From: Amery Hung <ameryhung@gmail.com>
To: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org, alexei.starovoitov@gmail.com,
andrii@kernel.org, daniel@iogearbox.net, memxor@gmail.com,
martin.lau@kernel.org, kpsingh@kernel.org,
yonghong.song@linux.dev, song@kernel.org, haoluo@google.com,
ameryhung@gmail.com, kernel-team@meta.com
Subject: [PATCH bpf-next v3 04/16] bpf: Convert bpf_selem_unlink to failable
Date: Thu, 18 Dec 2025 09:56:14 -0800 [thread overview]
Message-ID: <20251218175628.1460321-5-ameryhung@gmail.com> (raw)
In-Reply-To: <20251218175628.1460321-1-ameryhung@gmail.com>
To prepare changing both bpf_local_storage_map_bucket::lock and
bpf_local_storage::lock to rqspinlock, convert bpf_selem_unlink() to
failable. It still always succeeds and returns 0 until the change
happens. No functional change.
For bpf_local_storage_map_free(), WARN_ON() for now as no real error
will happen until we switch to rqspinlock.
__must_check is added to the function declaration locally to make sure
all callers are accounted for during the conversion.
Signed-off-by: Amery Hung <ameryhung@gmail.com>
---
include/linux/bpf_local_storage.h | 2 +-
kernel/bpf/bpf_cgrp_storage.c | 3 +--
kernel/bpf/bpf_inode_storage.c | 4 +---
kernel/bpf/bpf_local_storage.c | 8 +++++---
kernel/bpf/bpf_task_storage.c | 4 +---
net/core/bpf_sk_storage.c | 4 +---
6 files changed, 10 insertions(+), 15 deletions(-)
diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h
index 6cabf5154cf6..a94e12ddd83d 100644
--- a/include/linux/bpf_local_storage.h
+++ b/include/linux/bpf_local_storage.h
@@ -176,7 +176,7 @@ int bpf_local_storage_map_check_btf(const struct bpf_map *map,
void bpf_selem_link_storage_nolock(struct bpf_local_storage *local_storage,
struct bpf_local_storage_elem *selem);
-void bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool reuse_now);
+int bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool reuse_now);
int bpf_selem_link_map(struct bpf_local_storage_map *smap,
struct bpf_local_storage_elem *selem);
diff --git a/kernel/bpf/bpf_cgrp_storage.c b/kernel/bpf/bpf_cgrp_storage.c
index 0687a760974a..8fef24fcac68 100644
--- a/kernel/bpf/bpf_cgrp_storage.c
+++ b/kernel/bpf/bpf_cgrp_storage.c
@@ -118,8 +118,7 @@ static int cgroup_storage_delete(struct cgroup *cgroup, struct bpf_map *map)
if (!sdata)
return -ENOENT;
- bpf_selem_unlink(SELEM(sdata), false);
- return 0;
+ return bpf_selem_unlink(SELEM(sdata), false);
}
static long bpf_cgrp_storage_delete_elem(struct bpf_map *map, void *key)
diff --git a/kernel/bpf/bpf_inode_storage.c b/kernel/bpf/bpf_inode_storage.c
index e54cce2b9175..cedc99184dad 100644
--- a/kernel/bpf/bpf_inode_storage.c
+++ b/kernel/bpf/bpf_inode_storage.c
@@ -110,9 +110,7 @@ static int inode_storage_delete(struct inode *inode, struct bpf_map *map)
if (!sdata)
return -ENOENT;
- bpf_selem_unlink(SELEM(sdata), false);
-
- return 0;
+ return bpf_selem_unlink(SELEM(sdata), false);
}
static long bpf_fd_inode_storage_delete_elem(struct bpf_map *map, void *key)
diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c
index 0e3fa5fbaaf3..fa629a180e9e 100644
--- a/kernel/bpf/bpf_local_storage.c
+++ b/kernel/bpf/bpf_local_storage.c
@@ -367,7 +367,7 @@ static void bpf_selem_link_map_nolock(struct bpf_local_storage_map *smap,
hlist_add_head_rcu(&selem->map_node, &b->list);
}
-void bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool reuse_now)
+int bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool reuse_now)
{
struct bpf_local_storage *local_storage;
bool free_local_storage = false;
@@ -377,7 +377,7 @@ void bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool reuse_now)
if (unlikely(!selem_linked_to_storage_lockless(selem)))
/* selem has already been unlinked from sk */
- return;
+ return 0;
local_storage = rcu_dereference_check(selem->local_storage,
bpf_rcu_lock_held());
@@ -402,6 +402,8 @@ void bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool reuse_now)
if (free_local_storage)
bpf_local_storage_free(local_storage, reuse_now);
+
+ return err;
}
