Re: [PATCH V2 1/6] SLIMbus: Device management on SLIMbus

From: Sagar Dharia <sdharia@codeaurora.org>
To: Mark Brown <broonie@kernel.org>
Cc: gregkh@linuxfoundation.org, bp@suse.de, poeschel@lemonage.de,
	treding@nvidia.com, gong.chen@linux.intel.com,
	andreas.noever@gmail.com, alan@linux.intel.com,
	mathieu.poirier@linaro.org, daniel@ffwll.ch, oded.gabbay@amd.com,
	jkosina@suse.cz, sharon.dvir1@mail.huji.ac.il, joe@perches.com,
	davem@davemloft.net, james.hogan@imgtec.com,
	michael.opdenacker@free-electrons.com,
	daniel.thompson@linaro.org, linux-kernel@vger.kernel.org,
	nkaje@codeaurora.org, kheitke@audience.com,
	mlocke@codeaurora.org, agross@codeaurora.org,
	linux-arm-msm@vger.kernel.org
Subject: Re: [PATCH V2 1/6] SLIMbus: Device management on SLIMbus
Date: Wed, 17 Jun 2015 11:36:06 -0600	[thread overview]
Message-ID: <5581B006.6070804@codeaurora.org> (raw)
In-Reply-To: <20150617131609.GG3214@sirena.org.uk>

On 6/17/2015 7:16 AM, Mark Brown wrote:
> On Tue, Jun 16, 2015 at 07:45:59PM -0600, Sagar Dharia wrote:
>
>> +	if (status) {
>> +		slim_dev->driver = NULL;
>> +	} else if (driver->device_up) {
>> +		ctrl = slim_dev->ctrl;
>> +		queue_work(ctrl->wq, &slim_dev->wd);
>> +	}
> Nothing ever cleans this work up if it didn't manage to run or
> complete.
>
>> +static void slim_report(struct work_struct *work)
>> +{
>> +	struct slim_driver *sbdrv;
>> +	struct slim_device *sbdev = container_of(work, struct slim_device, wd);
>> +
>> +	if (!sbdev->dev.driver)
>> +		return;
> So we just forget about the device if we don't have a driver for it?
If device comes up before driver (e.g. dynamic module driver, or 
late-init driver), then to begin with: this doesn't do anything.
But once the driver-binding happens and probe succeeds, we queue 
device_up again.
>
>> +	/* check if device-up or down needs to be called */
>> +	if ((!sbdev->reported && !sbdev->notified) ||
>> +	    (sbdev->reported && sbdev->notified))
>> +		return;
> No locking here?
You are right, first I thought this was only touched in workqueue 
(singlethreaded), but this is also touched from logical-address 
assignment, driver removal etc.
I will add device-level lock for these.
Thanks
Sagar
>
>> +/**
>> + * slim_ctrl_add_boarddevs: Add devices registered by board-info
>> + * @ctrl: Controller to which these devices are to be added to.
>> + * This API is called by controller when it is up and running.
>> + * If devices on a controller were registered before controller,
>> + * this will make sure that they get probed when controller is up.
>> + */
>> +void slim_ctrl_add_boarddevs(struct slim_controller *ctrl)
> My concerns about the split here still remain.


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