|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 1 of 7 v2] blktap3/tapback: Introduce core defines and structure definitions
diff -r fbf47a5d98ff -r 0777319f0a6e tools/blktap3/tapback/tapback.h
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/blktap3/tapback/tapback.h Fri Jan 04 11:54:51 2013 +0000
@@ -0,0 +1,253 @@
+/*
+ * Copyright (C) 2012 Citrix Ltd.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
+ * USA.
+ */
+
+#ifndef __TAPBACK_H__
+#define __TAPBACK_H__
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <string.h>
+
+#include <xen/xen.h>
+#include <xenstore.h>
+#include <xen/io/xenbus.h>
+#include <xen/event_channel.h>
+#include <xen/grant_table.h>
+
+#include "tap-ctl.h"
+
+void tapback_log(int prio, const char *fmt, ...);
+void (*tapback_vlog) (int prio, const char *fmt, va_list ap);
+
+#define DBG(_fmt, _args...) tapback_log(LOG_DEBUG, "%s:%d "_fmt, __FILE__, \
+ __LINE__, ##_args)
+#define INFO(_fmt, _args...) tapback_log(LOG_INFO, _fmt, ##_args)
+#define WARN(_fmt, _args...) tapback_log(LOG_WARNING, "%s:%d "_fmt, __FILE__, \
+ __LINE__, ##_args)
+
+#define WARN_ON(_cond, fmt, ...) \
+ if (unlikely(_cond)) { \
+ printf(fmt, ##__VA_ARGS__); \
+ }
+
+#define BUG_ON(_cond) \
+ if (unlikely(_cond)) { \
+ assert(0); \
+ }
+
+/*
+ * XenStore path components.
+ *
+ * To avoid confusion with blktap2, we'll use a new kind of device for libxl
+ * defining it in tools/libxl/libxl_types_internal.idl. This will be done by
+ * the patch that adds libxl support for blktap3. TODO When that patch is sent,
+ * use the definition from there instead of hard-coding it here.
+ */
+#define XENSTORE_BACKEND "backend"
+#define BLKTAP3_BACKEND_NAME "xenio"
+#define BLKTAP3_BACKEND_PATH XENSTORE_BACKEND"/"BLKTAP3_BACKEND_NAME
+#define BLKTAP3_BACKEND_TOKEN XENSTORE_BACKEND"-"BLKTAP3_BACKEND_NAME
+#define BLKTAP3_FRONTEND_TOKEN "otherend-state"
+#define BLKTAP3_SERIAL BLKTAP3_BACKEND_NAME"-serial"
+
+/*
+ * TODO Put the rest of the front-end nodes defined in blkif.h here and group
+ * them. e.g. FRONTEND_NODE_xxx.
+ */
+#define RING_REF "ring-ref"
+#define FEAT_PERSIST "feature-persistent"
+
+/**
+ * A Virtual Block Device (VBD), represents a block device in a guest VM.
+ * Contains all relevant information.
+ */
+typedef struct vbd {
+
+ /**
+ * Device name, as retrieved from XenStore at probe-time.
+ */
+ char *name;
+
+ /**
+ * The device ID. Same as vbd.name, we keep it around because the tapdisk
+ * control libreary wants it as an int and not as a string.
+ */
+ int devid;
+
+ /**
+ * For linked lists.
+ */
+ TAILQ_ENTRY(vbd) backend_entry;
+
+ /**
+ * TODO Supposed to solve some kind of race condition with libxl?
+ */
+ long long serial;
+
+ /**
+ * The domain ID this VBD belongs to.
+ */
+ domid_t domid;
+
+ /**
+ * The root directory in XenStore for this VBD. This is where all
+ * directories and key/value pairs related to this VBD are stored.
+ */
+ char *frontend_path;
+
+ /**
+ * XenStore path to the VBD's state. This is just
+ * vbd.frontend_path + "/state", we keep it around so we don't have to
+ * allocate/free memory all the time.
+ */
+ char *frontend_state_path;
+
+ /**
+ * FIXME This is used but isn't initialised anywhere! This reflects
+ * tap_list.minor.
+ */
+ dev_t dev;
+
+ /**
+ * Indicates whether the tapdisk is connected to the shared ring.
+ */
+ bool connected;
+
+ /**
+ * Descriptor of the tapdisk process serving this virtual block device. We
+ * need this until the end of the VBD's lifetime in order to disconnect
+ * the tapdisk from the shared ring.
+ */
+ tap_list_t tap;
+
+ /*
+ * XXX We keep sector_size, sectors, and info because we need to
+ * communicate them to the front-end not only when the front-end goes to
+ * XenbusStateInitialised, but to XenbusStateConnected as well.
+ */
+
+ /**
+ * Sector size, supplied by the tapdisk, communicated to blkfront.
+ */
+ unsigned int sector_size;
+
+ /**
+ * Number of sectors, supplied by the tapdisk, communicated to blkfront.
+ */
+ unsigned long long sectors;
+
+ /**
+ * VDISK_???, defined in include/xen/interface/io/blkif.h.
+ */
+ unsigned int info;
+
+} vbd_t;
+
+TAILQ_HEAD(tqh_vbd, vbd);
+
+/**
+ * The collection of all necessary handles and descriptors.
+ */
+struct _blktap3_daemon {
+
+ /**
+ * A handle to XenStore.
+ */
+ struct xs_handle *xs;
+
+ /**
+ * For executing transacted operations on XenStore.
+ */
+ xs_transaction_t xst;
+
+ /**
+ * The list of virtual block devices.
+ *
+ * TODO We sometimes have to scan the whole list to find the device/domain
+ * we're interested in, should we optimize this? E.g. use a hash table
+ * for O(1) access?
+ */
+ struct tqh_vbd devices;
+
+ /**
+ * For allocating serials.
+ */
+ long long serial;
+
+ /**
+ * TODO From xen/include/public/io/blkif.h: "The maximum supported size of
+ * the request ring buffer"
+ */
+ int max_ring_page_order;
+};
+
+extern struct _blktap3_daemon blktap3_daemon;
+
+#define tapback_backend_for_each_device(_device, _next) \
+ TAILQ_FOREACH_SAFE(_device, &blktap3_daemon.devices, backend_entry,
_next)
+
+/**
+ * Iterates over all devices and returns the one for which the condition is
+ * true.
+ */
+#define tapback_backend_find_device(_device, _cond) \
+do {
\
+ vbd_t *__next;
\
+ int found = 0;
\
+ tapback_backend_for_each_device(_device, __next) { \
+ if (_cond) {
\
+ found = 1;
\
+ break;
\
+ }
\
+ }
\
+ if (!found)
\
+ _device = NULL;
\
+} while (0)
+
+/**
+ * Act in response to a change in the front-end XenStore path.
+ *
+ * @param path the front-end's XenStore path that changed
+ * @returns 0 on success, an error code otherwise
+ *
+ * XXX Only called by tapback_read_watch
+ */
+int
+tapback_backend_handle_otherend_watch(const char * const path);
+
+/**
+ * Act in response to a change in the back-end directory in XenStore.
+ *
+ * If the path is "/backend" or "/backend/<backend name>", all devices are
+ * probed. Otherwise, the path should be
+ * "backend/<backend name>/<domid>/<device name>"
+ * (i.e. backend/<backend name>/1/51712), and in this case this specific device
+ * is probed.
+ *
+ * @param path the back-end's XenStore path that changed @returns 0 on success,
+ * an error code otherwise
+ *
+ * XXX Only called by tapback_read_watch.
+ */
+int
+tapback_backend_handle_backend_watch(char * const path);
+
+#endif /* __TAPBACK_H__ */
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |