[PATCH v3 13/18] xen/pvcalls: implement release command

From: Stefano Stabellini
Date: Fri Jun 02 2017 - 15:33:44 EST


Release both active and passive sockets. For active sockets, make sure
to avoid possible conflicts with the ioworker reading/writing to those
sockets concurrently. Set map->release to let the ioworker know
atomically that the socket will be released soon, then wait until the
ioworker finishes (flush_work).

Unmap indexes pages and data rings.

Signed-off-by: Stefano Stabellini <stefano@xxxxxxxxxxx>
CC: boris.ostrovsky@xxxxxxxxxx
CC: jgross@xxxxxxxx
---
drivers/xen/pvcalls-back.c | 72 +++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 71 insertions(+), 1 deletion(-)

diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c
index 82f350d..b541887 100644
--- a/drivers/xen/pvcalls-back.c
+++ b/drivers/xen/pvcalls-back.c
@@ -265,13 +265,83 @@ static int pvcalls_back_release_active(struct xenbus_device *dev,
struct pvcalls_fedata *priv,
struct sock_mapping *map)
{
+ disable_irq(map->irq);
+ if (map->sock->sk != NULL) {
+ write_lock_bh(&map->sock->sk->sk_callback_lock);
+ map->sock->sk->sk_user_data = NULL;
+ map->sock->sk->sk_data_ready = map->saved_data_ready;
+ write_unlock_bh(&map->sock->sk->sk_callback_lock);
+ }
+
+ atomic_set(&map->release, 1);
+ flush_work(&map->ioworker.register_work);
+
+ down(&priv->socket_lock);
+ list_del(&map->list);
+ up(&priv->socket_lock);
+
+ xenbus_unmap_ring_vfree(dev, (void *)map->bytes);
+ xenbus_unmap_ring_vfree(dev, (void *)map->ring);
+ unbind_from_irqhandler(map->irq, map);
+
+ sock_release(map->sock);
+ kfree(map);
+
+ return 0;
+}
+
+static int pvcalls_back_release_passive(struct xenbus_device *dev,
+ struct pvcalls_fedata *priv,
+ struct sockpass_mapping *mappass)
+{
+ if (mappass->sock->sk != NULL) {
+ write_lock_bh(&mappass->sock->sk->sk_callback_lock);
+ mappass->sock->sk->sk_user_data = NULL;
+ mappass->sock->sk->sk_data_ready = mappass->saved_data_ready;
+ write_unlock_bh(&mappass->sock->sk->sk_callback_lock);
+ }
+ down(&priv->socket_lock);
+ radix_tree_delete(&priv->socketpass_mappings, mappass->id);
+ sock_release(mappass->sock);
+ flush_workqueue(mappass->wq);
+ destroy_workqueue(mappass->wq);
+ kfree(mappass);
+ up(&priv->socket_lock);
+
return 0;
}

static int pvcalls_back_release(struct xenbus_device *dev,
struct xen_pvcalls_request *req)
{
- return 0;
+ struct pvcalls_fedata *priv;
+ struct sock_mapping *map, *n;
+ struct sockpass_mapping *mappass;
+ int ret = 0;
+ struct xen_pvcalls_response *rsp;
+
+ priv = dev_get_drvdata(&dev->dev);
+
+ list_for_each_entry_safe(map, n, &priv->socket_mappings, list) {
+ if (map->id == req->u.release.id) {
+ ret = pvcalls_back_release_active(dev, priv, map);
+ goto out;
+ }
+ }
+ mappass = radix_tree_lookup(&priv->socketpass_mappings,
+ req->u.release.id);
+ if (mappass != NULL) {
+ ret = pvcalls_back_release_passive(dev, priv, mappass);
+ goto out;
+ }
+
+out:
+ rsp = RING_GET_RESPONSE(&priv->ring, priv->ring.rsp_prod_pvt++);
+ rsp->req_id = req->req_id;
+ rsp->u.release.id = req->u.release.id;
+ rsp->cmd = req->cmd;
+ rsp->ret = ret;
+ return ret;
}

static void __pvcalls_back_accept(struct work_struct *work)
--
1.9.1