[PATCH v7 7/9] virtio_mmio: Use the DMA API if enabled

[Andy Lutomirski]

This switches to vring_create_virtqueue, simplifying the driver and
adding DMA API support.

Signed-off-by: Andy Lutomirski 
---
 drivers/virtio/virtio_mmio.c | 67 ++--
 1 file changed, 15 insertions(+), 52 deletions(-)

diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index 745c6ee1bb3e..48bfea91dbca 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -99,12 +99,6 @@ struct virtio_mmio_vq_info {
/* the actual virtqueue */
struct virtqueue *vq;
 
-   /* the number of entries in the queue */
-   unsigned int num;
-
-   /* the virtual address of the ring queue */
-   void *queue;
-
/* the list node for the virtqueues list */
struct list_head node;
 };
@@ -322,15 +316,13 @@ 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 long flags;
unsigned int index = vq->index;
 
spin_lock_irqsave(_dev->lock, flags);
list_del(>node);
spin_unlock_irqrestore(_dev->lock, flags);
 
-   vring_del_virtqueue(vq);
-
/* Select and deactivate the queue */
writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
if (vm_dev->version == 1) {
@@ -340,8 +332,8 @@ static void vm_del_vq(struct virtqueue *vq)
WARN_ON(readl(vm_dev->base + VIRTIO_MMIO_QUEUE_READY));
}
 
-   size = PAGE_ALIGN(vring_size(info->num, VIRTIO_MMIO_VRING_ALIGN));
-   free_pages_exact(info->queue, size);
+   vring_del_virtqueue(vq);
+
kfree(info);
 }
 
@@ -356,8 +348,6 @@ static void vm_del_vqs(struct virtio_device *vdev)
free_irq(platform_get_irq(vm_dev->pdev, 0), vm_dev);
 }
 
-
-
 static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned 
index,
  void (*callback)(struct virtqueue *vq),
  const char *name)
@@ -365,7 +355,8 @@ static struct virtqueue *vm_setup_vq(struct virtio_device 
*vdev, unsigned index,
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
struct virtio_mmio_vq_info *info;
struct virtqueue *vq;
-   unsigned long flags, size;
+   unsigned long flags;
+   unsigned int num;
int err;
 
if (!name)
@@ -388,66 +379,40 @@ static struct virtqueue *vm_setup_vq(struct virtio_device 
*vdev, unsigned index,
goto error_kmalloc;
}
 
-   /* Allocate pages for the queue - start with a queue as big as
-* possible (limited by maximum size allowed by device), drop down
-* to a minimal size, just big enough to fit descriptor table
-* and two rings (which makes it "alignment_size * 2")
-*/
-   info->num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX);
-
-   /* If the device reports a 0 entry queue, we won't be able to
-* use it to perform I/O, and vring_new_virtqueue() can't create
-* empty queues anyway, so don't bother to set up the device.
-*/
-   if (info->num == 0) {
+   num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX);
+   if (num == 0) {
err = -ENOENT;
-   goto error_alloc_pages;
-   }
-
-   while (1) {
-   size = PAGE_ALIGN(vring_size(info->num,
-   VIRTIO_MMIO_VRING_ALIGN));
-   /* Did the last iter shrink the queue below minimum size? */
-   if (size < VIRTIO_MMIO_VRING_ALIGN * 2) {
-   err = -ENOMEM;
-   goto error_alloc_pages;
-   }
-
-   info->queue = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO);
-   if (info->queue)
-   break;
-
-   info->num /= 2;
+   goto error_new_virtqueue;
}
 
/* Create the vring */
-   vq = vring_new_virtqueue(index, info->num, VIRTIO_MMIO_VRING_ALIGN, 
vdev,
-true, info->queue, vm_notify, callback, name);
+   vq = vring_create_virtqueue(index, num, VIRTIO_MMIO_VRING_ALIGN, vdev,
+true, true, vm_notify, callback, name);
if (!vq) {
err = -ENOMEM;
goto error_new_virtqueue;
}
 
/* Activate the queue */
-   writel(info->num, vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
+   writel(virtqueue_get_vring_size(vq), vm_dev->base + 
VIRTIO_MMIO_QUEUE_NUM);
if (vm_dev->version == 1) {
writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN);
-   writel(virt_to_phys(info->queue) >> PAGE_SHIFT,
+   writel(virtqueue_get_desc_addr(vq) >> PAGE_SHIFT,
vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
} else {
u64 addr;
 
- 

[PATCH v7 7/9] virtio_mmio: Use the DMA API if enabled

[Andy Lutomirski]

This switches to vring_create_virtqueue, simplifying the driver and
adding DMA API support.

