linux-kernel - Re: [PATCH 2/2] nvme: Cleanup nvme_dev

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Date:	Tue, 21 Jan 2014 12:06:20 -0700 (MST)
From:	Keith Busch <keith.busch@...el.com>
To:	Alexander Gordeev <agordeev@...hat.com>
cc:	Keith Busch <keith.busch@...el.com>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Matthew Wilcox <willy@...ux.intel.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	linux-nvme@...ts.infradead.org,
	"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>
Subject: Re: [PATCH 2/2] nvme: Cleanup nvme_dev_start() and fix IRQ leak

On Tue, 21 Jan 2014, Alexander Gordeev wrote:
> This is an attempt to make handling of admin queue in a
> single scope. This update also fixes a IRQ leak in case
> nvme_setup_io_queues() failed to allocate enough iomem
> and bailed out with -ENOMEM errno.
>
> Signed-off-by: Alexander Gordeev <agordeev@...hat.com>
> ---

> +static void nvme_teardown_admin_queue(struct nvme_dev *dev)
> +{
> +	nvme_disable_queue(dev, 0);
> +	nvme_free_queue(dev->queues[0]);
> +}

> @@ -2402,11 +2398,20 @@ static int nvme_dev_start(struct nvme_dev *dev)
> 	list_add(&dev->node, &dev_list);
> 	spin_unlock(&dev_list_lock);
>
> -	result = nvme_setup_io_queues(dev);
> -	if (result && result != -EBUSY)
> +	result = set_queue_count(dev, num_online_cpus());
> +	if (result == -EBUSY)
> +		return -EBUSY;
> +
> +	nvme_teardown_admin_queue(dev);

Oh no! Your new teardown function is freeing the admin queue, but it
would be used immediatly after that in nvme_setup_io_queues ...

> +
> +	if (result)
> 		goto disable;

... but you'll never actually get to setup io queues because the 'result'
here is non-zero if we were successful, and is the number of queues the
controller can allocate. I think you meant to do this instead:

+	if (result < 0)

>
> -	return result;
> +	result = nvme_setup_io_queues(dev, result);
> +	if (result)
> +		goto disable;
> +
> +	return 0;

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