+ maple_tree-clarify-comments-on-mas_nomem.patch added to mm-unstable branch

The patch titled
     Subject: maple_tree: clarify comments on mas_nomem()
has been added to the -mm mm-unstable branch.  Its filename is
     maple_tree-clarify-comments-on-mas_nomem.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/maple_tree-clarify-comments-on-mas_nomem.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 R. Howlett (Oracle)" <[email protected]>
Subject: maple_tree: clarify comments on mas_nomem()
Date: Fri, 21 Aug 2026 15:26:15 -0400

When an allocation completely fails, the return is false.  If the
allocation succeeds or partially succeeds, return true to indicate a retry
of the operation.  Note that since the lock may have been dropped, the
operation is retried from the start - including potentially allocating
more memory.

Link: https://lore.kernel.org/[email protected]
Signed-off-by: Liam R. Howlett (Oracle) <[email protected]>
Cc: Boqun Feng <[email protected]>
Cc: Breno Leitao <[email protected]>
Cc: Chris Mason <[email protected]>
Cc: Chuck Lever <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Waiman Long <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---

 lib/maple_tree.c |    9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

--- a/lib/maple_tree.c~maple_tree-clarify-comments-on-mas_nomem
+++ a/lib/maple_tree.c
@@ -5677,10 +5677,11 @@ EXPORT_SYMBOL_GPL(mas_erase);
 
 /**
  * mas_nomem() - Check if there was an error allocating and do the allocation
- * if necessary If there are allocations, then free them.
+ * if necessary.
+ *
  * @mas: The maple state
  * @gfp: The GFP_FLAGS to use for allocations
- * Return: true on allocation, false otherwise.
+ * Return: False on no memory.  True otherwise (partial success as well)
  */
 bool mas_nomem(struct ma_state *mas, gfp_t gfp)
 	__must_hold(mas->tree->ma_lock)
@@ -5696,6 +5697,10 @@ bool mas_nomem(struct ma_state *mas, gfp
 		mas_alloc_nodes(mas, gfp);
 	}
 
+	/*
+	 * Return false on zero forward progress.  Partial allocations are kept
+	 * so the retry path will attempt to get the rest.
+	 */
 	if (!mas->sheaf && !mas->alloc)
 		return false;
 
_

Patches currently in -mm which might be from [email protected] are

maple_tree-add-rcu-locking-check-when-lockdep-is-enabled.patch
locking-lockdep-add-sequence-counter-to-held_lock.patch
maple_tree-add-write-lock-checking-with-lockdep-sequence-numbers.patch
maple_tree-documentation-fix.patch
maple_tree-drop-dead-code-from-mas_extend_spanning_null.patch
maple_tree-drop-maple_alloc_slots.patch
maple_tree-clarify-comments-on-mas_nomem.patch
maple_tree-use-prefetched-value-in-mas_wr_store_type.patch
maple_tree-optimise-mas_wr_node_store-when-not-in-rcu-mode.patch
maple_tree-micro-optimisation-of-mas_wr_store_type.patch
maple_tree-add-bulk-parent-set-helper.patch
maple_tree-catch-race-in-mas_alloc_cyclic.patch
maple_tree-document-that-erase-may-use-gfp_kernel-for-allocations.patch
maple_tree-avoid-mas_erase-and-mtree_erase-failures.patch
maple_tree-document-erase-and-allocations-better.patch
maple_tree-change-two-gfp-flags-in-tests.patch
maple_tree-fix-argument-name-in-header.patch
maple_tree-avoid-extra-gap-calculation.patch
maple_tree-add-helper-mas_make_walkable.patch