On Thu, Dec 27, 2018 at 04:21:38PM +0800, Ming Lei wrote: > On Wed, Dec 26, 2018 at 07:20:27PM +0100, Christoph Hellwig wrote: > > On Wed, Dec 26, 2018 at 06:37:55PM +0800, Ming Lei wrote: > > > It is observed on QEMU that pci_alloc_irq_vectors_affinity() may > > > returns -EINVAL when the requested number is too big(such as 64). > > > > Which is not how this API is supposed to work and documented to work. > > > > We need to fix pci_alloc_irq_vectors_affinity to not return a spurious > > error and just return the allocated number of vectors instead of > > hacking around that in drivers. > > Yeah, you are right. > > The issue is that QEMU nvme-pci is MSIX-capable only, and hasn't MSI > capability. > > __pci_enable_msix_range() actually returns -ENOSPC, but __pci_enable_msi_range() > returns -EINVAL because dev->msi_cap is zero. > > Maybe we need the following fix? Should it matter? We still get a negative vecs back, and still fall back to the next option. Unless ther are no irqs available at all for the selected types pci_alloc_irq_vectors_affinity should never return an error.
