The quilt patch titled
Subject: mm: memcg: add NULL check to obj_cgroup_put()
has been removed from the -mm tree. Its filename was
mm-memcg-add-null-check-to-obj_cgroup_put.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Subject: mm: memcg: add NULL check to obj_cgroup_put()
Date: Sat, 16 Mar 2024 01:58:03 +0000
9 out of 16 callers perform a NULL check before calling obj_cgroup_put().
Move the NULL check in the function, similar to mem_cgroup_put(). The
unlikely() NULL check in current_objcg_update() was left alone to avoid
dropping the unlikey() annotation as this a fast path.
Link: https://lkml.kernel.org/r/20240316015803.2777252-1-yosryahmed@xxxxxxxxxx
Signed-off-by: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Acked-by: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: Shakeel Butt <shakeel.butt@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/memcontrol.h | 3 ++-
kernel/bpf/memalloc.c | 6 ++----
mm/memcontrol.c | 18 ++++++------------
mm/zswap.c | 3 +--
4 files changed, 11 insertions(+), 19 deletions(-)
--- a/include/linux/memcontrol.h~mm-memcg-add-null-check-to-obj_cgroup_put
+++ a/include/linux/memcontrol.h
@@ -818,7 +818,8 @@ static inline void obj_cgroup_get_many(s
static inline void obj_cgroup_put(struct obj_cgroup *objcg)
{
- percpu_ref_put(&objcg->refcnt);
+ if (objcg)
+ percpu_ref_put(&objcg->refcnt);
}
static inline bool mem_cgroup_tryget(struct mem_cgroup *memcg)
--- a/kernel/bpf/memalloc.c~mm-memcg-add-null-check-to-obj_cgroup_put
+++ a/kernel/bpf/memalloc.c
@@ -759,8 +759,7 @@ void bpf_mem_alloc_destroy(struct bpf_me
rcu_in_progress += atomic_read(&c->call_rcu_ttrace_in_progress);
rcu_in_progress += atomic_read(&c->call_rcu_in_progress);
}
- if (ma->objcg)
- obj_cgroup_put(ma->objcg);
+ obj_cgroup_put(ma->objcg);
destroy_mem_alloc(ma, rcu_in_progress);
}
if (ma->caches) {
@@ -776,8 +775,7 @@ void bpf_mem_alloc_destroy(struct bpf_me
rcu_in_progress += atomic_read(&c->call_rcu_in_progress);
}
}
- if (ma->objcg)
- obj_cgroup_put(ma->objcg);
+ obj_cgroup_put(ma->objcg);
destroy_mem_alloc(ma, rcu_in_progress);
}
}
--- a/mm/memcontrol.c~mm-memcg-add-null-check-to-obj_cgroup_put
+++ a/mm/memcontrol.c
@@ -2369,8 +2369,7 @@ static void drain_local_stock(struct wor
clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
local_unlock_irqrestore(&memcg_stock.stock_lock, flags);
- if (old)
- obj_cgroup_put(old);
+ obj_cgroup_put(old);
}
/*
@@ -3145,8 +3144,7 @@ static struct obj_cgroup *current_objcg_
if (old) {
old = (struct obj_cgroup *)
((unsigned long)old & ~CURRENT_OBJCG_UPDATE_FLAG);
- if (old)
- obj_cgroup_put(old);
+ obj_cgroup_put(old);
old = NULL;
}
@@ -3418,8 +3416,7 @@ void mod_objcg_state(struct obj_cgroup *
mod_objcg_mlstate(objcg, pgdat, idx, nr);
local_unlock_irqrestore(&memcg_stock.stock_lock, flags);
- if (old)
- obj_cgroup_put(old);
+ obj_cgroup_put(old);
}
static bool consume_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes)
@@ -3546,8 +3543,7 @@ static void refill_obj_stock(struct obj_
}
local_unlock_irqrestore(&memcg_stock.stock_lock, flags);
- if (old)
- obj_cgroup_put(old);
+ obj_cgroup_put(old);
if (nr_pages)
obj_cgroup_uncharge_pages(objcg, nr_pages);
@@ -5468,8 +5464,7 @@ static void __mem_cgroup_free(struct mem
{
int node;
- if (memcg->orig_objcg)
- obj_cgroup_put(memcg->orig_objcg);
+ obj_cgroup_put(memcg->orig_objcg);
for_each_node(node)
free_mem_cgroup_per_node_info(memcg, node);
@@ -6620,8 +6615,7 @@ static void mem_cgroup_exit(struct task_
objcg = (struct obj_cgroup *)
((unsigned long)objcg & ~CURRENT_OBJCG_UPDATE_FLAG);
- if (objcg)
- obj_cgroup_put(objcg);
+ obj_cgroup_put(objcg);
/*
* Some kernel allocations can happen after this point,
--- a/mm/zswap.c~mm-memcg-add-null-check-to-obj_cgroup_put
+++ a/mm/zswap.c
@@ -1618,8 +1618,7 @@ put_pool:
freepage:
zswap_entry_cache_free(entry);
reject:
- if (objcg)
- obj_cgroup_put(objcg);
+ obj_cgroup_put(objcg);
check_old:
/*
* If the zswap store fails or zswap is disabled, we must invalidate the
_
Patches currently in -mm which might be from yosryahmed@xxxxxxxxxx are
mm-zswap-always-shrink-in-zswap_store-if-zswap_pool_reached_full.patch
mm-zswap-refactor-limit-checking-from-zswap_store.patch
mm-zswap-move-more-same-filled-pages-checks-outside-of-zswap_store.patch
mm-zswap-remove-same_filled-module-params.patch
mm-zswap-remove-same_filled-module-params-fix.patch
