On 2020-06-03 5:44 a.m., Piotr Stankiewicz wrote: > When debugging an issue where I was asking the PCI machinery to enable a > set of MSI-X vectors, without falling back on MSI, I ran across a > behaviour which seems odd. The pci_alloc_irq_vectors_affinity() will > always return -ENOSPC on failure, when allocating MSI-X vectors only, > whereas with MSI fallback it will forward any error returned by > __pci_enable_msi_range(). This is a confusing behaviour, so have the > pci_alloc_irq_vectors_affinity() forward the error code from > __pci_enable_msix_range() when appropriate. > > Signed-off-by: Piotr Stankiewicz <piotr.stankiewicz@xxxxxxxxx> > Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxx> > --- > drivers/pci/msi.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c > index 6b43a5455c7a..443cc324b196 100644 > --- a/drivers/pci/msi.c > +++ b/drivers/pci/msi.c > @@ -1231,8 +1231,9 @@ int pci_alloc_irq_vectors_affinity(struct pci_dev *dev, unsigned int min_vecs, > } > } > > - if (msix_vecs == -ENOSPC) > - return -ENOSPC; > + if (msix_vecs == -ENOSPC || > + (flags & (PCI_IRQ_MSI | PCI_IRQ_MSIX)) == PCI_IRQ_MSIX) > + return msix_vecs; > return msi_vecs; > } > EXPORT_SYMBOL(pci_alloc_irq_vectors_affinity); > It occurs to me that we could clean this function up a bit more... I don't see any need to have two variables for msi_vecs and msix_vecs and then have a complicated bit of logic at the end to decide which to return. Why not instead just have one variable which is set by __pci_enable_msix_range(), then __pci_enable_msi_range(), then returned if they both fail? Logan
