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Message-ID: <20251218175628.1460321-6-ameryhung@gmail.com>
Date: Thu, 18 Dec 2025 09:56:15 -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,
memxor@...il.com,
martin.lau@...nel.org,
kpsingh@...nel.org,
yonghong.song@...ux.dev,
song@...nel.org,
haoluo@...gle.com,
ameryhung@...il.com,
kernel-team@...a.com
Subject: [PATCH bpf-next v3 05/16] bpf: Change local_storage->lock and b->lock to rqspinlock
Change bpf_local_storage::lock and bpf_local_storage_map_bucket::lock to
from raw_spin_lock to rqspinlock.
Finally, propagate errors from raw_res_spin_lock_irqsave() to syscall
return or BPF helper return.
In bpf_local_storage_destroy(), WARN_ON for now. A later patch will
handle this properly.
For, __bpf_local_storage_map_cache(), instead of handling the error,
skip updating the cache.
Signed-off-by: Amery Hung <ameryhung@...il.com>
---
include/linux/bpf_local_storage.h | 5 ++-
kernel/bpf/bpf_local_storage.c | 72 ++++++++++++++++++++-----------
2 files changed, 51 insertions(+), 26 deletions(-)
diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h
index a94e12ddd83d..903559e2ca91 100644
--- a/include/linux/bpf_local_storage.h
+++ b/include/linux/bpf_local_storage.h
@@ -15,12 +15,13 @@
#include <linux/types.h>
#include <linux/bpf_mem_alloc.h>
#include <uapi/linux/btf.h>
+#include <asm/rqspinlock.h>
#define BPF_LOCAL_STORAGE_CACHE_SIZE 16
struct bpf_local_storage_map_bucket {
struct hlist_head list;
- raw_spinlock_t lock;
+ rqspinlock_t lock;
};
/* Thp map is not the primary owner of a bpf_local_storage_elem.
@@ -94,7 +95,7 @@ struct bpf_local_storage {
* bpf_local_storage_elem.
*/
struct rcu_head rcu;
- raw_spinlock_t lock; /* Protect adding/removing from the "list" */
+ rqspinlock_t lock; /* Protect adding/removing from the "list" */
bool use_kmalloc_nolock;
};
diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c
index fa629a180e9e..1d21ec11c80e 100644
--- a/kernel/bpf/bpf_local_storage.c
+++ b/kernel/bpf/bpf_local_storage.c
@@ -325,6 +325,7 @@ static int bpf_selem_unlink_map(struct bpf_local_storage_elem *selem)
struct bpf_local_storage_map *smap;
struct bpf_local_storage_map_bucket *b;
unsigned long flags;
+ int err;
if (unlikely(!selem_linked_to_map_lockless(selem)))
/* selem has already be unlinked from smap */
@@ -332,10 +333,13 @@ static int bpf_selem_unlink_map(struct bpf_local_storage_elem *selem)
smap = rcu_dereference_check(SDATA(selem)->smap, bpf_rcu_lock_held());
b = select_bucket(smap, selem);
- raw_spin_lock_irqsave(&b->lock, flags);
+ err = raw_res_spin_lock_irqsave(&b->lock, flags);
+ if (err)
+ return err;
+
if (likely(selem_linked_to_map(selem)))
hlist_del_init_rcu(&selem->map_node);
- raw_spin_unlock_irqrestore(&b->lock, flags);
+ raw_res_spin_unlock_irqrestore(&b->lock, flags);
return 0;
}
@@ -351,10 +355,14 @@ int bpf_selem_link_map(struct bpf_local_storage_map *smap,
{
struct bpf_local_storage_map_bucket *b = select_bucket(smap, selem);
unsigned long flags;
+ int err;
+
+ err = raw_res_spin_lock_irqsave(&b->lock, flags);
+ if (err)
+ return err;
- raw_spin_lock_irqsave(&b->lock, flags);
hlist_add_head_rcu(&selem->map_node, &b->list);
- raw_spin_unlock_irqrestore(&b->lock, flags);
+ raw_res_spin_unlock_irqrestore(&b->lock, flags);
return 0;
}
@@ -382,7 +390,10 @@ int bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool reuse_now)
local_storage = rcu_dereference_check(selem->local_storage,
bpf_rcu_lock_held());
- raw_spin_lock_irqsave(&local_storage->lock, flags);
+ err = raw_res_spin_lock_irqsave(&local_storage->lock, flags);
+ if (err)
+ return err;
+
if (likely(selem_linked_to_storage(selem))) {
/* Always unlink from map before unlinking from local_storage
* because selem will be freed after successfully unlinked from
@@ -396,7 +407,7 @@ int bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool reuse_now)
local_storage, selem, &selem_free_list);
}
out:
- raw_spin_unlock_irqrestore(&local_storage->lock, flags);
+ raw_res_spin_unlock_irqrestore(&local_storage->lock, flags);
bpf_selem_free_list(&selem_free_list, reuse_now);
@@ -411,16 +422,20 @@ void __bpf_local_storage_insert_cache(struct bpf_local_storage *local_storage,
struct bpf_local_storage_elem *selem)
{
unsigned long flags;
+ int err;
/* spinlock is needed to avoid racing with the
* parallel delete. Otherwise, publishing an already
* deleted sdata to the cache will become a use-after-free
* problem in the next bpf_local_storage_lookup().
