netdev - Re: [PATCH net 2/2] RDS: TCP: Synchrnozize accept() and connect() paths on t_conn

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Message-ID: <20160502164307.GE20517@oracle.com>
Date:	Mon, 2 May 2016 12:43:07 -0400
From:	Sowmini Varadhan <sowmini.varadhan@...cle.com>
To:	Santosh Shilimkar <santosh.shilimkar@...cle.com>
Cc:	netdev@...r.kernel.org, rds-devel@....oracle.com,
	davem@...emloft.net
Subject: Re: [PATCH net 2/2] RDS: TCP: Synchrnozize accept() and connect()
 paths on t_conn_lock.

On (05/02/16 09:33), Santosh Shilimkar wrote:
> >+	mutex_unlock(&tc->t_conn_lock);
> Just wondering whether the spin_lock() would better here considering
> entry into rds_tcp_conn_connect() & rds_tcp_accept_one() might be
> from softirq context. Ignore it if its not applicable.

It's not from softirq context (both are workqs), but I used a mutex
to follow c_cm_lock (which I considered reusing, given that it 
is only IB specific?) But spin_lock vs mutex may not be a big
differentiator here- this is really a one-time start up (corner-case)
issue in the control path.

> > 	rds_conn_transition(conn, RDS_CONN_DOWN, RDS_CONN_CONNECTING);
> Like patch 1/2, probably we can leverage return value of above. 
     :
> You probably don't need the local 'conn_state' and below should work.
> 	if (!rds_conn_connecting(conn) && !rds_conn_up(conn))

see explanation for comment to 1/2.


--Sowmini