mirror of https://gitee.com/openkylin/linux.git
570 lines
16 KiB
C
570 lines
16 KiB
C
/******************************************************************************
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* Client-facing interface for the Xenbus driver. In other words, the
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* interface between the Xenbus and the device-specific code, be it the
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* frontend or the backend of that driver.
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*
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* Copyright (C) 2005 XenSource Ltd
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation; or, when distributed
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* separately from the Linux kernel or incorporated into other
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* software packages, subject to the following license:
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this source file (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use, copy, modify,
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* merge, publish, distribute, sublicense, and/or sell copies of the Software,
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* and to permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*/
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#include <linux/types.h>
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#include <linux/vmalloc.h>
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#include <asm/xen/hypervisor.h>
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#include <xen/interface/xen.h>
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#include <xen/interface/event_channel.h>
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#include <xen/events.h>
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#include <xen/grant_table.h>
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#include <xen/xenbus.h>
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const char *xenbus_strstate(enum xenbus_state state)
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{
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static const char *const name[] = {
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[ XenbusStateUnknown ] = "Unknown",
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[ XenbusStateInitialising ] = "Initialising",
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[ XenbusStateInitWait ] = "InitWait",
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[ XenbusStateInitialised ] = "Initialised",
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[ XenbusStateConnected ] = "Connected",
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[ XenbusStateClosing ] = "Closing",
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[ XenbusStateClosed ] = "Closed",
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};
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return (state < ARRAY_SIZE(name)) ? name[state] : "INVALID";
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}
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EXPORT_SYMBOL_GPL(xenbus_strstate);
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/**
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* xenbus_watch_path - register a watch
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* @dev: xenbus device
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* @path: path to watch
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* @watch: watch to register
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* @callback: callback to register
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*
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* Register a @watch on the given path, using the given xenbus_watch structure
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* for storage, and the given @callback function as the callback. Return 0 on
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* success, or -errno on error. On success, the given @path will be saved as
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* @watch->node, and remains the caller's to free. On error, @watch->node will
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* be NULL, the device will switch to %XenbusStateClosing, and the error will
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* be saved in the store.
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*/
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int xenbus_watch_path(struct xenbus_device *dev, const char *path,
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struct xenbus_watch *watch,
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void (*callback)(struct xenbus_watch *,
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const char **, unsigned int))
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{
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int err;
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watch->node = path;
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watch->callback = callback;
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err = register_xenbus_watch(watch);
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if (err) {
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watch->node = NULL;
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watch->callback = NULL;
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xenbus_dev_fatal(dev, err, "adding watch on %s", path);
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}
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return err;
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}
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EXPORT_SYMBOL_GPL(xenbus_watch_path);
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/**
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* xenbus_watch_pathfmt - register a watch on a sprintf-formatted path
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* @dev: xenbus device
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* @watch: watch to register
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* @callback: callback to register
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* @pathfmt: format of path to watch
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*
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* Register a watch on the given @path, using the given xenbus_watch
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* structure for storage, and the given @callback function as the callback.
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* Return 0 on success, or -errno on error. On success, the watched path
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* (@path/@path2) will be saved as @watch->node, and becomes the caller's to
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* kfree(). On error, watch->node will be NULL, so the caller has nothing to
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* free, the device will switch to %XenbusStateClosing, and the error will be
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* saved in the store.
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*/
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int xenbus_watch_pathfmt(struct xenbus_device *dev,
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struct xenbus_watch *watch,
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void (*callback)(struct xenbus_watch *,
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const char **, unsigned int),
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const char *pathfmt, ...)
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{
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int err;
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va_list ap;
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char *path;
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va_start(ap, pathfmt);
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path = kvasprintf(GFP_NOIO | __GFP_HIGH, pathfmt, ap);
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va_end(ap);
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if (!path) {
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xenbus_dev_fatal(dev, -ENOMEM, "allocating path for watch");
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return -ENOMEM;
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}
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err = xenbus_watch_path(dev, path, watch, callback);
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if (err)
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kfree(path);
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return err;
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}
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EXPORT_SYMBOL_GPL(xenbus_watch_pathfmt);
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/**
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* xenbus_switch_state
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* @dev: xenbus device
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* @xbt: transaction handle
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* @state: new state
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*
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* Advertise in the store a change of the given driver to the given new_state.
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* Return 0 on success, or -errno on error. On error, the device will switch
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* to XenbusStateClosing, and the error will be saved in the store.
