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Commit 64d68718 authored by Stefano Stabellini's avatar Stefano Stabellini Committed by Juergen Gross
Browse files

pvcalls-front: introduce a per sock_mapping refcount 



Introduce a per sock_mapping refcount, in addition to the existing
global refcount. Thanks to the sock_mapping refcount, we can safely wait
for it to be 1 in pvcalls_front_release before freeing an active socket,
instead of waiting for the global refcount to be 1.

Signed-off-by: default avatarStefano Stabellini <stefano@aporeto.com>
Acked-by: default avatarJuergen Gross <jgross@suse.com>
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
parent 63e708f8

drivers/xen/pvcalls-front.c

+79 −112
Original line number Diff line number Diff line
@@ -60,6 +60,7 @@ struct sock_mapping { 
	bool active_socket;

	struct list_head list;

	struct socket *sock;

	atomic_t refcount;

	union {

		struct {

			int irq;
@@ -93,6 +94,32 @@ struct sock_mapping { 
	};

};



static inline struct sock_mapping *pvcalls_enter_sock(struct socket *sock)

{

	struct sock_mapping *map;



	if (!pvcalls_front_dev ||

		dev_get_drvdata(&pvcalls_front_dev->dev) == NULL)

		return ERR_PTR(-ENOTCONN);



	map = (struct sock_mapping *)sock->sk->sk_send_head;

	if (map == NULL)

		return ERR_PTR(-ENOTSOCK);



	pvcalls_enter();

	atomic_inc(&map->refcount);

	return map;

}



static inline void pvcalls_exit_sock(struct socket *sock)

{

	struct sock_mapping *map;



	map = (struct sock_mapping *)sock->sk->sk_send_head;

	atomic_dec(&map->refcount);

	pvcalls_exit();

}



static inline int get_request(struct pvcalls_bedata *bedata, int *req_id)

{

	*req_id = bedata->ring.req_prod_pvt & (RING_SIZE(&bedata->ring) - 1);
@@ -369,31 +396,23 @@ int pvcalls_front_connect(struct socket *sock, struct sockaddr *addr, 
	if (addr->sa_family != AF_INET || sock->type != SOCK_STREAM)

		return -EOPNOTSUPP;



	pvcalls_enter();

	if (!pvcalls_front_dev) {

		pvcalls_exit();

		return -ENOTCONN;

	}

	map = pvcalls_enter_sock(sock);

	if (IS_ERR(map))

		return PTR_ERR(map);



	bedata = dev_get_drvdata(&pvcalls_front_dev->dev);



	map = (struct sock_mapping *)sock->sk->sk_send_head;

	if (!map) {

		pvcalls_exit();

		return -ENOTSOCK;

	}



	spin_lock(&bedata->socket_lock);

	ret = get_request(bedata, &req_id);

	if (ret < 0) {

		spin_unlock(&bedata->socket_lock);

		pvcalls_exit();

		pvcalls_exit_sock(sock);

		return ret;

	}

	ret = create_active(map, &evtchn);

	if (ret < 0) {

		spin_unlock(&bedata->socket_lock);

		pvcalls_exit();

		pvcalls_exit_sock(sock);

		return ret;

	}
@@ -423,7 +442,7 @@ int pvcalls_front_connect(struct socket *sock, struct sockaddr *addr, 
	smp_rmb();

	ret = bedata->rsp[req_id].ret;

	bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;

	pvcalls_exit();

	pvcalls_exit_sock(sock);

	return ret;

}
@@ -488,23 +507,15 @@ int pvcalls_front_sendmsg(struct socket *sock, struct msghdr *msg, 
	if (flags & (MSG_CONFIRM|MSG_DONTROUTE|MSG_EOR|MSG_OOB))

		return -EOPNOTSUPP;



	pvcalls_enter();

	if (!pvcalls_front_dev) {

		pvcalls_exit();

		return -ENOTCONN;

	}

	map = pvcalls_enter_sock(sock);

	if (IS_ERR(map))

		return PTR_ERR(map);

	bedata = dev_get_drvdata(&pvcalls_front_dev->dev);



	map = (struct sock_mapping *) sock->sk->sk_send_head;

	if (!map) {

		pvcalls_exit();

		return -ENOTSOCK;

	}



	mutex_lock(&map->active.out_mutex);

	if ((flags & MSG_DONTWAIT) && !pvcalls_front_write_todo(map)) {

		mutex_unlock(&map->active.out_mutex);

		pvcalls_exit();

		pvcalls_exit_sock(sock);

		return -EAGAIN;

	}

	if (len > INT_MAX)
@@ -526,7 +537,7 @@ int pvcalls_front_sendmsg(struct socket *sock, struct msghdr *msg, 
		tot_sent = sent;



	mutex_unlock(&map->active.out_mutex);

	pvcalls_exit();

	pvcalls_exit_sock(sock);

	return tot_sent;

