[Patch bpf-next v7 05/13] skmsg: use rcu work for destroying psock

[Cong Wang]

From: Cong Wang <cong.w...@bytedance.com>

The RCU callback sk_psock_destroy() only queues work psock->gc,
so we can just switch to rcu work to simplify the code.

Cc: Daniel Borkmann <dan...@iogearbox.net>
Cc: Jakub Sitnicki <ja...@cloudflare.com>
Cc: Lorenz Bauer <l...@cloudflare.com>
Acked-by: John Fastabend <john.fastab...@gmail.com>
Signed-off-by: Cong Wang <cong.w...@bytedance.com>
---
 include/linux/skmsg.h |  5 +----
 net/core/skmsg.c      | 17 +++++------------
 2 files changed, 6 insertions(+), 16 deletions(-)

diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h
index 7382c4b518d7..e7aba150539d 100644
--- a/include/linux/skmsg.h
+++ b/include/linux/skmsg.h
@@ -102,10 +102,7 @@ struct sk_psock {
        struct mutex                    work_mutex;
        struct sk_psock_work_state      work_state;
        struct work_struct              work;
-       union {
-               struct rcu_head         rcu;
-               struct work_struct      gc;
-       };
+       struct rcu_work                 rwork;
 };
 
 int sk_msg_alloc(struct sock *sk, struct sk_msg *msg, int len,
diff --git a/net/core/skmsg.c b/net/core/skmsg.c
index 9c25020086a9..d43d43905d2c 100644
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -666,10 +666,10 @@ void sk_psock_stop(struct sk_psock *psock, bool wait)
 
 static void sk_psock_done_strp(struct sk_psock *psock);
 
-static void sk_psock_destroy_deferred(struct work_struct *gc)
+static void sk_psock_destroy(struct work_struct *work)
 {
-       struct sk_psock *psock = container_of(gc, struct sk_psock, gc);
-
+       struct sk_psock *psock = container_of(to_rcu_work(work),
+                                             struct sk_psock, rwork);
        /* No sk_callback_lock since already detached. */
 
        sk_psock_done_strp(psock);
@@ -688,14 +688,6 @@ static void sk_psock_destroy_deferred(struct work_struct 
*gc)
        kfree(psock);
 }
 
-static void sk_psock_destroy(struct rcu_head *rcu)
-{
-       struct sk_psock *psock = container_of(rcu, struct sk_psock, rcu);
-
-       INIT_WORK(&psock->gc, sk_psock_destroy_deferred);
-       schedule_work(&psock->gc);
-}
-
 void sk_psock_drop(struct sock *sk, struct sk_psock *psock)
 {
        sk_psock_stop(psock, false);
@@ -709,7 +701,8 @@ void sk_psock_drop(struct sock *sk, struct sk_psock *psock)
                sk_psock_stop_verdict(sk, psock);
        write_unlock_bh(&sk->sk_callback_lock);
 
-       call_rcu(&psock->rcu, sk_psock_destroy);
+       INIT_RCU_WORK(&psock->rwork, sk_psock_destroy);
+       queue_rcu_work(system_wq, &psock->rwork);
 }
 EXPORT_SYMBOL_GPL(sk_psock_drop);
 
-- 
2.25.1