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*/
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int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state state)
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{
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/* We check whether the state is currently set to the given value, and
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if not, then the state is set. We don't want to unconditionally
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write the given state, because we don't want to fire watches
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unnecessarily. Furthermore, if the node has gone, we don't write
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to it, as the device will be tearing down, and we don't want to
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resurrect that directory.
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Note that, because of this cached value of our state, this function
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will not work inside a Xenstore transaction (something it was
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trying to in the past) because dev->state would not get reset if
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the transaction was aborted.
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*/
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int current_state;
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int err;
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if (state == dev->state)
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return 0;
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err = xenbus_scanf(XBT_NIL, dev->nodename, "state", "%d",
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¤t_state);
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if (err != 1)
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return 0;
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err = xenbus_printf(XBT_NIL, dev->nodename, "state", "%d", state);
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if (err) {
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if (state != XenbusStateClosing) /* Avoid looping */
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xenbus_dev_fatal(dev, err, "writing new state");
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return err;
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}
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dev->state = state;
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return 0;
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}
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EXPORT_SYMBOL_GPL(xenbus_switch_state);
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int xenbus_frontend_closed(struct xenbus_device *dev)
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{
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xenbus_switch_state(dev, XenbusStateClosed);
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complete(&dev->down);
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return 0;
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}
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EXPORT_SYMBOL_GPL(xenbus_frontend_closed);
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/**
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* Return the path to the error node for the given device, or NULL on failure.
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* If the value returned is non-NULL, then it is the caller's to kfree.
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*/
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static char *error_path(struct xenbus_device *dev)
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{
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return kasprintf(GFP_KERNEL, "error/%s", dev->nodename);
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}
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static void xenbus_va_dev_error(struct xenbus_device *dev, int err,
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const char *fmt, va_list ap)
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{
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int ret;
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unsigned int len;
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char *printf_buffer = NULL;
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char *path_buffer = NULL;
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#define PRINTF_BUFFER_SIZE 4096
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printf_buffer = kmalloc(PRINTF_BUFFER_SIZE, GFP_KERNEL);
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if (printf_buffer == NULL)
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goto fail;
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len = sprintf(printf_buffer, "%i ", -err);
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ret = vsnprintf(printf_buffer+len, PRINTF_BUFFER_SIZE-len, fmt, ap);
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BUG_ON(len + ret > PRINTF_BUFFER_SIZE-1);
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dev_err(&dev->dev, "%s\n", printf_buffer);
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path_buffer = error_path(dev);
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if (path_buffer == NULL) {
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dev_err(&dev->dev, "failed to write error node for %s (%s)\n",
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dev->nodename, printf_buffer);
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goto fail;
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}
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if (xenbus_write(XBT_NIL, path_buffer, "error", printf_buffer) != 0) {
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dev_err(&dev->dev, "failed to write error node for %s (%s)\n",
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dev->nodename, printf_buffer);
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goto fail;
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}
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fail:
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kfree(printf_buffer);
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kfree(path_buffer);
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}
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/**
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* xenbus_dev_error
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* @dev: xenbus device
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* @err: error to report
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* @fmt: error message format
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*
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* Report the given negative errno into the store, along with the given
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* formatted message.
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*/
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void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt, ...)
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{
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va_list ap;
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va_start(ap, fmt);
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xenbus_va_dev_error(dev, err, fmt, ap);
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va_end(ap);
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}
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EXPORT_SYMBOL_GPL(xenbus_dev_error);
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/**
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* xenbus_dev_fatal
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* @dev: xenbus device
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* @err: error to report
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* @fmt: error message format
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*
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* Equivalent to xenbus_dev_error(dev, err, fmt, args), followed by
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* xenbus_switch_state(dev, NULL, XenbusStateClosing) to schedule an orderly
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* closedown of this driver and its peer.
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*/
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void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt, ...)
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{
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va_list ap;
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va_start(ap, fmt);
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xenbus_va_dev_error(dev, err, fmt, ap);
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va_end(ap);
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xenbus_switch_state(dev, XenbusStateClosing);
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}
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EXPORT_SYMBOL_GPL(xenbus_dev_fatal);
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/**
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* xenbus_grant_ring
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* @dev: xenbus device
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* @ring_mfn: mfn of ring to grant
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* Grant access to the given @ring_mfn to the peer of the given device. Return
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* 0 on success, or -errno on error. On error, the device will switch to
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* XenbusStateClosing, and the error will be saved in the store.