}
@@ -591,19 +602,11 @@ int pvcalls_front_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, 
	if (flags & (MSG_CMSG_CLOEXEC|MSG_ERRQUEUE|MSG_OOB|MSG_TRUNC))

		return -EOPNOTSUPP;



	pvcalls_enter();

	if (!pvcalls_front_dev) {

		pvcalls_exit();

		return -ENOTCONN;

	}

	map = pvcalls_enter_sock(sock);

	if (IS_ERR(map))

		return PTR_ERR(map);

	bedata = dev_get_drvdata(&pvcalls_front_dev->dev);



	map = (struct sock_mapping *) sock->sk->sk_send_head;

	if (!map) {

		pvcalls_exit();

		return -ENOTSOCK;

	}



	mutex_lock(&map->active.in_mutex);

	if (len > XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER))

		len = XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER);
@@ -623,7 +626,7 @@ int pvcalls_front_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, 
		ret = 0;



	mutex_unlock(&map->active.in_mutex);

	pvcalls_exit();

	pvcalls_exit_sock(sock);

	return ret;

}
@@ -637,24 +640,16 @@ int pvcalls_front_bind(struct socket *sock, struct sockaddr *addr, int addr_len) 
	if (addr->sa_family != AF_INET || sock->type != SOCK_STREAM)

		return -EOPNOTSUPP;



	pvcalls_enter();

	if (!pvcalls_front_dev) {

		pvcalls_exit();

		return -ENOTCONN;

	}

	map = pvcalls_enter_sock(sock);

	if (IS_ERR(map))

		return PTR_ERR(map);

	bedata = dev_get_drvdata(&pvcalls_front_dev->dev);



	map = (struct sock_mapping *) sock->sk->sk_send_head;

	if (map == NULL) {

		pvcalls_exit();

		return -ENOTSOCK;

	}



	spin_lock(&bedata->socket_lock);

	ret = get_request(bedata, &req_id);

	if (ret < 0) {

		spin_unlock(&bedata->socket_lock);

		pvcalls_exit();

		pvcalls_exit_sock(sock);

		return ret;

	}

	req = RING_GET_REQUEST(&bedata->ring, req_id);
@@ -684,7 +679,7 @@ int pvcalls_front_bind(struct socket *sock, struct sockaddr *addr, int addr_len) 
	bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;



	map->passive.status = PVCALLS_STATUS_BIND;

	pvcalls_exit();

	pvcalls_exit_sock(sock);

	return 0;

}
@@ -695,21 +690,13 @@ int pvcalls_front_listen(struct socket *sock, int backlog) 
	struct xen_pvcalls_request *req;

	int notify, req_id, ret;



	pvcalls_enter();

	if (!pvcalls_front_dev) {

		pvcalls_exit();

		return -ENOTCONN;

	}

	map = pvcalls_enter_sock(sock);

	if (IS_ERR(map))

		return PTR_ERR(map);

	bedata = dev_get_drvdata(&pvcalls_front_dev->dev);



	map = (struct sock_mapping *) sock->sk->sk_send_head;

	if (!map) {

		pvcalls_exit();

		return -ENOTSOCK;

	}



	if (map->passive.status != PVCALLS_STATUS_BIND) {

		pvcalls_exit();

		pvcalls_exit_sock(sock);

		return -EOPNOTSUPP;

	}
@@ -717,7 +704,7 @@ int pvcalls_front_listen(struct socket *sock, int backlog) 
	ret = get_request(bedata, &req_id);

	if (ret < 0) {

		spin_unlock(&bedata->socket_lock);

		pvcalls_exit();

		pvcalls_exit_sock(sock);

		return ret;

	}

	req = RING_GET_REQUEST(&bedata->ring, req_id);
@@ -741,7 +728,7 @@ int pvcalls_front_listen(struct socket *sock, int backlog) 
	bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;



	map->passive.status = PVCALLS_STATUS_LISTEN;

	pvcalls_exit();

	pvcalls_exit_sock(sock);

	return ret;

}
@@ -753,21 +740,13 @@ int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int flags) 
	struct xen_pvcalls_request *req;

	int notify, req_id, ret, evtchn, nonblock;



	pvcalls_enter();

	if (!pvcalls_front_dev) {

		pvcalls_exit();

		return -ENOTCONN;

	}

	map = pvcalls_enter_sock(sock);

	if (IS_ERR(map))

		return PTR_ERR(map);

	bedata = dev_get_drvdata(&pvcalls_front_dev->dev);



	map = (struct sock_mapping *) sock->sk->sk_send_head;

	if (!map) {

		pvcalls_exit();

		return -ENOTSOCK;

	}



	if (map->passive.status != PVCALLS_STATUS_LISTEN) {

		pvcalls_exit();

		pvcalls_exit_sock(sock);

		return -EINVAL;

	}
@@ -785,13 +764,13 @@ int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int flags) 
			goto received;

		}

		if (nonblock) {

			pvcalls_exit();

			pvcalls_exit_sock(sock);

			return -EAGAIN;

