/*
* Initial xendev setup. Read frontend path, register watch for it.
* Should succeed once xend finished setting up the backend device.
*
* Also sets initial state (-> Initializing) when done. Which
* only affects the xendev->be_state variable as xenbus should
* already be put into that state by xend.
*/
static int xen_be_try_setup(struct XenDevice *xendev)
{
char token[XEN_BUFSIZE];
int be_state;
if (xenstore_read_be_int(xendev, "state", &be_state) == -1) {
xen_be_printf(xendev, 0, "reading backend state failed\n");
return -1;
}
if (be_state != XenbusStateInitialising) {
xen_be_printf(xendev, 0, "initial backend state is wrong (%s)\n",
xenbus_strstate(be_state));
return -1;
}
xendev->fe = xenstore_read_be_str(xendev, "frontend");
if (xendev->fe == NULL) {
xen_be_printf(xendev, 0, "reading frontend path failed\n");
return -1;
}
/* setup frontend watch */
snprintf(token, sizeof(token), "fe:%p", xendev);
if (!xs_watch(xenstore, xendev->fe, token)) {
xen_be_printf(xendev, 0, "watching frontend path (%s) failed\n",
xendev->fe);
return -1;
}
xen_be_set_state(xendev, XenbusStateInitialising);
xen_be_backend_changed(xendev, NULL);
xen_be_frontend_changed(xendev, NULL);
return 0;
}
static void blk_parse_discard(struct XenBlkDev *blkdev)
{
struct XenDevice *xendev = &blkdev->xendev;
int enable;
blkdev->feature_discard = true;
if (xenstore_read_be_int(xendev, "discard-enable", &enable) == 0) {
blkdev->feature_discard = !!enable;
}
if (blkdev->feature_discard) {
xenstore_write_be_int(xendev, "feature-discard", 1);
}
}
