diff options
Diffstat (limited to 'drivers/xen/xenbus')
| -rw-r--r-- | drivers/xen/xenbus/Makefile | 7 | ||||
| -rw-r--r-- | drivers/xen/xenbus/xenbus_client.c | 569 | ||||
| -rw-r--r-- | drivers/xen/xenbus/xenbus_comms.c | 233 | ||||
| -rw-r--r-- | drivers/xen/xenbus/xenbus_comms.h | 46 | ||||
| -rw-r--r-- | drivers/xen/xenbus/xenbus_probe.c | 935 | ||||
| -rw-r--r-- | drivers/xen/xenbus/xenbus_probe.h | 74 | ||||
| -rw-r--r-- | drivers/xen/xenbus/xenbus_xs.c | 861 |
7 files changed, 2725 insertions, 0 deletions
diff --git a/drivers/xen/xenbus/Makefile b/drivers/xen/xenbus/Makefile new file mode 100644 index 000000000000..5571f5b84223 --- /dev/null +++ b/drivers/xen/xenbus/Makefile @@ -0,0 +1,7 @@ +obj-y += xenbus.o + +xenbus-objs = +xenbus-objs += xenbus_client.o +xenbus-objs += xenbus_comms.o +xenbus-objs += xenbus_xs.o +xenbus-objs += xenbus_probe.o diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c new file mode 100644 index 000000000000..9fd2f70ab46d --- /dev/null +++ b/drivers/xen/xenbus/xenbus_client.c @@ -0,0 +1,569 @@ +/****************************************************************************** + * 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 <linux/types.h> +#include <linux/vmalloc.h> +#include <asm/xen/hypervisor.h> +#include <xen/interface/xen.h> +#include <xen/interface/event_channel.h> +#include <xen/events.h> +#include <xen/grant_table.h> +#include <xen/xenbus.h> + +const char *xenbus_strstate(enum xenbus_state state) +{ + static const char *const name[] = { + [ XenbusStateUnknown ] = "Unknown", + [ XenbusStateInitialising ] = "Initialising", + [ XenbusStateInitWait ] = "InitWait", + [ XenbusStateInitialised ] = "Initialised", + [ XenbusStateConnected ] = "Connected", + [ XenbusStateClosing ] = "Closing", + [ XenbusStateClosed ] = "Closed", + }; + return (state < ARRAY_SIZE(name)) ? name[state] : "INVALID"; +} +EXPORT_SYMBOL_GPL(xenbus_strstate); + +/** + * xenbus_watch_path - register a watch + * @dev: xenbus device + * @path: path to watch + * @watch: watch to register + * @callback: callback to register + * + * Register a @watch on the given path, using the given xenbus_watch structure + * for storage, and the given @callback function as the callback. Return 0 on + * success, or -errno on error. On success, the given @path will be saved as + * @watch->node, and remains the caller's to free. On error, @watch->node will + * be NULL, the device will switch to %XenbusStateClosing, and the error will + * be saved in the store. + */ +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); + + +/** + * xenbus_watch_pathfmt - register a watch on a sprintf-formatted path + * @dev: xenbus device + * @watch: watch to register + * @callback: callback to register + * @pathfmt: format of path to watch + * + * Register a watch on the given @path, using the given xenbus_watch + * structure for storage, and the given @callback function as the callback. + * Return 0 on success, or -errno on error. On success, the watched path + * (@path/@path2) will be saved as @watch->node, and becomes the caller's to + * kfree(). On error, watch->node will be NULL, so the caller has nothing to + * free, the device will switch to %XenbusStateClosing, and the error will be + * saved in the store. + */ +int xenbus_watch_pathfmt(struct xenbus_device *dev, + struct xenbus_watch *watch, + void (*callback)(struct xenbus_watch *, + const char **, unsigned int), + const char *pathfmt, ...) +{ + int err; + va_list ap; + char *path; + + va_start(ap, pathfmt); + path = kvasprintf(GFP_KERNEL, pathfmt, ap); + va_end(ap); + + if (!path) { + xenbus_dev_fatal(dev, -ENOMEM, "allocating path for watch"); + return -ENOMEM; + } + err = xenbus_watch_path(dev, path, watch, callback); + + if (err) + kfree(path); + return err; +} +EXPORT_SYMBOL_GPL(xenbus_watch_pathfmt); + + +/** + * xenbus_switch_state + * @dev: xenbus device + * @xbt: transaction handle + * @state: new state + * + * Advertise in the store a change of the given driver to the given new_state. + * Return 0 on success, or -errno on error. On error, the device will switch + * to XenbusStateClosing, and the error will be saved in the store. + */ +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); + +int xenbus_frontend_closed(struct xenbus_device *dev) +{ + xenbus_switch_state(dev, XenbusStateClosed); + complete(&dev->down); + return 0; +} +EXPORT_SYMBOL_GPL(xenbus_frontend_closed); + +/** + * 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(GFP_KERNEL, "error/%s", dev->nodename); +} + + +static void xenbus_va_dev_error(struct xenbus_device *dev, int err, + const char *fmt, va_list ap) +{ + int ret; + unsigned int len; + char *printf_buffer = NULL; + char *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) { + dev_err(&dev->dev, "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) { + dev_err(&dev->dev, "failed to write error node for %s (%s)\n", + dev->nodename, printf_buffer); + goto fail; + } + +fail: + kfree(printf_buffer); + kfree(path_buffer); +} + + +/** + * xenbus_dev_error + * @dev: xenbus device + * @err: error to report + * @fmt: error message format + * + * Report the given negative errno into the store, along with the given + * formatted message. + */ +void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt, ...) +{ + va_list ap; + + va_start(ap, fmt); + xenbus_va_dev_error(dev, err, fmt, ap); + va_end(ap); +} +EXPORT_SYMBOL_GPL(xenbus_dev_error); + +/** + * xenbus_dev_fatal + * @dev: xenbus device + * @err: error to report + * @fmt: error message format + * + * Equivalent to xenbus_dev_error(dev, err, fmt, args), followed by + * xenbus_switch_state(dev, NULL, XenbusStateClosing) to schedule an orderly + * closedown of this driver and its peer. + */ + +void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt, ...) +{ + va_list ap; + + va_start(ap, fmt); + xenbus_va_dev_error(dev, err, fmt, ap); + va_end(ap); + + xenbus_switch_state(dev, XenbusStateClosing); +} +EXPORT_SYMBOL_GPL(xenbus_dev_fatal); + +/** + * xenbus_grant_ring + * @dev: xenbus device + * @ring_mfn: mfn of ring to grant + + * Grant access to the given @ring_mfn to the peer of the given device. Return + * 0 on success, or -errno on error. On error, the device will switch to + * XenbusStateClosing, and the error will be saved in the store. + */ +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); + + +/** + * Allocate an event channel for the given xenbus_device, assigning the newly + * created local port to *port. Return 0 on success, or -errno on error. On + * error, the device will switch to XenbusStateClosing, and the error will be + * saved in the store. + */ +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); + + +/** + * Bind to an existing interdomain event channel in another domain. Returns 0 + * on success and stores the local port in *port. On error, returns -errno, + * switches the device to XenbusStateClosing, and saves the error in XenStore. + */ +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); + + +/** + * Free an existing event channel. Returns 0 on success or -errno on error. + */ +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; +} +EXPORT_SYMBOL_GPL(xenbus_free_evtchn); + + +/** + * xenbus_map_ring_valloc + * @dev: xenbus device + * @gnt_ref: grant reference + * @vaddr: pointer to address to be filled out by mapping + * + * Based on Rusty Russell's skeleton driver's map_page. + * Map a page of memory into this domain from another domain's grant table. + * xenbus_map_ring_valloc allocates a page of virtual address