linux-kernel - Re: [PATCH 1/2] PCI: Deprecate pcim_iomap_regions() in favor of pcim_iomap

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Message-ID: <20240807202431.GA110503@bhelgaas>
Date: Wed, 7 Aug 2024 15:24:31 -0500
From: Bjorn Helgaas <helgaas@...nel.org>
To: Philipp Stanner <pstanner@...hat.com>, Dave Airlie <airlied@...hat.com>
Cc: Thomas Zimmermann <tzimmermann@...e.de>,
	Jocelyn Falempe <jfalempe@...hat.com>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	David Airlie <airlied@...il.com>, Daniel Vetter <daniel@...ll.ch>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
	linux-pci@...r.kernel.org
Subject: Re: [PATCH 1/2] PCI: Deprecate pcim_iomap_regions() in favor of
 pcim_iomap_region()

On Wed, Aug 07, 2024 at 10:30:18AM +0200, Philipp Stanner wrote:
> pcim_iomap_regions() is a complicated function that uses a bit mask to
> determine the BARs the user wishes to request and ioremap. Almost all
> users only ever set a single bit in that mask, making that mechanism
> questionable.
> 
> pcim_iomap_region() is now available as a more simple replacement.
> 
> Make pcim_iomap_region() a public function.
> 
> Mark pcim_iomap_regions() as deprecated.
> 
> Signed-off-by: Philipp Stanner <pstanner@...hat.com>

The interesting part of this little series is in ast_drv.c, but there
may be similar conversions for other drivers coming as well.

To avoid races during the merge window, I propose merging this via the
PCI tree so I can ensure that any other conversions happen after
pcim_iomap_region() becomes public.

That would require an ack from Dave.  But if you'd rather take this
yourself, Dave, here's my ack for the PCI piece:

Acked-by: Bjorn Helgaas <bhelgaas@...gle.com>

> ---
>  drivers/pci/devres.c | 8 ++++++--
>  include/linux/pci.h  | 2 ++
>  2 files changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/devres.c b/drivers/pci/devres.c
> index 3780a9f9ec00..89ec26ea1501 100644
> --- a/drivers/pci/devres.c
> +++ b/drivers/pci/devres.c
> @@ -728,7 +728,7 @@ EXPORT_SYMBOL(pcim_iounmap);
>   * Mapping and region will get automatically released on driver detach. If
>   * desired, release manually only with pcim_iounmap_region().
>   */
> -static void __iomem *pcim_iomap_region(struct pci_dev *pdev, int bar,
> +void __iomem *pcim_iomap_region(struct pci_dev *pdev, int bar,
>  				       const char *name)
>  {
>  	int ret;
> @@ -761,6 +761,7 @@ static void __iomem *pcim_iomap_region(struct pci_dev *pdev, int bar,
>  
>  	return IOMEM_ERR_PTR(ret);
>  }
> +EXPORT_SYMBOL(pcim_iomap_region);
>  
>  /**
>   * pcim_iounmap_region - Unmap and release a PCI BAR
> @@ -783,7 +784,7 @@ static void pcim_iounmap_region(struct pci_dev *pdev, int bar)
>  }
>  
>  /**
> - * pcim_iomap_regions - Request and iomap PCI BARs
> + * pcim_iomap_regions - Request and iomap PCI BARs (DEPRECATED)
>   * @pdev: PCI device to map IO resources for
>   * @mask: Mask of BARs to request and iomap
>   * @name: Name associated with the requests
> @@ -791,6 +792,9 @@ static void pcim_iounmap_region(struct pci_dev *pdev, int bar)
>   * Returns: 0 on success, negative error code on failure.
>   *
>   * Request and iomap regions specified by @mask.
> + *
> + * This function is DEPRECATED. Do not use it in new code.
> + * Use pcim_iomap_region() instead.
>   */
>  int pcim_iomap_regions(struct pci_dev *pdev, int mask, const char *name)
>  {
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 4cf89a4b4cbc..fc30176d28ca 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -2292,6 +2292,8 @@ static inline void pci_fixup_device(enum pci_fixup_pass pass,
>  void __iomem *pcim_iomap(struct pci_dev *pdev, int bar, unsigned long maxlen);
>  void pcim_iounmap(struct pci_dev *pdev, void __iomem *addr);
>  void __iomem * const *pcim_iomap_table(struct pci_dev *pdev);
> +void __iomem *pcim_iomap_region(struct pci_dev *pdev, int bar,
> +				       const char *name);
>  int pcim_iomap_regions(struct pci_dev *pdev, int mask, const char *name);
>  int pcim_iomap_regions_request_all(struct pci_dev *pdev, int mask,
>  				   const char *name);
> -- 
> 2.45.2
>