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authorMing Lei <ming.lei@redhat.com>2019-01-15 17:31:29 -0600
committerBjorn Helgaas <bhelgaas@google.com>2019-01-15 17:31:29 -0600
commit77f88abd4a6f73a1a68dbdc0e3f21575fd508fc3 (patch)
tree9ddd3f770241252842fb9e40cbad8a65645824fc /drivers/pci/msi.c
parent2e8cb2cf1bd6e90f58bd517eb9ca1938e64fa51c (diff)
PCI/MSI: Return -ENOSPC from pci_alloc_irq_vectors_affinity()
The API of pci_alloc_irq_vectors_affinity() says it returns -ENOSPC if fewer than @min_vecs interrupt vectors are available for @dev. However, if a device supports MSI-X but not MSI and a caller requests @min_vecs that can't be satisfied by MSI-X, we previously returned -EINVAL (from the failed attempt to enable MSI), not -ENOSPC. When -ENOSPC is returned, callers may reduce the number IRQs they request and try again. Most callers can use the @min_vecs and @max_vecs parameters to avoid this retry loop, but that doesn't work when using IRQ affinity "nr_sets" because rebalancing the sets is driver-specific. This return value bug has been present since pci_alloc_irq_vectors() was added in v4.10 by aff171641d18 ("PCI: Provide sensible IRQ vector alloc/free routines"), but it wasn't an issue because @min_vecs/@max_vecs removed the need for callers to iteratively reduce the number of IRQs requested and retry the allocation, so they didn't need to distinguish -ENOSPC from -EINVAL. In v5.0, 6da4b3ab9a6e ("genirq/affinity: Add support for allocating interrupt sets") added IRQ sets to the interface, which reintroduced the need to check for -ENOSPC and possibly reduce the number of IRQs requested and retry the allocation. Signed-off-by: Ming Lei <ming.lei@redhat.com> [bhelgaas: changelog] Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Cc: Jens Axboe <axboe@fb.com> Cc: Keith Busch <keith.busch@intel.com> Cc: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'drivers/pci/msi.c')
-rw-r--r--drivers/pci/msi.c22
1 files changed, 13 insertions, 9 deletions
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 7a1c8a09efa5..4c0b47867258 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -1168,7 +1168,8 @@ int pci_alloc_irq_vectors_affinity(struct pci_dev *dev, unsigned int min_vecs,
const struct irq_affinity *affd)
{
static const struct irq_affinity msi_default_affd;
- int vecs = -ENOSPC;
+ int msix_vecs = -ENOSPC;
+ int msi_vecs = -ENOSPC;
if (flags & PCI_IRQ_AFFINITY) {
if (!affd)
@@ -1179,16 +1180,17 @@ int pci_alloc_irq_vectors_affinity(struct pci_dev *dev, unsigned int min_vecs,
}
if (flags & PCI_IRQ_MSIX) {
- vecs = __pci_enable_msix_range(dev, NULL, min_vecs, max_vecs,
- affd);
- if (vecs > 0)
- return vecs;
+ msix_vecs = __pci_enable_msix_range(dev, NULL, min_vecs,
+ max_vecs, affd);
+ if (msix_vecs > 0)
+ return msix_vecs;
}
if (flags & PCI_IRQ_MSI) {
- vecs = __pci_enable_msi_range(dev, min_vecs, max_vecs, affd);
- if (vecs > 0)
- return vecs;
+ msi_vecs = __pci_enable_msi_range(dev, min_vecs, max_vecs,
+ affd);
+ if (msi_vecs > 0)
+ return msi_vecs;
}
/* use legacy irq if allowed */
@@ -1199,7 +1201,9 @@ int pci_alloc_irq_vectors_affinity(struct pci_dev *dev, unsigned int min_vecs,
}
}
- return vecs;
+ if (msix_vecs == -ENOSPC)
+ return -ENOSPC;
+ return msi_vecs;
}
EXPORT_SYMBOL(pci_alloc_irq_vectors_affinity);