X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;ds=sidebyside;f=drivers%2Fxen%2Fxenbus%2Fxenbus_client.c;fp=drivers%2Fxen%2Fxenbus%2Fxenbus_client.c;h=24661a861b98eb081e81bfb8a2b5f634277e0ad6;hb=1db395853d4f30d6120458bd279ede1f882a8525;hp=0000000000000000000000000000000000000000;hpb=34a75f0025b9cf803b6a88db032e6ad6950c9313;p=linux-2.6.git diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c new file mode 100644 index 000000000..24661a861 --- /dev/null +++ b/drivers/xen/xenbus/xenbus_client.c @@ -0,0 +1,281 @@ +/****************************************************************************** + * Client-facing interface for the Xenbus driver. In other words, the + * interface between the Xenbus and the device-specific code, be it the + * frontend or the backend of that driver. + * + * Copyright (C) 2005 XenSource Ltd + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License version 2 + * as published by the Free Software Foundation; or, when distributed + * separately from the Linux kernel or incorporated into other + * software packages, subject to the following license: + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this source file (the "Software"), to deal in the Software without + * restriction, including without limitation the rights to use, copy, modify, + * merge, publish, distribute, sublicense, and/or sell copies of the Software, + * and to permit persons to whom the Software is furnished to do so, subject to + * the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS + * IN THE SOFTWARE. + */ + +#include +#include +#include +#include + +/* xenbus_probe.c */ +extern char *kasprintf(const char *fmt, ...); + +#define DPRINTK(fmt, args...) \ + pr_debug("xenbus_client (%s:%d) " fmt ".\n", __FUNCTION__, __LINE__, ##args) + +int xenbus_watch_path(struct xenbus_device *dev, const char *path, + struct xenbus_watch *watch, + void (*callback)(struct xenbus_watch *, + const char **, unsigned int)) +{ + int err; + + watch->node = path; + watch->callback = callback; + + err = register_xenbus_watch(watch); + + if (err) { + watch->node = NULL; + watch->callback = NULL; + xenbus_dev_fatal(dev, err, "adding watch on %s", path); + } + + return err; +} +EXPORT_SYMBOL_GPL(xenbus_watch_path); + + +int xenbus_watch_path2(struct xenbus_device *dev, const char *path, + const char *path2, struct xenbus_watch *watch, + void (*callback)(struct xenbus_watch *, + const char **, unsigned int)) +{ + int err; + char *state = kasprintf("%s/%s", path, path2); + if (!state) { + xenbus_dev_fatal(dev, -ENOMEM, "allocating path for watch"); + return -ENOMEM; + } + err = xenbus_watch_path(dev, state, watch, callback); + + if (err) + kfree(state); + return err; +} +EXPORT_SYMBOL_GPL(xenbus_watch_path2); + + +int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state state) +{ + /* We check whether the state is currently set to the given value, and + if not, then the state is set. We don't want to unconditionally + write the given state, because we don't want to fire watches + unnecessarily. Furthermore, if the node has gone, we don't write + to it, as the device will be tearing down, and we don't want to + resurrect that directory. + + Note that, because of this cached value of our state, this function + will not work inside a Xenstore transaction (something it was + trying to in the past) because dev->state would not get reset if + the transaction was aborted. + + */ + + int current_state; + int err; + + if (state == dev->state) + return 0; + + err = xenbus_scanf(XBT_NIL, dev->nodename, "state", "%d", + ¤t_state); + if (err != 1) + return 0; + + err = xenbus_printf(XBT_NIL, dev->nodename, "state", "%d", state); + if (err) { + if (state != XenbusStateClosing) /* Avoid looping */ + xenbus_dev_fatal(dev, err, "writing new state"); + return err; + } + + dev->state = state; + + return 0; +} +EXPORT_SYMBOL_GPL(xenbus_switch_state); + + +/** + * Return the path to the error node for the given device, or NULL on failure. + * If the value returned is non-NULL, then it is the caller's to kfree. + */ +static char *error_path(struct xenbus_device *dev) +{ + return kasprintf("error/%s", dev->nodename); +} + + +void _dev_error(struct xenbus_device *dev, int err, const char *fmt, + va_list ap) +{ + int ret; + unsigned int len; + char *printf_buffer = NULL, *path_buffer = NULL; + +#define PRINTF_BUFFER_SIZE 4096 + printf_buffer = kmalloc(PRINTF_BUFFER_SIZE, GFP_KERNEL); + if (printf_buffer == NULL) + goto fail; + + len = sprintf(printf_buffer, "%i ", -err); + ret = vsnprintf(printf_buffer+len, PRINTF_BUFFER_SIZE-len, fmt, ap); + + BUG_ON(len + ret > PRINTF_BUFFER_SIZE-1); + + dev_err(&dev->dev, "%s\n", printf_buffer); + + path_buffer = error_path(dev); + + if (path_buffer == NULL) { + printk("xenbus: failed to write error node for %s (%s)\n", + dev->nodename, printf_buffer); + goto fail; + } + + if (xenbus_write(XBT_NIL, path_buffer, "error", printf_buffer) != 0) { + printk("xenbus: failed to write error node for %s (%s)\n", + dev->nodename, printf_buffer); + goto fail; + } + +fail: + if (printf_buffer) + kfree(printf_buffer); + if (path_buffer) + kfree(path_buffer); +} + + +void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt, + ...) +{ + va_list ap; + + va_start(ap, fmt); + _dev_error(dev, err, fmt, ap); + va_end(ap); +} +EXPORT_SYMBOL_GPL(xenbus_dev_error); + + +void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt, + ...) +{ + va_list ap; + + va_start(ap, fmt); + _dev_error(dev, err, fmt, ap); + va_end(ap); + + xenbus_switch_state(dev, XenbusStateClosing); +} +EXPORT_SYMBOL_GPL(xenbus_dev_fatal); + + +int xenbus_grant_ring(struct xenbus_device *dev, unsigned long ring_mfn) +{ + int err = gnttab_grant_foreign_access(dev->otherend_id, ring_mfn, 0); + if (err < 0) + xenbus_dev_fatal(dev, err, "granting access to ring page"); + return err; +} +EXPORT_SYMBOL_GPL(xenbus_grant_ring); + + +int xenbus_alloc_evtchn(struct xenbus_device *dev, int *port) +{ + struct evtchn_alloc_unbound alloc_unbound; + int err; + + alloc_unbound.dom = DOMID_SELF; + alloc_unbound.remote_dom = dev->otherend_id; + + err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound, + &alloc_unbound); + if (err) + xenbus_dev_fatal(dev, err, "allocating event channel"); + else + *port = alloc_unbound.port; + + return err; +} +EXPORT_SYMBOL_GPL(xenbus_alloc_evtchn); + + +int xenbus_bind_evtchn(struct xenbus_device *dev, int remote_port, int *port) +{ + struct evtchn_bind_interdomain bind_interdomain; + int err; + + bind_interdomain.remote_dom = dev->otherend_id; + bind_interdomain.remote_port = remote_port, + + err = HYPERVISOR_event_channel_op(EVTCHNOP_bind_interdomain, + &bind_interdomain); + if (err) + xenbus_dev_fatal(dev, err, + "binding to event channel %d from domain %d", + remote_port, dev->otherend_id); + else + *port = bind_interdomain.local_port; + + return err; +} +EXPORT_SYMBOL_GPL(xenbus_bind_evtchn); + + +int xenbus_free_evtchn(struct xenbus_device *dev, int port) +{ + struct evtchn_close close; + int err; + + close.port = port; + + err = HYPERVISOR_event_channel_op(EVTCHNOP_close, &close); + if (err) + xenbus_dev_error(dev, err, "freeing event channel %d", port); + + return err; +} + + +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 = XenbusStateClosed; + + return result; +} +EXPORT_SYMBOL_GPL(xenbus_read_driver_state);