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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 25 of 29 RFC] libxl: add libxl_hotplug_dispatch
On Thu, 2 Feb 2012, Roger Pau Monné wrote:
> 2012/2/2 Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>:
> > On Thu, 2 Feb 2012, Roger Pau Monne wrote:
> >> # HG changeset patch
> >> # User Roger Pau Monne <roger.pau@xxxxxxxxxxxxx>
> >> # Date 1328179686 -3600
> >> # Node ID 94532199f647fc03816fc5ae50ab53c8c5b80cd8
> >> # Parent  1506b1f2ab0fe5f4cd5bcd86a566d5a7be5f838b
> >> libxl: add libxl_hotplug_dispatch
> >>
> >> Added a new function to libxl API to handle device hotplug. Actions to
> >> execute upon hotplug device state changes are handled using the
> >> libxl_device_disk_hotplug_actions and libxl_device_nic_hotplug_actions
> >> depending on the type of device. Currently only VIF and VBD devices
> >> are handled by the hotplug mechanism.
> >>
> >> Signed-off-by: Roger Pau Monne <roger.pau@xxxxxxxxxxxxx>
> >>
> >> diff -r 1506b1f2ab0f -r 94532199f647 tools/libxl/libxl.c
> >> --- a/tools/libxl/libxl.c    Thu Feb 02 11:45:03 2012 +0100
> >> +++ b/tools/libxl/libxl.c    Thu Feb 02 11:48:06 2012 +0100
> >> @@ -982,6 +982,188 @@ out:
> >> Â Â Â return rc;
> >> Â }
> >>
> >> +static int libxl__hotplug_generic_dispatcher(libxl__gc *gc, char *path,
> >> + Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â uint32_t domid,
> >> + Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â libxl__hotplug_status
> >> state,
> >> + Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
> >> Â libxl__device_generic_hotplug_actions *action,
> >> + Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â void *device)
> >> +{
> >> + Â Â libxl_ctx *ctx = libxl__gc_owner(gc);
> >> + Â Â char *spath = libxl__sprintf(gc, "%s/state", path);
> >> + Â Â int rc = 0;
> >> +
> >> + Â Â LIBXL__LOG(ctx, LIBXL__LOG_DEBUG, "processing device %s with state
> >> %d",
> >> + Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â path, state);
> >> + Â Â switch(state) {
> >> + Â Â case HOTPLUG_DEVICE_INIT:
> >> + Â Â Â Â if (action->init) {
> >> + Â Â Â Â Â Â rc = action->init(ctx, domid, device);
> >> + Â Â Â Â Â Â if (rc < 0) {
> >> + Â Â Â Â Â Â Â Â LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "unable to init"
> >> + Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
> >> Â " device %s", path);
> >> + Â Â Â Â Â Â Â Â libxl__xs_write(gc, XBT_NULL, spath, "%d",
> >> + Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â HOTPLUG_DEVICE_ERROR);
> >> + Â Â Â Â Â Â Â Â break;
> >> + Â Â Â Â Â Â }
> >> + Â Â Â Â }
> >> + Â Â Â Â libxl__xs_write(gc, XBT_NULL, spath, "%d",
> >> HOTPLUG_DEVICE_CONNECT);
> >> + Â Â Â Â break;
> >> + Â Â case HOTPLUG_DEVICE_CONNECT:
> >> + Â Â Â Â if (action->connect) {
> >> + Â Â Â Â Â Â rc = action->connect(ctx, domid, device);
> >> + Â Â Â Â Â Â if (rc < 0) {
> >> + Â Â Â Â Â Â Â Â LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "unable to
> >> connect"
> >> + Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
> >> Â " device %s", path);
> >> + Â Â Â Â Â Â Â Â libxl__xs_write(gc, XBT_NULL, spath, "%d",
> >> + Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â HOTPLUG_DEVICE_ERROR);
> >> + Â Â Â Â Â Â Â Â break;
> >> + Â Â Â Â Â Â }
> >> + Â Â Â Â }
> >> + Â Â Â Â libxl__xs_write(gc, XBT_NULL, spath, "%d",
> >> HOTPLUG_DEVICE_CONNECTED);
> >> + Â Â Â Â break;
> >> + Â Â case HOTPLUG_DEVICE_CONNECTED:
> >> + Â Â Â Â if (action->connected) {
> >> + Â Â Â Â Â Â rc = action->connected(ctx, domid, device);
> >> + Â Â Â Â Â Â if (rc < 0) {
> >> + Â Â Â Â Â Â Â Â LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "unable to
> >> execute "
> >> + Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
> >> Â "connected action on"
> >> + Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
