Re: [PATCH 1/2] PCI/MSI: Introduce pci_msix_table_size()

[Grant Grundler <grundler@parisc-linux.org>]

On Sat, Jan 24, 2009 at 12:21:14AM +0100, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rjw@sisk.pl>
> 
> Introduce new function pci_msix_table_size() returning the size of
> the MSI-X table of given PCI device or 0 if the device doesn't
> support MSI-X.
> 
> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
> Reviewed-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
> ---
>  drivers/pci/msi.c   |   24 +++++++++++++++++++-----
>  include/linux/pci.h |    5 +++++
>  2 files changed, 24 insertions(+), 5 deletions(-)
> 
> Index: linux-2.6/drivers/pci/msi.c
> ===================================================================
> --- linux-2.6.orig/drivers/pci/msi.c
> +++ linux-2.6/drivers/pci/msi.c
> @@ -670,6 +670,23 @@ static int msi_free_irqs(struct pci_dev*
>  }
>  
>  /**
> + * pci_msix_table_size - return the number of device's MSI-X table entries
> + * @dev: pointer to the pci_dev data structure of MSI-X device function
> + */
> +int pci_msix_table_size(struct pci_dev *dev)

Is this intended to be used by drivers?

If so, can you please add (a) corresponding documentation in
either the MSI or pci.txt files and (b) EXPORT_SYMBOL_GPL?

If not, can this declaration be static?
(I haven't yet looked at the second patch...maybe this is obvious once
I do.)

thanks,
grant

> +{
> +	int pos;
> +	u16 control;
> +
> +	pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
> +	if (!pos)
> +		return 0;
> +
> +	pci_read_config_word(dev, msi_control_reg(pos), &control);
> +	return multi_msix_capable(control);
> +}
> +
> +/**
>   * pci_enable_msix - configure device's MSI-X capability structure
>   * @dev: pointer to the pci_dev data structure of MSI-X device function
>   * @entries: pointer to an array of MSI-X entries
> @@ -686,9 +703,8 @@ static int msi_free_irqs(struct pci_dev*
>   **/
>  int pci_enable_msix(struct pci_dev* dev, struct msix_entry *entries, int nvec)
>  {
> -	int status, pos, nr_entries;
> +	int status, nr_entries;
>  	int i, j;
> -	u16 control;
>  
>  	if (!entries)
>   		return -EINVAL;
> @@ -697,9 +713,7 @@ int pci_enable_msix(struct pci_dev* dev,
>  	if (status)
>  		return status;
>  
> -	pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
> -	pci_read_config_word(dev, msi_control_reg(pos), &control);
> -	nr_entries = multi_msix_capable(control);
> +	nr_entries = pci_msix_table_size(dev);
>  	if (nvec > nr_entries)
>  		return -EINVAL;
>  
> Index: linux-2.6/include/linux/pci.h
> ===================================================================
> --- linux-2.6.orig/include/linux/pci.h
> +++ linux-2.6/include/linux/pci.h
> @@ -799,6 +799,10 @@ static inline void pci_msi_shutdown(stru
>  static inline void pci_disable_msi(struct pci_dev *dev)
>  { }
>  
> +static inline int pci_msix_table_size(struct pci_dev *dev)
> +{
> +	return 0;
> +}
>  static inline int pci_enable_msix(struct pci_dev *dev,
>  				  struct msix_entry *entries, int nvec)
>  {
> @@ -823,6 +827,7 @@ static inline int pci_msi_enabled(void)
>  extern int pci_enable_msi(struct pci_dev *dev);
>  extern void pci_msi_shutdown(struct pci_dev *dev);
>  extern void pci_disable_msi(struct pci_dev *dev);
> +extern int pci_msix_table_size(struct pci_dev *dev);
>  extern int pci_enable_msix(struct pci_dev *dev,
>  	struct msix_entry *entries, int nvec);
>  extern void pci_msix_shutdown(struct pci_dev *dev);
> 
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