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*/
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int xenbus_grant_ring(struct xenbus_device *dev, unsigned long ring_mfn)
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{
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int err = gnttab_grant_foreign_access(dev->otherend_id, ring_mfn, 0);
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if (err < 0)
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xenbus_dev_fatal(dev, err, "granting access to ring page");
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return err;
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}
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EXPORT_SYMBOL_GPL(xenbus_grant_ring);
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/**
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* Allocate an event channel for the given xenbus_device, assigning the newly
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* created local port to *port. Return 0 on success, or -errno on error. On
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* error, the device will switch to XenbusStateClosing, and the error will be
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* saved in the store.
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*/
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int xenbus_alloc_evtchn(struct xenbus_device *dev, int *port)
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{
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struct evtchn_alloc_unbound alloc_unbound;
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int err;
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alloc_unbound.dom = DOMID_SELF;
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alloc_unbound.remote_dom = dev->otherend_id;
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err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
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&alloc_unbound);
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if (err)
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xenbus_dev_fatal(dev, err, "allocating event channel");
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else
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*port = alloc_unbound.port;
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return err;
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}
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EXPORT_SYMBOL_GPL(xenbus_alloc_evtchn);
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/**
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* Bind to an existing interdomain event channel in another domain. Returns 0
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* on success and stores the local port in *port. On error, returns -errno,
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* switches the device to XenbusStateClosing, and saves the error in XenStore.
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*/
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int xenbus_bind_evtchn(struct xenbus_device *dev, int remote_port, int *port)
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{
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struct evtchn_bind_interdomain bind_interdomain;
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int err;
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bind_interdomain.remote_dom = dev->otherend_id;
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bind_interdomain.remote_port = remote_port;
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err = HYPERVISOR_event_channel_op(EVTCHNOP_bind_interdomain,
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&bind_interdomain);
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if (err)
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xenbus_dev_fatal(dev, err,
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"binding to event channel %d from domain %d",
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remote_port, dev->otherend_id);
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else
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*port = bind_interdomain.local_port;
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return err;
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}
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EXPORT_SYMBOL_GPL(xenbus_bind_evtchn);
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/**
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* Free an existing event channel. Returns 0 on success or -errno on error.
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*/
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int xenbus_free_evtchn(struct xenbus_device *dev, int port)
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{
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struct evtchn_close close;
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int err;
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close.port = port;
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err = HYPERVISOR_event_channel_op(EVTCHNOP_close, &close);
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if (err)
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xenbus_dev_error(dev, err, "freeing event channel %d", port);
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return err;
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}
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EXPORT_SYMBOL_GPL(xenbus_free_evtchn);
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/**
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* xenbus_map_ring_valloc
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* @dev: xenbus device
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* @gnt_ref: grant reference
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* @vaddr: pointer to address to be filled out by mapping
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*
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* Based on Rusty Russell's skeleton driver's map_page.
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* Map a page of memory into this domain from another domain's grant table.
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* xenbus_map_ring_valloc allocates a page of virtual address space, maps the
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* page to that address, and sets *vaddr to that address.
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* Returns 0 on success, and GNTST_* (see xen/include/interface/grant_table.h)
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* or -ENOMEM on error. If an error is returned, device will switch to
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* XenbusStateClosing and the error message will be saved in XenStore.
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*/
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int xenbus_map_ring_valloc(struct xenbus_device *dev, int gnt_ref, void **vaddr)
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{
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struct gnttab_map_grant_ref op = {
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.flags = GNTMAP_host_map,
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.ref = gnt_ref,
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.dom = dev->otherend_id,
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};
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struct vm_struct *area;
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*vaddr = NULL;
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area = xen_alloc_vm_area(PAGE_SIZE);
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if (!area)
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return -ENOMEM;
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op.host_addr = (unsigned long)area->addr;
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if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
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BUG();
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if (op.status != GNTST_okay) {
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xen_free_vm_area(area);
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xenbus_dev_fatal(dev, op.status,
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"mapping in shared page %d from domain %d",
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gnt_ref, dev->otherend_id);
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return op.status;
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}
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/* Stuff the handle in an unused field */
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area->phys_addr = (unsigned long)op.handle;
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*vaddr = area->addr;
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return 0;
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}
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EXPORT_SYMBOL_GPL(xenbus_map_ring_valloc);
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/**
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* xenbus_map_ring
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* @dev: xenbus device
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* @gnt_ref: grant reference
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* @handle: pointer to grant handle to be filled
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* @vaddr: address to be mapped to
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*
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* Map a page of memory into this domain from another domain's grant table.
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* xenbus_map_ring does not allocate the virtual address space (you must do
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* this yourself!). It only maps in the page to the specified address.
