[dpdk-dev] [RFC 12/24] vhost: move slave_req_fd field to AF_UNIX transport

[Stefan Hajnoczi <stefanha@redhat.com>]

The slave request file descriptor is specific to the AF_UNIX transport.
Move the field out of struct virtio_net and into the trans_af_unix.c
private struct vhost_user_connection struct.

This change will allow future transports to implement the slave request
fd without relying on socket I/O.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 lib/librte_vhost/vhost.h         | 27 ++++++++++++++++++++++++--
 lib/librte_vhost/trans_af_unix.c | 41 +++++++++++++++++++++++++++++++++++++++-
 lib/librte_vhost/vhost.c         |  3 ++-
 lib/librte_vhost/vhost_user.c    | 18 +-----------------
 4 files changed, 68 insertions(+), 21 deletions(-)

diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
index ac9ceefb9..60e4d10bd 100644
--- a/lib/librte_vhost/vhost.h
+++ b/lib/librte_vhost/vhost.h
@@ -252,6 +252,16 @@ struct vhost_transport_ops {
 	 */
 	int (*socket_start)(struct vhost_user_socket *vsocket);
 
+	/**
+	* Free resources associated with this device.
+	*
+	* @param dev
+	*  vhost device
+	* @param destroy
+	*  0 on device reset, 1 on full cleanup.
+	*/
+	void (*cleanup_device)(struct virtio_net *dev, int destroy);
+
 	/**
 	 * Notify the guest that used descriptors have been added to the vring.
 	 * The VRING_AVAIL_F_NO_INTERRUPT flag has already been checked so this
@@ -290,6 +300,21 @@ struct vhost_transport_ops {
 	 */
 	int (*send_slave_req)(struct virtio_net *dev,
 			      struct VhostUserMsg *req);
+
+	/**
+	 * Process VHOST_USER_SET_SLAVE_REQ_FD message.  After this function
+	 * succeeds send_slave_req() may be called to submit requests to the
+	 * master.
+	 *
+	 * @param dev
+	 *  vhost device
+	 * @param msg
+	 *  message
+	 * @return
+	 *  0 on success, -1 on failure
+	 */
+	int (*set_slave_req_fd)(struct virtio_net *dev,
+				struct VhostUserMsg *msg);
 };
 
 /** The traditional AF_UNIX vhost-user protocol transport. */
@@ -331,8 +356,6 @@ struct virtio_net {
 	uint32_t		nr_guest_pages;
 	uint32_t		max_guest_pages;
 	struct guest_page       *guest_pages;
-
-	int			slave_req_fd;
 } __rte_cache_aligned;
 
 /*
diff --git a/lib/librte_vhost/trans_af_unix.c b/lib/librte_vhost/trans_af_unix.c
index 9e5a5c127..7128e121e 100644
--- a/lib/librte_vhost/trans_af_unix.c
+++ b/lib/librte_vhost/trans_af_unix.c
@@ -57,6 +57,7 @@ struct vhost_user_connection {
 	struct virtio_net device; /* must be the first field! */
 	struct vhost_user_socket *vsocket;
 	int connfd;
+	int slave_req_fd;
 
 	TAILQ_ENTRY(vhost_user_connection) next;
 };
@@ -173,10 +174,32 @@ af_unix_send_reply(struct virtio_net *dev, struct VhostUserMsg *msg)
 static int
 af_unix_send_slave_req(struct virtio_net *dev, struct VhostUserMsg *msg)
 {
-	return send_fd_message(dev->slave_req_fd, msg,
+	struct vhost_user_connection *conn =
+		container_of(dev, struct vhost_user_connection, device);
+
+	return send_fd_message(conn->slave_req_fd, msg,
 			       VHOST_USER_HDR_SIZE + msg->size, NULL, 0);
 }
 