Signed-off-by: Andy Lutomirski 
---
 drivers/virtio/virtio_mmio.c | 67 ++--
 1 file changed, 15 insertions(+), 52 deletions(-)

diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index 745c6ee1bb3e..48bfea91dbca 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -99,12 +99,6 @@ struct virtio_mmio_vq_info {
/* the actual virtqueue */
struct virtqueue *vq;
 
-   /* the number of entries in the queue */
-   unsigned int num;
-
-   /* the virtual address of the ring queue */
-   void *queue;
-
/* the list node for the virtqueues list */
struct list_head node;
 };
@@ -322,15 +316,13 @@ 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 long flags;
unsigned int index = vq->index;
 
spin_lock_irqsave(_dev->lock, flags);
list_del(>node);
spin_unlock_irqrestore(_dev->lock, flags);
 
-   vring_del_virtqueue(vq);
-
/* Select and deactivate the queue */
writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
if (vm_dev->version == 1) {
@@ -340,8 +332,8 @@ static void vm_del_vq(struct virtqueue *vq)
WARN_ON(readl(vm_dev->base + VIRTIO_MMIO_QUEUE_READY));
}
 
-   size = PAGE_ALIGN(vring_size(info->num, VIRTIO_MMIO_VRING_ALIGN));
-   free_pages_exact(info->queue, size);
+   vring_del_virtqueue(vq);
+
kfree(info);
 }
 
@@ -356,8 +348,6 @@ static void vm_del_vqs(struct virtio_device *vdev)
free_irq(platform_get_irq(vm_dev->pdev, 0), vm_dev);
 }
 
-
-
 static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned 
index,
  void (*callback)(struct virtqueue *vq),
  const char *name)
@@ -365,7 +355,8 @@ static struct virtqueue *vm_setup_vq(struct virtio_device 
*vdev, unsigned index,
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
struct virtio_mmio_vq_info *info;
struct virtqueue *vq;
-   unsigned long flags, size;
+   unsigned long flags;
+   unsigned int num;
int err;
 
if (!name)
@@ -388,66 +379,40 @@ static struct virtqueue *vm_setup_vq(struct virtio_device 
*vdev, unsigned index,
goto error_kmalloc;
}
 
-   /* Allocate pages for the queue - start with a queue as big as
-* possible (limited by maximum size allowed by device), drop down
-* to a minimal size, just big enough to fit descriptor table
-* and two rings (which makes it "alignment_size * 2")
-*/
-   info->num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX);
-
-   /* If the device reports a 0 entry queue, we won't be able to
-* use it to perform I/O, and vring_new_virtqueue() can't create
-* empty queues anyway, so don't bother to set up the device.
-*/
-   if (info->num == 0) {
+   num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX);
+   if (num == 0) {
err = -ENOENT;
-   goto error_alloc_pages;
-   }
-
-   while (1) {
-   size = PAGE_ALIGN(vring_size(info->num,
-   VIRTIO_MMIO_VRING_ALIGN));
-   /* Did the last iter shrink the queue below minimum size? */
-   if (size < VIRTIO_MMIO_VRING_ALIGN * 2) {
-   err = -ENOMEM;
-   goto error_alloc_pages;
-   }
-
-   info->queue = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO);
-   if (info->queue)
-   break;
-
-   info->num /= 2;
+   goto error_new_virtqueue;
}
 
/* Create the vring */
-   vq = vring_new_virtqueue(index, info->num, VIRTIO_MMIO_VRING_ALIGN, 
vdev,
-true, info->queue, vm_notify, callback, name);
+   vq = vring_create_virtqueue(index, num, VIRTIO_MMIO_VRING_ALIGN, vdev,
+true, true, vm_notify, callback, name);
if (!vq) {
err = -ENOMEM;
goto error_new_virtqueue;
}
 
/* Activate the queue */
-   writel(info->num, vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
+   writel(virtqueue_get_vring_size(vq), vm_dev->base + 
VIRTIO_MMIO_QUEUE_NUM);
if (vm_dev->version == 1) {
writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN);
-   writel(virt_to_phys(info->queue) >> PAGE_SHIFT,
+   writel(virtqueue_get_desc_addr(vq) >> PAGE_SHIFT,
vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
} else {