space, maps the + * page to that address, and sets *vaddr to that address. + * Returns 0 on success, and GNTST_* (see xen/include/interface/grant_table.h) + * or -ENOMEM on error. If an error is returned, device will switch to + * XenbusStateClosing and the error message will be saved in XenStore. + */ +int xenbus_map_ring_valloc(struct xenbus_device *dev, int gnt_ref, void **vaddr) +{ + struct gnttab_map_grant_ref op = { + .flags = GNTMAP_host_map, + .ref = gnt_ref, + .dom = dev->otherend_id, + }; + struct vm_struct *area; + + *vaddr = NULL; + + area = alloc_vm_area(PAGE_SIZE); + if (!area) + return -ENOMEM; + + op.host_addr = (unsigned long)area->addr; + + if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1)) + BUG(); + + if (op.status != GNTST_okay) { + free_vm_area(area); + xenbus_dev_fatal(dev, op.status, + "mapping in shared page %d from domain %d", + gnt_ref, dev->otherend_id); + return op.status; + } + + /* Stuff the handle in an unused field */ + area->phys_addr = (unsigned long)op.handle; + + *vaddr = area->addr; + return 0; +} +EXPORT_SYMBOL_GPL(xenbus_map_ring_valloc); + + +/** + * xenbus_map_ring + * @dev: xenbus device + * @gnt_ref: grant reference + * @handle: pointer to grant handle to be filled + * @vaddr: address to be mapped to + * + * Map a page of memory into this domain from another domain's grant table. + * xenbus_map_ring does not allocate the virtual address space (you must do + * this yourself!). It only maps in the page to the specified address. + * Returns 0 on success, and GNTST_* (see xen/include/interface/grant_table.h) + * or -ENOMEM on error. If an error is returned, device will switch to + * XenbusStateClosing and the error message will be saved in XenStore. + */ +int xenbus_map_ring(struct xenbus_device *dev, int gnt_ref, + grant_handle_t *handle, void *vaddr) +{ + struct gnttab_map_grant_ref op = { + .host_addr = (unsigned long)vaddr, + .flags = GNTMAP_host_map, + .ref = gnt_ref, + .dom = dev->otherend_id, + }; + + if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1)) + BUG(); + + if (op.status != GNTST_okay) { + xenbus_dev_fatal(dev, op.status, + "mapping in shared page %d from domain %d", + gnt_ref, dev->otherend_id); + } else + *handle = op.handle; + + return op.status; +} +EXPORT_SYMBOL_GPL(xenbus_map_ring); + + +/** + * xenbus_unmap_ring_vfree + * @dev: xenbus device + * @vaddr: addr to unmap + * + * Based on Rusty Russell's skeleton driver's unmap_page. + * Unmap a page of memory in this domain that was imported from another domain. + * Use xenbus_unmap_ring_vfree if you mapped in your memory with + * xenbus_map_ring_valloc (it will free the virtual address space). + * Returns 0 on success and returns GNTST_* on error + * (see xen/include/interface/grant_table.h). + */ +int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr) +{ + struct vm_struct *area; + struct gnttab_unmap_grant_ref op = { + .host_addr = (unsigned long)vaddr, + }; + + /* It'd be nice if linux/vmalloc.h provided a find_vm_area(void *addr) + * method so that we don't have to muck with vmalloc internals here. + * We could force the user to hang on to their struct vm_struct from + * xenbus_map_ring_valloc, but these 6 lines considerably simplify + * this API. + */ + read_lock(&vmlist_lock); + for (area = vmlist; area != NULL; area = area->next) { + if (area->addr == vaddr) + break; + } + read_unlock(&vmlist_lock); + + if (!area) { + xenbus_dev_error(dev, -ENOENT, + "can't find mapped virtual address %p", vaddr); + return GNTST_bad_virt_addr; + } + + 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) + 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); diff --git a/drivers/xen/xenbus/xenbus_comms.c b/drivers/xen/xenbus/xenbus_comms.c new file mode 100644 index 000000000000..6efbe3f29ca5 --- /dev/null +++ b/drivers/xen/xenbus/xenbus_comms.c @@ -0,0 +1,233 @@ +/****************************************************************************** + * xenbus_comms.c + * + * Low level code to talks to Xen Store: ringbuffer and event channel. + * + * Copyright (C) 2005 Rusty Russell, IBM Corporation + * + * 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 <linux/wait.h> +#include <linux/interrupt.h> +#include <linux/sched.h> +#include <linux/err.h> +#include <xen/xenbus.h> +#include <asm/xen/hypervisor.h> +#include <xen/events.h> +#include <xen/page.h> +#include "xenbus_comms.h" + +static int xenbus_irq; + +static DECLARE_WORK(probe_work, xenbus_probe); + +static DECLARE_WAIT_QUEUE_HEAD(xb_waitq); + +static irqreturn_t wake_waiting(int irq, void *unused) +{ + if (unlikely(xenstored_ready == 0)) { + xenstored_ready = 1; + schedule_work(&probe_work); + } + + wake_up(&xb_waitq); + return IRQ_HANDLED; +} + +static int check_indexes(XENSTORE_RING_IDX cons, XENSTORE_RING_IDX prod) +{ + return ((prod - cons) <= XENSTORE_RING_SIZE); +} + +static void *get_output_chunk(XENSTORE_RING_IDX cons, + XENSTORE_RING_IDX prod, + char *buf, uint32_t *len) +{ + *len = XENSTORE_RING_SIZE - MASK_XENSTORE_IDX(prod); + if ((XENSTORE_RING_SIZE - (prod - cons)) < *len) + *len = XENSTORE_RING_SIZE - (prod - cons); + return buf + MASK_XENSTORE_IDX(prod); +} + +static const void *get_input_chunk(XENSTORE_RING_IDX cons, + XENSTORE_RING_IDX prod, + const char *buf, uint32_t *len) +{ + *len = XENSTORE_RING_SIZE - MASK_XENSTORE_IDX(cons); + if ((prod - cons) < *len) + *len = prod - cons; + return buf + MASK_XENSTORE_IDX(cons); +} + +/** + * xb_write - low level write + * @data: buffer to send + * @len: length of buffer + * + * Returns 0 on success, error otherwise. + */ +int xb_write(const void *data, unsigned len) +{ + struct xenstore_domain_interface *intf = xen_store_interface; + XENSTORE_RING_IDX cons, prod; + int rc; + + while (len != 0) { + void *dst; + unsigned int avail; + + rc = wait_event_interruptible( + xb_waitq, + (intf->req_prod - intf->req_cons) != + XENSTORE_RING_SIZE); + if (rc < 0) + return rc; + + /* Read indexes, then verify. */ + cons = intf->req_cons; + prod = intf->req_prod; + if (!check_indexes(cons, prod)) { + intf->req_cons = intf->req_prod = 0; + return -EIO; + } + + dst = get_output_chunk(cons, prod, intf->req, &avail); + if (avail == 0) + continue; + if (avail > len) + avail = len; + + /* Must write data /after/ reading the consumer index. */ + mb(); + + memcpy(dst, data, avail); + data += avail; + len -= avail; + + /* Other side must not see new producer until data is there. */ + wmb(); + intf->req_prod += avail; + + /* Implies mb(): other side will see the updated producer. */ + notify_remote_via_evtchn(xen_store_evtchn); + } + + return 0; +} + +int xb_data_to_read(void) +{ + struct xenstore_domain_interface *intf = xen_store_interface; + return (intf->rsp_cons != intf->rsp_prod); +} + +int xb_wait_for_data_to_read(void) +{ + return wait_event_interruptible(xb_waitq, xb_data_to_read()); +} + +int xb_read(void *data, unsigned len) +{ + struct xenstore_domain_interface *intf = xen_store_interface; + XENSTORE_RING_IDX cons, prod; + int rc; + + while (len != 0) { + unsigned int avail; + const char *src; + + rc = xb_wait_for_data_to_read(); + if (rc < 0) + return rc; + + /* Read indexes, then verify. */ + cons = intf->rsp_cons; + prod = intf->rsp_prod; + if (!check_indexes(cons, prod)) { + intf->rsp_cons = intf->rsp_prod = 0; + return -EIO; + } + + src = get_input_chunk(cons, prod, intf->rsp, &avail); + if (avail == 0) + continue; + if (avail > len) + avail = len; + + /* Must read data /after/ reading the producer index. */ + rmb(); + + memcpy(data, src, avail); + data += avail; + len -= avail; + + /* Other side must not see free space until we've copied out */ + mb(); + intf->rsp_cons += avail; + + pr_debug("Finished read of %i bytes (%i to go)\n", avail, len); + + /* Implies mb(): other side will see the updated consumer. */ + notify_remote_via_evtchn(xen_store_evtchn); + } + + return 0; +} + +/** + * xb_init_comms - Set up interrupt handler off store event channel. + */ +int xb_init_comms(void) +{ + struct xenstore_domain_interface *intf = xen_store_interface; + int err; + + if (intf->req_prod != intf->req_cons) + printk(KERN_ERR "XENBUS request ring is not quiescent " + "(%08x:%08x)!