
+ while (!mas_rev_awalk(mas, size, &min, &max)) {
if (last == mas->node) {
if (!mas_rewind_node(mas))
return -EBUSY;
@@ -5395,17 +5402,9 @@ int mas_empty_area_rev(struct ma_state *
if (unlikely(mas->offset == MAPLE_NODE_SLOTS))
return -EBUSY;
- /*
- * mas_rev_awalk() has set mas->min and mas->max to the gap values. If
- * the maximum is outside the window we are searching, then use the last
- * location in the search.
- * mas->max and mas->min is the range of the gap.
- * mas->index and mas->last are currently set to the search range.
- */
-
/* Trim the upper limit to the max. */
- if (mas->max <= mas->last)
- mas->last = mas->max;
+ if (max <= mas->last)
+ mas->last = max;
mas->index = mas->last - size + 1;
return 0;
_
Patches currently in -mm which might be from Liam.Howlett@xxxxxxxxxx are
mm-mprotect-fix-do_mprotect_pkey-return-on-error.patch
mm-mempolicy-fix-use-after-free-of-vma-iterator.patch
maple_tree-make-maple-state-reusable-after-mas_empty_area_rev.patch
maple_tree-fix-mas_empty_area-search.patch
mm-mmap-regression-fix-for-unmapped_area_topdown.patch
