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

From: Michael Ellerman
Date: Tue Jan 20 2009 - 21:30:30 EST


On Wed, 2009-01-21 at 01:18 +0100, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rjw@xxxxxxx>
>
> 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@xxxxxxx>
> ---
> 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)
> +{
> + 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;

I see similar code in msix_capability_init(), although it still needs
pos. Did you deliberately not replace that, or just miss it?

cheers

--
Michael Ellerman
OzLabs, IBM Australia Development Lab

wwweb: http://michael.ellerman.id.au
phone: +61 2 6212 1183 (tie line 70 21183)

We do not inherit the earth from our ancestors,
we borrow it from our children. - S.M.A.R.T Person

Attachment: signature.asc
Description: This is a digitally signed message part