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From:   "Rafael J. Wysocki" <rjw@rjwysocki.net>
To:     Bjorn Helgaas <helgaas@kernel.org>
Cc:     linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-pm@vger.kernel.org, Keith Busch <keith.busch@intel.com>,
        Sinan Kaya <okaya@codeaurora.org>,
        Lukas Wunner <lukas@wunner.de>
Subject: Re: [PATCH v1 5/9] PCI/portdrv: Remove pcie_port_bus_type link order dependency
Date:   Wed, 07 Mar 2018 11:33:48 +0100
Message-ID: <7571217.yaDH5TzqWC@aspire.rjw.lan>
In-Reply-To: <152040323121.240786.5383276983544773869.stgit@bhelgaas-glaptop.roam.corp.google.com>
References: <152040297576.240786.1532465558381209070.stgit@bhelgaas-glaptop.roam.corp.google.com> <152040323121.240786.5383276983544773869.stgit@bhelgaas-glaptop.roam.corp.google.com>
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On Wednesday, March 7, 2018 7:13:51 AM CET Bjorn Helgaas wrote:
> From: Bjorn Helgaas <bhelgaas@google.com>
> 
> The pcie_port_bus_type must be registered before drivers that depend on it
> can be registered.  Those drivers include:
> 
>   pcied_init()                # PCIe native hotplug driver
>   aer_service_init()          # AER driver
>   dpc_service_init()          # DPC driver
>   pcie_pme_service_init()     # PME driver
> 
> Previously we registered pcie_port_bus_type from pcie_portdrv_init(), a
> device_initcall.  The callers of pcie_port_service_register() (above) are
> also device_initcalls.  This is fragile because the device_initcall
> ordering depends on link order, which is not explicit.
> 
> Register pcie_port_bus_type from pci_driver_init() along with pci_bus_type.
> This removes the link order dependency between portdrv and the pciehp, AER,
> DPC, and PCIe PME drivers.
> 
> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
> ---
>  drivers/pci/pci-driver.c       |   45 +++++++++++++++++++++++++++++++-
>  drivers/pci/pcie/Makefile      |    2 +
>  drivers/pci/pcie/portdrv_bus.c |   56 ----------------------------------------
>  drivers/pci/pcie/portdrv_pci.c |   13 +--------
>  4 files changed, 46 insertions(+), 70 deletions(-)
>  delete mode 100644 drivers/pci/pcie/portdrv_bus.c
> 
> diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
> index 38ee7c8b4d1a..4db85a0faf34 100644
> --- a/drivers/pci/pci-driver.c
> +++ b/drivers/pci/pci-driver.c
> @@ -7,6 +7,7 @@
>   */
>  
>  #include <linux/pci.h>
> +#include <linux/pcieport_if.h>
>  #include <linux/module.h>
>  #include <linux/init.h>
>  #include <linux/device.h>
> @@ -19,6 +20,7 @@
>  #include <linux/suspend.h>
>  #include <linux/kexec.h>
>  #include "pci.h"
> +#include "pcie/portdrv.h"
>  
>  struct pci_dynid {
>  	struct list_head node;
> @@ -1553,8 +1555,49 @@ struct bus_type pci_bus_type = {
>  };
>  EXPORT_SYMBOL(pci_bus_type);
>  
> +#ifdef CONFIG_PCIEPORTBUS
> +static int pcie_port_bus_match(struct device *dev, struct device_driver *drv)
> +{
> +	struct pcie_device *pciedev;
> +	struct pcie_port_service_driver *driver;
> +
> +	if (drv->bus != &pcie_port_bus_type || dev->bus != &pcie_port_bus_type)
> +		return 0;
> +
> +	pciedev = to_pcie_device(dev);
> +	driver = to_service_driver(drv);
> +
> +	if (driver->service != pciedev->service)
> +		return 0;
> +
> +	if ((driver->port_type != PCIE_ANY_PORT) &&
> +	    (driver->port_type != pci_pcie_type(pciedev->port)))
> +		return 0;
> +
> +	return 1;
> +}
> +
> +struct bus_type pcie_port_bus_type = {
> +	.name		= "pci_express",
> +	.match		= pcie_port_bus_match,