\n", intf->req_cons, intf->req_prod); + + if (intf->rsp_prod != intf->rsp_cons) { + printk(KERN_WARNING "XENBUS response ring is not quiescent " + "(%08x:%08x): fixing up\n", + intf->rsp_cons, intf->rsp_prod); + intf->rsp_cons = intf->rsp_prod; + } + + if (xenbus_irq) + unbind_from_irqhandler(xenbus_irq, &xb_waitq); + + err = bind_evtchn_to_irqhandler( + xen_store_evtchn, wake_waiting, + 0, "xenbus", &xb_waitq); + if (err <= 0) { + printk(KERN_ERR "XENBUS request irq failed %i\n", err); + return err; + } + + xenbus_irq = err; + + return 0; +} diff --git a/drivers/xen/xenbus/xenbus_comms.h b/drivers/xen/xenbus/xenbus_comms.h new file mode 100644 index 000000000000..c21db7513736 --- /dev/null +++ b/drivers/xen/xenbus/xenbus_comms.h @@ -0,0 +1,46 @@ +/* + * Private include for xenbus communications. + * + * Copyright (C) 2005 Rusty Russell, IBM Corporation + * + * 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. + */ + +#ifndef _XENBUS_COMMS_H +#define _XENBUS_COMMS_H + +int xs_init(void); +int xb_init_comms(void); + +/* Low level routines. */ +int xb_write(const void *data, unsigned len); +int xb_read(void *data, unsigned len); +int xb_data_to_read(void); +int xb_wait_for_data_to_read(void); +int xs_input_avail(void); +extern struct xenstore_domain_interface *xen_store_interface; +extern int xen_store_evtchn; + +#endif /* _XENBUS_COMMS_H */ diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c new file mode 100644 index 000000000000..0b769f7c4a48 --- /dev/null +++ b/drivers/xen/xenbus/xenbus_probe.c @@ -0,0 +1,935 @@ +/****************************************************************************** + * Talks to Xen Store to figure out what devices we have. + * + * Copyright (C) 2005 Rusty Russell, IBM Corporation + * Copyright (C) 2005 Mike Wray, Hewlett-Packard + * Copyright (C) 2005, 2006 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. + */ + +#define DPRINTK(fmt, args...) \ + pr_debug("xenbus_probe (%s:%d) " fmt ".\n", \ + __func__, __LINE__, ##args) + +#include <linux/kernel.h> +#include <linux/err.h> +#include <linux/string.h> +#include <linux/ctype.h> +#include <linux/fcntl.h> +#include <linux/mm.h> +#include <linux/notifier.h> +#include <linux/kthread.h> +#include <linux/mutex.h> +#include <linux/io.h> + +#include <asm/page.h> +#include <asm/pgtable.h> +#include <asm/xen/hypervisor.h> +#include <xen/xenbus.h> +#include <xen/events.h> +#include <xen/page.h> + +#include "xenbus_comms.h" +#include "xenbus_probe.h" + +int xen_store_evtchn; +struct xenstore_domain_interface *xen_store_interface; +static unsigned long xen_store_mfn; + +static BLOCKING_NOTIFIER_HEAD(xenstore_chain); + +static void wait_for_devices(struct xenbus_driver *xendrv); + +static int xenbus_probe_frontend(const char *type, const char *name); + +static void xenbus_dev_shutdown(struct device *_dev); + +/* If something in array of ids matches this device, return it. */ +static const struct xenbus_device_id * +match_device(const struct xenbus_device_id *arr, struct xenbus_device *dev) +{ + for (; *arr->devicetype != '\0'; arr++) { + if (!strcmp(arr->devicetype, dev->devicetype)) + return arr; + } + return NULL; +} + +int xenbus_match(struct device *_dev, struct device_driver *_drv) +{ + struct xenbus_driver *drv = to_xenbus_driver(_drv); + + if (!drv->ids) + return 0; + + return match_device(drv->ids, to_xenbus_device(_dev)) != NULL; +} + +/* device/<type>/<id> => <type>-<id> */ +static int frontend_bus_id(char bus_id[BUS_ID_SIZE], const char *nodename) +{ + nodename = strchr(nodename, '/'); + if (!nodename || strlen(nodename + 1) >= BUS_ID_SIZE) { + printk(KERN_WARNING "XENBUS: bad frontend %s\n", nodename); + return -EINVAL; + } + + strlcpy(bus_id, nodename + 1, BUS_ID_SIZE); + if (!strchr(bus_id, '/')) { + printk(KERN_WARNING "XENBUS: bus_id %s no slash\n", bus_id); + return -EINVAL; + } + *strchr(bus_id, '/') = '-'; + return 0; +} + + +static void free_otherend_details(struct xenbus_device *dev) +{ + kfree(dev->otherend); + dev->otherend = NULL; +} + + +static void free_otherend_watch(struct xenbus_device *dev) +{ + if (dev->otherend_watch.node) { + unregister_xenbus_watch(&dev->otherend_watch); + kfree(dev->otherend_watch.node); + dev->otherend_watch.node = NULL; + } +} + + +int read_otherend_details(struct xenbus_device *xendev, + char *id_node, char *path_node) +{ + int err = xenbus_gather(XBT_NIL, xendev->nodename, + id_node, "%i", &xendev->otherend_id, + path_node, NULL, &xendev->otherend, + NULL); + if (err) { + xenbus_dev_fatal(xendev, err, + "reading other end details from %s", + xendev->nodename); + return err; + } + if (strlen(xendev->otherend) == 0 || + !xenbus_exists(XBT_NIL, xendev->otherend, "")) { + xenbus_dev_fatal(xendev, -ENOENT, + "unable to read other end from %s. " + "missing or inaccessible.", + xendev->nodename); + free_otherend_details(xendev); + return -ENOENT; + } + + return 0; +} + + +static int read_backend_details(struct xenbus_device *xendev) +{ + return read_otherend_details(xendev, "backend-id", "backend"); +} + + +/* Bus type for frontend drivers. */ +static struct xen_bus_type xenbus_frontend = { + .root = "device", + .levels = 2, /* device/type/<id> */ + .get_bus_id = frontend_bus_id, + .probe = xenbus_probe_frontend, + .bus = { + .name = "xen", + .match = xenbus_match, + .probe = xenbus_dev_probe, + .remove = xenbus_dev_remove, + .shutdown = xenbus_dev_shutdown, + }, +}; + +static void otherend_changed(struct xenbus_watch *watch, + const char **vec, unsigned int len) +{ + struct xenbus_device *dev = + container_of(watch, struct xenbus_device, otherend_watch); + struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver); + enum xenbus_state state; + + /* Protect us against watches firing on old details when the otherend + details change, say immediately after a resume. */ + if (!dev->otherend || + strncmp(dev->otherend, vec[XS_WATCH_PATH], + strlen(dev->otherend))) { + dev_dbg(&dev->dev, "Ignoring watch at %s", vec[XS_WATCH_PATH]); + return; + } + + state = xenbus_read_driver_state(dev->otherend); + + dev_dbg(&dev->dev, "state is %d, (%s), %s, %s", + state, xenbus_strstate(state), dev->otherend_watch.node, + vec[XS_WATCH_PATH]); + + /* + * Ignore xenbus transitions during shutdown. This prevents us doing + * work that can fail e.g., when the rootfs is gone. + */ + if (system_state > SYSTEM_RUNNING) { + struct xen_bus_type *bus = bus; + bus = container_of(dev->dev.bus, struct xen_bus_type, bus); + /* If we're frontend, drive the state machine to Closed. */ + /* This should cause the backend to release our resources. */ + if ((bus == &xenbus_frontend) && (state == XenbusStateClosing)) + xenbus_frontend_closed(dev); + return; + } + + if (drv->otherend_changed) + drv->otherend_changed(dev, state); +} + + +static int talk_to_otherend(struct xenbus_device *dev) +{ + struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver); + + free_otherend_watch(dev); + free_otherend_details(dev); + + return drv->read_otherend_details(dev); +} + + +static int watch_otherend(struct xenbus_device *dev) +{ + return xenbus_watch_pathfmt(dev, &dev->otherend_watch, otherend_changed, + "%s/%s", dev->otherend, "state"); +} + + +int xenbus_dev_probe(struct device *_dev) +{ + struct xenbus_device *dev = to_xenbus_device(_dev); + struct xenbus_driver *drv = to_xenbus_driver(_dev->driver); + const struct xenbus_device_id *id; + int err; + + DPRINTK("%s", dev->nodename); + + if (!drv->probe) { + err = -ENODEV; + goto fail; + } + + id = match_device(drv->ids, dev); + if (!id) { + err = -ENODEV; + goto fail; + } + + err = talk_to_otherend(dev); + if (err) { + dev_warn(&dev->dev, "talk_to_otherend on %s failed.