libxl: change ao_device_remove to ao_device

Introduce a new structure to track state of device backends, that will
be used in following patches on this series.

This structure if used for both device creation and device
destruction and removes libxl__ao_device_remove.

Signed-off-by: Roger Pau Monne <roger.pau@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Campbell <ian.campbell@citrix.com>

1 files changed, 154 insertions, 39 deletions

diff --git a/tools/libxl/libxl_device.c b/tools/libxl/libxl_device.c
index d33ac68545..5a07ffb35b 100644
--- a/tools/libxl/libxl_device.c
+++ b/tools/libxl/libxl_device.c
@@ -361,11 +361,16 @@ int libxl__device_disk_dev_number(const char *virtpath, int *pdisk,
     return -1;
 }
 
+/* Device AO operations */
 
-typedef struct {
-    libxl__ao *ao;
-    libxl__ev_devstate ds;
-} libxl__ao_device_remove;
+void libxl__prepare_ao_device(libxl__ao *ao, libxl__ao_device *aodev)
+{
+    aodev->ao = ao;
+    aodev->rc = 0;
+    aodev->dev = NULL;
+    /* Initialize timer for QEMU Bodge */
+    libxl__ev_time_init(&aodev->timeout);
+}
 
 int libxl__device_destroy(libxl__gc *gc, libxl__device *dev)
 {
@@ -441,36 +446,81 @@ out:
 
 /* Callbacks for device related operations */
 
-static void device_remove_callback(libxl__egc *egc, libxl__ev_devstate *ds,
+/*
+ * device_backend_callback is the main callback entry point, for both device
+ * addition and removal. It gets called if we reach the desired state
+ * (XenbusStateClosed or XenbusStateInitWait). After that, all this
+ * functions get called in the order displayed below.
+ *
+ * If new device types are added, they should only need to modify the
+ * specific hotplug scripts call, which can be found in each OS specific
+ * file. If this new devices don't need a hotplug script, no modification
+ * should be needed.
+ */
+
+/* This callback is part of the Qemu devices Badge */
+static void device_qemu_timeout(libxl__egc *egc, libxl__ev_time *ev,
+                                const struct timeval *requested_abs);
+
+static void device_backend_callback(libxl__egc *egc, libxl__ev_devstate *ds,
                                    int rc);
 
-static void device_remove_cleanup(libxl__gc *gc,
-                                  libxl__ao_device_remove *aorm);
+static void device_backend_cleanup(libxl__gc *gc,
+                                   libxl__ao_device *aodev);
 
-int libxl__initiate_device_remove(libxl__egc *egc, libxl__ao *ao,
-                                  libxl__device *dev)
+static void device_hotplug_done(libxl__egc *egc, libxl__ao_device *aodev);
+
+void libxl__initiate_device_remove(libxl__egc *egc,
+                                   libxl__ao_device *aodev)
 {
-    AO_GC;
+    STATE_AO_GC(aodev->ao);
     xs_transaction_t t = 0;
-    char *be_path = libxl__device_backend_path(gc, dev);
+    char *be_path = libxl__device_backend_path(gc, aodev->dev);
     char *state_path = libxl__sprintf(gc, "%s/state", be_path);
     char *online_path = GCSPRINTF("%s/online", be_path);
     const char *state;
-
+    libxl_dominfo info;
+    uint32_t domid = aodev->dev->domid;
     int rc = 0;
-    libxl__ao_device_remove *aorm = 0;
+
+    libxl_dominfo_init(&info);
+    rc = libxl_domain_info(CTX, &info, domid);
+    if (rc) {
+        LOG(ERROR, "unable to get info for domain %d", domid);
+        goto out;
+    }
+    if (QEMU_BACKEND(aodev->dev) &&
+        (info.paused || info.dying || info.shutdown)) {
+        /*
+         * TODO: 4.2 Bodge due to QEMU, see comment on top of
+         * libxl__initiate_device_remove in libxl_internal.h
+         */
+        rc = libxl__ev_time_register_rel(gc, &aodev->timeout,
+                                         device_qemu_timeout,
+                                         LIBXL_QEMU_BODGE_TIMEOUT * 1000);
+        if (rc) {
+            LOG(ERROR, "unable to register timeout for Qemu device %s",
+                       be_path);
+            goto out;
+        }
+        return;
+    }
 
     for (;;) {
         rc = libxl__xs_transaction_start(gc, &t);
         if (rc) {
             LOG(ERROR, "unable to start transaction");
-            goto out_fail;
+            goto out;
         }
 
+        if (aodev->force)
+            libxl__xs_path_cleanup(gc, t,
+                                   libxl__device_frontend_path(gc, aodev->dev));
+
         rc = libxl__xs_read_checked(gc, t, state_path, &state);
         if (rc) {
             LOG(ERROR, "unable to read device state from path %s", state_path);
-            goto out_fail;
+            goto out;
         }
 