void __bpf_local_storage_insert_cache(struct bpf_local_storage *local_storage,
@@ -837,7 +839,7 @@ void bpf_local_storage_map_free(struct bpf_map *map,
struct bpf_local_storage_elem, map_node))) {
if (busy_counter)
this_cpu_inc(*busy_counter);
- bpf_selem_unlink(selem, true);
+ WARN_ON(bpf_selem_unlink(selem, true));
if (busy_counter)
this_cpu_dec(*busy_counter);
cond_resched_rcu();
diff --git a/kernel/bpf/bpf_task_storage.c b/kernel/bpf/bpf_task_storage.c
index a1dc1bf0848a..ab902364ac23 100644
--- a/kernel/bpf/bpf_task_storage.c
+++ b/kernel/bpf/bpf_task_storage.c
@@ -167,9 +167,7 @@ static int task_storage_delete(struct task_struct *task, struct bpf_map *map,
if (!nobusy)
return -EBUSY;
- bpf_selem_unlink(SELEM(sdata), false);
-
- return 0;
+ return bpf_selem_unlink(SELEM(sdata), false);
}
static long bpf_pid_task_storage_delete_elem(struct bpf_map *map, void *key)
diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c
index 4f8e917f49d9..fb1f041352a5 100644
--- a/net/core/bpf_sk_storage.c
+++ b/net/core/bpf_sk_storage.c
@@ -40,9 +40,7 @@ static int bpf_sk_storage_del(struct sock *sk, struct bpf_map *map)
if (!sdata)
return -ENOENT;
- bpf_selem_unlink(SELEM(sdata), false);
-
- return 0;
+ return bpf_selem_unlink(SELEM(sdata), false);
}
/* Called by __sk_destruct() & bpf_sk_storage_clone() */
--
2.47.3
next prev parent reply other threads:[~2025-12-18 17:56 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-18 17:56 [PATCH bpf-next v3 00/16] Remove task and cgroup local storage percpu counters Amery Hung
2025-12-18 17:56 ` [PATCH bpf-next v3 01/16] bpf: Convert bpf_selem_unlink_map to failable Amery Hung
2025-12-18 18:27 ` bot+bpf-ci
2026-01-08 20:40 ` Martin KaFai Lau
2026-01-08 20:29 ` Martin KaFai Lau
2026-01-09 18:39 ` Amery Hung
2026-01-09 21:53 ` Martin KaFai Lau
2026-01-12 17:47 ` Amery Hung
2025-12-18 17:56 ` [PATCH bpf-next v3 02/16] bpf: Convert bpf_selem_link_map " Amery Hung
2025-12-18 18:19 ` bot+bpf-ci
2025-12-18 17:56 ` [PATCH bpf-next v3 03/16] bpf: Open code bpf_selem_unlink_storage in bpf_selem_unlink Amery Hung
2026-01-09 17:42 ` Martin KaFai Lau
2026-01-09 18:49 ` Amery Hung
2025-12-18 17:56 ` Amery Hung [this message]
2025-12-18 18:27 ` [PATCH bpf-next v3 04/16] bpf: Convert bpf_selem_unlink to failable bot+bpf-ci
2026-01-09 18:16 ` Martin KaFai Lau
2026-01-09 18:49 ` Amery Hung
2025-12-18 17:56 ` [PATCH bpf-next v3 05/16] bpf: Change local_storage->lock and b->lock to rqspinlock Amery Hung
2025-12-18 18:27 ` bot+bpf-ci
2025-12-18 17:56 ` [PATCH bpf-next v3 06/16] bpf: Remove task local storage percpu counter Amery Hung
2025-12-18 17:56 ` [PATCH bpf-next v3 07/16] bpf: Remove cgroup " Amery Hung
2025-12-18 17:56 ` [PATCH bpf-next v3 08/16] bpf: Remove unused percpu counter from bpf_local_storage_map_free Amery Hung
2025-12-18 17:56 ` [PATCH bpf-next v3 09/16] bpf: Save memory allocation method and size in bpf_local_storage_elem Amery Hung
2025-12-18 17:56 ` [PATCH bpf-next v3 10/16] bpf: Support lockless unlink when freeing map or local storage Amery Hung
2026-01-09 20:16 ` Martin KaFai Lau
2026-01-09 20:47 ` Amery Hung
2026-01-09 21:38 ` Martin KaFai Lau
2026-01-12 22:38 ` Amery Hung
2026-01-13 0:15 ` Martin KaFai Lau
2026-01-12 15:36 ` Kumar Kartikeya Dwivedi
2026-01-12 15:49 ` Kumar Kartikeya Dwivedi
2026-01-12 21:17 ` Amery Hung
2025-12-18 17:56 ` [PATCH bpf-next v3 11/16] bpf: Switch to bpf_selem_unlink_lockless in bpf_local_storage_{map_free, destroy} Amery Hung
2025-12-18 17:56 ` [PATCH bpf-next v3 12/16] selftests/bpf: Update sk_storage_omem_uncharge test Amery Hung
2025-12-18 17:56 ` [PATCH bpf-next v3 13/16] selftests/bpf: Update task_local_storage/recursion test Amery Hung
2025-12-18 17:56 ` [PATCH bpf-next v3 14/16] selftests/bpf: Update task_local_storage/task_storage_nodeadlock test Amery Hung
2025-12-18 17:56 ` [PATCH bpf-next v3 15/16] selftests/bpf: Remove test_task_storage_map_stress_lookup Amery Hung
2025-12-18 17:56 ` [PATCH bpf-next v3 16/16] selftests/bpf: Choose another percpu variable in bpf for btf_dump test Amery Hung
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