+static int
+af_unix_set_slave_req_fd(struct virtio_net *dev, struct VhostUserMsg *msg)
+{
+	struct vhost_user_connection *conn =
+		container_of(dev, struct vhost_user_connection, device);
+	int fd = msg->fds[0];
+
+	if (fd < 0) {
+		RTE_LOG(ERR, VHOST_CONFIG,
+				"Invalid file descriptor for slave channel (%d)\n",
+				fd);
+		return -1;
+	}
+
+	conn->slave_req_fd = fd;
+
+	return 0;
+}
+
 static void
 vhost_user_add_connection(int fd, struct vhost_user_socket *vsocket)
 {
@@ -194,6 +217,7 @@ vhost_user_add_connection(int fd, struct vhost_user_socket *vsocket)
 
 	conn = container_of(dev, struct vhost_user_connection, device);
 	conn->connfd = fd;
+	conn->slave_req_fd = -1;
 	conn->vsocket = vsocket;
 
 	size = strnlen(vsocket->path, PATH_MAX);
@@ -657,6 +681,19 @@ af_unix_socket_start(struct vhost_user_socket *vsocket)
 		return vhost_user_start_client(vsocket);
 }
 
+static void
+af_unix_cleanup_device(struct virtio_net *dev __rte_unused,
+		       int destroy __rte_unused)
+{
+	struct vhost_user_connection *conn =
+		container_of(dev, struct vhost_user_connection, device);
+
+	if (conn->slave_req_fd >= 0) {
+		close(conn->slave_req_fd);
+		conn->slave_req_fd = -1;
+	}
+}
+
 static int
 af_unix_vring_call(struct virtio_net *dev __rte_unused,
 		   struct vhost_virtqueue *vq)
@@ -672,7 +709,9 @@ const struct vhost_transport_ops af_unix_trans_ops = {
 	.socket_init = af_unix_socket_init,
 	.socket_cleanup = af_unix_socket_cleanup,
 	.socket_start = af_unix_socket_start,
+	.cleanup_device = af_unix_cleanup_device,
 	.vring_call = af_unix_vring_call,
 	.send_reply = af_unix_send_reply,
 	.send_slave_req = af_unix_send_slave_req,
+	.set_slave_req_fd = af_unix_set_slave_req_fd,
 };
diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c
index 1168e137e..0d95a4b3a 100644
--- a/lib/librte_vhost/vhost.c
+++ b/lib/librte_vhost/vhost.c
@@ -96,6 +96,8 @@ cleanup_device(struct virtio_net *dev, int destroy)
 
 	for (i = 0; i < dev->nr_vring; i++)
 		cleanup_vq(dev->virtqueue[i], destroy);
+
+	dev->trans_ops->cleanup_device(dev, destroy);
 }
 
 void
@@ -286,7 +288,6 @@ vhost_new_device(const struct vhost_transport_ops *trans_ops)
 
 	vhost_devices[i] = dev;
 	dev->vid = i;
-	dev->slave_req_fd = -1;
 	dev->trans_ops = trans_ops;
 
 	return dev;
diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index 5f89453bc..ee1b0a1a2 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -96,11 +96,6 @@ vhost_backend_cleanup(struct virtio_net *dev)
 		munmap((void *)(uintptr_t)dev->log_addr, dev->log_size);
 		dev->log_addr = 0;
 	}
-
-	if (dev->slave_req_fd >= 0) {
-		close(dev->slave_req_fd);
-		dev->slave_req_fd = -1;
-	}
 }
 
 /*
@@ -1030,18 +1025,7 @@ vhost_user_net_set_mtu(struct virtio_net *dev, struct VhostUserMsg *msg)
 static int
 vhost_user_set_req_fd(struct virtio_net *dev, struct VhostUserMsg *msg)
 {
-	int fd = msg->fds[0];
-
-	if (fd < 0) {
-		RTE_LOG(ERR, VHOST_CONFIG,
-				"Invalid file descriptor for slave channel (%d)\n",
-				fd);
-		return -1;
-	}
-
-	dev->slave_req_fd = fd;
-
-	return 0;
+	return dev->trans_ops->set_slave_req_fd(dev, msg);
 }
 
 static int
-- 
2.14.3