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PCI/MSI: Forward MSI-X error code in pci_alloc_irq_vectors_affinity() 

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>
This commit is contained in:
Piotr Stankiewicz 2020-06-16 09:33:16 +02:00 committed by Bjorn Helgaas
parent b3a9e3b962
commit 30ff3e8c28
1 changed files with 9 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
drivers/pci/msi.c
View File

@ -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);