> +};
> +EXPORT_SYMBOL_GPL(pcie_port_bus_type);
> +#endif
> +
>  static int __init pci_driver_init(void)
>  {
> -	return bus_register(&pci_bus_type);
> +	int ret;
> +
> +	ret = bus_register(&pci_bus_type);
> +	if (ret)
> +		return ret;
> +
> +#ifdef CONFIG_PCIEPORTBUS
> +	ret = bus_register(&pcie_port_bus_type);
> +	if (ret)
> +		return ret;
> +#endif
> +
> +	return 0;
>  }
>  postcore_initcall(pci_driver_init);
> diff --git a/drivers/pci/pcie/Makefile b/drivers/pci/pcie/Makefile
> index 223e4c34c29a..e01c10c97b95 100644
> --- a/drivers/pci/pcie/Makefile
> +++ b/drivers/pci/pcie/Makefile
> @@ -6,7 +6,7 @@
>  # Build PCI Express ASPM if needed
>  obj-$(CONFIG_PCIEASPM)		+= aspm.o
>  
> -pcieportdrv-y			:= portdrv_core.o portdrv_pci.o portdrv_bus.o
> +pcieportdrv-y			:= portdrv_core.o portdrv_pci.o
>  pcieportdrv-$(CONFIG_ACPI)	+= portdrv_acpi.o
>  
>  obj-$(CONFIG_PCIEPORTBUS)	+= pcieportdrv.o
> diff --git a/drivers/pci/pcie/portdrv_bus.c b/drivers/pci/pcie/portdrv_bus.c
> deleted file mode 100644
> index f0fba552a0e2..000000000000
> --- a/drivers/pci/pcie/portdrv_bus.c
> +++ /dev/null
> @@ -1,56 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0
> -/*
> - * File:	portdrv_bus.c
> - * Purpose:	PCI Express Port Bus Driver's Bus Overloading Functions
> - *
> - * Copyright (C) 2004 Intel
> - * Copyright (C) Tom Long Nguyen (tom.l.nguyen@intel.com)
> - */
> -
> -#include <linux/module.h>
> -#include <linux/pci.h>
> -#include <linux/kernel.h>
> -#include <linux/errno.h>
> -#include <linux/pm.h>
> -
> -#include <linux/pcieport_if.h>
> -#include "portdrv.h"
> -
> -static int pcie_port_bus_match(struct device *dev, struct device_driver *drv);
> -
> -struct bus_type pcie_port_bus_type = {
> -	.name		= "pci_express",
> -	.match		= pcie_port_bus_match,
> -};
> -EXPORT_SYMBOL_GPL(pcie_port_bus_type);
> -
> -static int pcie_port_bus_match(struct device *dev, struct device_driver *drv)
> -{
> -	struct pcie_device *pciedev;
> -	struct pcie_port_service_driver *driver;
> -
> -	if (drv->bus != &pcie_port_bus_type || dev->bus != &pcie_port_bus_type)
> -		return 0;
> -
> -	pciedev = to_pcie_device(dev);
> -	driver = to_service_driver(drv);
> -
> -	if (driver->service != pciedev->service)
> -		return 0;
> -
> -	if ((driver->port_type != PCIE_ANY_PORT) &&
> -	    (driver->port_type != pci_pcie_type(pciedev->port)))
> -		return 0;
> -
> -	return 1;
> -}
> -
> -int pcie_port_bus_register(void)
> -{
> -	return bus_register(&pcie_port_bus_type);
> -}
> -
> -void pcie_port_bus_unregister(void)
> -{
> -	bus_unregister(&pcie_port_bus_type);
> -}
> diff --git a/drivers/pci/pcie/portdrv_pci.c b/drivers/pci/pcie/portdrv_pci.c
> index c08ebd237242..9475886eeb62 100644
> --- a/drivers/pci/pcie/portdrv_pci.c
> +++ b/drivers/pci/pcie/portdrv_pci.c
> @@ -259,22 +259,11 @@ static const struct dmi_system_id pcie_portdrv_dmi_table[] __initconst = {
>  
>  static int __init pcie_portdrv_init(void)
>  {
> -	int retval;
> -
>  	if (pcie_ports_disabled)
>  		return -EACCES;
>  
>  	dmi_check_system(pcie_portdrv_dmi_table);
>  
> -	retval = pcie_port_bus_register();
> -	if (retval) {
> -		printk(KERN_WARNING "PCIE: bus_register error: %d\n", retval);
> -		goto out;
> -	}
> -	retval = pci_register_driver(&pcie_portdriver);
> -	if (retval)
> -		pcie_port_bus_unregister();
> - out:
> -	return retval;
> +	return pci_register_driver(&pcie_portdriver);
>  }
>  device_initcall(pcie_portdrv_init);
> 
> 

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