Re: [PATCH net-next v8 5/7] net: vhost: introduce bitmap for vhost_poll

From: Tonghao Zhang <redacted>

The bitmap of vhost_dev can help us to check if the
specified poll is scheduled. This patch will be used
for next two patches.

Signed-off-by: Tonghao Zhang <redacted>
---
  drivers/vhost/net.c   | 11 +++++++++--
  drivers/vhost/vhost.c | 17 +++++++++++++++--
  drivers/vhost/vhost.h |  7 ++++++-
  3 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 1eff72d..23d7ffc 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c

@@ -1135,8 +1135,15 @@ static int vhost_net_open(struct inode *inode, struct file *f)
  	}
  	vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX);
  
-	vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, EPOLLOUT, dev);
-	vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, EPOLLIN, dev);
+	vhost_poll_init(n->poll + VHOST_NET_VQ_TX,
+			handle_tx_net,
+			VHOST_NET_VQ_TX,
+			EPOLLOUT, dev);
+
+	vhost_poll_init(n->poll + VHOST_NET_VQ_RX,
+			handle_rx_net,
+			VHOST_NET_VQ_RX,
+			EPOLLIN, dev);
  
  	f->private_data = n;
  

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index a1c06e7..dc88a60 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c

@@ -186,7 +186,7 @@ void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn)
  
  /* Init poll structure */
  void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
-		     __poll_t mask, struct vhost_dev *dev)
+		     __u8 poll_id, __poll_t mask, struct vhost_dev *dev)
  {
  	init_waitqueue_func_entry(&poll->wait, vhost_poll_wakeup);
  	init_poll_funcptr(&poll->table, vhost_poll_func);

@@ -194,6 +194,7 @@ void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
  	poll->dev = dev;
  	poll->wqh = NULL;
  
+	poll->poll_id = poll_id;
  	vhost_work_init(&poll->work, fn);
  }
  EXPORT_SYMBOL_GPL(vhost_poll_init);

@@ -276,8 +277,16 @@ bool vhost_has_work(struct vhost_dev *dev)
  }
  EXPORT_SYMBOL_GPL(vhost_has_work);
  
+bool vhost_has_work_pending(struct vhost_dev *dev, int poll_id)
+{
+	return !llist_empty(&dev->work_list) &&
+		test_bit(poll_id, dev->work_pending);

+}
+EXPORT_SYMBOL_GPL(vhost_has_work_pending);
+
  void vhost_poll_queue(struct vhost_poll *poll)
  {
+	set_bit(poll->poll_id, poll->dev->work_pending);
  	vhost_work_queue(poll->dev, &poll->work);
  }
  EXPORT_SYMBOL_GPL(vhost_poll_queue);

@@ -354,6 +363,7 @@ static int vhost_worker(void *data)
  		if (!node)
  			schedule();
  
+		bitmap_zero(dev->work_pending, VHOST_DEV_MAX_VQ);
  		node = llist_reverse_order(node);
  		/* make sure flag is seen after deletion */
  		smp_wmb();

@@ -420,6 +430,8 @@ void vhost_dev_init(struct vhost_dev *dev,
  	struct vhost_virtqueue *vq;
  	int i;
  
+	BUG_ON(nvqs > VHOST_DEV_MAX_VQ);
+
  	dev->vqs = vqs;
  	dev->nvqs = nvqs;
  	mutex_init(&dev->mutex);

@@ -428,6 +440,7 @@ void vhost_dev_init(struct vhost_dev *dev,
  	dev->iotlb = NULL;
  	dev->mm = NULL;
  	dev->worker = NULL;
+	bitmap_zero(dev->work_pending, VHOST_DEV_MAX_VQ);
  	init_llist_head(&dev->work_list);
  	init_waitqueue_head(&dev->wait);
  	INIT_LIST_HEAD(&dev->read_list);

@@ -445,7 +458,7 @@ void vhost_dev_init(struct vhost_dev *dev,
  		vhost_vq_reset(dev, vq);
  		if (vq->handle_kick)
  			vhost_poll_init(&vq->poll, vq->handle_kick,
-					EPOLLIN, dev);
+					i, EPOLLIN, dev);
  	}
  }
  EXPORT_SYMBOL_GPL(vhost_dev_init);

diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index 6c844b9..60b6f6d 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h

@@ -30,6 +30,7 @@ struct vhost_poll {
  	wait_queue_head_t        *wqh;
  	wait_queue_entry_t              wait;
  	struct vhost_work	  work;
+	__u8			  poll_id;
  	__poll_t		  mask;
  	struct vhost_dev	 *dev;
  };

@@ -37,9 +38,10 @@ struct vhost_poll {
  void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn);
  void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work);
  bool vhost_has_work(struct vhost_dev *dev);
+bool vhost_has_work_pending(struct vhost_dev *dev, int poll_id);
  
  void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
-		     __poll_t mask, struct vhost_dev *dev);
+		     __u8 id, __poll_t mask, struct vhost_dev *dev);
  int vhost_poll_start(struct vhost_poll *poll, struct file *file);
  void vhost_poll_stop(struct vhost_poll *poll);
  void vhost_poll_flush(struct vhost_poll *poll);

@@ -152,6 +154,8 @@ struct vhost_msg_node {
    struct list_head node;
  };
  
+#define VHOST_DEV_MAX_VQ	128
+
  struct vhost_dev {
  	struct mm_struct *mm;
  	struct mutex mutex;

@@ -159,6 +163,7 @@ struct vhost_dev {
  	int nvqs;
  	struct eventfd_ctx *log_ctx;
  	struct llist_head work_list;
+	DECLARE_BITMAP(work_pending, VHOST_DEV_MAX_VQ);
  	struct task_struct *worker;
  	struct vhost_umem *umem;
  	struct vhost_umem *iotlb;