\n", + dev->nodename); + return err; + } + + err = drv->probe(dev, id); + if (err) + goto fail; + + err = watch_otherend(dev); + if (err) { + dev_warn(&dev->dev, "watch_otherend on %s failed.\n", + dev->nodename); + return err; + } + + return 0; +fail: + xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename); + xenbus_switch_state(dev, XenbusStateClosed); + return -ENODEV; +} + +int xenbus_dev_remove(struct device *_dev) +{ + struct xenbus_device *dev = to_xenbus_device(_dev); + struct xenbus_driver *drv = to_xenbus_driver(_dev->driver); + + DPRINTK("%s", dev->nodename); + + free_otherend_watch(dev); + free_otherend_details(dev); + + if (drv->remove) + drv->remove(dev); + + xenbus_switch_state(dev, XenbusStateClosed); + return 0; +} + +static void xenbus_dev_shutdown(struct device *_dev) +{ + struct xenbus_device *dev = to_xenbus_device(_dev); + unsigned long timeout = 5*HZ; + + DPRINTK("%s", dev->nodename); + + get_device(&dev->dev); + if (dev->state != XenbusStateConnected) { + printk(KERN_INFO "%s: %s: %s != Connected, skipping\n", __func__, + dev->nodename, xenbus_strstate(dev->state)); + goto out; + } + xenbus_switch_state(dev, XenbusStateClosing); + timeout = wait_for_completion_timeout(&dev->down, timeout); + if (!timeout) + printk(KERN_INFO "%s: %s timeout closing device\n", + __func__, dev->nodename); + out: + put_device(&dev->dev); +} + +int xenbus_register_driver_common(struct xenbus_driver *drv, + struct xen_bus_type *bus, + struct module *owner, + const char *mod_name) +{ + drv->driver.name = drv->name; + drv->driver.bus = &bus->bus; + drv->driver.owner = owner; + drv->driver.mod_name = mod_name; + + return driver_register(&drv->driver); +} + +int __xenbus_register_frontend(struct xenbus_driver *drv, + struct module *owner, const char *mod_name) +{ + int ret; + + drv->read_otherend_details = read_backend_details; + + ret = xenbus_register_driver_common(drv, &xenbus_frontend, + owner, mod_name); + if (ret) + return ret; + + /* If this driver is loaded as a module wait for devices to attach. */ + wait_for_devices(drv); + + return 0; +} +EXPORT_SYMBOL_GPL(__xenbus_register_frontend); + +void xenbus_unregister_driver(struct xenbus_driver *drv) +{ + driver_unregister(&drv->driver); +} +EXPORT_SYMBOL_GPL(xenbus_unregister_driver); + +struct xb_find_info +{ + struct xenbus_device *dev; + const char *nodename; +}; + +static int cmp_dev(struct device *dev, void *data) +{ + struct xenbus_device *xendev = to_xenbus_device(dev); + struct xb_find_info *info = data; + + if (!strcmp(xendev->nodename, info->nodename)) { + info->dev = xendev; + get_device(dev); + return 1; + } + return 0; +} + +struct xenbus_device *xenbus_device_find(const char *nodename, + struct bus_type *bus) +{ + struct xb_find_info info = { .dev = NULL, .nodename = nodename }; + + bus_for_each_dev(bus, NULL, &info, cmp_dev); + return info.dev; +} + +static int cleanup_dev(struct device *dev, void *data) +{ + struct xenbus_device *xendev = to_xenbus_device(dev); + struct xb_find_info *info = data; + int len = strlen(info->nodename); + + DPRINTK("%s", info->nodename); + + /* Match the info->nodename path, or any subdirectory of that path. */ + if (strncmp(xendev->nodename, info->nodename, len)) + return 0; + + /* If the node name is longer, ensure it really is a subdirectory. */ + if ((strlen(xendev->nodename) > len) && (xendev->nodename[len] != '/')) + return 0; + + info->dev = xendev; + get_device(dev); + return 1; +} + +static void xenbus_cleanup_devices(const char *path, struct bus_type *bus) +{ + struct xb_find_info info = { .nodename = path }; + + do { + info.dev = NULL; + bus_for_each_dev(bus, NULL, &info, cleanup_dev); + if (info.dev) { + device_unregister(&info.dev->dev); + put_device(&info.dev->dev); + } + } while (info.dev); +} + +static void xenbus_dev_release(struct device *dev) +{ + if (dev) + kfree(to_xenbus_device(dev)); +} + +static ssize_t xendev_show_nodename(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "%s\n", to_xenbus_device(dev)->nodename); +} +DEVICE_ATTR(nodename, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_nodename, NULL); + +static ssize_t xendev_show_devtype(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "%s\n", to_xenbus_device(dev)->devicetype); +} +DEVICE_ATTR(devtype, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_devtype, NULL); + + +int xenbus_probe_node(struct xen_bus_type *bus, + const char *type, + const char *nodename) +{ + int err; + struct xenbus_device *xendev; + size_t stringlen; + char *tmpstring; + + enum xenbus_state state = xenbus_read_driver_state(nodename); + + if (state != XenbusStateInitialising) { + /* Device is not new, so ignore it. This can happen if a + device is going away after switching to Closed. */ + return 0; + } + + stringlen = strlen(nodename) + 1 + strlen(type) + 1; + xendev = kzalloc(sizeof(*xendev) + stringlen, GFP_KERNEL); + if (!xendev) + return -ENOMEM; + + xendev->state = XenbusStateInitialising; + + /* Copy the strings into the extra space. */ + + tmpstring = (char *)(xendev + 1); + strcpy(tmpstring, nodename); + xendev->nodename = tmpstring; + + tmpstring += strlen(tmpstring) + 1; + strcpy(tmpstring, type); + xendev->devicetype = tmpstring; + init_completion(&xendev->down); + + xendev->dev.bus = &bus->bus; + xendev->dev.release = xenbus_dev_release; + + err = bus->get_bus_id(xendev->dev.bus_id, xendev->nodename); + if (err) + goto fail; + + /* Register with generic device framework. */ + err = device_register(&xendev->dev); + if (err) + goto fail; + + err = device_create_file(&xendev->dev, &dev_attr_nodename); + if (err) + goto fail_unregister; + + err = device_create_file(&xendev->dev, &dev_attr_devtype); + if (err) + goto fail_remove_file; + + return 0; +fail_remove_file: + device_remove_file(&xendev->dev, &dev_attr_nodename); +fail_unregister: + device_unregister(&xendev->dev); +fail: + kfree(xendev); + return err; +} + +/* device/<typename>/<name> */ +static int xenbus_probe_frontend(const char *type, const char *name) +{ + char *nodename; + int err; + + nodename = kasprintf(GFP_KERNEL, "%s/%s/%s", + xenbus_frontend.root, type, name); + if (!nodename) + return -ENOMEM; + + DPRINTK("%s", nodename); + + err = xenbus_probe_node(&xenbus_frontend, type, nodename); + kfree(nodename); + return err; +} + +static int xenbus_probe_device_type(struct xen_bus_type *bus, const char *type) +{ + int err = 0; + char **dir; + unsigned int dir_n = 0; + int i; + + dir = xenbus_directory(XBT_NIL, bus->root, type, &dir_n); + if (IS_ERR(dir)) + return PTR_ERR(dir); + + for (i = 0; i < dir_n; i++) { + err = bus->probe(type, dir[i]); + if (err) + break; + } + kfree(dir); + return err; +} + +int xenbus_probe_devices(struct xen_bus_type *bus) +{ + int err = 0; + char **dir; + unsigned int i, dir_n; + + dir = xenbus_directory(XBT_NIL, bus->root, "", &dir_n); + if (IS_ERR(dir)) + return PTR_ERR(dir); + + for (i = 0; i < dir_n; i++) { + err = xenbus_probe_device_type(bus, dir[i]); + if (err) + break; + } + kfree(dir); + return err; +} + +static unsigned int char_count(const char *str, char c) +{ + unsigned int i, ret = 0; + + for (i = 0; str[i]; i++) + if (str[i] == c) + ret++; + return ret; +} + +static int strsep_len(const char *str, char c, unsigned int len) +{ + unsigned int i; + + for (i = 0; str[i]; i++) + if (str[i] == c) { + if (len == 0) + return i; + len--; + } + return (len == 0) ? i : -ERANGE; +} + +void xenbus_dev_changed(const char *node, struct xen_bus_type *bus) +{ + int exists, rootlen; + struct xenbus_device *dev; + char type[BUS_ID_SIZE]; + const char *p, *root; + + if (char_count(node, '/') < 2) + return; + + exists = xenbus_exists(XBT_NIL, node, ""); + if (!exists) { + xenbus_cleanup_devices(node, &bus->bus); + return; + } + + /* backend/<type>/... or device/<type>/... */ + p = strchr(node, '/') + 1; + snprintf(type, BUS_ID_SIZE, "%.