> >> Â " device %s", path);
> >> + Â Â Â Â Â Â Â Â libxl__xs_write(gc, XBT_NULL, spath, "%d",
> >> + Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â HOTPLUG_DEVICE_ERROR);
> >> + Â Â Â Â Â Â Â Â break;
> >> + Â Â Â Â Â Â }
> >> + Â Â Â Â }
> >> + Â Â Â Â break;
> >> + Â Â case HOTPLUG_DEVICE_DISCONNECT:
> >> + Â Â Â Â if (action->disconnect) {
> >> + Â Â Â Â Â Â rc = action->disconnect(ctx, domid, device);
> >> + Â Â Â Â Â Â if (rc < 0) {
> >> + Â Â Â Â Â Â Â Â LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "unable to
> >> unplug"
> >> + Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
> >> Â " device %s", path);
> >> + Â Â Â Â Â Â Â Â libxl__xs_write(gc, XBT_NULL, spath, "%d",
> >> + Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â HOTPLUG_DEVICE_ERROR);
> >> + Â Â Â Â Â Â Â Â break;
> >> + Â Â Â Â Â Â }
> >> + Â Â Â Â }
> >> + Â Â Â Â libxl__xs_write(gc, XBT_NULL, spath, "%d",
> >> + Â Â Â Â Â Â Â Â Â Â Â Â HOTPLUG_DEVICE_DISCONNECTED);
> >> + Â Â Â Â break;
> >> + Â Â case HOTPLUG_DEVICE_DISCONNECTED:
> >> + Â Â Â Â if (action->disconnected) {
> >> + Â Â Â Â Â Â rc = action->disconnected(ctx, domid, device);
> >> + Â Â Â Â Â Â if (rc < 0) {
> >> + Â Â Â Â Â Â Â Â LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "unable to
> >> execute "
> >> + Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
> >> Â "unpluged action on"
> >> + Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
> >> Â " device %s", path);
> >> + Â Â Â Â Â Â Â Â libxl__xs_write(gc, XBT_NULL, spath, "%d",
> >> + Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â HOTPLUG_DEVICE_ERROR);
> >> + Â Â Â Â Â Â Â Â break;
> >> + Â Â Â Â Â Â }
> >> + Â Â Â Â }
> >> + Â Â Â Â break;
> >> + Â Â case HOTPLUG_DEVICE_FORCE_DISCONNECT:
> >> + Â Â Â Â if (action->force_disconnect) {
> >> + Â Â Â Â Â Â rc = action->force_disconnect(ctx, domid, device);
> >> + Â Â Â Â Â Â if (rc < 0) {
> >> + Â Â Â Â Â Â Â Â LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "unable to
> >> force "
> >> + Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
> >> Â "disconnect device "
> >> + Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
> >> Â "%s", path);
> >> + Â Â Â Â Â Â Â Â libxl__xs_write(gc, XBT_NULL, spath, "%d",
> >> + Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â HOTPLUG_DEVICE_ERROR);
> >> + Â Â Â Â Â Â Â Â break;
> >> + Â Â Â Â Â Â }
> >> + Â Â Â Â }
> >> + Â Â Â Â libxl__xs_write(gc, XBT_NULL, spath, "%d",
> >> + Â Â Â Â Â Â Â Â Â Â Â Â HOTPLUG_DEVICE_DISCONNECTED);
> >> + Â Â Â Â break;
> >> + Â Â case HOTPLUG_DEVICE_ERROR:
> >> + Â Â Â Â if (action->error)
> >> + Â Â Â Â Â Â rc = action->error(ctx, domid, device);
> >> + Â Â Â Â break;
> >> + Â Â }
> >> + Â Â return rc;
> >
> > I can see that we are writing an error code to xenstore in case of
> > errors, but I fail to see where we are writing back a positive response.
> > Of course the caller of libxl_device_disk/nic_hotplug_add could watch
> > the backend state waiting for it to come up, but I think that having an
> > explicit ACK under /hotplug would be much better.
>
> The Sequence is the following, but I'm not really sure this is the
> most correct way. All states can go to HOTPLUG_DEVICE_ERROR, and the
> following state changes:
>
> HOTPLUG_DEVICE_INIT no state change
> HOTPLUG_DEVICE_CONNECT -> HOTPLUG_DEVICE_CONNECTED (on success)
> HOTPLUG_DEVICE_CONNECTED no change
> HOTPLUG_DEVICE_DISCONNECT -> HOTPLUG_DEVICE_DISCONNECTED (on success)
> HOTPLUG_DEVICE_FORCE_DISCONNECT -> HOTPLUG_DEVICE_DISCONNECTED (on success)
I see: it is the same as before but under the hotplug path. Somehow I
missed the code that is handling all that, however it is not a bad idea
to keep the same protocol._______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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