[PATCH 02/15] PCI/MSI: forward MSIx vector enable error code in pci_alloc_irq_vectors_affinity

From: Piotr Stankiewicz
Date: Tue Jun 02 2020 - 05:20:03 EST

When debugging an issue where I was asking the PCI machinery to enable a
set of MSIx 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 MSIx 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 | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 6b43a5455c7a..9db9ce5dddb3 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -1231,8 +1231,8 @@ 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_TYPES) == PCI_IRQ_MSIX)
+ return msix_vecs;
return msi_vecs;