Hi Geliang,
On 03/03/2025 05:22, Geliang Tang wrote:
> From: Geliang Tang <tanggeliang@kylinos.cn>
>
> Add a struct mptcp_pm_ops pointer "ops" in struct mptcp_pm_data, and two
> functions mptcp_pm_initialize() and mptcp_pm_release(), to set and release
> this pointer. mptcp_pm_initialize() is invoked in mptcp_pm_data_reset(),
> while mptcp_pm_release() is invoked in mptcp_pm_destroy().
>
> Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
> ---
> net/mptcp/pm.c | 42 +++++++++++++++++++++++++++++++++++++++---
> net/mptcp/protocol.h | 3 +++
> 2 files changed, 42 insertions(+), 3 deletions(-)
>
> diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
> index 98f81221786f..e8b34f2ecb35 100644
> --- a/net/mptcp/pm.c
> +++ b/net/mptcp/pm.c
> @@ -973,15 +973,15 @@ void mptcp_pm_worker(struct mptcp_sock *msk)
> void mptcp_pm_destroy(struct mptcp_sock *msk)
> {
> mptcp_pm_free_anno_list(msk);
> -
> - if (mptcp_pm_is_userspace(msk))
> - mptcp_userspace_pm_free_local_addr_list(msk);
> + mptcp_pm_release(msk);
> }
>
> void mptcp_pm_data_reset(struct mptcp_sock *msk)
> {
> + const char *path_manager = mptcp_get_path_manager(sock_net((struct sock *)msk));
> u8 pm_type = mptcp_get_pm_type(sock_net((struct sock *)msk));
> struct mptcp_pm_data *pm = &msk->pm;
> + int ret;
>
> pm->add_addr_signaled = 0;
> pm->add_addr_accepted = 0;
> @@ -991,6 +991,12 @@ void mptcp_pm_data_reset(struct mptcp_sock *msk)
> pm->rm_list_rx.nr = 0;
> WRITE_ONCE(pm->pm_type, pm_type);
>
> + rcu_read_lock();
> + ret = mptcp_pm_initialize(msk, mptcp_pm_find(path_manager));
> + rcu_read_unlock();
> + if (ret)
> + return;
Mmh, that's annoying if pm->ops has not been set here! I don't think
mptcp_pm_initialize() can fail and if it does, it should stop the
connection.
> +
> if (pm_type == MPTCP_PM_TYPE_KERNEL) {> bool subflows_allowed = !!mptcp_pm_get_subflows_max(msk);
>
> @@ -1102,3 +1108,33 @@ void mptcp_pm_get_available(char *buf, size_t maxlen)
> }
> rcu_read_unlock();
> }
> +
> +int mptcp_pm_initialize(struct mptcp_sock *msk, struct mptcp_pm_ops *pm)
> +{
> + if (!pm)
I guess this should never happen, right? Or maybe yes if a BPF PM has
been unloaded?
> + pm = &mptcp_kernel_pm;
> +
> + if (!bpf_try_module_get(pm, pm->owner))
> + return -EBUSY;
Should it not fallback to the kernel PM + print a warning (once?)?
pr_warn_once("%pm %s couldn't be initialized, falling back to 'kernel'",
pm->name);
pm = &mptcp_kernel_pm;
> +
> + msk->pm.ops = pm;
> + if (msk->pm.ops->init)
> + msk->pm.ops->init(msk);
> +
> + pr_debug("pm %s initialized\n", pm->name);
> + return 0;
> +}
> +
> +void mptcp_pm_release(struct mptcp_sock *msk)
> +{
> + struct mptcp_pm_ops *pm = msk->pm.ops;
> +
> + if (!pm)
> + return;
> +
> + msk->pm.ops = NULL;
> + if (pm->release)
> + pm->release(msk);
> +
> + bpf_module_put(pm, pm->owner);
> +}
Can you not declare mptcp_pm_release() and mptcp_pm_initialize() as
static and move them above mptcp_pm_destroy() and mptcp_pm_data_reset()?
It would make more sense, and no need to export them in protocol.h.
Cheers,
Matt
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