[PATCH v9 01/32] virtio: add helper virtqueue_get_vring_max_size()

[Xuan Zhuo <xuanzhuo@linux.alibaba.com>]

Record the maximum queue num supported by the device.

virtio-net can display the maximum (supported by hardware) ring size in
ethtool -g eth0.

When the subsequent patch implements vring reset, it can judge whether
the ring size passed by the driver is legal based on this.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
 arch/um/drivers/virtio_uml.c             |  1 +
 drivers/platform/mellanox/mlxbf-tmfifo.c |  2 ++
 drivers/remoteproc/remoteproc_virtio.c   |  2 ++
 drivers/s390/virtio/virtio_ccw.c         |  3 +++
 drivers/virtio/virtio_mmio.c             |  2 ++
 drivers/virtio/virtio_pci_legacy.c       |  2 ++
 drivers/virtio/virtio_pci_modern.c       |  2 ++
 drivers/virtio/virtio_ring.c             | 14 ++++++++++++++
 drivers/virtio/virtio_vdpa.c             |  2 ++
 include/linux/virtio.h                   |  2 ++
 10 files changed, 32 insertions(+)

diff --git a/arch/um/drivers/virtio_uml.c b/arch/um/drivers/virtio_uml.c
index ba562d68dc04..904993d15a85 100644
--- a/arch/um/drivers/virtio_uml.c
+++ b/arch/um/drivers/virtio_uml.c
@@ -945,6 +945,7 @@ static struct virtqueue *vu_setup_vq(struct virtio_device *vdev,
 		goto error_create;
 	}
 	vq->priv = info;
+	vq->num_max = num;
 	num = virtqueue_get_vring_size(vq);
 
 	if (vu_dev->protocol_features &
diff --git a/drivers/platform/mellanox/mlxbf-tmfifo.c b/drivers/platform/mellanox/mlxbf-tmfifo.c
index 38800e86ed8a..1ae3c56b66b0 100644
--- a/drivers/platform/mellanox/mlxbf-tmfifo.c
+++ b/drivers/platform/mellanox/mlxbf-tmfifo.c
@@ -959,6 +959,8 @@ static int mlxbf_tmfifo_virtio_find_vqs(struct virtio_device *vdev,
 			goto error;
 		}
 
+		vq->num_max = vring->num;
+
 		vqs[i] = vq;
 		vring->vq = vq;
 		vq->priv = vring;
diff --git a/drivers/remoteproc/remoteproc_virtio.c b/drivers/remoteproc/remoteproc_virtio.c
index 70ab496d0431..7611755d0ae2 100644
--- a/drivers/remoteproc/remoteproc_virtio.c
+++ b/drivers/remoteproc/remoteproc_virtio.c
@@ -125,6 +125,8 @@ static struct virtqueue *rp_find_vq(struct virtio_device *vdev,
 		return ERR_PTR(-ENOMEM);
 	}
 
+	vq->num_max = len;
+
 	rvring->vq = vq;
 	vq->priv = rvring;
 
diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
index d35e7a3f7067..468da60b56c5 100644
--- a/drivers/s390/virtio/virtio_ccw.c
+++ b/drivers/s390/virtio/virtio_ccw.c
@@ -529,6 +529,9 @@ static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
 		err = -ENOMEM;
 		goto out_err;
 	}
+
+	vq->num_max = info->num;
+
 	/* it may have been reduced */
 	info->num = virtqueue_get_vring_size(vq);
 
diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index 56128b9c46eb..a41abc8051b9 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -390,6 +390,8 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
 		goto error_new_virtqueue;
 	}
 
+	vq->num_max = num;
+
 	/* Activate the queue */
 	writel(virtqueue_get_vring_size(vq), vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
 	if (vm_dev->version == 1) {
diff --git a/drivers/virtio/virtio_pci_legacy.c b/drivers/virtio/virtio_pci_legacy.c
index 34141b9abe27..b68934fe6b5d 100644
--- a/drivers/virtio/virtio_pci_legacy.c
+++ b/drivers/virtio/virtio_pci_legacy.c
@@ -135,6 +135,8 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
 	if (!vq)
 		return ERR_PTR(-ENOMEM);
 
+	vq->num_max = num;
+
 	q_pfn = virtqueue_get_desc_addr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT;
 	if (q_pfn >> 32) {
 		dev_err(&vp_dev->pci_dev->dev,
diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
index 5455bc041fb6..86d301f272b8 100644
--- a/drivers/virtio/virtio_pci_modern.c
+++ b/drivers/virtio/virtio_pci_modern.c
@@ -218,6 +218,8 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
 	if (!vq)
 		return ERR_PTR(-ENOMEM);
 
+	vq->num_max = num;
+
 	/* activate the queue */
 	vp_modern_set_queue_size(mdev, index, virtqueue_get_vring_size(vq));
 	vp_modern_queue_address(mdev, index, virtqueue_get_desc_addr(vq),
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 962f1477b1fa..b87130c8f312 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -2371,6 +2371,20 @@ void vring_transport_features(struct virtio_device *vdev)
 }
 EXPORT_SYMBOL_GPL(vring_transport_features);
 
+/**
+ * virtqueue_get_vring_max_size - return the max size of the virtqueue's vring
+ * @_vq: the struct virtqueue containing the vring of interest.
+ *
+ * Returns the max size of the vring.
+ *
+ * Unlike other operations, this need not be serialized.
+ */
+unsigned int virtqueue_get_vring_max_size(struct virtqueue *_vq)
+{
+	return _vq->num_max;
+}
+EXPORT_SYMBOL_GPL(virtqueue_get_vring_max_size);
+
 /**
  * virtqueue_get_vring_size - return the size of the virtqueue's vring
  * @_vq: the struct virtqueue containing the vring of interest.
diff --git a/drivers/virtio/virtio_vdpa.c b/drivers/virtio/virtio_vdpa.c
index 7767a7f0119b..39e4c08eb0f2 100644
--- a/drivers/virtio/virtio_vdpa.c
+++ b/drivers/virtio/virtio_vdpa.c
@@ -183,6 +183,8 @@ virtio_vdpa_setup_vq(struct virtio_device *vdev, unsigned int index,
 		goto error_new_virtqueue;
 	}
 
+	vq->num_max = max_num;
+
 	/* Setup virtqueue callback */
 	cb.callback = virtio_vdpa_virtqueue_cb;
 	cb.private = info;
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 72292a62cd90..d59adc4be068 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -31,6 +31,7 @@ struct virtqueue {
 	struct virtio_device *vdev;
 	unsigned int index;
 	unsigned int num_free;
+	unsigned int num_max;
 	void *priv;
 };
 
@@ -80,6 +81,7 @@ bool virtqueue_enable_cb_delayed(struct virtqueue *vq);
 
 void *virtqueue_detach_unused_buf(struct virtqueue *vq);
 
+unsigned int virtqueue_get_vring_max_size(struct virtqueue *vq);
 unsigned int virtqueue_get_vring_size(struct virtqueue *vq);
 
 bool virtqueue_is_broken(struct virtqueue *vq);
-- 
2.31.0