*s", (int)strcspn(p, "/"), p); + type[BUS_ID_SIZE-1] = '\0'; + + rootlen = strsep_len(node, '/', bus->levels); + if (rootlen < 0) + return; + root = kasprintf(GFP_KERNEL, "%.*s", rootlen, node); + if (!root) + return; + + dev = xenbus_device_find(root, &bus->bus); + if (!dev) + xenbus_probe_node(bus, type, root); + else + put_device(&dev->dev); + + kfree(root); +} + +static void frontend_changed(struct xenbus_watch *watch, + const char **vec, unsigned int len) +{ + DPRINTK(""); + + xenbus_dev_changed(vec[XS_WATCH_PATH], &xenbus_frontend); +} + +/* We watch for devices appearing and vanishing. */ +static struct xenbus_watch fe_watch = { + .node = "device", + .callback = frontend_changed, +}; + +static int suspend_dev(struct device *dev, void *data) +{ + int err = 0; + struct xenbus_driver *drv; + struct xenbus_device *xdev; + + DPRINTK(""); + + if (dev->driver == NULL) + return 0; + drv = to_xenbus_driver(dev->driver); + xdev = container_of(dev, struct xenbus_device, dev); + if (drv->suspend) + err = drv->suspend(xdev); + if (err) + printk(KERN_WARNING + "xenbus: suspend %s failed: %i\n", dev->bus_id, err); + return 0; +} + +static int suspend_cancel_dev(struct device *dev, void *data) +{ + int err = 0; + struct xenbus_driver *drv; + struct xenbus_device *xdev; + + DPRINTK(""); + + if (dev->driver == NULL) + return 0; + drv = to_xenbus_driver(dev->driver); + xdev = container_of(dev, struct xenbus_device, dev); + if (drv->suspend_cancel) + err = drv->suspend_cancel(xdev); + if (err) + printk(KERN_WARNING + "xenbus: suspend_cancel %s failed: %i\n", + dev->bus_id, err); + return 0; +} + +static int resume_dev(struct device *dev, void *data) +{ + int err; + struct xenbus_driver *drv; + struct xenbus_device *xdev; + + DPRINTK(""); + + if (dev->driver == NULL) + return 0; + + drv = to_xenbus_driver(dev->driver); + xdev = container_of(dev, struct xenbus_device, dev); + + err = talk_to_otherend(xdev); + if (err) { + printk(KERN_WARNING + "xenbus: resume (talk_to_otherend) %s failed: %i\n", + dev->bus_id, err); + return err; + } + + xdev->state = XenbusStateInitialising; + + if (drv->resume) { + err = drv->resume(xdev); + if (err) { + printk(KERN_WARNING + "xenbus: resume %s failed: %i\n", + dev->bus_id, err); + return err; + } + } + + err = watch_otherend(xdev); + if (err) { + printk(KERN_WARNING + "xenbus_probe: resume (watch_otherend) %s failed: " + "%d.\n", dev->bus_id, err); + return err; + } + + return 0; +} + +void xenbus_suspend(void) +{ + DPRINTK(""); + + bus_for_each_dev(&xenbus_frontend.bus, NULL, NULL, suspend_dev); + xenbus_backend_suspend(suspend_dev); + xs_suspend(); +} +EXPORT_SYMBOL_GPL(xenbus_suspend); + +void xenbus_resume(void) +{ + xb_init_comms(); + xs_resume(); + bus_for_each_dev(&xenbus_frontend.bus, NULL, NULL, resume_dev); + xenbus_backend_resume(resume_dev); +} +EXPORT_SYMBOL_GPL(xenbus_resume); + +void xenbus_suspend_cancel(void) +{ + xs_suspend_cancel(); + bus_for_each_dev(&xenbus_frontend.bus, NULL, NULL, suspend_cancel_dev); + xenbus_backend_resume(suspend_cancel_dev); +} +EXPORT_SYMBOL_GPL(xenbus_suspend_cancel); + +/* A flag to determine if xenstored is 'ready' (i.e. has started) */ +int xenstored_ready = 0; + + +int register_xenstore_notifier(struct notifier_block *nb) +{ + int ret = 0; + + if (xenstored_ready > 0) + ret = nb->notifier_call(nb, 0, NULL); + else + blocking_notifier_chain_register(&xenstore_chain, nb); + + return ret; +} +EXPORT_SYMBOL_GPL(register_xenstore_notifier); + +void unregister_xenstore_notifier(struct notifier_block *nb) +{ + blocking_notifier_chain_unregister(&xenstore_chain, nb); +} +EXPORT_SYMBOL_GPL(unregister_xenstore_notifier); + +void xenbus_probe(struct work_struct *unused) +{ + BUG_ON((xenstored_ready <= 0)); + + /* Enumerate devices in xenstore and watch for changes. */ + xenbus_probe_devices(&xenbus_frontend); + register_xenbus_watch(&fe_watch); + xenbus_backend_probe_and_watch(); + + /* Notify others that xenstore is up */ + blocking_notifier_call_chain(&xenstore_chain, 0, NULL); +} + +static int __init xenbus_probe_init(void) +{ + int err = 0; + + DPRINTK(""); + + err = -ENODEV; + if (!is_running_on_xen()) + goto out_error; + + /* Register ourselves with the kernel bus subsystem */ + err = bus_register(&xenbus_frontend.bus); + if (err) + goto out_error; + + err = xenbus_backend_bus_register(); + if (err) + goto out_unreg_front; + + /* + * Domain0 doesn't have a store_evtchn or store_mfn yet. + */ + if (is_initial_xendomain()) { + /* dom0 not yet supported */ + } else { + xenstored_ready = 1; + xen_store_evtchn = xen_start_info->store_evtchn; + xen_store_mfn = xen_start_info->store_mfn; + } + xen_store_interface = mfn_to_virt(xen_store_mfn); + + /* Initialize the interface to xenstore. */ + err = xs_init(); + if (err) { + printk(KERN_WARNING + "XENBUS: Error initializing xenstore comms: %i\n", err); + goto out_unreg_back; + } + + if (!is_initial_xendomain()) + xenbus_probe(NULL); + + return 0; + + out_unreg_back: + xenbus_backend_bus_unregister(); + + out_unreg_front: + bus_unregister(&xenbus_frontend.bus); + + out_error: + return err; +} + +postcore_initcall(xenbus_probe_init); + +MODULE_LICENSE("GPL"); + +static int is_disconnected_device(struct device *dev, void *data) +{ + struct xenbus_device *xendev = to_xenbus_device(dev); + struct device_driver *drv = data; + + /* + * A device with no driver will never connect. We care only about + * devices which should currently be in the process of connecting. + */ + if (!dev->driver) + return 0; + + /* Is this search limited to a particular driver? */ + if (drv && (dev->driver != drv)) + return 0; + + return (xendev->state != XenbusStateConnected); +} + +static int exists_disconnected_device(struct device_driver *drv) +{ + return bus_for_each_dev(&xenbus_frontend.bus, NULL, drv, + is_disconnected_device); +} + +static int print_device_status(struct device *dev, void *data) +{ + struct xenbus_device *xendev = to_xenbus_device(dev); + struct device_driver *drv = data; + + /* Is this operation limited to a particular driver? */ + if (drv && (dev->driver != drv)) + return 0; + + if (!dev->driver) { + /* Information only: is this too noisy? */ + printk(KERN_INFO "XENBUS: Device with no driver: %s\n", + xendev->nodename); + } else if (xendev->state != XenbusStateConnected) { + printk(KERN_WARNING "XENBUS: Timeout connecting " + "to device: %s (state %d)\n", + xendev->nodename, xendev->state); + } + + return 0; +} + +/* We only wait for device setup after most initcalls have run. */ +static