From: Andreas Schultz <aschultz@tpip•net>
To: pablo <pablo@netfilter•org>
Cc: netdev <netdev@vger•kernel.org>, laforge <laforge@gnumonks•org>,
Lionel Gauthier <Lionel.Gauthier@eurecom•fr>,
openbsc <openbsc@lists•osmocom.org>
Subject: Re: [PATCH net-next v2 5/6] gtp: add socket to pdp context
Date: Thu, 2 Feb 2017 16:07:23 +0100 (CET) [thread overview]
Message-ID: <2083605423.731432.1486048043458.JavaMail.zimbra@tpip.net> (raw)
In-Reply-To: <20170202144606.GA19992@salvia>
----- On Feb 2, 2017, at 3:46 PM, pablo pablo@netfilter•org wrote:
> On Thu, Feb 02, 2017 at 03:38:07PM +0100, Andreas Schultz wrote:
>>
>>
>> ----- On Feb 2, 2017, at 3:28 PM, pablo pablo@netfilter•org wrote:
>>
>> > On Thu, Feb 02, 2017 at 03:12:55PM +0100, Andreas Schultz wrote:
>> >> Hi,
>> >>
>> >> ----- On Feb 2, 2017, at 2:56 PM, pablo pablo@netfilter•org wrote:
>> >>
>> >> > On Mon, Jan 30, 2017 at 05:37:12PM +0100, Andreas Schultz wrote:
>> >> >> Having the socket present in context simplifies the sending logic.
>> >> >> It also fixes the invalid assumption that we have to use the same
>> >> >> sending socket for all client IP's on a specific gtp interface.
>> >> >>
>> >> >> Signed-off-by: Andreas Schultz <aschultz@tpip•net>
>> >> >> ---
>> >> >> drivers/net/gtp.c | 72 ++++++++++++++++++++++++++++++-------------------------
>> >> >> 1 file changed, 39 insertions(+), 33 deletions(-)
>> >> >>
>> >> >> diff --git a/drivers/net/gtp.c b/drivers/net/gtp.c
>> >> >> index 68c6c9b..ff00597 100644
>> >> >> --- a/drivers/net/gtp.c
>> >> >> +++ b/drivers/net/gtp.c
>> >> > [...]
>> >> >> @@ -984,16 +966,26 @@ static int ipv4_pdp_add(struct gtp_dev *gtp, struct
>> >> >> genl_info *info)
>> >> >> return 0;
>> >> >> }
>> >> >>
>> >> >> +static void pdp_context_free(struct rcu_head *head)
>> >> >> +{
>> >> >> + struct pdp_ctx *pctx = container_of(head, struct pdp_ctx, rcu_head);
>> >> >> +
>> >> >> + sock_put(pctx->sk);
>> >> >> + kfree(pctx);
>> >> >> +}
>> >> >> +
>> >> >> static void pdp_context_delete(struct pdp_ctx *pctx)
>> >> >> {
>> >> >> hlist_del_rcu(&pctx->hlist_tid);
>> >> >> hlist_del_rcu(&pctx->hlist_addr);
>> >> >> - kfree(pctx);
>> >> >> + call_rcu(&pctx->rcu_head, pdp_context_free);
>> >> >
>> >> > This is fixing incorrect rcu conversion in 4/6. Please, fix this there.
>> >>
>> >> Ehm, right, but the kfree in 4/6 could have been a kfree_rcu instead without
>> >> the call_rcu.
>> >>
>> >> Do you prefer to introduce the call_rcu in 4/6 and then just add the sock_put
>> >> in this patch or should I change 4/6 to kfree_rcu and do the call_rcu
>> >> conversion here?
>> >
>> > I suggest you just call kfree_rcu() from 4/6.
>> >
>> > Regarding holding socket reference, see my comment for patch 1/6.
>>
>> This is going to be a problem at this stage of the changes.
>>
>> The final goal is to have a reference from the socket to the pdp context.
>
> Is this just a cleanup? Or you need this sk caching for some follow up
> work?
It's not caching, the plan is to completely remove the socket from the
GTP netdevice (as far as that is possible without breaking the existing API).
A GGSN or PGW can serve multiple APN's on the same GTP-U socket. Those APN's
can have overlapping IP address ranges. The only sensible way to handle
this, is to have a netdevice per APN. This breaks the current 1:1 relation
between sockets and netdevices.
Andreas
>
>> Then, when the socket is closed, the pdp context can be destroyed.
>>
>> However, at this point, only the netdevice knows about the contexts. So
>> when the socket is closed, the pdp context would have a dangling reference
>> to the socket.
>>
>> I can integrate this change into the later one. But it will make that
>> change larger and more difficult to review.
>>
>> I guess, I'm going to drop this change from this series and see if can
>> reorder the next part so that it still makes and I easy to review....
>
> Agreed. Thanks.
next prev parent reply other threads:[~2017-02-02 15:07 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-30 16:37 [PATCH net-next v2 0/6] gtp: misc improvements Andreas Schultz
2017-01-30 16:37 ` [PATCH net-next v2 1/6] gtp: make GTP sockets in gtp_newlink optional Andreas Schultz
2017-02-02 14:10 ` Pablo Neira Ayuso
2017-02-02 14:30 ` Andreas Schultz
2017-02-02 14:32 ` Pablo Neira Ayuso
2017-02-06 13:51 ` Harald Welte
2017-01-30 16:37 ` [PATCH net-next v2 2/6] gtp: merge gtp_get_net and gtp_genl_find_dev Andreas Schultz
2017-02-06 13:55 ` Harald Welte
2017-02-13 14:13 ` Andreas Schultz
2017-02-13 14:51 ` Pablo Neira Ayuso
2017-01-30 16:37 ` [PATCH net-next v2 3/6] gtp: unify genl_find_pdp and prepare for per socket lookup Andreas Schultz
2017-02-02 14:19 ` Pablo Neira Ayuso
2017-02-02 14:27 ` Andreas Schultz
2017-02-02 14:31 ` Pablo Neira Ayuso
2017-02-06 13:56 ` Harald Welte
2017-01-30 16:37 ` [PATCH net-next v2 4/6] gtp: consolidate pdp context destruction into helper Andreas Schultz
2017-02-06 13:58 ` Harald Welte
2017-02-13 14:14 ` Andreas Schultz
2017-01-30 16:37 ` [PATCH net-next v2 5/6] gtp: add socket to pdp context Andreas Schultz
2017-02-02 13:56 ` Pablo Neira Ayuso
2017-02-02 14:12 ` Andreas Schultz
2017-02-02 14:28 ` Pablo Neira Ayuso
2017-02-02 14:38 ` Andreas Schultz
2017-02-02 14:46 ` Pablo Neira Ayuso
2017-02-02 15:07 ` Andreas Schultz [this message]
2017-02-06 14:04 ` Harald Welte
2017-01-30 16:37 ` [PATCH net-next v2 6/6] gtp: consolidate gtp socket rx path Andreas Schultz
2017-01-31 18:05 ` [PATCH net-next v2 0/6] gtp: misc improvements David Miller
2017-02-06 13:46 ` Harald Welte
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