Re: [PATCHv5 for-rc1 v5 4/8] RDMA/rxe: Implement dellink in rxe

[Bob Pearson <rpearsonhpe@gmail.com>]

On 6/20/23 21:13, Zhu Yanjun wrote:
> 
> 在 2023/6/21 4:21, Bob Pearson 写道:
>> On 4/28/23 04:39, Zhu Yanjun wrote:
>>> From: Zhu Yanjun <yanjun.zhu@linux.dev>
>>>
>>> When running "rdma link del" command, dellink function will be called.
>>> If the sock refcnt is greater than the refcnt needed for udp tunnel,
>>> the sock refcnt will be decreased by 1.
>>>
>>> If equal, the last rdma link is removed. The udp tunnel will be
>>> destroyed.
>>>
>>> Tested-by: Rain River <rain.1986.08.12@gmail.com>
>>> Signed-off-by: Zhu Yanjun <yanjun.zhu@linux.dev>
>>> ---
>>>   drivers/infiniband/sw/rxe/rxe.c     | 12 +++++++++++-
>>>   drivers/infiniband/sw/rxe/rxe_net.c | 17 +++++++++++++++--
>>>   drivers/infiniband/sw/rxe/rxe_net.h |  1 +
>>>   3 files changed, 27 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/infiniband/sw/rxe/rxe.c b/drivers/infiniband/sw/rxe/rxe.c
>>> index 0ce6adb43cfc..ebfabc6d6b76 100644
>>> --- a/drivers/infiniband/sw/rxe/rxe.c
>>> +++ b/drivers/infiniband/sw/rxe/rxe.c
>>> @@ -166,10 +166,12 @@ void rxe_set_mtu(struct rxe_dev *rxe, unsigned int ndev_mtu)
>>>   /* called by ifc layer to create new rxe device.
>>>    * The caller should allocate memory for rxe by calling ib_alloc_device.
>>>    */
>>> +static struct rdma_link_ops rxe_link_ops;
>>>   int rxe_add(struct rxe_dev *rxe, unsigned int mtu, const char *ibdev_name)
>>>   {
>>>       rxe_init(rxe);
>>>       rxe_set_mtu(rxe, mtu);
>>> +    rxe->ib_dev.link_ops = &rxe_link_ops;
>>>         return rxe_register_device(rxe, ibdev_name);
>>>   }
>>> @@ -206,9 +208,17 @@ static int rxe_newlink(const char *ibdev_name, struct net_device *ndev)
>>>       return err;
>>>   }
>>>   -struct rdma_link_ops rxe_link_ops = {
>>> +static int rxe_dellink(struct ib_device *dev)
>>> +{
>>> +    rxe_net_del(dev);
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static struct rdma_link_ops rxe_link_ops = {
>>>       .type = "rxe",
>>>       .newlink = rxe_newlink,
>>> +    .dellink = rxe_dellink,
>>>   };
>>>     static int __init rxe_module_init(void)
>>> diff --git a/drivers/infiniband/sw/rxe/rxe_net.c b/drivers/infiniband/sw/rxe/rxe_net.c
>>> index 3ca92e062800..4cc7de7b115b 100644
>>> --- a/drivers/infiniband/sw/rxe/rxe_net.c
>>> +++ b/drivers/infiniband/sw/rxe/rxe_net.c
>>> @@ -530,6 +530,21 @@ int rxe_net_add(const char *ibdev_name, struct net_device *ndev)
>>>       return 0;
>>>   }
>>>   +#define SK_REF_FOR_TUNNEL    2
>>> +void rxe_net_del(struct ib_device *dev)
>>> +{
>>> +    if (refcount_read(&recv_sockets.sk6->sk->sk_refcnt) > SK_REF_FOR_TUNNEL)
>>> +        __sock_put(recv_sockets.sk6->sk);
>>> +    else
>>> +        rxe_release_udp_tunnel(recv_sockets.sk6);
>>> +
>>> +    if (refcount_read(&recv_sockets.sk4->sk->sk_refcnt) > SK_REF_FOR_TUNNEL)
>>> +        __sock_put(recv_sockets.sk4->sk);
>>> +    else
>>> +        rxe_release_udp_tunnel(recv_sockets.sk4);
>>> +}
>>> +#undef SK_REF_FOR_TUNNEL
>>> +
>>>   static void rxe_port_event(struct rxe_dev *rxe,
>>>                  enum ib_event_type event)
>>>   {
>>> @@ -689,8 +704,6 @@ int rxe_register_notifier(void)
>>>     void rxe_net_exit(void)
>>>   {
>>> -    rxe_release_udp_tunnel(recv_sockets.sk6);
>>> -    rxe_release_udp_tunnel(recv_sockets.sk4);
>>>       unregister_netdevice_notifier(&rxe_net_notifier);
>>>   }
>> These calls are moved to rxe_net_del which is called by an explicit unlink command.
>> But if rxe_net_init fails and returns an error code this will never happen.
>> This will result in leaking resources.
> 
> Thanks a lot. Bob.
> 
> Sure, if ipv6 tunnel fails to be created, the resource related with ipv4 should be released.
> 
> I will fix it in the latest version.
> 
> Zhu Yanjun

I haven't had a chance to test netns yet. I am sure it works but I will test it.
The only other thing I noticed are some stylistic differences with the rest of
the rxe driver. You use

struct rxe_dev *rdev;

elsewhere it is

struct rxe_dev *rxe;

Yours is more like the mlx drivers where they use dev for ib_device and mdev for mlx_device.
rxe tries to use ibdev ibqp, ibmr, etc for the ib objects and no prefix for the driver
specific ones. It's less typing that way.

With a couple of exceptions all the printk's are now in the form

rxe_[type]_[obj](obj, "message", ...) or rxe_[type] if there isn't an obj to refer to.

where type = info, err, warn, or dbg and obj = rxe, ah, pd, qp, cq, etc. These are basically
adapted from the siw driver.

Regards,

Bob

> 
>>
>> Bob
>>>   diff --git a/drivers/infiniband/sw/rxe/rxe_net.h b/drivers/infiniband/sw/rxe/rxe_net.h
>>> index a222c3eeae12..f48f22f3353b 100644
>>> --- a/drivers/infiniband/sw/rxe/rxe_net.h
>>> +++ b/drivers/infiniband/sw/rxe/rxe_net.h
>>> @@ -17,6 +17,7 @@ struct rxe_recv_sockets {
>>>   };
>>>     int rxe_net_add(const char *ibdev_name, struct net_device *ndev);
>>> +void rxe_net_del(struct ib_device *dev);
>>>     int rxe_register_notifier(void);
>>>   int rxe_net_init(void);