+ mm-memcontrol-constify-obj_cgroup_memcg-and-friends.patch added to mm-new branch

+ mm-memcontrol-constify-obj_cgroup_memcg-and-friends.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: mm: memcontrol: constify obj_cgroup_memcg() and friends
has been added to the -mm mm-new branch.  Its filename is
     mm-memcontrol-constify-obj_cgroup_memcg-and-friends.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-memcontrol-constify-obj_cgroup_memcg-and-friends.patch

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

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

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   a) Consider who else should be cc'ed
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

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and is updated there most days

------------------------------------------------------
From: Tal Zussman <tz2294@columbia.edu>
Subject: mm: memcontrol: constify obj_cgroup_memcg() and friends
Date: Tue, 15 Sep 2026 19:20:06 -0400

obj_cgroup_memcg() and get_mem_cgroup_from_objcg() only read from the
objcg.  Constify them.

Link: https://lore.kernel.org/20260915-folio_memcg-const-v3-2-c239a6010b58@columbia.edu
Signed-off-by: Tal Zussman <tz2294@columbia.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <baoquan.he@linux.dev>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
---

 include/linux/memcontrol.h |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

--- a/include/linux/memcontrol.h~mm-memcontrol-constify-obj_cgroup_memcg-and-friends
+++ a/include/linux/memcontrol.h
@@ -396,7 +396,7 @@ enum objext_flags {
  *
  * The caller must ensure that the returned memcg won't be released.
  */
-static inline struct mem_cgroup *obj_cgroup_memcg(struct obj_cgroup *objcg)
+static inline struct mem_cgroup *obj_cgroup_memcg(const struct obj_cgroup *objcg)
 {
 	lockdep_assert_once(rcu_read_lock_held() || lockdep_is_held(&cgroup_mutex));
 	return objcg ? READ_ONCE(objcg->memcg) : NULL;
@@ -505,7 +505,7 @@ static inline struct mem_cgroup *page_me
 	return folio_memcg_check((const struct folio *)page);
 }
 
-static inline struct mem_cgroup *get_mem_cgroup_from_objcg(struct obj_cgroup *objcg)
+static inline struct mem_cgroup *get_mem_cgroup_from_objcg(const struct obj_cgroup *objcg)
 {
 	struct mem_cgroup *memcg;
 
@@ -1075,7 +1075,7 @@ void mem_cgroup_flush_workqueue(void);
 extern int mem_cgroup_init(void);
 #else /* CONFIG_MEMCG */
 
-static inline struct mem_cgroup *obj_cgroup_memcg(struct obj_cgroup *objcg)
+static inline struct mem_cgroup *obj_cgroup_memcg(const struct obj_cgroup *objcg)
 {
 	return NULL;
 }
@@ -1104,7 +1104,7 @@ static inline struct mem_cgroup *page_me
 	return NULL;
 }
 
-static inline struct mem_cgroup *get_mem_cgroup_from_objcg(struct obj_cgroup *objcg)
+static inline struct mem_cgroup *get_mem_cgroup_from_objcg(const struct obj_cgroup *objcg)
 {
 	return NULL;
 }
_

Patches currently in -mm which might be from tz2294@columbia.edu are

mm-page_io-convert-write-completion-handlers-to-folios.patch
mm-remove-pagereclaim.patch
mm-page_io-use-swap-entries-directly-in-zeromap-helpers.patch
mm-page_io-rename-bio_associate_blkg_from_page.patch
mm-page_io-refer-to-folios-in-swap_writeout-comments.patch
mm-swap-rename-__swap_writepage-to-__swap_writeout.patch
mm-remove-unused-mark_page_reserved.patch
mm-remove-unused-totalram_pages_inc-and-totalram_pages_dec.patch
mm-remove-pagewriteback.patch
mm-swap-add-folio_swap_entry-and-folio_page_swap_entry.patch
mm-swap-add-folio_swap_entry-and-folio_page_swap_entry-fix.patch
mm-huge_memory-add-a-comment-to-the-open-coded-swap-entry.patch
mm-rmap-use-folio_page_swap_entry-in-ttu_anon_swapbacked_folio.patch
mm-zswap-use-folio_swap_entry-in-zswap_store_page.patch
mm-swapfile-use-folio_page_swap_entry.patch
arm64-mte-make-mte_save_tags-and-mte_restore_tags-static.patch
arm64-mte-pass-the-swap-entry-to-mte_save_tags.patch
mm-swap-remove-page_swap_entry.patch
mm-memcontrol-take-a-const-folio-in-folio_memcg-and-friends.patch
mm-memcontrol-constify-obj_cgroup_memcg-and-friends.patch
mm-memcontrol-constify-the-lruvec-helpers.patch
mm-page_io-take-a-const-folio-in-bio_associate_blkg_from_folio.patch
mm-memcontrol-constify-the-mem_cgroup-accessors.patch
mm-page_counter-constify-page_counter_read-and-page_counter_margin.patch
mm-memcontrol-constify-the-reclaim-protection-helpers.patch
mm-memcontrol-constify-the-memcg-and-lruvec-stat-readers.patch
mm-memcontrol-constify-the-swap-accounting-helpers.patch
mm-memcontrol-constify-mem_cgroup_swappiness-and-mem_cgroup_get_max.patch
mm-memcontrol-constify-the-zswap-and-socket-pressure-helpers.patch