From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S937888AbdEYQkl (ORCPT ); Thu, 25 May 2017 12:40:41 -0400 Received: from foss.arm.com ([217.140.101.70]:52004 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936076AbdEYQki (ORCPT ); Thu, 25 May 2017 12:40:38 -0400 Date: Thu, 25 May 2017 17:40:31 +0100 From: Alexey Klimov To: Jassi Brar Cc: Jassi Brar , Sudeep Holla , lkml Subject: Re: [PATCH] mailbox: fix completion order for blocking requests Message-ID: <20170525164030.GA9999@arm.com> References: <1490809381-28869-1-git-send-email-jaswinder.singh@linaro.org> <64c77cc8-7327-d822-5976-c84b3d452ac5@arm.com> <20170406165806.GA27174@arm.com> <20170411124538.GB4973@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jassi, Sorry for delay -- this is not my main activity so please be patient. On Sun, Apr 23, 2017 at 03:33:39PM +0530, Jassi Brar wrote: > On Tue, Apr 11, 2017 at 6:15 PM, Alexey Klimov wrote: > > On Thu, Apr 06, 2017 at 10:45:26PM +0530, Jassi Brar wrote: > >> On 6 April 2017 at 22:28, Alexey Klimov wrote: > >> > Hi Jassi/Sudeep, > >> > > >> > On Wed, Mar 29, 2017 at 07:01:09PM +0100, Sudeep Holla wrote: > >> >> > >> >> > >> >> On 29/03/17 18:43, Jassi Brar wrote: > >> ... > >> > >> >> > diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c > >> >> > index 9dfbf7e..e06c50c 100644 > >> >> > --- a/drivers/mailbox/mailbox.c > >> >> > +++ b/drivers/mailbox/mailbox.c > >> >> > @@ -41,6 +41,7 @@ static int add_to_rbuf(struct mbox_chan *chan, void *mssg) > >> >> > > >> >> > idx = chan->msg_free; > >> >> > chan->msg_data[idx] = mssg; > >> >> > + init_completion(&chan->tx_cmpl[idx]); > >> >> > >> >> reinit would be better. > >> > > >> Of course. > >> > >> .... > >> > From: Alexey Klimov > >> > Date: Thu, 6 Apr 2017 13:57:02 +0100 > >> > Subject: [RFC][PATCH] mailbox: per-channel arrays with msg data and completion > >> > structures > >> > > >> > When a mailbox client doesn't serialize sending of the message itself, > >> > and asks mailbox framework to block on mbox_send_message(), one > >> > completion structure per channel is not enough. Client can make a few > >> > mbox_send_message() calls at the same time, and there is no guaranteed > >> > order of going to sleep on completion. > >> > > >> > If mailbox controller acks a message transfer, then tx_tick() wakes up > >> > the first thread that waits on completion. > >> > If mailbox controller doesn't ack the transfer and timeout happens, then > >> > tx_tick() calls complete, and the next caller trying to sleep on > >> > completion wakes up immediately. > >> > > >> > This patch fixes this by changing completion structures to be inserted > >> > into an array that contains a) pointer to data provided by client and > >> > b) the completion structure. Thus active_req field tracks the index of > >> > the current running request that was submitted to mailbox controller. > >> > > >> > Signed-off-by: Alexey Klimov > >> > --- > >> > drivers/mailbox/mailbox.c | 40 +++++++++++++++++++++++--------------- > >> > drivers/mailbox/pcc.c | 10 +++++++--- > >> > include/linux/mailbox_controller.h | 24 +++++++++++++++++------ > >> ... > >> > 3 files changed, 49 insertions(+), 25 deletions(-) > >> > > >> Versus 4 files changed, 17 insertions(+), 8 deletions(-) > >> > >> I think we should just keep it simpler if it works just as fine. > > > > Along with this patch you still need at least one patch from Sudeep with subject: > > "[PATCH 1/3] mailbox: always wait in mbox_send_message for blocking Tx mode" > > > Yes. Just so we are on same page, can you please redo your tests and > see if this and Sudeep's patch-1/3 does the trick? Yes, for such kind of behaviour to make things work I need to apply Sudeep's patches and this your (or mine) patch that changes completion behaviour. Or do I miss something and have you already applied it? Thanks! Alexey.