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* Returns 0 on success, and GNTST_* (see xen/include/interface/grant_table.h)
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* or -ENOMEM on error. If an error is returned, device will switch to
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* XenbusStateClosing and the error message will be saved in XenStore.
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*/
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int xenbus_map_ring(struct xenbus_device *dev, int gnt_ref,
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grant_handle_t *handle, void *vaddr)
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{
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struct gnttab_map_grant_ref op = {
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.host_addr = (unsigned long)vaddr,
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.flags = GNTMAP_host_map,
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.ref = gnt_ref,
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.dom = dev->otherend_id,
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};
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if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
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BUG();
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if (op.status != GNTST_okay) {
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xenbus_dev_fatal(dev, op.status,
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"mapping in shared page %d from domain %d",
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gnt_ref, dev->otherend_id);
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} else
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*handle = op.handle;
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return op.status;
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}
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EXPORT_SYMBOL_GPL(xenbus_map_ring);
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/**
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* xenbus_unmap_ring_vfree
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* @dev: xenbus device
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* @vaddr: addr to unmap
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*
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* Based on Rusty Russell's skeleton driver's unmap_page.
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* Unmap a page of memory in this domain that was imported from another domain.
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* Use xenbus_unmap_ring_vfree if you mapped in your memory with
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* xenbus_map_ring_valloc (it will free the virtual address space).
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* Returns 0 on success and returns GNTST_* on error
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* (see xen/include/interface/grant_table.h).
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*/
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int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr)
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{
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struct vm_struct *area;
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struct gnttab_unmap_grant_ref op = {
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.host_addr = (unsigned long)vaddr,
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};
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/* It'd be nice if linux/vmalloc.h provided a find_vm_area(void *addr)
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* method so that we don't have to muck with vmalloc internals here.
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* We could force the user to hang on to their struct vm_struct from
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* xenbus_map_ring_valloc, but these 6 lines considerably simplify
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* this API.
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*/
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read_lock(&vmlist_lock);
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for (area = vmlist; area != NULL; area = area->next) {
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if (area->addr == vaddr)
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break;
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}
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read_unlock(&vmlist_lock);
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if (!area) {
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xenbus_dev_error(dev, -ENOENT,
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"can't find mapped virtual address %p", vaddr);
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return GNTST_bad_virt_addr;
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}
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|
|
op.handle = (grant_handle_t)area->phys_addr;
|
|
|
|
if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
|
|
BUG();
|
|
|
|
if (op.status == GNTST_okay)
|
|
xen_free_vm_area(area);
|
|
else
|
|
xenbus_dev_error(dev, op.status,
|
|
"unmapping page at handle %d error %d",
|
|
(int16_t)area->phys_addr, op.status);
|
|
|
|
return op.status;
|
|
}
|
|
EXPORT_SYMBOL_GPL(xenbus_unmap_ring_vfree);
|
|
|
|
|
|
/**
|
|
* xenbus_unmap_ring
|
|
* @dev: xenbus device
|
|
* @handle: grant handle
|
|
* @vaddr: addr to unmap
|
|
*
|
|
* Unmap a page of memory in this domain that was imported from another domain.
|
|
* Returns 0 on success and returns GNTST_* on error
|
|
* (see xen/include/interface/grant_table.h).
|
|
*/
|
|
int xenbus_unmap_ring(struct xenbus_device *dev,
|
|
grant_handle_t handle, void *vaddr)
|
|
{
|
|
struct gnttab_unmap_grant_ref op = {
|
|
.host_addr = (unsigned long)vaddr,
|
|
.handle = handle,
|
|
};
|
|
|
|
if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
|
|
BUG();
|
|
|
|
if (op.status != GNTST_okay)
|
|
xenbus_dev_error(dev, op.status,
|
|
"unmapping page at handle %d error %d",
|
|
handle, op.status);
|
|
|
|
return op.status;
|
|
}
|
|
EXPORT_SYMBOL_GPL(xenbus_unmap_ring);
|
|
|
|
|
|
/**
|
|
* xenbus_read_driver_state
|
|
* @path: path for driver
|
|
*
|
|
* Return the state of the driver rooted at the given store path, or
|
|
* XenbusStateUnknown if no state can be read.
|
|
*/
|
|
enum xenbus_state xenbus_read_driver_state(const char *path)
|
|
{
|
|
enum xenbus_state result;
|
|
int err = xenbus_gather(XBT_NIL, path, "state", "%d", &result, NULL);
|
|
if (err)
|
|
result = XenbusStateUnknown;
|
|
|
|
return result;
|
|
}
|
|
EXPORT_SYMBOL_GPL(xenbus_read_driver_state);
|