linux-kernel - Re: [PATCH v3] PCI: Move pci_dev_is/assign

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Date:   Fri, 20 Aug 2021 17:37:34 -0500
From:   Bjorn Helgaas <helgaas@...nel.org>
To:     Niklas Schnelle <schnelle@...ux.ibm.com>
Cc:     Bjorn Helgaas <bhelgaas@...gle.com>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Paul Mackerras <paulus@...ba.org>, linux-pci@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-s390@...r.kernel.org,
        linux-arch@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH v3] PCI: Move pci_dev_is/assign_added() to pci.h

On Tue, Jul 20, 2021 at 05:01:45PM +0200, Niklas Schnelle wrote:
> The helper function pci_dev_is_added() from drivers/pci/pci.h is used in
> PCI arch code of both s390 and powerpc leading to awkward relative
> includes. Move it to the global include/linux/pci.h and get rid of these
> includes just for that one function.

I agree the includes are awkward.

But the arch code *using* pci_dev_is_added() seems awkward, too.

AFAICS, in powerpc, pci_dev_is_added() is only used by
pnv_pci_ioda_fixup_iov() and pseries_pci_fixup_iov_resources().  Those
are only called from pcibios_add_device(), which is only called from
pci_device_add().

Is it even possible for pci_dev_is_added() to be true in that path?

s390 uses pci_dev_is_added() in recover_store(), but I don't know what
that is (looks like a sysfs file, but it's not documented) or why s390
is the only arch that does this.

Maybe we should make powerpc and s390 less special?

> Signed-off-by: Niklas Schnelle <schnelle@...ux.ibm.com>
> ---
> Since v1 (and bad v2):
> - Fixed accidental removal of PCI_DPC_RECOVERED, PCI_DPC_RECOVERING
>   defines and also move these to include/linux/pci.h
> 
>  arch/powerpc/platforms/powernv/pci-sriov.c |  3 ---
>  arch/powerpc/platforms/pseries/setup.c     |  1 -
>  arch/s390/pci/pci_sysfs.c                  |  2 --
>  drivers/pci/hotplug/acpiphp_glue.c         |  1 -
>  drivers/pci/pci.h                          | 15 ---------------
>  include/linux/pci.h                        | 15 +++++++++++++++
>  6 files changed, 15 insertions(+), 22 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/powernv/pci-sriov.c b/arch/powerpc/platforms/powernv/pci-sriov.c
> index 28aac933a439..2e0ca5451e85 100644
> --- a/arch/powerpc/platforms/powernv/pci-sriov.c
> +++ b/arch/powerpc/platforms/powernv/pci-sriov.c
> @@ -9,9 +9,6 @@
>  
>  #include "pci.h"
>  
> -/* for pci_dev_is_added() */
> -#include "../../../../drivers/pci/pci.h"
> -
>  /*
>   * The majority of the complexity in supporting SR-IOV on PowerNV comes from
>   * the need to put the MMIO space for each VF into a separate PE. Internally
> diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
> index 631a0d57b6cd..17585ec9f955 100644
> --- a/arch/powerpc/platforms/pseries/setup.c
> +++ b/arch/powerpc/platforms/pseries/setup.c
> @@ -74,7 +74,6 @@
>  #include <asm/hvconsole.h>
>  
>  #include "pseries.h"
> -#include "../../../../drivers/pci/pci.h"
>  
>  DEFINE_STATIC_KEY_FALSE(shared_processor);
>  EXPORT_SYMBOL_GPL(shared_processor);
> diff --git a/arch/s390/pci/pci_sysfs.c b/arch/s390/pci/pci_sysfs.c
> index 6e2450c2b9c1..8dbe54ef8f8e 100644
> --- a/arch/s390/pci/pci_sysfs.c
> +++ b/arch/s390/pci/pci_sysfs.c
> @@ -13,8 +13,6 @@
>  #include <linux/stat.h>
>  #include <linux/pci.h>
>  
> -#include "../../../drivers/pci/pci.h"
> -
>  #include <asm/sclp.h>
>  
>  #define zpci_attr(name, fmt, member)					\
> diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
> index f031302ad401..4cb963f88183 100644
> --- a/drivers/pci/hotplug/acpiphp_glue.c
> +++ b/drivers/pci/hotplug/acpiphp_glue.c
> @@ -38,7 +38,6 @@
>  #include <linux/slab.h>
>  #include <linux/acpi.h>
>  
> -#include "../pci.h"
>  #include "acpiphp.h"
>  
>  static LIST_HEAD(bridge_list);
> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
> index 93dcdd431072..a159cd0f6f05 100644
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -383,21 +383,6 @@ static inline bool pci_dev_is_disconnected(const struct pci_dev *dev)
>  	return dev->error_state == pci_channel_io_perm_failure;
>  }
>  
> -/* pci_dev priv_flags */
> -#define PCI_DEV_ADDED 0
> -#define PCI_DPC_RECOVERED 1
> -#define PCI_DPC_RECOVERING 2
> -
> -static inline void pci_dev_assign_added(struct pci_dev *dev, bool added)
> -{
> -	assign_bit(PCI_DEV_ADDED, &dev->priv_flags, added);
> -}
> -
> -static inline bool pci_dev_is_added(const struct pci_dev *dev)
> -{
> -	return test_bit(PCI_DEV_ADDED, &dev->priv_flags);
> -}
> -
>  #ifdef CONFIG_PCIEAER
>  #include <linux/aer.h>
>  
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 540b377ca8f6..ea0e23dbc8ec 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -507,6 +507,21 @@ struct pci_dev {
>  	unsigned long	priv_flags;	/* Private flags for the PCI driver */
>  };
>  
> +/* pci_dev priv_flags */
> +#define PCI_DEV_ADDED 0
> +#define PCI_DPC_RECOVERED 1
> +#define PCI_DPC_RECOVERING 2
> +
> +static inline void pci_dev_assign_added(struct pci_dev *dev, bool added)
> +{
> +	assign_bit(PCI_DEV_ADDED, &dev->priv_flags, added);
> +}
> +
> +static inline bool pci_dev_is_added(const struct pci_dev *dev)
> +{
> +	return test_bit(PCI_DEV_ADDED, &dev->priv_flags);
> +}
> +
>  static inline struct pci_dev *pci_physfn(struct pci_dev *dev)
>  {
>  #ifdef CONFIG_PCI_IOV
> -- 
> 2.25.1
>