qemu-nbd: Pass max connections to blockdev layer

The next patch wants to adjust whether the NBD server code advertises MULTI_CONN based on whether it is known if the server limits to exactly one client. For a server started by QMP, this information is obtained through nbd_server_start (which can support more than one export); but for qemu-nbd (which supports exactly one export), it is controlled only by the command-line option -e/--shared. Since we already have a hook function used by qemu-nbd, it's easiest to just alter its signature to fit our needs. Signed-off-by: Eric Blake <[email protected]> Message-Id: <[email protected]> Signed-off-by: Kevin Wolf <[email protected]>
antangelo · May 12, 2022 · a5fced4 · a5fced4
1 parent 46609b9
commit a5fced4
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Showing 3 changed files with 6 additions and 6 deletions.
diff --git a/blockdev-nbd.c b/blockdev-nbd.c
@@ -30,18 +30,18 @@ typedef struct NBDServerData {
 } NBDServerData;
 
 static NBDServerData *nbd_server;
-static bool is_qemu_nbd;
+static int qemu_nbd_connections = -1; /* Non-negative if this is qemu-nbd */
 
 static void nbd_update_server_watch(NBDServerData *s);
 
-void nbd_server_is_qemu_nbd(bool value)
+void nbd_server_is_qemu_nbd(int max_connections)
 {
-    is_qemu_nbd = value;
+    qemu_nbd_connections = max_connections;
 }
 
 bool nbd_server_is_running(void)
 {
-    return nbd_server || is_qemu_nbd;
+    return nbd_server || qemu_nbd_connections >= 0;
 }
 
 static void nbd_blockdev_client_closed(NBDClient *client, bool ignored)

diff --git a/include/block/nbd.h b/include/block/nbd.h
@@ -344,7 +344,7 @@ void nbd_client_new(QIOChannelSocket *sioc,
 void nbd_client_get(NBDClient *client);
 void nbd_client_put(NBDClient *client);
 
-void nbd_server_is_qemu_nbd(bool value);
+void nbd_server_is_qemu_nbd(int max_connections);
 bool nbd_server_is_running(void);
 void nbd_server_start(SocketAddress *addr, const char *tls_creds,
                       const char *tls_authz, uint32_t max_connections,

diff --git a/qemu-nbd.c b/qemu-nbd.c
@@ -1095,7 +1095,7 @@ int main(int argc, char **argv)
 
     bs->detect_zeroes = detect_zeroes;
 
-    nbd_server_is_qemu_nbd(true);
+    nbd_server_is_qemu_nbd(shared);
 
     export_opts = g_new(BlockExportOptions, 1);
     *export_opts = (BlockExportOptions) {