[Xen-devel] [PATCH v2 06/13] xen/pvcalls: implement listen command

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

Send PVCALLS_LISTEN to the backend.

Signed-off-by: Stefano Stabellini <stefano@xxxxxxxxxxx>
CC: boris.ostrovsky@xxxxxxxxxx
CC: jgross@xxxxxxxx
---
 drivers/xen/pvcalls-front.c | 48 +++++++++++++++++++++++++++++++++++++++++++++
 drivers/xen/pvcalls-front.h |  1 +
 2 files changed, 49 insertions(+)

diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index af2ce20..3b5d50e 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -365,6 +365,54 @@ int pvcalls_front_bind(struct socket *sock, struct 
sockaddr *addr, int addr_len)
        return 0;
 }
 
+int pvcalls_front_listen(struct socket *sock, int backlog)
+{
+       struct pvcalls_bedata *bedata;
+       struct sock_mapping *map;
+       struct xen_pvcalls_request *req;
+       int notify, req_id, ret;
+
+       if (!pvcalls_front_dev)
+               return -ENOTCONN;
+       bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
+
+       map = (struct sock_mapping *) READ_ONCE(sock->sk->sk_send_head);
+       if (!map)
+               return -ENOTSOCK;
+
+       if (map->passive.status != PVCALLS_STATUS_BIND)
+               return -EOPNOTSUPP;
+
+       spin_lock(&bedata->pvcallss_lock);
+       req_id = bedata->ring.req_prod_pvt & (RING_SIZE(&bedata->ring) - 1);
+       if (RING_FULL(&bedata->ring) ||
+           bedata->rsp[req_id].req_id != PVCALLS_INVALID_ID) {
+               spin_unlock(&bedata->pvcallss_lock);
+               return -EAGAIN;
+       }
+       req = RING_GET_REQUEST(&bedata->ring, req_id);
+       req->req_id = req_id;
+       req->cmd = PVCALLS_LISTEN;
+       req->u.listen.id = (uint64_t) sock;
+       req->u.listen.backlog = backlog;
+
+       bedata->ring.req_prod_pvt++;
+       RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify);
+       spin_unlock(&bedata->pvcallss_lock);
+       if (notify)
+               notify_remote_via_irq(bedata->irq);
+
+       wait_event(bedata->inflight_req,
+                  READ_ONCE(bedata->rsp[req_id].req_id) == req_id);
+
+       map->passive.status = PVCALLS_STATUS_LISTEN;
+       ret = bedata->rsp[req_id].ret;
+       /* read ret, then set this rsp slot to be reused */
+       smp_mb();
+       WRITE_ONCE(bedata->rsp[req_id].req_id, PVCALLS_INVALID_ID);
+       return ret;
+}
+
 static const struct xenbus_device_id pvcalls_front_ids[] = {
        { "pvcalls" },
        { "" }
diff --git a/drivers/xen/pvcalls-front.h b/drivers/xen/pvcalls-front.h
index 8b0a274..aa8fe10 100644
--- a/drivers/xen/pvcalls-front.h
+++ b/drivers/xen/pvcalls-front.h
@@ -9,5 +9,6 @@ int pvcalls_front_connect(struct socket *sock, struct sockaddr 
*addr,
 int pvcalls_front_bind(struct socket *sock,
                       struct sockaddr *addr,
                       int addr_len);
+int pvcalls_front_listen(struct socket *sock, int backlog);
 
 #endif
-- 
1.9.1


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