int ready_to_wait_for_devices; + +/* + * On a 10 second timeout, wait for all devices currently configured. We need + * to do this to guarantee that the filesystems and / or network devices + * needed for boot are available, before we can allow the boot to proceed. + * + * This needs to be on a late_initcall, to happen after the frontend device + * drivers have been initialised, but before the root fs is mounted. + * + * A possible improvement here would be to have the tools add a per-device + * flag to the store entry, indicating whether it is needed at boot time. + * This would allow people who knew what they were doing to accelerate their + * boot slightly, but of course needs tools or manual intervention to set up + * those flags correctly. + */ +static void wait_for_devices(struct xenbus_driver *xendrv) +{ + unsigned long timeout = jiffies + 10*HZ; + struct device_driver *drv = xendrv ? &xendrv->driver : NULL; + + if (!ready_to_wait_for_devices || !is_running_on_xen()) + return; + + while (exists_disconnected_device(drv)) { + if (time_after(jiffies, timeout)) + break; + schedule_timeout_interruptible(HZ/10); + } + + bus_for_each_dev(&xenbus_frontend.bus, NULL, drv, + print_device_status); +} + +#ifndef MODULE +static int __init boot_wait_for_devices(void) +{ + ready_to_wait_for_devices = 1; + wait_for_devices(NULL); + return 0; +} + +late_initcall(boot_wait_for_devices); +#endif diff --git a/drivers/xen/xenbus/xenbus_probe.h b/drivers/xen/xenbus/xenbus_probe.h new file mode 100644 index 000000000000..e09b19415a40 --- /dev/null +++ b/drivers/xen/xenbus/xenbus_probe.h @@ -0,0 +1,74 @@ +/****************************************************************************** + * xenbus_probe.h + * + * Talks to Xen Store to figure out what devices we have. + * + * Copyright (C) 2005 Rusty Russell, IBM Corporation + * 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. + */ + +#ifndef _XENBUS_PROBE_H +#define _XENBUS_PROBE_H + +#ifdef CONFIG_XEN_BACKEND +extern void xenbus_backend_suspend(int (*fn)(struct device *, void *)); +extern void xenbus_backend_resume(int (*fn)(struct device *, void *)); +extern void xenbus_backend_probe_and_watch(void); +extern int xenbus_backend_bus_register(void); +extern void xenbus_backend_bus_unregister(void); +#else +static inline void xenbus_backend_suspend(int (*fn)(struct device *, void *)) {} +static inline void xenbus_backend_resume(int (*fn)(struct device *, void *)) {} +static inline void xenbus_backend_probe_and_watch(void) {} +static inline int xenbus_backend_bus_register(void) { return 0; } +static inline void xenbus_backend_bus_unregister(void) {} +#endif + +struct xen_bus_type +{ + char *root; + unsigned int levels; + int (*get_bus_id)(char bus_id[BUS_ID_SIZE], const char *nodename); + int (*probe)(const char *type, const char *dir); + struct bus_type bus; +}; + +extern int xenbus_match(struct device *_dev, struct device_driver *_drv); +extern int xenbus_dev_probe(struct device *_dev); +extern int xenbus_dev_remove(struct device *_dev); +extern int xenbus_register_driver_common(struct xenbus_driver *drv, + struct xen_bus_type *bus, + struct module *owner, + const char *mod_name); +extern int xenbus_probe_node(struct xen_bus_type *bus, + const char *type, + const char *nodename); +extern int xenbus_probe_devices(struct xen_bus_type *bus); + +extern void xenbus_dev_changed(const char *node, struct xen_bus_type *bus); + +#endif diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c new file mode 100644 index 000000000000..9e943fbce81b --- /dev/null +++ b/drivers/xen/xenbus/xenbus_xs.c @@ -0,0 +1,861 @@ +/****************************************************************************** + * xenbus_xs.c + * + * This is the kernel equivalent of the "xs" library. We don't need everything + * and we use xenbus_comms for communication. + * + * Copyright (C) 2005 Rusty Russell, IBM Corporation + * + * 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 <linux/unistd.h> +#include <linux/errno.h> +#include <linux/types.h> +#include <linux/uio.h> +#include <linux/kernel.h> +#include <linux/string.h> +#include <linux/err.h> +#include <linux/slab.h> +#include <linux/fcntl.h> +#include <linux/kthread.h> +#include <linux/rwsem.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <xen/xenbus.h> +#include "xenbus_comms.h" + +struct xs_stored_msg { + struct list_head list; + + struct xsd_sockmsg hdr; + + union { + /* Queued replies. */ + struct { + char *body; + } reply; + + /* Queued watch events. */ + struct { + struct xenbus_watch *handle; + char **vec; + unsigned int vec_size; + } watch; + } u; +}; + +struct xs_handle { + /* A list of replies. Currently only one will ever be outstanding. */ + struct list_head reply_list; + spinlock_t reply_lock; + wait_queue_head_t reply_waitq; + + /* + * Mutex ordering: transaction_mutex -> watch_mutex -> request_mutex. + * response_mutex is never taken simultaneously with the other three. + */ + + /* One request at a time. */ + struct mutex request_mutex; + + /* Protect xenbus reader thread against save/restore. */ + struct mutex response_mutex; + + /* Protect transactions against save/restore. */ + struct rw_semaphore transaction_mutex; + + /* Protect watch (de)register against save/restore. */ + struct rw_semaphore watch_mutex; +}; + +static struct xs_handle xs_state; + +/* List of registered watches, and a lock to protect it. */ +static LIST_HEAD(watches); +static DEFINE_SPINLOCK(watches_lock); + +/* List of pending watch callback events, and a lock to protect it. */ +static LIST_HEAD(watch_events); +static DEFINE_SPINLOCK(watch_events_lock); + +/* + * Details of the xenwatch callback kernel thread. The thread waits on the + * watch_events_waitq for work to do (queued on watch_events list). When it + * wakes up it acquires the xenwatch_mutex before reading the list and + * carrying out work. + */ +static pid_t xenwatch_pid; +static DEFINE_MUTEX(xenwatch_mutex); +static DECLARE_WAIT_QUEUE_HEAD(watch_events_waitq); + +static int get_error(const char *errorstring) +{ + unsigned int i; + + for (i = 0; strcmp(errorstring, xsd_errors[i].errstring) != 0; i++) { + if (i == ARRAY_SIZE(xsd_errors) - 1) { + printk(KERN_WARNING + "XENBUS xen store gave: unknown error %s", + errorstring); + return EINVAL; + } + } + return xsd_errors[i].errnum; +} + +static void *read_reply(enum xsd_sockmsg_type *type, unsigned int *len) +{ + struct xs_stored_msg *msg; + char *body; + + spin_lock(&xs_state.reply_lock); + + while (list_empty(&xs_state.reply_list)) { + spin_unlock(&xs_state.reply_lock); + /* XXX FIXME: Avoid synchronous wait for response here. */ + wait_event(xs_state.reply_waitq, + !list_empty(&xs_state.reply_list)); + spin_lock(&xs_state.reply_lock); + } + + msg = list_entry(xs_state.reply_list.next, + struct xs_stored_msg, list); + list_del(&msg->list); + + spin_unlock(&xs_state.reply_lock); + + *type = msg->hdr.type; + if (len) + *len = msg->hdr.len; + body = msg->u.reply.body; + + kfree(msg); + + return body; +} + +void *xenbus_dev_request_and_reply(struct xsd_sockmsg *msg) +{ + void *ret; + struct xsd_sockmsg req_msg = *msg; + int err; + + if (req_msg.type == XS_TRANSACTION_START) + down_read(&xs_state.transaction_mutex); + + mutex_lock(&xs_state.request_mutex); + + err = xb_write(msg, sizeof(*msg) + msg->len); + if (err) { + msg->type = XS_ERROR; + ret = ERR_PTR(err); + } else + ret = read_reply(&msg->type, &msg->len); + + mutex_unlock(&xs_state.request_mutex); + + if ((msg->type == XS_TRANSACTION_END) || + ((req_msg.type == XS_TRANSACTION_START) && + (msg->type == XS_ERROR))) + up_read(&xs_state.transaction_mutex); + + return ret; +} + +/* Send message to xs, get kmalloc'ed reply. ERR_PTR() on error. */ +static void *xs_talkv(struct xenbus_transaction t, + enum xsd_sockmsg_type type, + const struct kvec *iovec, + unsigned int num_vecs, + unsigned int *len) +{ + struct xsd_sockmsg msg; + void *ret = NULL; + unsigned int i; + int err; + + msg.tx_id = t.id; + msg.req_id = 0; + msg.type = type; + msg.len = 0; + for (i = 0; i < num_vecs; i++) + msg.len += iovec[i].iov_len; + + mutex_lock(&xs_state.request_mutex); + + err = xb_write(&msg, sizeof(msg)); + if (err) { + mutex_unlock(&xs_state.request_mutex); + return ERR_PTR(err); + } + + for (i = 0; i < num_vecs; i++) { + err = xb_write(iovec[i].iov_base, iovec[i].iov_len); + if (err) { + mutex_unlock(&xs_state.request_mutex); + return ERR_PTR(err); + } + } + + ret = read_reply(&msg.type, len); + + mutex_unlock(&xs_state.request_mutex); + + if (IS_ERR(ret)) + return ret; + + if (msg.type == XS_ERROR) { + err = get_error(ret); + kfree(ret); + return ERR_PTR(-err); + } + + if (msg.type != type) { + if (printk_ratelimit()) + printk(KERN_WARNING + "XENBUS unexpected type [%d], expected [%d]\n", + msg.type, type); + kfree(ret); + return ERR_PTR(-EINVAL); + } + return ret; +} + +/* Simplified version of xs_talkv: single message. */ +static void *xs_single(struct xenbus_transaction t, + enum xsd_sockmsg_type type, + const char *string, + unsigned int *len) +{ + struct kvec iovec; + + iovec.iov_base = (void *)string; + iovec.iov_len = strlen(string) + 1; + return xs_talkv(t, type, &iovec, 1, len); +} + +/* Many commands only need an ack, don't care what it says. */ +static int xs_error(char *reply) +{ + if (IS_ERR(reply)) + return PTR_ERR(reply); + kfree(reply); + return 0; +} + +static unsigned int count_strings(const char *strings, unsigned int len) +{ + unsigned int num; + const char *p; + + for (p = strings, num = 0; p < strings + len; p += strlen(p) + 1) + num++; + + return num; +} + +/* Return the path to dir with /name appended. Buffer must be kfree()'ed. */ +static char *join(const char *dir, const char *name) +{ + char *buffer; + + if (strlen(name) == 0) + buffer = kasprintf(GFP_KERNEL, "%s", dir); + else + buffer = kasprintf(GFP_KERNEL, "%s/%s", dir, name); + return (!buffer) ? ERR_PTR(-ENOMEM) : buffer; +} + +static char **split(char *strings, unsigned int len, unsigned int *num) +{ + char *p, **ret; + + /* Count the strings. */ + *num = count_strings(strings, len); + + /* Transfer to one big alloc for easy freeing. */ + ret = kmalloc(*num * sizeof(char *) + len, GFP_KERNEL); + if (!ret) { + kfree(strings); + return ERR_PTR(-ENOMEM); + } + memcpy(&ret[*num], strings, len); + kfree(strings); + + strings = (char *)&ret[*num]; + for (p = strings, *num = 0; p < strings + len; p += strlen(p) + 1) + ret[(*num)++] = p; + + return ret; +} + +char **xenbus_directory(struct xenbus_transaction t, + const char *dir, const char *node, unsigned int *num) +{ + char *strings, *path; + unsigned int len; + + path = join(dir, node); + if (IS_ERR(path)) + return (char **)path; + + strings = xs_single(t, XS_DIRECTORY, path, &len); + kfree(path); + if (IS_ERR(strings)) + return (char **)strings; + + return split(strings, len, num); +} +EXPORT_SYMBOL_GPL(xenbus_directory); + +/* Check if a path exists. Return 1 if it does. */ +int xenbus_exists(struct xenbus_transaction t, + const char *dir, const char *node) +{ + char **d; + int dir_n; + + d = xenbus_directory(t, dir, node, &dir_n); + if (IS_ERR(d)) + return 0; + kfree(d); + return 1; +} +EXPORT_SYMBOL_GPL(xenbus_exists); + +/* Get the value of a single file. + * Returns a kmalloced value: call free() on it after use. + * len indicates length in bytes. + */ +void *xenbus_read(struct xenbus_transaction t, + const char *dir, const char *node, unsigned int *len) +{ + char *path; + void *ret; + + path = join(dir, node); + if (IS_ERR(path)) + return (void *)path; + + ret = xs_single(t, XS_READ, path, len); + kfree(path); + return ret; +} +EXPORT_SYMBOL_GPL(xenbus_read); + +/* Write the value of a single file. + * Returns -err on failure. + */ +int xenbus_write(struct xenbus_transaction t, + const char *dir, const char *node, const char *string) +{ + const char *path; + struct kvec iovec[2]; + int ret; + + path = join(dir, node); + if (IS_ERR(path)) + return PTR_ERR(path); + + iovec[0].iov_base = (void *)path; + iovec[0].iov_len = strlen(path) + 1; + iovec[1].iov_base = (void *)string; + iovec[1].iov_len = strlen(string); + + ret = xs_error(xs_talkv(t, XS_WRITE, iovec, ARRAY_SIZE(iovec), NULL)); + kfree(path); + return ret; +} +EXPORT_SYMBOL_GPL(xenbus_write); + +/* Create a new directory. */ +int xenbus_mkdir(struct xenbus_transaction t, + const char *dir, const char *node) +{ + char *path; + int ret; + + path = join(dir, node); + if (IS_ERR(path)) + return PTR_ERR(path); + + ret = xs_error(xs_single(t, XS_MKDIR, path, NULL)); + kfree(path); + return ret; +} +EXPORT_SYMBOL_GPL(xenbus_mkdir); + +/* Destroy a file or directory (directories must be empty). */ +int xenbus_rm(struct xenbus_transaction t, const char *dir, const char *node) +{ + char *path; + int ret; + + path = join(dir, node); + if (IS_ERR(path)) + return PTR_ERR(path); + + ret = xs_error(xs_single(t, XS_RM, path, NULL)); + kfree(path); + return ret; +} +EXPORT_SYMBOL_GPL(xenbus_rm); + +/* Start a transaction: changes by others will not be seen during this + * transaction, and changes will not be visible to others until end. + */ +int xenbus_transaction_start(struct xenbus_transaction *t) +{ + char *id_str; + + down_read(&xs_state.transaction_mutex); + + id_str = xs_single(XBT_NIL, XS_TRANSACTION_START, "", NULL); + if (IS_ERR(id_str)) { + up_read(&xs_state.transaction_mutex); + return PTR_ERR(id_str); + } + + t->id = simple_strtoul(id_str, NULL, 0); + kfree(id_str); + return 0; +} +EXPORT_SYMBOL_GPL(xenbus_transaction_start); + +/* End a transaction. + * If abandon is true, transaction is discarded instead of committed. + */ +int xenbus_transaction_end(struct xenbus_transaction t, int abort) +{ + char abortstr[2]; + int err; + + if (abort) + strcpy(abortstr, "F"); + else + strcpy(abortstr, "T"); + + err = xs_error(xs_single(t, XS_TRANSACTION_END, abortstr, NULL)); + + up_read(&xs_state.transaction_mutex); + + return err; +} +EXPORT_SYMBOL_GPL(xenbus_transaction_end); + +/* Single read and scanf: returns -errno or num scanned. */ +int xenbus_scanf(struct xenbus_transaction t, + const char *dir, const char *node, const char *fmt, ...) +{ + va_list ap; + int ret; + char *val; + + val = xenbus_read(t, dir, node, NULL); + if (IS_ERR(val)) + return PTR_ERR(val); + + va_start(ap, fmt); + ret = vsscanf(val, fmt, ap); + va_end(ap); + kfree(val); + /* Distinctive errno. */ + if (ret == 0) + return -ERANGE; + return ret; +} +EXPORT_SYMBOL_GPL(xenbus_scanf); + +/* Single printf and write: returns -errno or 0. */ +int xenbus_printf(struct xenbus_transaction t, + const char *dir, const char *node, const char *fmt, ...) +{ + va_list ap; + int ret; +#define PRINTF_BUFFER_SIZE 4096 + char *printf_buffer; + + printf_buffer = kmalloc(PRINTF_BUFFER_SIZE, GFP_KERNEL); + if (printf_buffer == NULL) + return -ENOMEM; + + va_start(ap, fmt); + ret = vsnprintf(printf_buffer, PRINTF_BUFFER_SIZE, fmt, ap); + va_end(ap); + + BUG_ON(ret > PRINTF_BUFFER_SIZE-1); + ret = xenbus_write(t, dir, node, printf_buffer); + + kfree(printf_buffer); + + return ret; +} +EXPORT_SYMBOL_GPL(xenbus_printf); + +/* Takes tuples of names, scanf-style args, and