virtio-ring: move queue_index to vring_virtqueue

Instead of storing the queue index in transport-specific virtio structs,
this patch moves them to vring_virtqueue and introduces an helper to get
the value.  This lets drivers simplify their management and tracing of
virtqueues.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

8 files changed, 29 insertions, 21 deletions

diff --git a/drivers/lguest/lguest_device.c b/drivers/lguest/lguest_device.c
index 9e8388efd88e..ccb7dfb028fa 100644
--- a/drivers/lguest/lguest_device.c
+++ b/drivers/lguest/lguest_device.c
@@ -296,7 +296,7 @@ static struct virtqueue *lg_find_vq(struct virtio_device *vdev,
          * to 'true': the host just a(nother) SMP CPU, so we only need inter-cpu
          * barriers.
          */
-        vq = vring_new_virtqueue(lvq->config.num, LGUEST_VRING_ALIGN, vdev,
+        vq = vring_new_virtqueue(index, lvq->config.num, LGUEST_VRING_ALIGN, vdev,
                                  true, lvq->pages, lg_notify, callback, name);
         if (!vq) {
                 err = -ENOMEM;
diff --git a/drivers/remoteproc/remoteproc_virtio.c b/drivers/remoteproc/remoteproc_virtio.c
index 3541b4492f64..343c1941c123 100644
--- a/drivers/remoteproc/remoteproc_virtio.c
+++ b/drivers/remoteproc/remoteproc_virtio.c
@@ -103,7 +103,7 @@ static struct virtqueue *rp_find_vq(struct virtio_device *vdev,
          * Create the new vq, and tell virtio we're not interested in
          * the 'weak' smp barriers, since we're talking with a real device.
          */
-        vq = vring_new_virtqueue(len, rvring->align, vdev, false, addr,
+        vq = vring_new_virtqueue(id, len, rvring->align, vdev, false, addr,
                                         rproc_virtio_notify, callback, name);
         if (!vq) {
                 dev_err(dev, "vring_new_virtqueue %s failed\n", name);
diff --git a/drivers/s390/kvm/kvm_virtio.c b/drivers/s390/kvm/kvm_virtio.c
index 47cccd52aae8..5565af20592f 100644
--- a/drivers/s390/kvm/kvm_virtio.c
+++ b/drivers/s390/kvm/kvm_virtio.c
@@ -198,7 +198,7 @@ static struct virtqueue *kvm_find_vq(struct virtio_device *vdev,
         if (err)
                 goto out;
 
-        vq = vring_new_virtqueue(config->num, KVM_S390_VIRTIO_RING_ALIGN,
+        vq = vring_new_virtqueue(index, config->num, KVM_S390_VIRTIO_RING_ALIGN,
                                  vdev, true, (void *) config->address,
                                  kvm_notify, callback, name);
         if (!vq) {
diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index 453db0c403d8..008bf58bdaae 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -131,9 +131,6 @@ struct virtio_mmio_vq_info {
         /* the number of entries in the queue */
         unsigned int num;
 
-        /* the index of the queue */
-        int queue_index;
-
         /* the virtual address of the ring queue */
         void *queue;
 
@@ -225,11 +222,10 @@ static void vm_reset(struct virtio_device *vdev)
 static void vm_notify(struct virtqueue *vq)
 {
         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
-        struct virtio_mmio_vq_info *info = vq->priv;
 
         /* We write the queue's selector into the notification register to
          * signal the other end */
-        writel(info->queue_index, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY);
+        writel(virtqueue_get_queue_index(vq), vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY);
 }
 
 /* Notify all virtqueues on an interrupt. */
@@ -270,6 +266,7 @@ static void vm_del_vq(struct virtqueue *vq)
         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
         struct virtio_mmio_vq_info *info = vq->priv;
         unsigned long flags, size;
+        unsigned int index = virtqueue_get_queue_index(vq);
 
         spin_lock_irqsave(&vm_dev->lock, flags);
         list_del(&info->node);
@@ -278,7 +275,7 @@ static void vm_del_vq(struct virtqueue *vq)
         vring_del_virtqueue(vq);
 
         /* Select and deactivate the queue */
-        writel(info->queue_index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
+        writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
         writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
 
         size = PAGE_ALIGN(vring_size(info->num, VIRTIO_MMIO_VRING_ALIGN));
@@ -324,7 +321,6 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
                 err = -ENOMEM;
                 goto error_kmalloc;
         }
-        info->queue_index = index;
 
         /* Allocate pages for the queue - start with a queue as big as
          * possible (limited by maximum size allowed by device), drop down
@@ -356,7 +352,7 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
                         vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
 
         /* Create the vring */
-        vq = vring_new_virtqueue(info->num, VIRTIO_MMIO_VRING_ALIGN, vdev,
+        vq = vring_new_virtqueue(index, info->num, VIRTIO_MMIO_VRING_ALIGN, vdev,
                                  true, info->queue, vm_notify, callback, name);
         if (!vq) {
                 err = -ENOMEM;
diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
index 2e03d416b9af..d902464b89ce 100644
--- a/drivers/virtio/virtio_pci.c
+++ b/drivers/virtio/virtio_pci.c
@@ -79,9 +79,6 @@ struct virtio_pci_vq_info
         /* the number of entries in the queue */
         int num;
 
