On Mon, Dec 06, 2021 at 11:27:26PM +0100, Thomas Gleixner wrote: > pci_irq_vector() and pci_irq_get_affinity() use the list position to find the > MSI-X descriptor at a given index. That's correct for the normal case where > the entry number is the same as the list position. > > But it's wrong for cases where MSI-X was allocated with an entries array > describing sparse entry numbers into the hardware message descriptor > table. That's inconsistent at best. > > Make it always check the entry number because that's what the zero base > index really means. This change won't break existing users which use a > sparse entries array for allocation because these users retrieve the Linux > interrupt number from the entries array after allocation and none of them > uses pci_irq_vector() or pci_irq_get_affinity(). > > Fixes: aff171641d18 ("PCI: Provide sensible IRQ vector alloc/free routines") > Signed-off-by: Thomas Gleixner <t...@linutronix.de> > Tested-by: Juergen Gross <jgr...@suse.com> > Reviewed-by: Jason Gunthorpe <j...@nvidia.com>
Acked-by: Bjorn Helgaas <bhelg...@google.com> > --- > V2: Fix typo in subject - Jason > --- > drivers/pci/msi.c | 26 ++++++++++++++++++-------- > 1 file changed, 18 insertions(+), 8 deletions(-) > > --- a/drivers/pci/msi.c > +++ b/drivers/pci/msi.c > @@ -1187,19 +1187,24 @@ EXPORT_SYMBOL(pci_free_irq_vectors); > > /** > * pci_irq_vector - return Linux IRQ number of a device vector > - * @dev: PCI device to operate on > - * @nr: device-relative interrupt vector index (0-based). > + * @dev: PCI device to operate on > + * @nr: Interrupt vector index (0-based) > + * > + * @nr has the following meanings depending on the interrupt mode: > + * MSI-X: The index in the MSI-X vector table > + * MSI: The index of the enabled MSI vectors > + * INTx: Must be 0 > + * > + * Return: The Linux interrupt number or -EINVAl if @nr is out of range. > */ > int pci_irq_vector(struct pci_dev *dev, unsigned int nr) > { > if (dev->msix_enabled) { > struct msi_desc *entry; > - int i = 0; > > for_each_pci_msi_entry(entry, dev) { > - if (i == nr) > + if (entry->msi_attrib.entry_nr == nr) > return entry->irq; > - i++; > } > WARN_ON_ONCE(1); > return -EINVAL; > @@ -1223,17 +1228,22 @@ EXPORT_SYMBOL(pci_irq_vector); > * pci_irq_get_affinity - return the affinity of a particular MSI vector > * @dev: PCI device to operate on > * @nr: device-relative interrupt vector index (0-based). > + * > + * @nr has the following meanings depending on the interrupt mode: > + * MSI-X: The index in the MSI-X vector table > + * MSI: The index of the enabled MSI vectors > + * INTx: Must be 0 > + * > + * Return: A cpumask pointer or NULL if @nr is out of range > */ > const struct cpumask *pci_irq_get_affinity(struct pci_dev *dev, int nr) > { > if (dev->msix_enabled) { > struct msi_desc *entry; > - int i = 0; > > for_each_pci_msi_entry(entry, dev) { > - if (i == nr) > + if (entry->msi_attrib.entry_nr == nr) > return &entry->affinity->mask; > - i++; > } > WARN_ON_ONCE(1); > return NULL; >