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Message-ID: <20251114201329.3275875-4-ameryhung@gmail.com>
Date: Fri, 14 Nov 2025 12:13:25 -0800
From: Amery Hung <ameryhung@...il.com>
To: bpf@...r.kernel.org
Cc: netdev@...r.kernel.org,
alexei.starovoitov@...il.com,
andrii@...nel.org,
daniel@...earbox.net,
martin.lau@...nel.org,
memxor@...il.com,
kpsingh@...nel.org,
yonghong.song@...ux.dev,
song@...nel.org,
ameryhung@...il.com,
kernel-team@...a.com
Subject: [PATCH v2 bpf-next 3/4] bpf: Save memory alloction info in bpf_local_storage
Save the memory allocation method used for bpf_local_storage in the
struct explicitly so that we don't need to go through the hassle to
find out the info. When a later patch replaces BPF memory allocator
with kmalloc_noloc(), bpf_local_storage_free() will no longer need
smap->storage_ma to return the memory and completely remove the
dependency on smap in bpf_local_storage_free().
Signed-off-by: Amery Hung <ameryhung@...il.com>
---
include/linux/bpf_local_storage.h | 1 +
kernel/bpf/bpf_local_storage.c | 52 +++++--------------------------
2 files changed, 9 insertions(+), 44 deletions(-)
diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h
index 4ab137e75f33..7fef0cec8340 100644
--- a/include/linux/bpf_local_storage.h
+++ b/include/linux/bpf_local_storage.h
@@ -97,6 +97,7 @@ struct bpf_local_storage {
*/
struct rcu_head rcu;
raw_spinlock_t lock; /* Protect adding/removing from the "list" */
+ bool bpf_ma;
};
/* U16_MAX is much more than enough for sk local storage
diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c
index 95a5ea618cc5..3c04b9d85860 100644
--- a/kernel/bpf/bpf_local_storage.c
+++ b/kernel/bpf/bpf_local_storage.c
@@ -157,12 +157,12 @@ static void __bpf_local_storage_free(struct bpf_local_storage *local_storage,
static void bpf_local_storage_free(struct bpf_local_storage *local_storage,
struct bpf_local_storage_map *smap,
- bool bpf_ma, bool reuse_now)
+ bool reuse_now)
{
if (!local_storage)
return;
- if (!bpf_ma) {
+ if (!local_storage->bpf_ma) {
__bpf_local_storage_free(local_storage, reuse_now);
return;
}
@@ -336,47 +336,12 @@ static bool bpf_selem_unlink_storage_nolock(struct bpf_local_storage *local_stor
return free_local_storage;
}
-static bool check_storage_bpf_ma(struct bpf_local_storage *local_storage,
- struct bpf_local_storage_map *storage_smap,
- struct bpf_local_storage_elem *selem)
-{
-
- struct bpf_local_storage_map *selem_smap;
-
- /* local_storage->smap may be NULL. If it is, get the bpf_ma
- * from any selem in the local_storage->list. The bpf_ma of all
- * local_storage and selem should have the same value
- * for the same map type.
- *
- * If the local_storage->list is already empty, the caller will not
- * care about the bpf_ma value also because the caller is not
- * responsible to free the local_storage.
- */
-
- if (storage_smap)
- return storage_smap->bpf_ma;
-
- if (!selem) {
- struct hlist_node *n;
-
- n = rcu_dereference_check(hlist_first_rcu(&local_storage->list),
- bpf_rcu_lock_held());
- if (!n)
- return false;
-
- selem = hlist_entry(n, struct bpf_local_storage_elem, snode);
- }
- selem_smap = rcu_dereference_check(SDATA(selem)->smap, bpf_rcu_lock_held());
-
- return selem_smap->bpf_ma;
-}
-
static void bpf_selem_unlink_storage(struct bpf_local_storage_elem *selem,
bool reuse_now)
{
struct bpf_local_storage_map *storage_smap;
struct bpf_local_storage *local_storage;
- bool bpf_ma, free_local_storage = false;
+ bool free_local_storage = false;
HLIST_HEAD(selem_free_list);
unsigned long flags;
@@ -388,7 +353,6 @@ static void bpf_selem_unlink_storage(struct bpf_local_storage_elem *selem,
bpf_rcu_lock_held());
storage_smap = rcu_dereference_check(local_storage->smap,
bpf_rcu_lock_held());
- bpf_ma = check_storage_bpf_ma(local_storage, storage_smap, selem);
raw_spin_lock_irqsave(&local_storage->lock, flags);
if (likely(selem_linked_to_storage(selem)))
@@ -399,7 +363,7 @@ static void bpf_selem_unlink_storage(struct bpf_local_storage_elem *selem,
bpf_selem_free_list(&selem_free_list, reuse_now);
if (free_local_storage)
- bpf_local_storage_free(local_storage, storage_smap, bpf_ma, reuse_now);
+ bpf_local_storage_free(local_storage, storage_smap, reuse_now);
}
void bpf_selem_link_storage_nolock(struct bpf_local_storage *local_storage,
@@ -506,6 +470,7 @@ int bpf_local_storage_alloc(void *owner,
INIT_HLIST_HEAD(&storage->list);
raw_spin_lock_init(&storage->lock);
storage->owner = owner;
+ storage->bpf_ma = smap->bpf_ma;
bpf_selem_link_storage_nolock(storage, first_selem);
bpf_selem_link_map(smap, first_selem);
@@ -542,7 +507,7 @@ int bpf_local_storage_alloc(void *owner,
return 0;
uncharge:
- bpf_local_storage_free(storage, smap, smap->bpf_ma, true);
+ bpf_local_storage_free(storage, smap, true);
mem_uncharge(smap, owner, sizeof(*storage));
return err;
}
@@ -731,13 +696,12 @@ void bpf_local_storage_destroy(struct bpf_local_storage *local_storage)
{
struct bpf_local_storage_map *storage_smap;
struct bpf_local_storage_elem *selem;
- bool bpf_ma, free_storage = false;
+ bool free_storage = false;
HLIST_HEAD(free_selem_list);
struct hlist_node *n;
unsigned long flags;
storage_smap = rcu_dereference_check(local_storage->smap, bpf_rcu_lock_held());
- bpf_ma = check_storage_bpf_ma(local_storage, storage_smap, NULL);
/* Neither the bpf_prog nor the bpf_map's syscall
* could be modifying the local_storage->list now.
@@ -768,7 +732,7 @@ void bpf_local_storage_destroy(struct bpf_local_storage *local_storage)
bpf_selem_free_list(&free_selem_list, true);
if (free_storage)
- bpf_local_storage_free(local_storage, storage_smap, bpf_ma, true);
+ bpf_local_storage_free(local_storage, storage_smap, true);
}
u64 bpf_local_storage_map_mem_usage(const struct bpf_map *map)
--
2.47.3
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