Execute both ressind and offer messages in the same work context. This
serializes these
operations and naturally addresses the various corner cases.
Signed-off-by: K. Y. Srinivasan <k...@microsoft.com>
---
- Execute blocking operations in the per-channel work elements [Dexuan Cui
<de...@microsoft.com>]
drivers/hv/channel_mgmt.c | 115 ++++++++++++++++++++++++---------------------
1 files changed, 62 insertions(+), 53 deletions(-)
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index b933891..f8528e1 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -134,6 +134,34 @@ fw_error:
EXPORT_SYMBOL_GPL(vmbus_prep_negotiate_resp);
+static void vmbus_process_device_unregister(struct work_struct *work)
+{
+ struct device *dev;
+ struct vmbus_channel *channel = container_of(work,
+ struct vmbus_channel,
+ work);
+
+ dev = get_device(&channel->device_obj->device);
+ if (dev) {
+ vmbus_device_unregister(channel->device_obj);
+ put_device(dev);
+ }
+}
+
+static void vmbus_sc_creation_cb(struct work_struct *work)
+{
+ struct vmbus_channel *newchannel = container_of(work,
+ struct vmbus_channel,
+ work);
+ struct vmbus_channel *primary_channel = newchannel->primary_channel;
+
+ /*
+ * On entry sc_creation_callback has been already verified to
+ * be non-NULL.
+ */
+ primary_channel->sc_creation_callback(newchannel);
+}
+
/*
* alloc_channel - Allocate and initialize a vmbus channel object
*/
@@ -244,29 +272,6 @@ void hv_process_channel_removal(struct vmbus_channel
*channel, u32 relid)
free_channel(channel);
}
-/*
- * vmbus_process_rescind_offer -
- * Rescind the offer by initiating a device removal
- */
-static void vmbus_process_rescind_offer(struct work_struct *work)
-{
- struct vmbus_channel *channel = container_of(work,
- struct vmbus_channel,
- work);
- struct device *dev;
-
- if (channel->device_obj) {
- dev = get_device(&channel->device_obj->device);
- if (dev) {
- vmbus_device_unregister(channel->device_obj);
- put_device(dev);
- }
- } else {
- hv_process_channel_removal(channel,
- channel->offermsg.child_relid);
- }
-}
-
void vmbus_free_channels(void)
{
struct vmbus_channel *channel;
@@ -281,11 +286,8 @@ void vmbus_free_channels(void)
* vmbus_process_offer - Process the offer by creating a channel/device
* associated with this offer
*/
-static void vmbus_process_offer(struct work_struct *work)
+static void vmbus_process_offer(struct vmbus_channel *newchannel)
{
- struct vmbus_channel *newchannel = container_of(work,
- struct vmbus_channel,
- work);
struct vmbus_channel *channel;
bool fnew = true;
bool enq = false;
@@ -349,9 +351,19 @@ static void vmbus_process_offer(struct work_struct *work)
newchannel->state = CHANNEL_OPEN_STATE;
if (channel->sc_creation_callback != NULL)
- channel->sc_creation_callback(newchannel);
-
- goto done_init_rescind;
+ /*
+ * We need to invoke the sub-channel creation
+ * callback; invoke this in a seperate work
+ * context since we are currently running on
+ * the global work context in which we handle
+ * messages from the host.
+ */
+ INIT_WORK(&newchannel->work,
+ vmbus_sc_creation_cb);
+ queue_work(newchannel->controlwq,
+ &newchannel->work);
+
+ return;
}
goto err_free_chan;
@@ -392,15 +404,9 @@ static void vmbus_process_offer(struct work_struct *work)
kfree(newchannel->device_obj);
goto err_free_chan;
}
-done_init_rescind:
- spin_lock_irqsave(&newchannel->lock, flags);
- /* The next possible work is rescind handling */
- INIT_WORK(&newchannel->work, vmbus_process_rescind_offer);
- /* Check if rescind offer was already received */
- if (newchannel->rescind)
- queue_work(newchannel->controlwq, &newchannel->work);
- spin_unlock_irqrestore(&newchannel->lock, flags);
+
return;
+
err_free_chan:
free_channel(newchannel);
}
@@ -526,8 +532,7 @@ static void vmbus_onoffer(struct
vmbus_channel_message_header *hdr)
newchannel->monitor_grp = (u8)offer->monitorid / 32;
newchannel->monitor_bit = (u8)offer->monitorid % 32;
- INIT_WORK(&newchannel->work, vmbus_process_offer);
- queue_work(newchannel->controlwq, &newchannel->work);
+ vmbus_process_offer(newchannel);
}
/*
@@ -544,24 +549,28 @@ static void vmbus_onoffer_rescind(struct
vmbus_channel_message_header *hdr)
rescind = (struct vmbus_channel_rescind_offer *)hdr;
channel = relid2channel(rescind->child_relid);
- if (channel == NULL)
- /* Just return here, no channel found */
+ if (channel == NULL) {
+ hv_process_channel_removal(NULL, rescind->child_relid);
return;
+ }
spin_lock_irqsave(&channel->lock, flags);
channel->rescind = true;
- /*
- * channel->work.func != vmbus_process_rescind_offer means we are still
- * processing offer request and the rescind offer processing should be
- * postponed. It will be done at the very end of vmbus_process_offer()
- * as rescind flag is being checked there.
- */
- if (channel->work.func == vmbus_process_rescind_offer)
- /* work is initialized for vmbus_process_rescind_offer() from
- * vmbus_process_offer() where the channel got created */
- queue_work(channel->controlwq, &channel->work);
-
spin_unlock_irqrestore(&channel->lock, flags);
+
+ if (channel->device_obj) {
+ /*
+ * We will have to unregister this device from the
+ * driver core. Do this in the per-channel work context.
+ * Note that we are currently executing on the global
+ * workq for handling messages from the host.
+ */
+ INIT_WORK(&channel->work, vmbus_process_device_unregister);
+ queue_work(channel->controlwq, &channel->work);
+ } else {
+ hv_process_channel_removal(channel,
+ channel->offermsg.child_relid);
+ }
}
/*
--
1.7.4.1
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