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authorMing Lei <ming.lei@redhat.com>2019-01-16 02:31:29 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-12-05 11:21:06 +0300
commit3e059545043dc13774d2b689edb44dbed071869f (patch)
tree3294e6298d827f67de65291c2c2624043b5489e2 /drivers/pci
parentd5c58be987bb73c6f5e9e24f9a4dc2703d035849 (diff)
downloadlinux-3e059545043dc13774d2b689edb44dbed071869f.tar.xz
PCI/MSI: Return -ENOSPC from pci_alloc_irq_vectors_affinity()
[ Upstream commit 77f88abd4a6f73a1a68dbdc0e3f21575fd508fc3 ] 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> Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/pci')
-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 af24ed50a245..971dddf62374 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -1155,7 +1155,8 @@ 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)
@@ -1166,16 +1167,17 @@ 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 */
@@ -1186,7 +1188,9 @@ 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);