On Tue, Nov 26, 2013 at 10:09:59AM +0100, Alexander Gordeev wrote: > Make pci_msix_table_size() function to return a negative errno > if device does not support MSI-X interrupts. After this update > pci_msix_table_size() can fail and callers must always check > the returned value. > > This update is needed to create a consistent MSI-X counterpart > for pci_get_msi_cap() MSI interface. Device drivers can use this > function to obtain maximum number of MSI-X interrupts the device > supports and i.e. use that number in a following call to > pci_enable_msix() interface.
If pci_msix_table_size() is a counterpart to pci_get_msi_cap(), can we make the names similar? > The only user of pci_msix_table_size() function is PCI-Express > port driver, which is also updated by this change. > > Signed-off-by: Alexander Gordeev <[email protected]> > Reviewed-by: Tejun Heo <[email protected]> > --- > Documentation/PCI/MSI-HOWTO.txt | 13 +++++++++++++ > drivers/pci/msi.c | 12 ++++++++++-- > drivers/pci/pcie/portdrv_core.c | 5 +++-- > include/linux/pci.h | 2 +- > 4 files changed, 27 insertions(+), 5 deletions(-) > > diff --git a/Documentation/PCI/MSI-HOWTO.txt b/Documentation/PCI/MSI-HOWTO.txt > index 1fe4900..5955389 100644 > --- a/Documentation/PCI/MSI-HOWTO.txt > +++ b/Documentation/PCI/MSI-HOWTO.txt > @@ -243,6 +243,19 @@ MSI-X Table. This address is mapped by the PCI > subsystem, and should not > be accessed directly by the device driver. If the driver wishes to > mask or unmask an interrupt, it should call disable_irq() / enable_irq(). > > +4.3.4 pci_msix_table_size > + > +int pci_msix_table_size(struct pci_dev *dev) > + > +This function could be used to retrieve number of entries in the device > +MSI-X table. > + > +If this function returns a negative number, it indicates the device is > +not capable of sending MSI-Xs. > + > +If this function returns a positive number, it indicates the maximum > +number of MSI-X interrupt vectors that could be allocated. > + > 4.4 Handling devices implementing both MSI and MSI-X capabilities > > If a device implements both MSI and MSI-X capabilities, it can > diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c > index e4b02ac..6fe0add 100644 > --- a/drivers/pci/msi.c > +++ b/drivers/pci/msi.c > @@ -932,17 +932,23 @@ EXPORT_SYMBOL(pci_disable_msi); > /** > * 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 > - */ > + > + * This function returns the number of device's MSI-X table entries and > + * therefore the number of MSI-X vectors device is capable to send. > + * It returns a negative errno if the device is not capable sending MSI-X > + * interrupts. > + **/ > int pci_msix_table_size(struct pci_dev *dev) > { > u16 control; > > if (!dev->msix_cap) > - return 0; > + return -EINVAL; > > pci_read_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, &control); > return msix_table_size(control); > } > +EXPORT_SYMBOL(pci_msix_table_size); > > /** > * pci_enable_msix - configure device's MSI-X capability structure > @@ -972,6 +978,8 @@ int pci_enable_msix(struct pci_dev *dev, struct > msix_entry *entries, int nvec) > return status; > > nr_entries = pci_msix_table_size(dev); > + if (nr_entries < 0) > + return nr_entries; > if (nvec > nr_entries) > return nr_entries; > > diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c > index 08d131f..5bebeec 100644 > --- a/drivers/pci/pcie/portdrv_core.c > +++ b/drivers/pci/pcie/portdrv_core.c > @@ -80,8 +80,9 @@ static int pcie_port_enable_msix(struct pci_dev *dev, int > *vectors, int mask) > u32 reg32; > > nr_entries = pci_msix_table_size(dev); > - if (!nr_entries) > - return -EINVAL; > + if (nr_entries < 0) > + return nr_entries; > + BUG_ON(!nr_entries); > if (nr_entries > PCIE_PORT_MAX_MSIX_ENTRIES) > nr_entries = PCIE_PORT_MAX_MSIX_ENTRIES; > > diff --git a/include/linux/pci.h b/include/linux/pci.h > index 9ab1692..8af1217 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -1172,7 +1172,7 @@ static inline void pci_disable_msi(struct pci_dev *dev) > > static inline int pci_msix_table_size(struct pci_dev *dev) > { > - return 0; > + return -ENOSYS; > } > static inline int pci_enable_msix(struct pci_dev *dev, > struct msix_entry *entries, int nvec) > -- > 1.7.7.6 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
