+ rbtree-inline-rb_last.patch added to mm-nonmm-unstable branch

+ rbtree-inline-rb_last.patch added to mm-nonmm-unstable branch

[Andrew Morton]

The patch titled
     Subject: rbtree: inline rb_last()
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     rbtree-inline-rb_last.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/rbtree-inline-rb_last.patch

This patch will later appear in the mm-nonmm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Eric Dumazet <edumazet@google.com>
Subject: rbtree: inline rb_last()
Date: Fri, 14 Nov 2025 14:06:46 +0000

This is a very small function, inlining it save cpu cycles in TCP
by reducing register pressure and removing call/ret overhead.

It also reduces vmlinux text size by 122 bytes on a typical x86_64 build.

Before:

size vmlinux
   text    data     bss     dec     hex filename
34811781        22177365        5685248 62674394        3bc55da vmlinux

After:

size vmlinux
   text	   data	    bss	    dec	    hex	filename
34811659	22177365	5685248	62674272	3bc5560	vmlinux

Link: https://lkml.kernel.org/r/20251114140646.3817319-3-edumazet@google.com
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kacinski <kuba@kernel.org>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/rbtree.h |   16 +++++++++++++++-
 lib/rbtree.c           |   13 -------------
 2 files changed, 15 insertions(+), 14 deletions(-)

--- a/include/linux/rbtree.h~rbtree-inline-rb_last
+++ a/include/linux/rbtree.h
@@ -58,7 +58,21 @@ static inline struct rb_node *rb_first(c
 		n = n->rb_left;
 	return n;
 }
-extern struct rb_node *rb_last(const struct rb_root *);
+
+/*
+ * This function returns the last node (in sort order) of the tree.
+ */
+static inline struct rb_node *rb_last(const struct rb_root *root)
+{
+	struct rb_node	*n;
+
+	n = root->rb_node;
+	if (!n)
+		return NULL;
+	while (n->rb_right)
+		n = n->rb_right;
+	return n;
+}
 
 /* Postorder iteration - always visit the parent after its children */
 extern struct rb_node *rb_first_postorder(const struct rb_root *);
--- a/lib/rbtree.c~rbtree-inline-rb_last
+++ a/lib/rbtree.c
@@ -460,19 +460,6 @@ void __rb_insert_augmented(struct rb_nod
 }
 EXPORT_SYMBOL(__rb_insert_augmented);
 
-struct rb_node *rb_last(const struct rb_root *root)
-{
-	struct rb_node	*n;
-
-	n = root->rb_node;
-	if (!n)
-		return NULL;
-	while (n->rb_right)
-		n = n->rb_right;
-	return n;
-}
-EXPORT_SYMBOL(rb_last);
-
 struct rb_node *rb_next(const struct rb_node *node)
 {
 	struct rb_node *parent;
_

Patches currently in -mm which might be from edumazet@google.com are

rbtree-inline-rb_first.patch
rbtree-inline-rb_last.patch