linux-kernel - Re: [PATCHv5 2/4] mailbox: Introduce framework for mailbox

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Message-ID: <20140521172701.GV12304@sirena.org.uk>
Date:	Wed, 21 May 2014 18:27:01 +0100
From:	Mark Brown <broonie@...nel.org>
To:	Jassi Brar <jassisinghbrar@...il.com>
Cc:	linux-kernel@...r.kernel.org, gregkh@...uxfoundation.org,
	s-anna@...com, loic.pallardy@...com, lftan.linux@...il.com,
	slapdau@...oo.com.au, courtney.cavin@...ymobile.com,
	robherring2@...il.com, arnd@...db.de, joshc@...eaurora.org,
	linus.walleij@...aro.org, galak@...eaurora.org,
	ks.giri@...sung.com, Jassi Brar <jaswinder.singh@...aro.org>
Subject: Re: [PATCHv5 2/4] mailbox: Introduce framework for mailbox

On Thu, May 15, 2014 at 11:41:00AM +0530, Jassi Brar wrote:
> Introduce common framework for client/protocol drivers and
> controller drivers of Inter-Processor-Communication (IPC).

This looks pretty nice, though I do have a few *very* small nits beyond
those Arnd had.

> +	if (chan->cl->tx_block && chan->active_req) {
> +		int ret;
> +		init_completion(&chan->tx_complete);

reinit_completion().

> +	if (!cl->tx_tout) /* wait for ever */
> +		cl->tx_tout = msecs_to_jiffies(3600000);
> +	else
> +		cl->tx_tout = msecs_to_jiffies(cl->tx_tout);

Is the default wait for ever the best timeout - I'm not sure it's best
from a defensiveness point of view.  It should be fine either way,
it's just a matter of taste.

> +	ret = chan->mbox->ops->startup(chan);
> +	if (ret) {
> +		pr_err("Unable to startup the chan\n");

Perhaps print the error codes?  Might be helpful to users.

> +	/* The queued TX requests are simply aborted, no callbacks are made */
> +	spin_lock_irqsave(&chan->lock, flags);
> +	chan->cl = NULL;
> +	chan->active_req = NULL;
> +	if (chan->txdone_method == (TXDONE_BY_POLL | TXDONE_BY_ACK))
> +		chan->txdone_method = TXDONE_BY_POLL;
> +
> +	module_put(chan->mbox->dev->driver->owner);
> +	spin_unlock_irqrestore(&chan->lock, flags);

Is the module_put() safe in atomic context?

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