PCI/MSI: Forward MSI-X error code in pci_alloc_irq_vectors_affinity() (30ff3e8c) · Commits · 戴 / test

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. Link: https://lore.kernel.org/r/20200616073318.20229-1-piotr.stankiewicz@intel.com Signed-off-by:

Piotr Stankiewicz <piotr.stankiewicz@intel.com> Signed-off-by:

Bjorn Helgaas <bhelgaas@google.com> Reviewed-by:

Andy Shevchenko <andriy.shevchenko@intel.com> Reviewed-by:

Logan Gunthorpe <logang@deltatee.com> Reviewed-by:

Christoph Hellwig <hch@lst.de>

drivers/pci/msi.c

+9 −13

Original line number	Diff line number	Diff line
		@@ -1191,8 +1191,7 @@ int pci_alloc_irq_vectors_affinity(struct pci_dev *dev, unsigned int min_vecs,
		struct irq_affinity *affd)
		{
		struct irq_affinity msi_default_affd = {0};
		int msix_vecs = -ENOSPC;
		int msi_vecs = -ENOSPC;
		int nvecs = -ENOSPC;

		if (flags & PCI_IRQ_AFFINITY) {
		if (!affd)
		@@ -1203,17 +1202,16 @@ int pci_alloc_irq_vectors_affinity(struct pci_dev *dev, unsigned int min_vecs,
		}

		if (flags & PCI_IRQ_MSIX) {
		msix_vecs = __pci_enable_msix_range(dev, NULL, min_vecs,
		max_vecs, affd, flags);
		if (msix_vecs > 0)
		return msix_vecs;
		nvecs = __pci_enable_msix_range(dev, NULL, min_vecs, max_vecs,
		affd, flags);
		if (nvecs > 0)
		return nvecs;
		}

		if (flags & PCI_IRQ_MSI) {
		msi_vecs = __pci_enable_msi_range(dev, min_vecs, max_vecs,
		affd);
		if (msi_vecs > 0)
		return msi_vecs;
		nvecs = __pci_enable_msi_range(dev, min_vecs, max_vecs, affd);
		if (nvecs > 0)
		return nvecs;
		}

		/* use legacy IRQ if allowed */
		@@ -1231,9 +1229,7 @@ int pci_alloc_irq_vectors_affinity(struct pci_dev *dev, unsigned int min_vecs,
		}
		}

		if (msix_vecs == -ENOSPC)
		return -ENOSPC;
		return msi_vecs;
		return nvecs;
		}
		EXPORT_SYMBOL(pci_alloc_irq_vectors_affinity);

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