*/
- raw_spin_lock_irqsave(&local_storage->lock, flags);
+ err = raw_res_spin_lock_irqsave(&local_storage->lock, flags);
+ if (err)
+ return;
+
if (selem_linked_to_storage(selem))
rcu_assign_pointer(local_storage->cache[smap->cache_idx], SDATA(selem));
- raw_spin_unlock_irqrestore(&local_storage->lock, flags);
+ raw_res_spin_unlock_irqrestore(&local_storage->lock, flags);
}
static int check_flags(const struct bpf_local_storage_data *old_sdata,
@@ -465,14 +480,17 @@ int bpf_local_storage_alloc(void *owner,
RCU_INIT_POINTER(storage->smap, smap);
INIT_HLIST_HEAD(&storage->list);
- raw_spin_lock_init(&storage->lock);
+ raw_res_spin_lock_init(&storage->lock);
storage->owner = owner;
storage->use_kmalloc_nolock = smap->use_kmalloc_nolock;
bpf_selem_link_storage_nolock(storage, first_selem);
b = select_bucket(smap, first_selem);
- raw_spin_lock_irqsave(&b->lock, flags);
+ err = raw_res_spin_lock_irqsave(&b->lock, flags);
+ if (err)
+ goto uncharge;
+
bpf_selem_link_map_nolock(smap, first_selem, b);
owner_storage_ptr =
@@ -490,11 +508,11 @@ int bpf_local_storage_alloc(void *owner,
prev_storage = cmpxchg(owner_storage_ptr, NULL, storage);
if (unlikely(prev_storage)) {
bpf_selem_unlink_map_nolock(first_selem);
- raw_spin_unlock_irqrestore(&b->lock, flags);
+ raw_res_spin_unlock_irqrestore(&b->lock, flags);
err = -EAGAIN;
goto uncharge;
}
- raw_spin_unlock_irqrestore(&b->lock, flags);
+ raw_res_spin_unlock_irqrestore(&b->lock, flags);
return 0;
@@ -577,7 +595,9 @@ bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap,
if (!alloc_selem)
return ERR_PTR(-ENOMEM);
- raw_spin_lock_irqsave(&local_storage->lock, flags);
+ err = raw_res_spin_lock_irqsave(&local_storage->lock, flags);
+ if (err)
+ return ERR_PTR(err);
/* Recheck local_storage->list under local_storage->lock */
if (unlikely(hlist_empty(&local_storage->list))) {
@@ -609,10 +629,15 @@ bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap,
old_b = old_b == b ? NULL : old_b;
}
- raw_spin_lock_irqsave(&b->lock, b_flags);
+ err = raw_res_spin_lock_irqsave(&b->lock, b_flags);
+ if (err)
+ goto unlock;
- if (old_b)
- raw_spin_lock_irqsave(&old_b->lock, old_b_flags);
+ if (old_b) {
+ err = raw_res_spin_lock_irqsave(&old_b->lock, old_b_flags);
+ if (err)
+ goto unlock_b;
+ }
alloc_selem = NULL;
/* First, link the new selem to the map */
@@ -629,12 +654,11 @@ bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap,
}
if (old_b)
- raw_spin_unlock_irqrestore(&old_b->lock, old_b_flags);
-
- raw_spin_unlock_irqrestore(&b->lock, b_flags);
-
+ raw_res_spin_unlock_irqrestore(&old_b->lock, old_b_flags);
+unlock_b:
+ raw_res_spin_unlock_irqrestore(&b->lock, b_flags);
unlock:
- raw_spin_unlock_irqrestore(&local_storage->lock, flags);
+ raw_res_spin_unlock_irqrestore(&local_storage->lock, flags);
bpf_selem_free_list(&old_selem_free_list, false);
if (alloc_selem) {
mem_uncharge(smap, owner, smap->elem_size);
@@ -719,7 +743,7 @@ void bpf_local_storage_destroy(struct bpf_local_storage *local_storage)
* when unlinking elem from the local_storage->list and
* the map's bucket->list.
*/
- raw_spin_lock_irqsave(&local_storage->lock, flags);
+ WARN_ON(raw_res_spin_lock_irqsave(&local_storage->lock, flags));
hlist_for_each_entry_safe(selem, n, &local_storage->list, snode) {
/* Always unlink from map before unlinking from
* local_storage.
@@ -734,7 +758,7 @@ void bpf_local_storage_destroy(struct bpf_local_storage *local_storage)
free_storage = bpf_selem_unlink_storage_nolock(
local_storage, selem, &free_selem_list);
}
- raw_spin_unlock_irqrestore(&local_storage->lock, flags);
+ raw_res_spin_unlock_irqrestore(&local_storage->lock, flags);
bpf_selem_free_list(&free_selem_list, true);
@@ -781,7 +805,7 @@ bpf_local_storage_map_alloc(union bpf_attr *attr,
for (i = 0; i < nbuckets; i++) {
INIT_HLIST_HEAD(&smap->buckets[i].list);
- raw_spin_lock_init(&smap->buckets[i].lock);
+ raw_res_spin_lock_init(&smap->buckets[i].lock);
}
smap->elem_size = offsetof(struct bpf_local_storage_elem,
--
2.47.3
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