[PATCH v4 09/26] vhost: introduce backend ops

[Maxime Coquelin]

This patch introduces backend ops struct, that will enable
calling backend specifics callbacks (Vhost-user, VDUSE), in
shared code.

This is an empty shell for now, it will be filled in later
patches.

Signed-off-by: Maxime Coquelin <maxime.coque...@redhat.com>
Reviewed-by: Chenbo Xia <chenbo....@intel.com>
---
 lib/vhost/socket.c     |  2 +-
 lib/vhost/vhost.c      |  8 +++++++-
 lib/vhost/vhost.h      | 10 +++++++++-
 lib/vhost/vhost_user.c |  8 ++++++++
 lib/vhost/vhost_user.h |  1 +
 5 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/lib/vhost/socket.c b/lib/vhost/socket.c
index cb0218b7bc..407d0011c3 100644
--- a/lib/vhost/socket.c
+++ b/lib/vhost/socket.c
@@ -223,7 +223,7 @@ vhost_user_add_connection(int fd, struct vhost_user_socket 
*vsocket)
                return;
        }
 
-       vid = vhost_new_device();
+       vid = vhost_user_new_device();
        if (vid == -1) {
                goto err;
        }
diff --git a/lib/vhost/vhost.c b/lib/vhost/vhost.c
index 7e1af487c1..d054772bf8 100644
--- a/lib/vhost/vhost.c
+++ b/lib/vhost/vhost.c
@@ -680,11 +680,16 @@ reset_device(struct virtio_net *dev)
  * there is a new virtio device being attached).
  */
 int
-vhost_new_device(void)
+vhost_new_device(struct vhost_backend_ops *ops)
 {
        struct virtio_net *dev;
        int i;
 
+       if (ops == NULL) {
+               VHOST_LOG_CONFIG("device", ERR, "missing backend ops.\n");
+               return -1;
+       }
+
        pthread_mutex_lock(&vhost_dev_lock);
        for (i = 0; i < RTE_MAX_VHOST_DEVICE; i++) {
                if (vhost_devices[i] == NULL)
@@ -712,6 +717,7 @@ vhost_new_device(void)
        dev->backend_req_fd = -1;
        dev->postcopy_ufd = -1;
        rte_spinlock_init(&dev->backend_req_lock);
+       dev->backend_ops = ops;
 
        return i;
 }
diff --git a/lib/vhost/vhost.h b/lib/vhost/vhost.h
index de84c115b7..966b6dd67a 100644
--- a/lib/vhost/vhost.h
+++ b/lib/vhost/vhost.h
@@ -89,6 +89,12 @@
        for (iter = val; iter < num; iter++)
 #endif
 
+/**
+ * Structure that contains backend-specific ops.
+ */
+struct vhost_backend_ops {
+};
+
 /**
  * Structure contains buffer address, length and descriptor index
  * from vring to do scatter RX.
@@ -516,6 +522,8 @@ struct virtio_net {
        void                    *extern_data;
        /* pre and post vhost user message handlers for the device */
        struct rte_vhost_user_extern_ops extern_ops;
+
+       struct vhost_backend_ops *backend_ops;
 } __rte_cache_aligned;
 
 static inline void
@@ -815,7 +823,7 @@ get_device(int vid)
        return dev;
 }
 
-int vhost_new_device(void);
+int vhost_new_device(struct vhost_backend_ops *ops);
 void cleanup_device(struct virtio_net *dev, int destroy);
 void reset_device(struct virtio_net *dev);
 void vhost_destroy_device(int);
diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
index 98d8b8ac79..2cd86686a5 100644
--- a/lib/vhost/vhost_user.c
+++ b/lib/vhost/vhost_user.c
@@ -3464,3 +3464,11 @@ int rte_vhost_host_notifier_ctrl(int vid, uint16_t qid, 
bool enable)
 
        return ret;
 }
+
+static struct vhost_backend_ops vhost_user_backend_ops;
+
+int
+vhost_user_new_device(void)
+{
+       return vhost_new_device(&vhost_user_backend_ops);
+}
diff --git a/lib/vhost/vhost_user.h b/lib/vhost/vhost_user.h
index a0987a58f9..61456049c8 100644
--- a/lib/vhost/vhost_user.h
+++ b/lib/vhost/vhost_user.h
@@ -185,5 +185,6 @@ int vhost_user_iotlb_miss(struct virtio_net *dev, uint64_t 
iova, uint8_t perm);
 int read_fd_message(char *ifname, int sockfd, char *buf, int buflen, int *fds, 
int max_fds,
                int *fd_num);
 int send_fd_message(char *ifname, int sockfd, char *buf, int buflen, int *fds, 
int fd_num);
+int vhost_user_new_device(void);
 
 #endif
-- 
2.40.1