vp_request_msix_vectors() bumps desc->pre_vectors in place to reserve
the virtio config vector. vp_find_vqs() may call it more than once while
retrying MSI-X with different per-vq policies, so the caller's
irq_affinity keeps accumulating and later attempts get the wrong
affinity layout.
Copy the descriptor to a stack local, adjust pre_vectors there, and
pass that to pci_alloc_irq_vectors_affinity().
Fixes: ba74b6f7fcc0 ("virtio_pci: fix cpu affinity support")
Cc: [email protected]
Signed-off-by: Xiong Weimin <[email protected]>
---
drivers/virtio/virtio_pci_common.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
diff --git a/drivers/virtio/virtio_pci_common.c
b/drivers/virtio/virtio_pci_common.c
index 164f480b1..9e75fd03e 100644
--- a/drivers/virtio/virtio_pci_common.c
+++ b/drivers/virtio/virtio_pci_common.c
@@ -128,6 +128,7 @@ static int vp_request_msix_vectors(struct virtio_device
*vdev, int nvectors,
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
const char *name = dev_name(&vp_dev->vdev.dev);
+ struct irq_affinity tmp_aff, *aff = NULL;
unsigned int flags = PCI_IRQ_MSIX;
unsigned int i, v;
int err = -ENOMEM;
@@ -146,16 +147,19 @@ static int vp_request_msix_vectors(struct virtio_device
*vdev, int nvectors,
GFP_KERNEL))
goto error;
- if (!per_vq_vectors)
- desc = NULL;
-
- if (desc) {
+ if (per_vq_vectors && desc) {
+ /*
+ * Do not mutate the caller's irq_affinity across MSI-X
+ * fallback retries in vp_find_vqs().
+ */
+ tmp_aff = *desc;
+ tmp_aff.pre_vectors++; /* virtio config vector */
+ aff = &tmp_aff;
flags |= PCI_IRQ_AFFINITY;
- desc->pre_vectors++; /* virtio config vector */
}
err = pci_alloc_irq_vectors_affinity(vp_dev->pci_dev, nvectors,
- nvectors, flags, desc);
+ nvectors, flags, aff);
if (err < 0)
goto error;
vp_dev->msix_enabled = 1;
--
2.43.0
