diff options
Diffstat (limited to 'drivers/xen/xenbus/xenbus_client.c')
| -rw-r--r-- | drivers/xen/xenbus/xenbus_client.c | 90 |
1 files changed, 66 insertions, 24 deletions
diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c index 7b3e973..7e49527 100644 --- a/drivers/xen/xenbus/xenbus_client.c +++ b/drivers/xen/xenbus/xenbus_client.c @@ -133,17 +133,12 @@ int xenbus_watch_pathfmt(struct xenbus_device *dev, } EXPORT_SYMBOL_GPL(xenbus_watch_pathfmt); +static void xenbus_switch_fatal(struct xenbus_device *, int, int, + const char *, ...); -/** - * xenbus_switch_state - * @dev: xenbus device - * @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) +static int +__xenbus_switch_state(struct xenbus_device *dev, + enum xenbus_state state, int depth) { /* 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 @@ -152,35 +147,65 @@ int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state state) 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. - + Note that, because of this cached value of our state, this + function will not take a caller's Xenstore transaction + (something it was trying to in the past) because dev->state + would not get reset if the transaction was aborted. */ + struct xenbus_transaction xbt; int current_state; - int err; + int err, abort; if (state == dev->state) return 0; - err = xenbus_scanf(XBT_NIL, dev->nodename, "state", "%d", - ¤t_state); - if (err != 1) +again: + abort = 1; + + err = xenbus_transaction_start(&xbt); + if (err) { + xenbus_switch_fatal(dev, depth, err, "starting transaction"); return 0; + } + + err = xenbus_scanf(xbt, dev->nodename, "state", "%d", ¤t_state); + if (err != 1) + goto abort; - err = xenbus_printf(XBT_NIL, dev->nodename, "state", "%d", state); + err = xenbus_printf(xbt, dev->nodename, "state", "%d", state); if (err) { - if (state != XenbusStateClosing) /* Avoid looping */ - xenbus_dev_fatal(dev, err, "writing new state"); - return err; + xenbus_switch_fatal(dev, depth, err, "writing new state"); + goto abort; } - dev->state = state; + abort = 0; +abort: + err = xenbus_transaction_end(xbt, abort); + if (err) { + if (err == -EAGAIN && !abort) + goto again; + xenbus_switch_fatal(dev, depth, err, "ending transaction"); + } else + dev->state = state; return 0; } + +/** + * xenbus_switch_state + * @dev: xenbus device + * @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) +{ + return __xenbus_switch_state(dev, state, 0); +} + EXPORT_SYMBOL_GPL(xenbus_switch_state); int xenbus_frontend_closed(struct xenbus_device *dev) @@ -284,6 +309,23 @@ void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt, ...) EXPORT_SYMBOL_GPL(xenbus_dev_fatal); /** + * Equivalent to xenbus_dev_fatal(dev, err, fmt, args), but helps + * avoiding recursion within xenbus_switch_state. + */ +static void xenbus_switch_fatal(struct xenbus_device *dev, int depth, int err, + const char *fmt, ...) +{ + va_list ap; + + va_start(ap, fmt); + xenbus_va_dev_error(dev, err, fmt, ap); + va_end(ap); + + if (!depth) + __xenbus_switch_state(dev, XenbusStateClosing, 1); +} + +/** * xenbus_grant_ring * @dev: xenbus device * @ring_mfn: mfn of ring to grant |