freebsd-skq/sys/xen/xenbus/xenbusb_if.m
gibbs c8e3d11e24 Monitor and emit events for XenStore changes to XenBus trees
of the devices we manage.  These changes can be due to writes
we make ourselves or due to changes made by the control domain.
The goal of these changes is to insure that all state transitions
can be detected regardless of their source and to allow common
device policies (e.g. "onlined" backend devices) to be centralized
in the XenBus bus code.

sys/xen/xenbus/xenbusvar.h:
sys/xen/xenbus/xenbus.c:
sys/xen/xenbus/xenbus_if.m:
	Add a new method for XenBus drivers "localend_changed".
	This method is invoked whenever a write is detected to
	a device's XenBus tree.  The default implementation of
	this method is a no-op.

sys/xen/xenbus/xenbus_if.m:
sys/dev/xen/netfront/netfront.c:
sys/dev/xen/blkfront/blkfront.c:
sys/dev/xen/blkback/blkback.c:
	Change the signature of the "otherend_changed" method.
	This notification cannot fail, so it should return void.

sys/xen/xenbus/xenbusb_back.c:
	Add "online" device handling to the XenBus Back Bus
	support code.  An online backend device remains active
	after a front-end detaches as a reconnect is expected
	to occur in the near future.

sys/xen/interface/io/xenbus.h:
	Add comment block further explaining the meaning and
	driver responsibilities associated with the XenBus
	Closed state.

sys/xen/xenbus/xenbusb.c:
sys/xen/xenbus/xenbusb.h:
sys/xen/xenbus/xenbusb_back.c:
sys/xen/xenbus/xenbusb_front.c:
sys/xen/xenbus/xenbusb_if.m:
	o Register a XenStore watch against the local XenBus tree
	  for all devices.
	o Cache the string length of the path to our local tree.
	o Allow the xenbus front and back drivers to hook/filter both
	  local and otherend watch processing.
	o Update the device ivar version of "state" when we detect
	  a XenStore update of that node.

sys/dev/xen/control/control.c:
sys/xen/xenbus/xenbus.c:
sys/xen/xenbus/xenbusb.c:
sys/xen/xenbus/xenbusb.h:
sys/xen/xenbus/xenbusvar.h:
sys/xen/xenstore/xenstorevar.h:
	Allow clients of the XenStore watch mechanism to attach
	a single uintptr_t worth of client data to the watch.
	This removes the need to carefully place client watch
	data within enclosing objects so that a cast or offsetof
	calculation can be used to convert from watch to enclosing
	object.

Sponsored by:	Spectra Logic Corporation
MFC after:	1 week
2011-06-11 04:59:01 +00:00

112 lines
3.9 KiB
Objective-C

#-
# Copyright (c) 2010 Spectra Logic Corporation
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
# notice, this list of conditions, and the following disclaimer,
# without modification.
# 2. Redistributions in binary form must reproduce at minimum a disclaimer
# substantially similar to the "NO WARRANTY" disclaimer below
# ("Disclaimer") and any redistribution must be conditioned upon
# including a substantially similar Disclaimer requirement for further
# binary redistribution.
#
# NO WARRANTY
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
# STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
# IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGES.
#
# $FreeBSD$
#
#include <sys/bus.h>
#include <sys/lock.h>
#include <sys/sx.h>
#include <sys/taskqueue.h>
#include <xen/xenstore/xenstorevar.h>
#include <xen/xenbus/xenbusb.h>
INTERFACE xenbusb;
/**
* \brief Enumerate all devices of the given type on this bus.
*
* \param _dev NewBus device_t for this XenBus (front/back) bus instance.
* \param _type String indicating the device sub-tree (e.g. "vfb", "vif")
* to enumerate.
*
* \return On success, 0. Otherwise an errno value indicating the
* type of failure.
*
* Devices that are found should be entered into the NewBus hierarchy via
* xenbusb_add_device(). xenbusb_add_device() ignores duplicate detects
* and ignores duplicate devices, so it can be called unconditionally
* for any device found in the XenStore.
*/
METHOD int enumerate_type {
device_t _dev;
const char *_type;
};
/**
* \brief Determine and store the XenStore path for the other end of
* a split device whose local end is represented by ivars.
*
* If successful, the xd_otherend_path field of the child's instance
* variables must be updated.
*
* \param _dev NewBus device_t for this XenBus (front/back) bus instance.
* \param _ivars Instance variables from the XenBus child device for
* which to perform this function.
*
* \return On success, 0. Otherwise an errno value indicating the
* type of failure.
*/
METHOD int get_otherend_node {
device_t _dev;
struct xenbus_device_ivars *_ivars;
}
/**
* \brief Handle a XenStore change detected in the peer tree of a child
* device of the bus.
*
* \param _bus NewBus device_t for this XenBus (front/back) bus instance.
* \param _child NewBus device_t for the child device whose peer XenStore
* tree has changed.
* \param _state The current state of the peer.
*/
METHOD void otherend_changed {
device_t _bus;
device_t _child;
enum xenbus_state _state;
} DEFAULT xenbusb_otherend_changed;
/**
* \brief Handle a XenStore change detected in the local tree of a child
* device of the bus.
*
* \param _bus NewBus device_t for this XenBus (front/back) bus instance.
* \param _child NewBus device_t for the child device whose peer XenStore
* tree has changed.
* \param _path The tree relative sub-path to the modified node. The empty
* string indicates the root of the tree was destroyed.
*/
METHOD void localend_changed {
device_t _bus;
device_t _child;
const char * _path;
} DEFAULT xenbusb_localend_changed;