* Re: [PATCH bpf-next] bpf: Use rcu_read_lock_dont_migrate() and and rcu_read_unlock_migrate()
[not found] <20251005150816.38799-1-wangfushuai@baidu.com>
@ 2025-10-07 3:49 ` Menglong Dong
0 siblings, 0 replies; only message in thread
From: Menglong Dong @ 2025-10-07 3:49 UTC (permalink / raw)
To: Fushuai Wang
Cc: davem, edumazet, kuba, pabeni, horms, ast, martin.lau, houtao1,
jkangas, netdev, linux-kernel, Fushuai Wang, bpf
On 2025/10/5 23:08, Fushuai Wang wrote:
> Replace the combination of migrate_disable()/migrate_enable() and rcu_read_lock()/rcu_read_unlock()
> with rcu_read_lock_dont_migrate()/rcu_read_unlock_migrate() in bpf_sk_storage.c.
Hi, Fushuai. There are some nits in you patch:
1. The title is too fuzzy. It can be
"bpf: Use rcu_read_lock_dont_migrate in bpf_sk_storage.c"
2. You can wrap the commit log and don't exceed 75 character per line.
This is not necessary, but it can stop the check_patch from
complaining.
And I think you shoud CC bpf@vger.kernel.org too. Before you
send the patch, you can check it with ./scripts/checkpatch.pl to
find potential problems.
Thanks!
Menglong Dong
>
> Signed-off-by: Fushuai Wang <wangfushuai@baidu.com>
> ---
> net/core/bpf_sk_storage.c | 12 ++++--------
> 1 file changed, 4 insertions(+), 8 deletions(-)
>
> diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c
> index 2e538399757f..bdb70cf89ae1 100644
> --- a/net/core/bpf_sk_storage.c
> +++ b/net/core/bpf_sk_storage.c
> @@ -50,16 +50,14 @@ void bpf_sk_storage_free(struct sock *sk)
> {
> struct bpf_local_storage *sk_storage;
>
> - migrate_disable();
> - rcu_read_lock();
> + rcu_read_lock_dont_migrate();
> sk_storage = rcu_dereference(sk->sk_bpf_storage);
> if (!sk_storage)
> goto out;
>
> bpf_local_storage_destroy(sk_storage);
> out:
> - rcu_read_unlock();
> - migrate_enable();
> + rcu_read_unlock_migrate();
> }
>
> static void bpf_sk_storage_map_free(struct bpf_map *map)
> @@ -161,8 +159,7 @@ int bpf_sk_storage_clone(const struct sock *sk, struct sock *newsk)
>
> RCU_INIT_POINTER(newsk->sk_bpf_storage, NULL);
>
> - migrate_disable();
> - rcu_read_lock();
> + rcu_read_lock_dont_migrate();
> sk_storage = rcu_dereference(sk->sk_bpf_storage);
>
> if (!sk_storage || hlist_empty(&sk_storage->list))
> @@ -213,9 +210,8 @@ int bpf_sk_storage_clone(const struct sock *sk, struct sock *newsk)
> }
>
> out:
> - rcu_read_unlock();
> - migrate_enable();
>
> + rcu_read_unlock_migrate();
> /* In case of an error, don't free anything explicitly here, the
> * caller is responsible to call bpf_sk_storage_free.
> */
>
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