netdev - Re: [PATCHv2] sctp: Enforce retransmission limit during shutdown

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Message-ID: <20110706141902.GB19518@hmsreliant.think-freely.org>
Date:	Wed, 6 Jul 2011 10:19:02 -0400
From:	Neil Horman <nhorman@...driver.com>
To:	Thomas Graf <tgraf@...hat.com>
Cc:	Vladislav Yasevich <vladislav.yasevich@...com>,
	netdev@...r.kernel.org, davem@...emloft.net,
	Wei Yongjun <yjwei@...fujitsu.com>,
	Sridhar Samudrala <sri@...ibm.com>, linux-sctp@...r.kernel.org
Subject: Re: [PATCHv2] sctp: Enforce retransmission limit during shutdown

On Wed, Jul 06, 2011 at 03:16:24PM +0200, Thomas Graf wrote:
> On Wed, 2011-07-06 at 08:15 -0400, Neil Horman wrote: 
> > On Mon, Jul 04, 2011 at 09:50:19AM -0400, Thomas Graf wrote:
> 
> > > --- a/net/sctp/sm_statefuns.c
> > > +++ b/net/sctp/sm_statefuns.c
> > > @@ -5154,7 +5154,7 @@ sctp_disposition_t sctp_sf_do_9_2_start_shutdown(
> > >  	 * The sender of the SHUTDOWN MAY also start an overall guard timer
> > >  	 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
> > >  	 */
> > > -	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
> > > +	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
> > >  			SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
> > >  
> > How come you're modifying this chunk to use TIMER_RESTART rather than
> > TIMER_START? start shutdown is where the t5 timer is actually started, isn't it?
> 
> Since we also start the timer in SHUTDOWN_PENDING now if we hit
> the retransmission limit the timer may be running already and
> needs to be restarted (at least in theory).
> 
> In reality the timer should be stopped though, we can only go
> from SHUTDOWN_PENDING into SHUTDOWN by actually SACKing bytes which
> will delete the timer. This may change though and I did not want
> this to bite us later on.
> 
> 
> 
Ok, makes sense
Acked-by: Neil Horman <nhorman@...driver.com>

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