Re: [PATCH v3 2/2] PCI: Add missing link delays required by the PCIe spec

From: Lukas Wunner <lukas@wunner.de>
To: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Len Brown <lenb@kernel.org>, Keith Busch <keith.busch@intel.com>,
	Alex Williamson <alex.williamson@redhat.com>,
	Alexandru Gagniuc <mr.nuke.me@gmail.com>,
	Kai-Heng Feng <kai.heng.feng@canonical.com>,
	Paul Menzel <pmenzel@molgen.mpg.de>,
	Nicholas Johnson <nicholas.johnson-opensource@outlook.com.au>,
	linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 2/2] PCI: Add missing link delays required by the PCIe spec
Date: Sat, 9 Nov 2019 15:49:19 +0100	[thread overview]
Message-ID: <20191109144919.a2whrvyih4k4fu42@wunner.de> (raw)
In-Reply-To: <20191107121847.24781-3-mika.westerberg@linux.intel.com>

On Thu, Nov 07, 2019 at 03:18:47PM +0300, Mika Westerberg wrote:
> +static int pci_bus_max_d3cold_delay(const struct pci_bus *bus)
> +{
> +	const struct pci_dev *pdev;
> +	int min_delay = 100;
> +	int max_delay = 0;
> +
> +	list_for_each_entry(pdev, &bus->devices, bus_list) {
> +		if (pdev->d3cold_delay < min_delay)
> +			min_delay = pdev->d3cold_delay;
> +		if (pdev->d3cold_delay > max_delay)
> +			max_delay = pdev->d3cold_delay;
> +	}

You need to hold pci_bus_sem when accessing the devices list.

> +	if (!dev->subordinate || list_empty(&dev->subordinate->devices))
> +		return;

Same here.

> +	child = list_first_entry(&dev->subordinate->devices, struct pci_dev,
> +				 bus_list);

And again.

Thanks,

Lukas