This patch introduces a per virtqueue waitqueue to allow driver to sleep and wait for more used. Two new helpers are introduced to allow driver to sleep and wake up.
Signed-off-by: Jason Wang <[email protected]> --- drivers/virtio/virtio_ring.c | 31 +++++++++++++++++++++++++++++++ include/linux/virtio.h | 4 ++++ 2 files changed, 35 insertions(+) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 90c2034a77f3..4a2d5ac30b0f 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -13,6 +13,7 @@ #include <linux/dma-mapping.h> #include <linux/kmsan.h> #include <linux/spinlock.h> +#include <linux/wait.h> #include <xen/xen.h> #ifdef DEBUG @@ -59,6 +60,7 @@ dev_err(&_vq->vq.vdev->dev, \ "%s:"fmt, (_vq)->vq.name, ##args); \ (_vq)->broken = true; \ + wake_up_interruptible(&(_vq)->wq); \ } while (0) #define START_USE(vq) #define END_USE(vq) @@ -202,6 +204,9 @@ struct vring_virtqueue { /* DMA, allocation, and size information */ bool we_own_ring; + /* Wait for buffer to be used */ + wait_queue_head_t wq; + #ifdef DEBUG /* They're supposed to lock for us. */ unsigned int in_use; @@ -2023,6 +2028,8 @@ static struct virtqueue *vring_create_virtqueue_packed( if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM)) vq->weak_barriers = false; + init_waitqueue_head(&vq->wq); + err = vring_alloc_state_extra_packed(&vring_packed); if (err) goto err_state_extra; @@ -2516,6 +2523,8 @@ static struct virtqueue *__vring_new_virtqueue(unsigned int index, if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM)) vq->weak_barriers = false; + init_waitqueue_head(&vq->wq); + err = vring_alloc_state_extra_split(vring_split); if (err) { kfree(vq); @@ -2653,6 +2662,8 @@ static void vring_free(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); + wake_up_interruptible(&vq->wq); + if (vq->we_own_ring) { if (vq->packed_ring) { vring_free_queue(vq->vq.vdev, @@ -2863,4 +2874,24 @@ const struct vring *virtqueue_get_vring(struct virtqueue *vq) } EXPORT_SYMBOL_GPL(virtqueue_get_vring); +int virtqueue_wait_for_used(struct virtqueue *_vq, + unsigned int *len) +{ + struct vring_virtqueue *vq = to_vvq(_vq); + + /* Use a better timeout or simply start from no timeout */ + return wait_event_interruptible_timeout(vq->wq, + virtqueue_get_buf(_vq, len), + HZ); +} +EXPORT_SYMBOL_GPL(virtqueue_wait_for_used); + +void virtqueue_wake_up(struct virtqueue *_vq) +{ + struct vring_virtqueue *vq = to_vvq(_vq); + + wake_up_interruptible(&vq->wq); +} +EXPORT_SYMBOL_GPL(virtqueue_wake_up); + MODULE_LICENSE("GPL"); diff --git a/include/linux/virtio.h b/include/linux/virtio.h index dcab9c7e8784..4df098b8f1ca 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -72,6 +72,10 @@ void *virtqueue_get_buf(struct virtqueue *vq, unsigned int *len); void *virtqueue_get_buf_ctx(struct virtqueue *vq, unsigned int *len, void **ctx); +int virtqueue_wait_for_used(struct virtqueue *vq, + unsigned int *len); +void virtqueue_wake_up(struct virtqueue *vq); + void virtqueue_disable_cb(struct virtqueue *vq); bool virtqueue_enable_cb(struct virtqueue *vq); -- 2.25.1 _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
