[PATCH 2/6] libxl: introduce libxl__device_generic_add_t

[Stefano Stabellini <stefano.stabellini@eu.citrix.com>]

Introduce libxl__device_generic_add_t that takes an xs_transaction_t as
parameter.
Use libxl__device_generic_add_t to implement libxl__device_generic_add.


Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
 tools/libxl/libxl_device.c   |   36 ++++++++++++++++++++++++++----------
 tools/libxl/libxl_internal.h |    2 ++
 2 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/tools/libxl/libxl_device.c b/tools/libxl/libxl_device.c
index c2880e0..c6f9044 100644
--- a/tools/libxl/libxl_device.c
+++ b/tools/libxl/libxl_device.c
@@ -61,12 +61,37 @@ int libxl__parse_backend_path(libxl__gc *gc,
 int libxl__device_generic_add(libxl__gc *gc, libxl__device *device,
                              char **bents, char **fents)
 {
+    int rc = 0;
+    xs_transaction_t t;
+    libxl_ctx *ctx = libxl__gc_owner(gc);
+
+retry_transaction:
+    t = xs_transaction_start(ctx->xsh);
+
+    rc = libxl__device_generic_add_t(gc, t, device, bents, fents);
+
+    if (!xs_transaction_end(ctx->xsh, t, 0)) {
+        if (errno == EAGAIN)
+            goto retry_transaction;
+        else
+            LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR, "xs transaction failed");
+    }
+    return rc;
+}
+
+int libxl__device_generic_add_t(libxl__gc *gc, xs_transaction_t t,
+        libxl__device *device, char **bents, char **fents)
+{
     libxl_ctx *ctx = libxl__gc_owner(gc);
     char *frontend_path, *backend_path;
-    xs_transaction_t t;
     struct xs_permissions frontend_perms[2];
     struct xs_permissions backend_perms[2];
 
+    if (t == XBT_NULL)
+        /* we need a valid transaction: call libxl__device_generic_add
+         * to create one for us */
+        return libxl__device_generic_add(gc, device, bents, fents);
+
     frontend_path = libxl__device_frontend_path(gc, device);
     backend_path = libxl__device_backend_path(gc, device);
 
@@ -80,8 +105,6 @@ int libxl__device_generic_add(libxl__gc *gc, libxl__device *device,
     backend_perms[1].id = device->domid;
     backend_perms[1].perms = XS_PERM_READ;
 
-retry_transaction:
-    t = xs_transaction_start(ctx->xsh);
     /* FIXME: read frontend_path and check state before removing stuff */
 
     if (fents) {
@@ -100,13 +123,6 @@ retry_transaction:
         libxl__xs_writev(gc, t, backend_path, bents);
     }
 
-    if (!xs_transaction_end(ctx->xsh, t, 0)) {
-        if (errno == EAGAIN)
-            goto retry_transaction;
-        else
-            LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR, "xs transaction failed");
-    }
-
     return 0;
 }
 
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index e0a1070..f97213f 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -667,6 +667,8 @@ _hidden int libxl__device_console_add(libxl__gc *gc, uint32_t domid,
 
 _hidden int libxl__device_generic_add(libxl__gc *gc, libxl__device *device,
                              char **bents, char **fents);
+_hidden int libxl__device_generic_add_t(libxl__gc *gc, xs_transaction_t t,
+        libxl__device *device, char **bents, char **fents);
 _hidden char *libxl__device_backend_path(libxl__gc *gc, libxl__device *device);
 _hidden char *libxl__device_frontend_path(libxl__gc *gc, libxl__device *device);
 _hidden int libxl__parse_backend_path(libxl__gc *gc, const char *path,
-- 
1.7.2.5