diff mbox series

[mptcp-next,v3,09/10] mptcp: pm: add rm_addr_received() interface

Message ID e14151bf63b9ae2fa6f75061e1d0d2de069ec6b1.1742521397.git.tanggeliang@kylinos.cn (mailing list archive)
State Superseded, archived
Delegated to: Matthieu Baerts
Headers show
Series BPF path manager, part 6 | expand

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Commit Message

Geliang Tang March 21, 2025, 1:45 a.m. UTC 
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.
This patch unlocks the pm lock before invoking this interface in
mptcp_pm_worker(), while holding this lock in mptcp_pm_rm_addr_recv().

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(-)

Comments

Matthieu Baerts March 21, 2025, 10:35 a.m. UTC | #1 
On 21/03/2025 02:45, Geliang Tang wrote:
> 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.
> This patch unlocks the pm lock before invoking this interface in
> mptcp_pm_worker(), while holding this lock in mptcp_pm_rm_addr_recv().
> 
> 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.

From what I understand, you are changing the behaviour for the userspace
PM, no?

When a RM_ADDR is received, for the moment, both the in-kernel and
userspace PM removes the corresponding subflow(s). Now it is only the
case with the in-kernel PM.

Technically, it would be fine to let the userspace daemon reacting to
the RM_ADDR event, but that's changing the behaviour.

(...)

> diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
> index 7b34a59977cf..bb456e203665 100644
> --- a/net/mptcp/pm.c
> +++ b/net/mptcp/pm.c
> @@ -677,15 +677,17 @@ 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);

As an alternative not to break the behaviour, you could add the hook here:

  if (removed && pm->ops->rm_addr_received)
      pm->ops->rm_addr_received(msk, rm_id);

Cheers,
Matt
diff mbox series

Patch

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 7b34a59977cf..bb456e203665 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -677,15 +677,17 @@  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,
@@ -705,6 +707,9 @@  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;
@@ -931,7 +936,9 @@  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(&pm->lock);
+		pm->ops->rm_addr_received(msk);
+		spin_lock_bh(&pm->lock);
 	}
 	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 1a434abcf862..4f7b2e0e998d 100644
--- a/net/mptcp/pm_kernel.c
+++ b/net/mptcp/pm_kernel.c
@@ -1446,6 +1446,11 @@  static int mptcp_pm_kernel_add_addr_received(struct mptcp_sock *msk,
 	return ret;
 }
 
+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);
@@ -1475,6 +1480,7 @@  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 784e787cf667..4883f786e8ea 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -1031,6 +1031,7 @@  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,