linux-kernel - Re: [PATCH v8 08/13] PCI: Move pinned status bit to struct pci

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Message-ID: <bae495cf171db1415cf14c44fb450b81148a6e0d.camel@redhat.com>
Date: Mon, 10 Jun 2024 12:19:58 +0200
From: Philipp Stanner <pstanner@...hat.com>
To: Hans de Goede <hdegoede@...hat.com>, Maarten Lankhorst
 <maarten.lankhorst@...ux.intel.com>, Maxime Ripard <mripard@...nel.org>, 
 Thomas Zimmermann <tzimmermann@...e.de>, David Airlie <airlied@...il.com>,
 Daniel Vetter <daniel@...ll.ch>, Bjorn Helgaas <bhelgaas@...gle.com>, Sam
 Ravnborg <sam@...nborg.org>, dakr@...hat.com
Cc: dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org, 
	linux-pci@...r.kernel.org
Subject: Re: [PATCH v8 08/13] PCI: Move pinned status bit to struct pci_dev

On Mon, 2024-06-10 at 11:31 +0200, Philipp Stanner wrote:
> The bit describing whether the PCI device is currently pinned is stored
> in struct pci_devres. To clean up and simplify the PCI devres API, it's
> better if this information is stored in struct pci_dev.
> 
> This will later permit simplifying pcim_enable_device().
> 
> Move the 'pinned' boolean bit to struct pci_dev.
> 
> Restructure bits in struct pci_dev so the pm / pme fields are next to
> each other.
> 
> Signed-off-by: Philipp Stanner <pstanner@...hat.com>
> ---
>  drivers/pci/devres.c | 14 ++++----------
>  drivers/pci/pci.h    |  1 -
>  include/linux/pci.h  |  4 +++-
>  3 files changed, 7 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/pci/devres.c b/drivers/pci/devres.c
> index 9d25940ce260..2696baef5c2c 100644
> --- a/drivers/pci/devres.c
> +++ b/drivers/pci/devres.c
> @@ -403,7 +403,7 @@ static void pcim_release(struct device *gendev, void *res)
>         if (this->restore_intx)
>                 pci_intx(dev, this->orig_intx);
>  
> -       if (pci_is_enabled(dev) && !this->pinned)
> +       if (pci_is_enabled(dev) && !dev->pinned)
>                 pci_disable_device(dev);
>  }
>  
> @@ -459,18 +459,12 @@ EXPORT_SYMBOL(pcim_enable_device);
>   * pcim_pin_device - Pin managed PCI device
>   * @pdev: PCI device to pin
>   *
> - * Pin managed PCI device @pdev.  Pinned device won't be disabled on
> - * driver detach.  @pdev must have been enabled with
> - * pcim_enable_device().
> + * Pin managed PCI device @pdev. Pinned device won't be disabled on driver
> + * detach. @pdev must have been enabled with pcim_enable_device().
>   */
>  void pcim_pin_device(struct pci_dev *pdev)
>  {
> -       struct pci_devres *dr;
> -
> -       dr = find_pci_dr(pdev);
> -       WARN_ON(!dr || !pci_is_enabled(pdev));
> -       if (dr)
> -               dr->pinned = 1;
> +       pdev->pinned = true;
>  }
>  EXPORT_SYMBOL(pcim_pin_device);
>  
> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
> index d7f00b43b098..6e02ba1b5947 100644
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -821,7 +821,6 @@ static inline pci_power_t mid_pci_get_power_state(struct pci_dev *pdev)
>   * then remove them from here.
>   */
>  struct pci_devres {
> -       unsigned int pinned:1;
>         unsigned int orig_intx:1;
>         unsigned int restore_intx:1;
>         unsigned int mwi:1;
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index fb004fd4e889..cc9247f78158 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -367,10 +367,12 @@ struct pci_dev {
>                                            this is D0-D3, D0 being fully
>                                            functional, and D3 being off. */
>         u8              pm_cap;         /* PM capability offset */
> -       unsigned int    imm_ready:1;    /* Supports Immediate Readiness */
>         unsigned int    pme_support:5;  /* Bitmask of states from which PME#
>                                            can be generated */
>         unsigned int    pme_poll:1;     /* Poll device's PME status bit */
> +       unsigned int    enabled:1;      /* Whether this dev is enabled */

Ah crap, here it survived for some reason...

Should just be dead code and not have any effect. In any case, we
should remove it.

@Bjorn: Feel free to remove it yourself. Otherwise I could provide a v9
together with potential further feedback taken into account in a few
days

Thx,
P.

> +       unsigned int    pinned:1;       /* Whether this dev is pinned */
> +       unsigned int    imm_ready:1;    /* Supports Immediate Readiness */
>         unsigned int    d1_support:1;   /* Low power state D1 is supported */
>         unsigned int    d2_support:1;   /* Low power state D2 is supported */
>         unsigned int    no_d1d2:1;      /* D1 and D2 are forbidden */