From mboxrd@z Thu Jan  1 00:00:00 1970
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From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>, Len Brown <lenb@kernel.org>,
        Mario.Limonciello@dell.com,
        Michael Jamet <michael.jamet@intel.com>,
        Yehezkel Bernat <yehezkel.bernat@intel.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Lukas Wunner <lukas@wunner.de>, linux-pci@vger.kernel.org,
        linux-acpi@vger.kernel.org
Subject: Re: [PATCH RESEND v4 6/9] PCI: Move resource distribution for a single bridge outside of the loop
Date: Tue, 10 Apr 2018 17:01:37 +0200
Message-ID: <3309767.InJdpLfA95@aspire.rjw.lan>
In-Reply-To: <20180403145225.22371-7-mika.westerberg@linux.intel.com>
References: <20180403145225.22371-1-mika.westerberg@linux.intel.com> <20180403145225.22371-7-mika.westerberg@linux.intel.com>
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Sender: linux-acpi-owner@vger.kernel.org
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On Tuesday, April 3, 2018 4:52:22 PM CEST Mika Westerberg wrote:
> There is a special case where there is only single bridge on the bus. In
> that case we just assign all resources to it. Currently this is done as
> a part of the resource distribution loop but it does not have to be
> there, and moving it outside actually improves readability.
> 
> While there we can add hotplug_bridges == 1 && normal_bridges == 0 to
> the same block because they are dealt the same way.
> 
> Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> ---
>  drivers/pci/setup-bus.c | 28 +++++++++++++++++-----------
>  1 file changed, 17 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
> index f1e6172734f0..b5eefd20d78d 100644
> --- a/drivers/pci/setup-bus.c
> +++ b/drivers/pci/setup-bus.c
> @@ -1951,6 +1951,22 @@ static void pci_bus_distribute_available_resources(struct pci_bus *bus,
>  	mmio_start = mmio_res->start;
>  	mmio_pref_start = mmio_pref_res->start;
>  
> +	/*
> +	 * There is only one bridge on the bus so it gets all available
> +	 * resources which it can then distribute to the possible
> +	 * hotplug bridges below.
> +	 */
> +	if ((hotplug_bridges == 0 && normal_bridges == 1) ||
> +	    (hotplug_bridges == 1 && normal_bridges == 0)) {
> +		dev = list_first_entry(&bus->devices, struct pci_dev, bus_list);
> +		if (dev->subordinate) {
> +			pci_bus_distribute_available_resources(dev->subordinate,
> +				add_list, available_io, available_mmio,
> +				available_mmio_pref);
> +		}
> +		return;
> +	}
> +
>  	/*
>  	 * Go over devices on this bus and distribute the remaining
>  	 * resource space between hotplug bridges.
> @@ -1963,17 +1979,7 @@ static void pci_bus_distribute_available_resources(struct pci_bus *bus,
>  		if (!b)
>  			continue;
>  
> -		if (!hotplug_bridges && normal_bridges == 1) {
> -			/*
> -			 * There is only one bridge on the bus (upstream
> -			 * port) so it gets all available resources
> -			 * which it can then distribute to the possible
> -			 * hotplug bridges below.
> -			 */
> -			pci_bus_distribute_available_resources(b, add_list,
> -				available_io, available_mmio,
> -				available_mmio_pref);
> -		} else if (dev->is_hotplug_bridge) {
> +		if (dev->is_hotplug_bridge) {
>  			resource_size_t io, mmio, mmio_pref;
>  
>  			/*
> 

Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>