         /*
@@ -481,53 +531,118 @@ int libxl__initiate_device_remove(libxl__egc *egc, libxl__ao *ao,
             rc = libxl__xs_write_checked(gc, t, online_path, "0");
             if (rc) {
                 LOG(ERROR, "unable to write to xenstore path %s", online_path);
-                goto out_fail;
+                goto out;
             }
             rc = libxl__xs_write_checked(gc, t, state_path, "5");
             if (rc) {
                 LOG(ERROR, "unable to write to xenstore path %s", state_path);
-                goto out_fail;
+                goto out;
             }
         }
 
         rc = libxl__xs_transaction_commit(gc, &t);
         if (!rc) break;
-        if (rc < 0) goto out_fail;
+        if (rc < 0) goto out;
     }
 
     libxl__device_destroy_tapdisk(gc, be_path);
 
-    aorm = libxl__zalloc(gc, sizeof(*aorm));
-    aorm->ao = ao;
-    libxl__ev_devstate_init(&aorm->ds);
-
-    rc = libxl__ev_devstate_wait(gc, &aorm->ds, device_remove_callback,
+    rc = libxl__ev_devstate_wait(gc, &aodev->backend_ds,
+                                 device_backend_callback,
                                  state_path, XenbusStateClosed,
                                  LIBXL_DESTROY_TIMEOUT * 1000);
-    if (rc) goto out_fail;
+    if (rc) {
+        LOG(ERROR, "unable to remove device %s", be_path);
+        goto out;
+    }
 
-    libxl__ao_complete(egc, ao, 0);
-    return 0;
+    libxl_dominfo_dispose(&info);
+    return;
 
- out_fail:
-    assert(rc);
+out:
+    aodev->rc = rc;
+    libxl_dominfo_dispose(&info);
     libxl__xs_transaction_abort(gc, &t);
-    device_remove_cleanup(gc, aorm);
-    return rc;
+    device_hotplug_done(egc, aodev);
+    return;
+}
+
+static void device_qemu_timeout(libxl__egc *egc, libxl__ev_time *ev,
+                                const struct timeval *requested_abs)
+{
+    libxl__ao_device *aodev = CONTAINER_OF(ev, *aodev, timeout);
+    STATE_AO_GC(aodev->ao);
+    char *be_path = libxl__device_backend_path(gc, aodev->dev);
+    char *state_path = GCSPRINTF("%s/state", be_path);
+    int rc = 0;
+
+    libxl__ev_time_deregister(gc, &aodev->timeout);
+
+    rc = libxl__xs_write_checked(gc, XBT_NULL, state_path, "6");
+    if (rc) goto out;
+
+out:
+    aodev->rc = rc;
+    device_hotplug_done(egc, aodev);
 }
 
-static void device_remove_callback(libxl__egc *egc, libxl__ev_devstate *ds,
+static void device_backend_callback(libxl__egc *egc, libxl__ev_devstate *ds,
                                    int rc) {
-    libxl__ao_device_remove *aorm = CONTAINER_OF(ds, *aorm, ds);
-    libxl__gc *gc = &aorm->ao->gc;
-    libxl__ao_complete(egc, aorm->ao, rc);
-    device_remove_cleanup(gc, aorm);
+    libxl__ao_device *aodev = CONTAINER_OF(ds, *aodev, backend_ds);
+    STATE_AO_GC(aodev->ao);
+
+    device_backend_cleanup(gc, aodev);
+
+    if (rc == ERROR_TIMEDOUT && aodev->action == DEVICE_DISCONNECT &&
+        !aodev->force) {
+        aodev->force = 1;
+        libxl__initiate_device_remove(egc, aodev);
+        return;
+    }
+
+    if (rc) {
+        LOG(ERROR, "unable to disconnect device with path %s",
+                   libxl__device_backend_path(gc, aodev->dev));
+        goto out;
+    }
+
+out:
+    aodev->rc = rc;
+    device_hotplug_done(egc, aodev);
+    return;
 }
 
-static void device_remove_cleanup(libxl__gc *gc,
-                                  libxl__ao_device_remove *aorm) {
-    if (!aorm) return;
-    libxl__ev_devstate_cancel(gc, &aorm->ds);
+static void device_backend_cleanup(libxl__gc *gc, libxl__ao_device *aodev)
+{
+    if (!aodev) return;
+    libxl__ev_devstate_cancel(gc, &aodev->backend_ds);
+}
+
+static void device_hotplug_done(libxl__egc *egc, libxl__ao_device *aodev)
+{
+    STATE_AO_GC(aodev->ao);
+    char *be_path = libxl__device_backend_path(gc, aodev->dev);
+    char *fe_path = libxl__device_frontend_path(gc, aodev->dev);
+    xs_transaction_t t = 0;
+    int rc;
+
+    if (aodev->action == DEVICE_DISCONNECT) {
+        for (;;) {
+            rc = libxl__xs_transaction_start(gc, &t);
+            if (rc) goto out;
+
+            libxl__xs_path_cleanup(gc, t, fe_path);
+            libxl__xs_path_cleanup(gc, t, be_path);
+
+            rc = libxl__xs_transaction_commit(gc, &t);
+            if (!rc) break;
+            if (rc < 0) goto out;
+        }
+    }
+
+out:
+    aodev->callback(egc, aodev);
+    return;
 }
 
 int libxl__wait_for_device_model(libxl__gc *gc,