From: Geliang Tang <tanggeliang@kylinos.cn>

This patch adds an optional .rm_addr_received interface for struct
mptcp_pm_ops and invokes it in mptcp_pm_worker() without PM lock.
Since mptcp_subflow_shutdown() and mptcp_close_ssk() are sleepable
kfuncs, .rm_addr_received interface of BPF PM should be invoked by
__bpf_prog_enter_sleepable(), which can't be invoked under a lock.

Export mptcp_pm_rm_addr_recv() is to allow the MPTCP_PM_RM_ADDR_RECEIVED
worker can be invoke from the in-kernel PM.

With this, mptcp_pm_is_kernel() in mptcp_pm_rm_addr_or_subflow() can
be dropped.

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 include/net/mptcp.h   |  1 +
 net/mptcp/pm.c        | 13 ++++++++++---
 net/mptcp/pm_kernel.c |  6 ++++++
 net/mptcp/protocol.h  |  1 +
 4 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/include/net/mptcp.h b/include/net/mptcp.h
index 90fda6d1468c..bd8a20b9d02b 100644
--- a/include/net/mptcp.h
+++ b/include/net/mptcp.h
@@ -137,6 +137,7 @@ struct mptcp_pm_ops {
 	/* optional */
 	int (*add_addr_received)(struct mptcp_sock *msk,
 				 const struct mptcp_addr_info *addr);
+	void (*rm_addr_received)(struct mptcp_sock *msk);
 
 	char			name[MPTCP_PM_NAME_MAX];
 	struct module		*owner;
diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index d5cb7c60d177..70611946dfbf 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -676,15 +676,17 @@ static void mptcp_pm_rm_addr_or_subflow(struct mptcp_sock *msk,
 
 		if (rm_type == MPTCP_MIB_RMADDR) {
 			__MPTCP_INC_STATS(sock_net(sk), rm_type);
-			if (removed && mptcp_pm_is_kernel(msk))
+			if (removed)
 				mptcp_pm_nl_rm_addr(msk, rm_id);
 		}
 	}
 }
 
-static void mptcp_pm_rm_addr_recv(struct mptcp_sock *msk)
+void mptcp_pm_rm_addr_recv(struct mptcp_sock *msk)
 {
+	spin_lock_bh(&msk->pm.lock);
 	mptcp_pm_rm_addr_or_subflow(msk, &msk->pm.rm_list_rx, MPTCP_MIB_RMADDR);
+	spin_unlock_bh(&msk->pm.lock);
 }
 
 void mptcp_pm_rm_subflow(struct mptcp_sock *msk,
@@ -704,6 +706,9 @@ void mptcp_pm_rm_addr_received(struct mptcp_sock *msk,
 	for (i = 0; i < rm_list->nr; i++)
 		mptcp_event_addr_removed(msk, rm_list->ids[i]);
 
+	if (!pm->ops->rm_addr_received)
+		return;
+
 	spin_lock_bh(&pm->lock);
 	if (mptcp_pm_schedule_work(msk, MPTCP_PM_RM_ADDR_RECEIVED))
 		pm->rm_list_rx = *rm_list;
@@ -930,7 +935,9 @@ void mptcp_pm_worker(struct mptcp_sock *msk)
 	}
 	if (pm->status & BIT(MPTCP_PM_RM_ADDR_RECEIVED)) {
 		pm->status &= ~BIT(MPTCP_PM_RM_ADDR_RECEIVED);
-		mptcp_pm_rm_addr_recv(msk);
+		spin_unlock_bh(&msk->pm.lock);
+		pm->ops->rm_addr_received(msk);
+		return;
 	}
 	if (pm->status & BIT(MPTCP_PM_ESTABLISHED)) {
 		pm->status &= ~BIT(MPTCP_PM_ESTABLISHED);
diff --git a/net/mptcp/pm_kernel.c b/net/mptcp/pm_kernel.c
index 74838e2c66ba..d04dd1cece09 100644
--- a/net/mptcp/pm_kernel.c
+++ b/net/mptcp/pm_kernel.c
@@ -1441,6 +1441,11 @@ static int mptcp_pm_kernel_add_addr_received(struct mptcp_sock *msk,
 	return -EINVAL;
 }
 
+static void mptcp_pm_kernel_rm_addr_received(struct mptcp_sock *msk)
+{
+	mptcp_pm_rm_addr_recv(msk);
+}
+
 static void mptcp_pm_kernel_init(struct mptcp_sock *msk)
 {
 	bool subflows_allowed = !!mptcp_pm_get_subflows_max(msk);
@@ -1470,6 +1475,7 @@ struct mptcp_pm_ops mptcp_pm_kernel = {
 	.accept_new_subflow	= mptcp_pm_kernel_accept_new_subflow,
 	.add_addr_echo		= mptcp_pm_kernel_add_addr_echo,
 	.add_addr_received	= mptcp_pm_kernel_add_addr_received,
+	.rm_addr_received	= mptcp_pm_kernel_rm_addr_received,
 	.init			= mptcp_pm_kernel_init,
 	.name			= "kernel",
 	.owner			= THIS_MODULE,
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 8663350fac2f..d8b46f8ef8d3 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -1030,6 +1030,7 @@ void mptcp_pm_rm_subflow(struct mptcp_sock *msk,
 			 const struct mptcp_rm_list *rm_list);
 void mptcp_pm_rm_addr_received(struct mptcp_sock *msk,
 			       const struct mptcp_rm_list *rm_list);
+void mptcp_pm_rm_addr_recv(struct mptcp_sock *msk);
 void mptcp_pm_mp_prio_received(struct sock *sk, u8 bkup);
 void mptcp_pm_mp_fail_received(struct sock *sk, u64 fail_seq);
 int mptcp_pm_mp_prio_send_ack(struct mptcp_sock *msk,
-- 
2.45.2