		}

		if (wait_event_interruptible(map->passive.inflight_accept_req,

			!test_and_set_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,

					  (void *)&map->passive.flags))) {

			pvcalls_exit();

			pvcalls_exit_sock(sock);

			return -EINTR;

		}

	}
@@ -802,7 +781,7 @@ int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int flags) 
		clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,

			  (void *)&map->passive.flags);

		spin_unlock(&bedata->socket_lock);

		pvcalls_exit();

		pvcalls_exit_sock(sock);

		return ret;

	}

	map2 = kzalloc(sizeof(*map2), GFP_ATOMIC);
@@ -810,7 +789,7 @@ int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int flags) 
		clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,

			  (void *)&map->passive.flags);

		spin_unlock(&bedata->socket_lock);

		pvcalls_exit();

		pvcalls_exit_sock(sock);

		return -ENOMEM;

	}

	ret = create_active(map2, &evtchn);
@@ -819,7 +798,7 @@ int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int flags) 
		clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,

			  (void *)&map->passive.flags);

		spin_unlock(&bedata->socket_lock);

		pvcalls_exit();

		pvcalls_exit_sock(sock);

		return ret;

	}

	list_add_tail(&map2->list, &bedata->socket_mappings);
@@ -841,13 +820,13 @@ int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int flags) 
	/* We could check if we have received a response before returning. */

	if (nonblock) {

		WRITE_ONCE(map->passive.inflight_req_id, req_id);

		pvcalls_exit();

		pvcalls_exit_sock(sock);

		return -EAGAIN;

	}



	if (wait_event_interruptible(bedata->inflight_req,

		READ_ONCE(bedata->rsp[req_id].req_id) == req_id)) {

		pvcalls_exit();

		pvcalls_exit_sock(sock);

		return -EINTR;

	}

	/* read req_id, then the content */
@@ -862,7 +841,7 @@ int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int flags) 
		clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,

			  (void *)&map->passive.flags);

		pvcalls_front_free_map(bedata, map2);

		pvcalls_exit();

		pvcalls_exit_sock(sock);

		return -ENOMEM;

	}

	newsock->sk->sk_send_head = (void *)map2;
@@ -874,7 +853,7 @@ int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int flags) 
	clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, (void *)&map->passive.flags);

	wake_up(&map->passive.inflight_accept_req);



	pvcalls_exit();

	pvcalls_exit_sock(sock);

	return ret;

}
@@ -965,23 +944,16 @@ __poll_t pvcalls_front_poll(struct file *file, struct socket *sock, 
	struct sock_mapping *map;

	__poll_t ret;



	pvcalls_enter();

	if (!pvcalls_front_dev) {

		pvcalls_exit();

	map = pvcalls_enter_sock(sock);

	if (IS_ERR(map))

		return EPOLLNVAL;

	}

	bedata = dev_get_drvdata(&pvcalls_front_dev->dev);



	map = (struct sock_mapping *) sock->sk->sk_send_head;

	if (!map) {

		pvcalls_exit();

		return EPOLLNVAL;

	}

	if (map->active_socket)

		ret = pvcalls_front_poll_active(file, bedata, map, wait);

	else

		ret = pvcalls_front_poll_passive(file, bedata, map, wait);

	pvcalls_exit();

	pvcalls_exit_sock(sock);

	return ret;

}
@@ -995,25 +967,20 @@ int pvcalls_front_release(struct socket *sock) 
	if (sock->sk == NULL)

		return 0;



	pvcalls_enter();

	if (!pvcalls_front_dev) {

		pvcalls_exit();

	map = pvcalls_enter_sock(sock);

	if (IS_ERR(map)) {

		if (PTR_ERR(map) == -ENOTCONN)

			return -EIO;

	}



	bedata = dev_get_drvdata(&pvcalls_front_dev->dev);



	map = (struct sock_mapping *) sock->sk->sk_send_head;

	if (map == NULL) {

		pvcalls_exit();

		else

			return 0;

	}

	bedata = dev_get_drvdata(&pvcalls_front_dev->dev);



	spin_lock(&bedata->socket_lock);

	ret = get_request(bedata, &req_id);

	if (ret < 0) {

		spin_unlock(&bedata->socket_lock);

		pvcalls_exit();

		pvcalls_exit_sock(sock);

		return ret;

	}

	sock->sk->sk_send_head = NULL;
@@ -1043,10 +1010,10 @@ int pvcalls_front_release(struct socket *sock) 
		/*

		 * We need to make sure that sendmsg/recvmsg on this socket have

		 * not started before we've cleared sk_send_head here. The

		 * easiest (though not optimal) way to guarantee this is to see

		 * that no pvcall (other than us) is in progress.

		 * easiest way to guarantee this is to see that no pvcalls

		 * (other than us) is in progress on this socket.

		 */

		while (atomic_read(&pvcalls_refcount) > 1)

		while (atomic_read(&map->refcount) > 1)

			cpu_relax();



		pvcalls_front_free_map(bedata, map);