Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1667176

[PATCH v4 16/18] xen/pvcalls: implement read

Show all headers | View raw

When an active socket has data available, increment the io and read
counters, and schedule the ioworker.

Implement the read function by reading from the socket, writing the data
to the data ring.

Set in_error on error.

Signed-off-by: Stefano Stabellini <stefano@aporeto.com>
CC: boris.ostrovsky@oracle.com
CC: jgross@suse.com
---
 drivers/xen/pvcalls-back.c | 85 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 85 insertions(+)

diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c
index b9a10b9..65d9eba 100644
--- a/drivers/xen/pvcalls-back.c
+++ b/drivers/xen/pvcalls-back.c
@@ -100,6 +100,81 @@ static int pvcalls_back_release_active(struct xenbus_device *dev,
 
 static void pvcalls_conn_back_read(void *opaque)
 {
+	struct sock_mapping *map = (struct sock_mapping *)opaque;
+	struct msghdr msg;
+	struct kvec vec[2];
+	RING_IDX cons, prod, size, wanted, array_size, masked_prod, masked_cons;
+	int32_t error;
+	struct pvcalls_data_intf *intf = map->ring;
+	struct pvcalls_data *data = &map->data;
+	unsigned long flags;
+	int ret;
+
+	array_size = XEN_FLEX_RING_SIZE(map->ring_order);
+	cons = intf->in_cons;
+	prod = intf->in_prod;
+	error = intf->in_error;
+	/* read the indexes first, then deal with the data */
+	virt_mb();
+
+	if (error)
+		return;
+
+	size = pvcalls_queued(prod, cons, array_size);
+	if (size >= array_size)
+		return;
+	spin_lock_irqsave(&map->sock->sk->sk_receive_queue.lock, flags);
+	if (skb_queue_empty(&map->sock->sk->sk_receive_queue)) {
+		atomic_set(&map->read, 0);
+		spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock,
+				flags);
+		return;
+	}
+	spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock, flags);
+	wanted = array_size - size;
+	masked_prod = pvcalls_mask(prod, array_size);
+	masked_cons = pvcalls_mask(cons, array_size);
+
+	memset(&msg, 0, sizeof(msg));
+	msg.msg_iter.type = ITER_KVEC|WRITE;
+	msg.msg_iter.count = wanted;
+	if (masked_prod < masked_cons) {
+		vec[0].iov_base = data->in + masked_prod;
+		vec[0].iov_len = wanted;
+		msg.msg_iter.kvec = vec;
+		msg.msg_iter.nr_segs = 1;
+	} else {
+		vec[0].iov_base = data->in + masked_prod;
+		vec[0].iov_len = array_size - masked_prod;
+		vec[1].iov_base = data->in;
+		vec[1].iov_len = wanted - vec[0].iov_len;
+		msg.msg_iter.kvec = vec;
+		msg.msg_iter.nr_segs = 2;
+	}
+
+	atomic_set(&map->read, 0);
+	ret = inet_recvmsg(map->sock, &msg, wanted, MSG_DONTWAIT);
+	WARN_ON(ret > wanted);
+	if (ret == -EAGAIN) /* shouldn't happen */
+		return;
+	if (!ret)
+		ret = -ENOTCONN;
+	spin_lock_irqsave(&map->sock->sk->sk_receive_queue.lock, flags);
+	if (ret > 0 && !skb_queue_empty(&map->sock->sk->sk_receive_queue))
+		atomic_inc(&map->read);
+	spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock, flags);
+
+	/* write the data, then modify the indexes */
+	virt_wmb();
+	if (ret < 0)
+		intf->in_error = ret;
+	else
+		intf->in_prod = prod + ret;
+	/* update the indexes, then notify the other end */
+	virt_wmb();
+	notify_remote_via_irq(map->irq);
+
+	return;
 }
 
