libxl: convert libxl_device_disk_add to an async op

This patch converts libxl_device_disk_add to an ao operation that
waits for device backend to reach state XenbusStateInitWait and then
marks the operation as completed. This is not really useful now, but
will be used by later patches that will launch hotplug scripts after
we reached the desired xenbus state.

As usual, libxl_device_disk_add callers have been modified, and the
internal function libxl__device_disk_add has been used if the call was
inside an already running ao.

Signed-off-by: Roger Pau Monne <roger.pau@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
[ ijc -- drop hunk modifying libxl_cdrom_insert which is not needed after
         25670:3666e9712eaf "libxl: make libxl_cdrom_insert async" ]
Committed-by: Ian Campbell <ian.campbell@citrix.com>

1 files changed, 37 insertions, 2 deletions

diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 03a32faad4..19a9cdc39c 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -72,6 +72,7 @@
 #include "_libxl_types_internal.h"
 #include "_libxl_types_internal_json.h"
 
+#define LIBXL_INIT_TIMEOUT 10
 #define LIBXL_DESTROY_TIMEOUT 10
 #define LIBXL_DEVICE_MODEL_START_TIMEOUT 10
 #define LIBXL_QEMU_BODGE_TIMEOUT 2
@@ -1338,8 +1339,6 @@ _hidden void libxl__device_destroy_tapdisk(libxl__gc *gc, char *be_path);
 _hidden int libxl__device_from_disk(libxl__gc *gc, uint32_t domid,
                                    libxl_device_disk *disk,
                                    libxl__device *device);
-_hidden int libxl__device_disk_add(libxl__gc *gc, uint32_t domid,
-                                   libxl_device_disk *disk);
 
 _hidden char *libxl__uuid2string(libxl__gc *gc, const libxl_uuid uuid);
 
@@ -1923,6 +1922,27 @@ struct libxl__ao_devices {
  *                   DONE.
  */
 
+/* AO operation to connect a disk device, called by
+ * libxl_device_disk_add and libxl__add_disks. This function calls
+ * libxl__wait_device_connection to wait for the device to
+ * finish the connection (might involve executing hotplug scripts).
+ *
+ * Once finished, aodev->callback will be executed.
+ */
+_hidden void libxl__device_disk_add(libxl__egc *egc, uint32_t domid,
+                                    libxl_device_disk *disk,
+                                    libxl__ao_device *aodev);
+
+/* Waits for the passed device to reach state XenbusStateInitWait.
+ * This is not really useful by itself, but is important when executing
+ * hotplug scripts, since we need to be sure the device is in the correct
+ * state before executing them.
+ *
+ * Once finished, aodev->callback will be executed.
+ */
+_hidden void libxl__wait_device_connection(libxl__egc*,
+                                           libxl__ao_device *aodev);
+
 /* Arranges that dev will be removed to the guest, and the
  * hotplug scripts will be executed (if necessary). When
  * this is done (or an error happens), the callback in
@@ -2295,6 +2315,19 @@ _hidden void libxl__destroy_domid(libxl__egc *egc,
 _hidden void libxl__devices_destroy(libxl__egc *egc,
                                     libxl__devices_remove_state *drs);
 
+/* Helper function to add a bunch of disks. This should be used when
+ * the caller is inside an async op. "devices" will NOT be prepared by this
+ * function, so the caller must make sure to call _prepare before calling this
+ * function. The start parameter contains the position inside the aodevs array
+ * that should be used to store the state of this devices.
+ *
+ * The "callback" will be called for each device, and the user is responsible
+ * for calling libxl__ao_device_check_last on the callback.
+ */
+_hidden void libxl__add_disks(libxl__egc *egc, libxl__ao *ao, uint32_t domid,
+                              int start, libxl_domain_config *d_config,
+                              libxl__ao_devices *aodevs);
+
 /*----- device model creation -----*/
 
 /* First layer; wraps libxl__spawn_spawn. */
@@ -2329,6 +2362,7 @@ typedef struct {
     libxl__domain_build_state dm_state;
     libxl__dm_spawn_state pvqemu;
     libxl__destroy_domid_state dis;
+    libxl__ao_devices aodevs;
 } libxl__stub_dm_spawn_state;
 
 _hidden void libxl__spawn_stub_dm(libxl__egc *egc, libxl__stub_dm_spawn_state*);
@@ -2360,6 +2394,7 @@ struct libxl__domain_create_state {
     libxl__save_helper_state shs;
     /* necessary if the domain creation failed and we have to destroy it */
     libxl__domain_destroy_state dds;
+    libxl__ao_devices aodevs;
 };
 
 /*----- Domain suspend (save) functions -----*/