From: Oleksandr Andrushchenko oleksandr_andrushchenko@epam.com
Initial handling for Xen bus states: implement Xen bus state machine for the front driver according to the state diagram and recovery flow from sound para-virtualized protocol: xen/interface/io/sndif.h.
Signed-off-by: Oleksandr Andrushchenko oleksandr_andrushchenko@epam.com --- sound/drivers/xen-front.c | 92 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 92 insertions(+)
diff --git a/sound/drivers/xen-front.c b/sound/drivers/xen-front.c index 8c5de7b0e7b5..c4fd21cac3a7 100644 --- a/sound/drivers/xen-front.c +++ b/sound/drivers/xen-front.c @@ -36,9 +36,99 @@ static void xdrv_remove_internal(struct xdrv_info *drv_info) { }
+static int xdrv_be_on_initwait(struct xdrv_info *drv_info) +{ + return 0; +} + +static inline int xdrv_be_on_connected(struct xdrv_info *drv_info) +{ + return 0; +} + +static inline void xdrv_be_on_disconnected(struct xdrv_info *drv_info) +{ + xdrv_remove_internal(drv_info); +} + static void xdrv_be_on_changed(struct xenbus_device *xb_dev, enum xenbus_state backend_state) { + struct xdrv_info *drv_info = dev_get_drvdata(&xb_dev->dev); + int ret; + + switch (backend_state) { + case XenbusStateReconfiguring: + /* fall through */ + case XenbusStateReconfigured: + /* fall through */ + case XenbusStateInitialised: + /* fall through */ + break; + + case XenbusStateInitialising: + if (xb_dev->state == XenbusStateInitialising) + break; + + /* recovering after backend unexpected closure */ + mutex_lock(&drv_info->mutex); + xdrv_be_on_disconnected(drv_info); + mutex_unlock(&drv_info->mutex); + xenbus_switch_state(xb_dev, XenbusStateInitialising); + break; + + case XenbusStateInitWait: + if (xb_dev->state != XenbusStateInitialising) + break; + + mutex_lock(&drv_info->mutex); + ret = xdrv_be_on_initwait(drv_info); + mutex_unlock(&drv_info->mutex); + if (ret < 0) { + xenbus_dev_fatal(xb_dev, ret, + "initializing " XENSND_DRIVER_NAME); + break; + } + + xenbus_switch_state(xb_dev, XenbusStateInitialised); + break; + + case XenbusStateConnected: + if (xb_dev->state != XenbusStateInitialised) + break; + + mutex_lock(&drv_info->mutex); + ret = xdrv_be_on_connected(drv_info); + mutex_unlock(&drv_info->mutex); + if (ret < 0) { + xenbus_dev_fatal(xb_dev, ret, + "connecting " XENSND_DRIVER_NAME); + break; + } + + xenbus_switch_state(xb_dev, XenbusStateConnected); + break; + + case XenbusStateClosing: + /* + * in this state backend starts freeing resources, + * so let it go into closed state first, so we can also + * remove ours + */ + break; + + case XenbusStateUnknown: + /* fall through */ + case XenbusStateClosed: + if (xb_dev->state == XenbusStateClosed) + break; + + mutex_lock(&drv_info->mutex); + xdrv_be_on_disconnected(drv_info); + mutex_unlock(&drv_info->mutex); + xenbus_switch_state(xb_dev, XenbusStateInitialising); + break; + } }
static int xdrv_probe(struct xenbus_device *xb_dev, @@ -56,6 +146,7 @@ static int xdrv_probe(struct xenbus_device *xb_dev, spin_lock_init(&drv_info->io_lock); mutex_init(&drv_info->mutex); dev_set_drvdata(&xb_dev->dev, drv_info); + xenbus_switch_state(xb_dev, XenbusStateInitialising); return 0; }
@@ -63,6 +154,7 @@ static int xdrv_remove(struct xenbus_device *dev) { struct xdrv_info *drv_info = dev_get_drvdata(&dev->dev);
+ xenbus_switch_state(dev, XenbusStateClosed); mutex_lock(&drv_info->mutex); xdrv_remove_internal(drv_info); mutex_unlock(&drv_info->mutex);