 static int pvcalls_conn_back_write(struct sock_mapping *map)
@@ -172,6 +247,16 @@ static void pvcalls_sk_state_change(struct sock *sock)
 
 static void pvcalls_sk_data_ready(struct sock *sock)
 {
+	struct sock_mapping *map = sock->sk_user_data;
+	struct pvcalls_ioworker *iow;
+
+	if (map == NULL)
+		return;
+
+	iow = &map->ioworker;
+	atomic_inc(&map->read);
+	atomic_inc(&map->io);
+	queue_work(iow->wq, &iow->register_work);
 }
 
 static struct sock_mapping *pvcalls_new_active_socket(
-- 
1.9.1

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH v4 00/18] introduce the Xen PV Calls backend Stefano Stabellini <sstabellini@kernel.org> - 2017-06-15 21:10 +0200
  [PATCH v4 06/18] xen/pvcalls: handle commands from the frontend Stefano Stabellini <sstabellini@kernel.org> - 2017-06-15 21:20 +0200
  [PATCH v4 04/18] xen/pvcalls: xenbus state handling Stefano Stabellini <sstabellini@kernel.org> - 2017-06-15 21:20 +0200
  [PATCH v4 16/18] xen/pvcalls: implement read Stefano Stabellini <sstabellini@kernel.org> - 2017-06-15 21:20 +0200
  [PATCH v4 08/18] xen/pvcalls: implement connect command Stefano Stabellini <sstabellini@kernel.org> - 2017-06-15 21:20 +0200
  [PATCH v4 15/18] xen/pvcalls: implement the ioworker functions Stefano Stabellini <sstabellini@kernel.org> - 2017-06-15 21:20 +0200
  [PATCH v4 12/18] xen/pvcalls: implement poll command Stefano Stabellini <sstabellini@kernel.org> - 2017-06-15 21:20 +0200
  [PATCH v4 02/18] xen/pvcalls: introduce the pvcalls xenbus backend Stefano Stabellini <sstabellini@kernel.org> - 2017-06-15 21:20 +0200
  [PATCH v4 10/18] xen/pvcalls: implement listen command Stefano Stabellini <sstabellini@kernel.org> - 2017-06-15 21:20 +0200
  [PATCH v4 09/18] xen/pvcalls: implement bind command Stefano Stabellini <sstabellini@kernel.org> - 2017-06-15 21:20 +0200
  [PATCH v4 17/18] xen/pvcalls: implement write Stefano Stabellini <sstabellini@kernel.org> - 2017-06-15 21:20 +0200
  [PATCH v4 07/18] xen/pvcalls: implement socket command Stefano Stabellini <sstabellini@kernel.org> - 2017-06-15 21:20 +0200
  [PATCH v4 03/18] xen/pvcalls: initialize the module and register the xenbus backend Stefano Stabellini <sstabellini@kernel.org> - 2017-06-15 21:20 +0200
  [PATCH v4 18/18] xen: introduce a Kconfig option to enable the pvcalls backend Stefano Stabellini <sstabellini@kernel.org> - 2017-06-15 21:20 +0200
  [PATCH v4 05/18] xen/pvcalls: connect to a frontend Stefano Stabellini <sstabellini@kernel.org> - 2017-06-15 21:20 +0200
  [PATCH v4 14/18] xen/pvcalls: disconnect and module_exit Stefano Stabellini <sstabellini@kernel.org> - 2017-06-15 21:20 +0200
  [PATCH v4 01/18] xen: introduce the pvcalls interface header Stefano Stabellini <sstabellini@kernel.org> - 2017-06-15 21:20 +0200
    [PATCH v4 13/18] xen/pvcalls: implement release command Stefano Stabellini <sstabellini@kernel.org> - 2017-06-15 21:20 +0200
    [PATCH v4 11/18] xen/pvcalls: implement accept command Stefano Stabellini <sstabellini@kernel.org> - 2017-06-15 21:20 +0200

csiph-web