void **, NULL terminated. */ +int xenbus_gather(struct xenbus_transaction t, const char *dir, ...) +{ + va_list ap; + const char *name; + int ret = 0; + + va_start(ap, dir); + while (ret == 0 && (name = va_arg(ap, char *)) != NULL) { + const char *fmt = va_arg(ap, char *); + void *result = va_arg(ap, void *); + char *p; + + p = xenbus_read(t, dir, name, NULL); + if (IS_ERR(p)) { + ret = PTR_ERR(p); + break; + } + if (fmt) { + if (sscanf(p, fmt, result) == 0) + ret = -EINVAL; + kfree(p); + } else + *(char **)result = p; + } + va_end(ap); + return ret; +} +EXPORT_SYMBOL_GPL(xenbus_gather); + +static int xs_watch(const char *path, const char *token) +{ + struct kvec iov[2]; + + iov[0].iov_base = (void *)path; + iov[0].iov_len = strlen(path) + 1; + iov[1].iov_base = (void *)token; + iov[1].iov_len = strlen(token) + 1; + + return xs_error(xs_talkv(XBT_NIL, XS_WATCH, iov, + ARRAY_SIZE(iov), NULL)); +} + +static int xs_unwatch(const char *path, const char *token) +{ + struct kvec iov[2]; + + iov[0].iov_base = (char *)path; + iov[0].iov_len = strlen(path) + 1; + iov[1].iov_base = (char *)token; + iov[1].iov_len = strlen(token) + 1; + + return xs_error(xs_talkv(XBT_NIL, XS_UNWATCH, iov, + ARRAY_SIZE(iov), NULL)); +} + +static struct xenbus_watch *find_watch(const char *token) +{ + struct xenbus_watch *i, *cmp; + + cmp = (void *)simple_strtoul(token, NULL, 16); + + list_for_each_entry(i, &watches, list) + if (i == cmp) + return i; + + return NULL; +} + +/* Register callback to watch this node. */ +int register_xenbus_watch(struct xenbus_watch *watch) +{ + /* Pointer in ascii is the token. */ + char token[sizeof(watch) * 2 + 1]; + int err; + + sprintf(token, "%lX", (long)watch); + + down_read(&xs_state.watch_mutex); + + spin_lock(&watches_lock); + BUG_ON(find_watch(token)); + list_add(&watch->list, &watches); + spin_unlock(&watches_lock); + + err = xs_watch(watch->node, token); + + /* Ignore errors due to multiple registration. */ + if ((err != 0) && (err != -EEXIST)) { + spin_lock(&watches_lock); + list_del(&watch->list); + spin_unlock(&watches_lock); + } + + up_read(&xs_state.watch_mutex); + + return err; +} +EXPORT_SYMBOL_GPL(register_xenbus_watch); + +void unregister_xenbus_watch(struct xenbus_watch *watch) +{ + struct xs_stored_msg *msg, *tmp; + char token[sizeof(watch) * 2 + 1]; + int err; + + sprintf(token, "%lX", (long)watch); + + down_read(&xs_state.watch_mutex); + + spin_lock(&watches_lock); + BUG_ON(!find_watch(token)); + list_del(&watch->list); + spin_unlock(&watches_lock); + + err = xs_unwatch(watch->node, token); + if (err) + printk(KERN_WARNING + "XENBUS Failed to release watch %s: %i\n", + watch->node, err); + + up_read(&xs_state.watch_mutex); + + /* Make sure there are no callbacks running currently (unless + its us) */ + if (current->pid != xenwatch_pid) + mutex_lock(&xenwatch_mutex); + + /* Cancel pending watch events. */ + spin_lock(&watch_events_lock); + list_for_each_entry_safe(msg, tmp, &watch_events, list) { + if (msg->u.watch.handle != watch) + continue; + list_del(&msg->list); + kfree(msg->u.watch.vec); + kfree(msg); + } + spin_unlock(&watch_events_lock); + + if (current->pid != xenwatch_pid) + mutex_unlock(&xenwatch_mutex); +} +EXPORT_SYMBOL_GPL(unregister_xenbus_watch); + +void xs_suspend(void) +{ + down_write(&xs_state.transaction_mutex); + down_write(&xs_state.watch_mutex); + mutex_lock(&xs_state.request_mutex); + mutex_lock(&xs_state.response_mutex); +} + +void xs_resume(void) +{ + struct xenbus_watch *watch; + char token[sizeof(watch) * 2 + 1]; + + mutex_unlock(&xs_state.response_mutex); + mutex_unlock(&xs_state.request_mutex); + up_write(&xs_state.transaction_mutex); + + /* No need for watches_lock: the watch_mutex is sufficient. */ + list_for_each_entry(watch, &watches, list) { + sprintf(token, "%lX", (long)watch); + xs_watch(watch->node, token); + } + + up_write(&xs_state.watch_mutex); +} + +void xs_suspend_cancel(void) +{ + mutex_unlock(&xs_state.response_mutex); + mutex_unlock(&xs_state.request_mutex); + up_write(&xs_state.watch_mutex); + up_write(&xs_state.transaction_mutex); +} + +static int xenwatch_thread(void *unused) +{ + struct list_head *ent; + struct xs_stored_msg *msg; + + for (;;) { + wait_event_interruptible(watch_events_waitq, + !list_empty(&watch_events)); + + if (kthread_should_stop()) + break; + + mutex_lock(&xenwatch_mutex); + + spin_lock(&watch_events_lock); + ent = watch_events.next; + if (ent != &watch_events) + list_del(ent); + spin_unlock(&watch_events_lock); + + if (ent != &watch_events) { + msg = list_entry(ent, struct xs_stored_msg, list); + msg->u.watch.handle->callback( + msg->u.watch.handle, + (const char **)msg->u.watch.vec, + msg->u.watch.vec_size); + kfree(msg->u.watch.vec); + kfree(msg); + } + + mutex_unlock(&xenwatch_mutex); + } + + return 0; +} + +static int process_msg(void) +{ + struct xs_stored_msg *msg; + char *body; + int err; + + /* + * We must disallow save/restore while reading a xenstore message. + * A partial read across s/r leaves us out of sync with xenstored. + */ + for (;;) { + err = xb_wait_for_data_to_read(); + if (err) + return err; + mutex_lock(&xs_state.response_mutex); + if (xb_data_to_read()) + break; + /* We raced with save/restore: pending data 'disappeared'. */ + mutex_unlock(&xs_state.response_mutex); + } + + + msg = kmalloc(sizeof(*msg), GFP_KERNEL); + if (msg == NULL) { + err = -ENOMEM; + goto out; + } + + err = xb_read(&msg->hdr, sizeof(msg->hdr)); + if (err) { + kfree(msg); + goto out; + } + + body = kmalloc(msg->hdr.len + 1, GFP_KERNEL); + if (body == NULL) { + kfree(msg); + err = -ENOMEM; + goto out; + } + + err = xb_read(body, msg->hdr.len); + if (err) { + kfree(body); + kfree(msg); + goto out; + } + body[msg->hdr.len] = '\0'; + + if (msg->hdr.type == XS_WATCH_EVENT) { + msg->u.watch.vec = split(body, msg->hdr.len, + &msg->u.watch.vec_size); + if (IS_ERR(msg->u.watch.vec)) { + kfree(msg); + err = PTR_ERR(msg->u.watch.vec); + goto out; + } + + spin_lock(&watches_lock); + msg->u.watch.handle = find_watch( + msg->u.watch.vec[XS_WATCH_TOKEN]); + if (msg->u.watch.handle != NULL) { + spin_lock(&watch_events_lock); + list_add_tail(&msg->list, &watch_events); + wake_up(&watch_events_waitq); + spin_unlock(&watch_events_lock); + } else { + kfree(msg->u.watch.vec); + kfree(msg); + } + spin_unlock(&watches_lock); + } else { + msg->u.reply.body = body; + spin_lock(&xs_state.reply_lock); + list_add_tail(&msg->list, &xs_state.reply_list); + spin_unlock(&xs_state.reply_lock); + wake_up(&xs_state.reply_waitq); + } + + out: + mutex_unlock(&xs_state.response_mutex); + return err; +} + +static int xenbus_thread(void *unused) +{ + int err; + + for (;;) { + err = process_msg(); + if (err) + printk(KERN_WARNING "XENBUS error %d while reading " + "message\n", err); + if (kthread_should_stop()) + break; + } + + return 0; +} + +int xs_init(void) +{ + int err; + struct task_struct *task; + + INIT_LIST_HEAD(&xs_state.reply_list); + spin_lock_init(&xs_state.reply_lock); + init_waitqueue_head(&xs_state.reply_waitq); + + mutex_init(&xs_state.request_mutex); + mutex_init(&xs_state.response_mutex); + init_rwsem(&xs_state.transaction_mutex); + init_rwsem(&xs_state.watch_mutex); + + /* Initialize the shared memory rings to talk to xenstored */ + err = xb_init_comms(); + if (err) + return err; + + task = kthread_run(xenwatch_thread, NULL, "xenwatch"); + if (IS_ERR(task)) + return PTR_ERR(task); + xenwatch_pid = task->pid; + + task = kthread_run(xenbus_thread, NULL, "xenbus"); + if (IS_ERR(task)) + return PTR_ERR(task); + + return 0; +} |
