block/nbd: reuse nbd_co_do_establish_connection() in nbd_open()

The only last step we need to reuse the function is coroutine-wrapper.
nbd_open() may be called from non-coroutine context. So, generate the
wrapper and use it.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210610100802.5888-31-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>

2 files changed, 11 insertions, 98 deletions

diff --git a/block/coroutines.h b/block/coroutines.h
index 4cfb494..514d169 100644
--- a/block/coroutines.h
+++ b/block/coroutines.h
@@ -66,4 +66,10 @@ int coroutine_fn bdrv_co_readv_vmstate(BlockDriverState *bs,
 int coroutine_fn bdrv_co_writev_vmstate(BlockDriverState *bs,
                                         QEMUIOVector *qiov, int64_t pos);
 
+int generated_co_wrapper
+nbd_do_establish_connection(BlockDriverState *bs, Error **errp);
+int coroutine_fn
+nbd_co_do_establish_connection(BlockDriverState *bs, Error **errp);
+
+
 #endif /* BLOCK_COROUTINES_INT_H */
diff --git a/block/nbd.c b/block/nbd.c
index bf2e939..5e7e238 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -44,6 +44,7 @@
 #include "block/qdict.h"
 #include "block/nbd.h"
 #include "block/block_int.h"
+#include "block/coroutines.h"
 
 #include "qemu/yank.h"
 
@@ -99,11 +100,6 @@ typedef struct BDRVNBDState {
     NBDClientConnection *conn;
 } BDRVNBDState;
 
-static QIOChannelSocket *nbd_establish_connection(BlockDriverState *bs,
-                                                  SocketAddress *saddr,
-                                                  Error **errp);
-static int nbd_client_handshake(BlockDriverState *bs, QIOChannelSocket *sioc,
-                                Error **errp);
 static void nbd_yank(void *opaque);
 
 static void nbd_clear_bdrvstate(BlockDriverState *bs)
@@ -356,8 +352,8 @@ static int nbd_handle_updated_info(BlockDriverState *bs, Error **errp)
     return 0;
 }
 
-static int coroutine_fn nbd_co_do_establish_connection(BlockDriverState *bs,
-                                                       Error **errp)
+int coroutine_fn nbd_co_do_establish_connection(BlockDriverState *bs,
+                                                Error **errp)
 {
     BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
     int ret;
@@ -1573,83 +1569,6 @@ static void nbd_client_close(BlockDriverState *bs)
     nbd_teardown_connection(bs);
 }
 
-static QIOChannelSocket *nbd_establish_connection(BlockDriverState *bs,
-                                                  SocketAddress *saddr,
-                                                  Error **errp)
-{
-    ERRP_GUARD();
-    QIOChannelSocket *sioc;
-
-    sioc = qio_channel_socket_new();
-    qio_channel_set_name(QIO_CHANNEL(sioc), "nbd-client");
-
-    qio_channel_socket_connect_sync(sioc, saddr, errp);
-    if (*errp) {
-        object_unref(OBJECT(sioc));
-        return NULL;
-    }
-
-    yank_register_function(BLOCKDEV_YANK_INSTANCE(bs->node_name), nbd_yank, bs);
-    qio_channel_set_delay(QIO_CHANNEL(sioc), false);
-
-    return sioc;
-}
-
-/* nbd_client_handshake takes ownership on sioc. */
-static int nbd_client_handshake(BlockDriverState *bs, QIOChannelSocket *sioc,
-                                Error **errp)
-{
-    BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
-    AioContext *aio_context = bdrv_get_aio_context(bs);
-    int ret;
-
-    trace_nbd_client_handshake(s->export);
-    qio_channel_set_blocking(QIO_CHANNEL(sioc), false, NULL);
-    qio_channel_attach_aio_context(QIO_CHANNEL(sioc), aio_context);
-
-    s->info.request_sizes = true;
-    s->info.structured_reply = true;
-    s->info.base_allocation = true;
-    s->info.x_dirty_bitmap = g_strdup(s->x_dirty_bitmap);
-    s->info.name = g_strdup(s->export ?: "");
-    ret = nbd_receive_negotiate(aio_context, QIO_CHANNEL(sioc), s->tlscreds,
-                                s->hostname, &s->ioc, &s->info, errp);
-    g_free(s->info.x_dirty_bitmap);
-    g_free(s->info.name);
-    if (ret < 0) {
-        yank_unregister_function(BLOCKDEV_YANK_INSTANCE(bs->node_name),
-                                 nbd_yank, bs);
-        object_unref(OBJECT(sioc));
-        return ret;
-    }
-
-    if (s->ioc) {
-        /* sioc is referenced by s->ioc */
-        object_unref(OBJECT(sioc));
-    } else {
-        s->ioc = QIO_CHANNEL(sioc);
-    }
-    sioc = NULL;
-
-    ret = nbd_handle_updated_info(bs, errp);
-    if (ret < 0) {
-        /*
-         * We have connected, but must fail for other reasons.
-         * Send NBD_CMD_DISC as a courtesy to the server.
-         */
-        NBDRequest request = { .type = NBD_CMD_DISC };
-
-        nbd_send_request(s->ioc, &request);
-
-        yank_unregister_function(BLOCKDEV_YANK_INSTANCE(bs->node_name),
-                                 nbd_yank, bs);
-        object_unref(OBJECT(s->ioc));
-        s->ioc = NULL;
-        return ret;
-    }
-
-    return 0;
-}
 
 /*
  * Parse nbd_open options
@@ -2039,7 +1958,6 @@ static int nbd_open(BlockDriverState *bs, QDict *options, int flags,
 {
     int ret;
     BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
-    QIOChannelSocket *sioc;
 
     s->bs = bs;
     qemu_co_mutex_init(&s->send_mutex);
@@ -2057,22 +1975,11 @@ static int nbd_open(BlockDriverState *bs, QDict *options, int flags,
     s->conn = nbd_client_connection_new(s->saddr, true, s->export,
                                         s->x_dirty_bitmap, s->tlscreds);
 
-    /*
-     * establish TCP connection, return error if it fails
-     * TODO: Configurable retry-until-timeout behaviour.
-     */
-    sioc = nbd_establish_connection(bs, s->saddr, errp);
-    if (!sioc) {
-        ret = -ECONNREFUSED;
-        goto fail;
-    }
-
-    ret = nbd_client_handshake(bs, sioc, errp);
+    /* TODO: Configurable retry-until-timeout behaviour. */
+    ret = nbd_do_establish_connection(bs, errp);
     if (ret < 0) {
         goto fail;
     }
-    /* successfully connected */
-    s->state = NBD_CLIENT_CONNECTED;
 
     s->connection_co = qemu_coroutine_create(nbd_connection_entry, s);
     bdrv_inc_in_flight(bs);