[PATCH 1/3][Disco] virtio_pci: use queue idx instead of array idx to set up the vq

[Colin King]

From: Wei Wang <wei.w.wang at intel.com>

BugLink: http://bugs.launchpad.net/bugs/1811259

When find_vqs, there will be no vq[i] allocation if its corresponding
names[i] is NULL. For example, the caller may pass in names[i] (i=4)
with names[2] being NULL because the related feature bit is turned off,
so technically there are 3 queues on the device, and name[4] should
correspond to the 3rd queue on the device.

So we use queue_idx as the queue index, which is increased only when the
queue exists.

Signed-off-by: Wei Wang <wei.w.wang at intel.com>
Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
Signed-off-by: Wei Wang <wei.w.wang at intel.com>
Signed-off-by: Wei Wang <wei.w.wang at intel.com>
(cherry picked from commit ddbeac07a39a81d82331a312d0578fab94fccbf1)
 https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git linux-next)
Signed-off-by: Colin Ian King <colin.king at canonical.com>
---
 drivers/virtio/virtio_pci_common.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
index 465a6f5..d0584c0 100644
--- a/drivers/virtio/virtio_pci_common.c
+++ b/drivers/virtio/virtio_pci_common.c
@@ -285,7 +285,7 @@ static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned nvqs,
 {
 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 	u16 msix_vec;
-	int i, err, nvectors, allocated_vectors;
+	int i, err, nvectors, allocated_vectors, queue_idx = 0;
 
 	vp_dev->vqs = kcalloc(nvqs, sizeof(*vp_dev->vqs), GFP_KERNEL);
 	if (!vp_dev->vqs)
@@ -321,7 +321,7 @@ static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned nvqs,
 			msix_vec = allocated_vectors++;
 		else
 			msix_vec = VP_MSIX_VQ_VECTOR;
-		vqs[i] = vp_setup_vq(vdev, i, callbacks[i], names[i],
+		vqs[i] = vp_setup_vq(vdev, queue_idx++, callbacks[i], names[i],
 				     ctx ? ctx[i] : false,
 				     msix_vec);
 		if (IS_ERR(vqs[i])) {
@@ -356,7 +356,7 @@ static int vp_find_vqs_intx(struct virtio_device *vdev, unsigned nvqs,
 		const char * const names[], const bool *ctx)
 {
 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
-	int i, err;
+	int i, err, queue_idx = 0;
 
 	vp_dev->vqs = kcalloc(nvqs, sizeof(*vp_dev->vqs), GFP_KERNEL);
 	if (!vp_dev->vqs)
@@ -374,7 +374,7 @@ static int vp_find_vqs_intx(struct virtio_device *vdev, unsigned nvqs,
 			vqs[i] = NULL;
 			continue;
 		}
-		vqs[i] = vp_setup_vq(vdev, i, callbacks[i], names[i],
+		vqs[i] = vp_setup_vq(vdev, queue_idx++, callbacks[i], names[i],
 				     ctx ? ctx[i] : false,
 				     VIRTIO_MSI_NO_VECTOR);
 		if (IS_ERR(vqs[i])) {
-- 
2.7.4