-        /* the index of the queue */
-        int queue_index;
-
         /* the virtual address of the ring queue */
         void *queue;
 
@@ -202,11 +199,11 @@ static void vp_reset(struct virtio_device *vdev)
 static void vp_notify(struct virtqueue *vq)
 {
         struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
-        struct virtio_pci_vq_info *info = vq->priv;
 
         /* we write the queue's selector into the notification register to
          * signal the other end */
-        iowrite16(info->queue_index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NOTIFY);
+        iowrite16(virtqueue_get_queue_index(vq),
+                  vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NOTIFY);
 }
 
 /* Handle a configuration change: Tell driver if it wants to know. */
@@ -402,7 +399,6 @@ static struct virtqueue *setup_vq(struct virtio_device *vdev, unsigned index,
         if (!info)
                 return ERR_PTR(-ENOMEM);
 
-        info->queue_index = index;
         info->num = num;
         info->msix_vector = msix_vec;
 
@@ -418,7 +414,7 @@ static struct virtqueue *setup_vq(struct virtio_device *vdev, unsigned index,
                   vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
 
         /* create the vring */
-        vq = vring_new_virtqueue(info->num, VIRTIO_PCI_VRING_ALIGN, vdev,
+        vq = vring_new_virtqueue(index, info->num, VIRTIO_PCI_VRING_ALIGN, vdev,
                                  true, info->queue, vp_notify, callback, name);
         if (!vq) {
                 err = -ENOMEM;
@@ -467,7 +463,8 @@ static void vp_del_vq(struct virtqueue *vq)
         list_del(&info->node);
         spin_unlock_irqrestore(&vp_dev->lock, flags);
 
-        iowrite16(info->queue_index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
+        iowrite16(virtqueue_get_queue_index(vq),
+                vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
 
         if (vp_dev->msix_enabled) {
                 iowrite16(VIRTIO_MSI_NO_VECTOR,
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 5aa43c3392a2..e639584b2dbd 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -106,6 +106,9 @@ struct vring_virtqueue
         /* How to notify other side. FIXME: commonalize hcalls! */
         void (*notify)(struct virtqueue *vq);
 
+        /* Index of the queue */
+        int queue_index;
+
 #ifdef DEBUG
         /* They're supposed to lock for us. */
         unsigned int in_use;
@@ -171,6 +174,13 @@ static int vring_add_indirect(struct vring_virtqueue *vq,
         return head;
 }
 
+int virtqueue_get_queue_index(struct virtqueue *_vq)
+{
+        struct vring_virtqueue *vq = to_vvq(_vq);
+        return vq->queue_index;
+}
+EXPORT_SYMBOL_GPL(virtqueue_get_queue_index);
+
 /**
  * virtqueue_add_buf - expose buffer to other end
  * @vq: the struct virtqueue we're talking about.
@@ -616,7 +626,8 @@ irqreturn_t vring_interrupt(int irq, void *_vq)
 }
 EXPORT_SYMBOL_GPL(vring_interrupt);
 
-struct virtqueue *vring_new_virtqueue(unsigned int num,
+struct virtqueue *vring_new_virtqueue(unsigned int index,
+                                      unsigned int num,
                                       unsigned int vring_align,
                                       struct virtio_device *vdev,
                                       bool weak_barriers,
@@ -647,6 +658,7 @@ struct virtqueue *vring_new_virtqueue(unsigned int num,
         vq->broken = false;
         vq->last_used_idx = 0;
         vq->num_added = 0;
+        vq->queue_index = index;
         list_add_tail(&vq->vq.list, &vdev->vqs);
 #ifdef DEBUG
         vq->in_use = false;
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index a1ba8bbd9fbe..533b1157f22e 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -50,6 +50,8 @@ void *virtqueue_detach_unused_buf(struct virtqueue *vq);
 
 unsigned int virtqueue_get_vring_size(struct virtqueue *vq);
 
+int virtqueue_get_queue_index(struct virtqueue *vq);
+
 /**
  * virtio_device - representation of a device using virtio
  * @index: unique position on the virtio bus
diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h
index e338730c2660..c2d793a06ad7 100644
--- a/include/linux/virtio_ring.h
+++ b/include/linux/virtio_ring.h
@@ -165,7 +165,8 @@ static inline int vring_need_event(__u16 event_idx, __u16 new_idx, __u16 old)
 struct virtio_device;
 struct virtqueue;
 
-struct virtqueue *vring_new_virtqueue(unsigned int num,
+struct virtqueue *vring_new_virtqueue(unsigned int index,
+                                      unsigned int num,
                                       unsigned int vring_align,
                                       struct virtio_device *vdev,
                                       bool weak_barriers,