[PATCH RESEND1 03/12] ALSA: vsnd: Implement Xen bus state handling

[Oleksandr Andrushchenko]

From: Oleksandr Andrushchenko 

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 
---
 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(_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(_info->mutex);
+   xdrv_be_on_disconnected(drv_info);
+   mutex_unlock(_info->mutex);
+   xenbus_switch_state(xb_dev, XenbusStateInitialising);
+   break;
+
+   case XenbusStateInitWait:
+   if (xb_dev->state != XenbusStateInitialising)
+   break;
+
+   mutex_lock(_info->mutex);
+   ret = xdrv_be_on_initwait(drv_info);
+   mutex_unlock(_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(_info->mutex);
+   ret = xdrv_be_on_connected(drv_info);
+   mutex_unlock(_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(_info->mutex);
+   xdrv_be_on_disconnected(drv_info);
+   mutex_unlock(_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(_info->io_lock);
mutex_init(_info->mutex);
dev_set_drvdata(_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);
 
+   xenbus_switch_state(dev, XenbusStateClosed);
mutex_lock(_info->mutex);
xdrv_remove_internal(drv_info);
mutex_unlock(_info->mutex);
-- 
2.7.4

[PATCH RESEND1 03/12] ALSA: vsnd: Implement Xen bus state handling

[Oleksandr Andrushchenko]

From: Oleksandr Andrushchenko 

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 
---
 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(_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(_info->mutex);
+   xdrv_be_on_disconnected(drv_info);
+   mutex_unlock(_info->mutex);
+   xenbus_switch_state(xb_dev, XenbusStateInitialising);
+   break;
+
+   case XenbusStateInitWait:
+   if (xb_dev->state != XenbusStateInitialising)
+   break;
+
+   mutex_lock(_info->mutex);
+   ret = xdrv_be_on_initwait(drv_info);
+   mutex_unlock(_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(_info->mutex);
+   ret = xdrv_be_on_connected(drv_info);
+   mutex_unlock(_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(_info->mutex);
+   xdrv_be_on_disconnected(drv_info);
+   mutex_unlock(_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(_info->io_lock);
mutex_init(_info->mutex);
dev_set_drvdata(_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);
 
+   xenbus_switch_state(dev, XenbusStateClosed);
mutex_lock(_info->mutex);
xdrv_remove_internal(drv_info);
mutex_unlock(_info->mutex);
-- 
2.7.4