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path: root/drivers/hv/channel_mgmt.c
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Diffstat (limited to 'drivers/hv/channel_mgmt.c')
-rw-r--r--drivers/hv/channel_mgmt.c69
1 files changed, 53 insertions, 16 deletions
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 685572bae1f0..4bbb8dea4727 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -427,7 +427,6 @@ void vmbus_free_channels(void)
{
struct vmbus_channel *channel, *tmp;
- mutex_lock(&vmbus_connection.channel_mutex);
list_for_each_entry_safe(channel, tmp, &vmbus_connection.chn_list,
listentry) {
/* hv_process_channel_removal() needs this */
@@ -435,7 +434,6 @@ void vmbus_free_channels(void)
vmbus_device_unregister(channel->device_obj);
}
- mutex_unlock(&vmbus_connection.channel_mutex);
}
/*
@@ -482,8 +480,10 @@ static void vmbus_process_offer(struct vmbus_channel *newchannel)
list_add_tail(&newchannel->sc_list, &channel->sc_list);
channel->num_sc++;
spin_unlock_irqrestore(&channel->lock, flags);
- } else
+ } else {
+ atomic_dec(&vmbus_connection.offer_in_progress);
goto err_free_chan;
+ }
}
dev_type = hv_get_dev_type(newchannel);
@@ -510,6 +510,7 @@ static void vmbus_process_offer(struct vmbus_channel *newchannel)
if (!fnew) {
if (channel->sc_creation_callback != NULL)
channel->sc_creation_callback(newchannel);
+ atomic_dec(&vmbus_connection.offer_in_progress);
return;
}
@@ -531,9 +532,7 @@ static void vmbus_process_offer(struct vmbus_channel *newchannel)
* binding which eventually invokes the device driver's AddDevice()
* method.
*/
- mutex_lock(&vmbus_connection.channel_mutex);
ret = vmbus_device_register(newchannel->device_obj);
- mutex_unlock(&vmbus_connection.channel_mutex);
if (ret != 0) {
pr_err("unable to add child device object (relid %d)\n",
@@ -541,6 +540,8 @@ static void vmbus_process_offer(struct vmbus_channel *newchannel)
kfree(newchannel->device_obj);
goto err_deq_chan;
}
+
+ atomic_dec(&vmbus_connection.offer_in_progress);
return;
err_deq_chan:
@@ -796,6 +797,7 @@ static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
newchannel = alloc_channel();
if (!newchannel) {
vmbus_release_relid(offer->child_relid);
+ atomic_dec(&vmbus_connection.offer_in_progress);
pr_err("Unable to allocate channel object\n");
return;
}
@@ -842,16 +844,38 @@ static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
rescind = (struct vmbus_channel_rescind_offer *)hdr;
+ /*
+ * The offer msg and the corresponding rescind msg
+ * from the host are guranteed to be ordered -
+ * offer comes in first and then the rescind.
+ * Since we process these events in work elements,
+ * and with preemption, we may end up processing
+ * the events out of order. Given that we handle these
+ * work elements on the same CPU, this is possible only
+ * in the case of preemption. In any case wait here
+ * until the offer processing has moved beyond the
+ * point where the channel is discoverable.
+ */
+
+ while (atomic_read(&vmbus_connection.offer_in_progress) != 0) {
+ /*
+ * We wait here until any channel offer is currently
+ * being processed.
+ */
+ msleep(1);
+ }
+
mutex_lock(&vmbus_connection.channel_mutex);
channel = relid2channel(rescind->child_relid);
+ mutex_unlock(&vmbus_connection.channel_mutex);
if (channel == NULL) {
/*
- * This is very impossible, because in
- * vmbus_process_offer(), we have already invoked
- * vmbus_release_relid() on error.
+ * We failed in processing the offer message;
+ * we would have cleaned up the relid in that
+ * failure path.
*/
- goto out;
+ return;
}
spin_lock_irqsave(&channel->lock, flags);
@@ -863,7 +887,7 @@ static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
if (channel->device_obj) {
if (channel->chn_rescind_callback) {
channel->chn_rescind_callback(channel);
- goto out;
+ return;
}
/*
* We will have to unregister this device from the
@@ -874,13 +898,26 @@ static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
vmbus_device_unregister(channel->device_obj);
put_device(dev);
}
- } else {
- hv_process_channel_removal(channel,
- channel->offermsg.child_relid);
}
-
-out:
- mutex_unlock(&vmbus_connection.channel_mutex);
+ if (channel->primary_channel != NULL) {
+ /*
+ * Sub-channel is being rescinded. Following is the channel
+ * close sequence when initiated from the driveri (refer to
+ * vmbus_close() for details):
+ * 1. Close all sub-channels first
+ * 2. Then close the primary channel.
+ */
+ if (channel->state == CHANNEL_OPEN_STATE) {
+ /*
+ * The channel is currently not open;
+ * it is safe for us to cleanup the channel.
+ */
+ mutex_lock(&vmbus_connection.channel_mutex);
+ hv_process_channel_removal(channel,
+ channel->offermsg.child_relid);
+ mutex_unlock(&vmbus_connection.channel_mutex);
+ }
+ }
}
void vmbus_hvsock_device_unregister(struct vmbus_channel *channel)