From 5ad9918ffc4157f239f2e7849b4987d3b20f917e Mon Sep 17 00:00:00 2001 From: Stefano Stabellini Date: Thu, 6 Jul 2017 11:01:08 -0700 Subject: xen/pvcalls: implement write When the other end notifies us that there is data to be written (pvcalls_back_conn_event), increment the io and write counters, and schedule the ioworker. Implement the write function called by ioworker by reading the data from the data ring, writing it to the socket by calling inet_sendmsg. Set out_error on error. Signed-off-by: Stefano Stabellini Reviewed-by: Juergen Gross CC: boris.ostrovsky@oracle.com CC: jgross@suse.com Signed-off-by: Boris Ostrovsky --- drivers/xen/pvcalls-back.c | 71 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 71 insertions(+) (limited to 'drivers/xen') diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c index 2519e46bd470..3201a0c5dbcf 100644 --- a/drivers/xen/pvcalls-back.c +++ b/drivers/xen/pvcalls-back.c @@ -177,6 +177,64 @@ static void pvcalls_conn_back_read(void *opaque) static void pvcalls_conn_back_write(struct sock_mapping *map) { + struct pvcalls_data_intf *intf = map->ring; + struct pvcalls_data *data = &map->data; + struct msghdr msg; + struct kvec vec[2]; + RING_IDX cons, prod, size, array_size; + int ret; + + cons = intf->out_cons; + prod = intf->out_prod; + /* read the indexes before dealing with the data */ + virt_mb(); + + array_size = XEN_FLEX_RING_SIZE(map->ring_order); + size = pvcalls_queued(prod, cons, array_size); + if (size == 0) + return; + + memset(&msg, 0, sizeof(msg)); + msg.msg_flags |= MSG_DONTWAIT; + msg.msg_iter.type = ITER_KVEC|READ; + msg.msg_iter.count = size; + if (pvcalls_mask(prod, array_size) > pvcalls_mask(cons, array_size)) { + vec[0].iov_base = data->out + pvcalls_mask(cons, array_size); + vec[0].iov_len = size; + msg.msg_iter.kvec = vec; + msg.msg_iter.nr_segs = 1; + } else { + vec[0].iov_base = data->out + pvcalls_mask(cons, array_size); + vec[0].iov_len = array_size - pvcalls_mask(cons, array_size); + vec[1].iov_base = data->out; + vec[1].iov_len = size - vec[0].iov_len; + msg.msg_iter.kvec = vec; + msg.msg_iter.nr_segs = 2; + } + + atomic_set(&map->write, 0); + ret = inet_sendmsg(map->sock, &msg, size); + if (ret == -EAGAIN || (ret >= 0 && ret < size)) { + atomic_inc(&map->write); + atomic_inc(&map->io); + } + if (ret == -EAGAIN) + return; + + /* write the data, then update the indexes */ + virt_wmb(); + if (ret < 0) { + intf->out_error = ret; + } else { + intf->out_error = 0; + intf->out_cons = cons + ret; + prod = intf->out_prod; + } + /* update the indexes, then notify the other end */ + virt_wmb(); + if (prod != cons + ret) + atomic_inc(&map->write); + notify_remote_via_irq(map->irq); } static void pvcalls_back_ioworker(struct work_struct *work) @@ -847,6 +905,19 @@ static irqreturn_t pvcalls_back_event(int irq, void *dev_id) static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map) { + struct sock_mapping *map = sock_map; + struct pvcalls_ioworker *iow; + + if (map == NULL || map->sock == NULL || map->sock->sk == NULL || + map->sock->sk->sk_user_data != map) + return IRQ_HANDLED; + + iow = &map->ioworker; + + atomic_inc(&map->write); + atomic_inc(&map->io); + queue_work(iow->wq, &iow->register_work); + return IRQ_HANDLED; } -- cgit v1.2.3