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authorK. Y. Srinivasan <kys@microsoft.com>2017-11-14 06:53:33 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-11-28 16:56:26 +0100
commit7fa32e5ec28b1609abc0b797b58267f725fc3964 (patch)
tree71055aa21cc5ab790e6386adac62e9a60af93348
parentfb2c445277e7b0b4ffe10de8114bad4eccaca948 (diff)
Drivers: hv: vmbus: Fix a rescind issue
The current rescind processing code will not correctly handle the case where the host immediately rescinds a channel that has been offerred. In this case, we could be blocked in the open call and since the channel is rescinded, the host will not respond and we could be blocked forever in the vmbus open call.i Fix this problem. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/hv/channel.c10
-rw-r--r--drivers/hv/channel_mgmt.c7
-rw-r--r--include/linux/hyperv.h1
3 files changed, 13 insertions, 5 deletions
diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index 19f0cf37e0ed..ba0a092ae085 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -659,22 +659,28 @@ void vmbus_close(struct vmbus_channel *channel)
*/
return;
}
- mutex_lock(&vmbus_connection.channel_mutex);
/*
* Close all the sub-channels first and then close the
* primary channel.
*/
list_for_each_safe(cur, tmp, &channel->sc_list) {
cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
- vmbus_close_internal(cur_channel);
if (cur_channel->rescind) {
+ wait_for_completion(&cur_channel->rescind_event);
+ mutex_lock(&vmbus_connection.channel_mutex);
+ vmbus_close_internal(cur_channel);
hv_process_channel_removal(
cur_channel->offermsg.child_relid);
+ } else {
+ mutex_lock(&vmbus_connection.channel_mutex);
+ vmbus_close_internal(cur_channel);
}
+ mutex_unlock(&vmbus_connection.channel_mutex);
}
/*
* Now close the primary.
*/
+ mutex_lock(&vmbus_connection.channel_mutex);
vmbus_close_internal(channel);
mutex_unlock(&vmbus_connection.channel_mutex);
}
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index ec5454f3f4a6..c21020b69114 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -333,6 +333,7 @@ static struct vmbus_channel *alloc_channel(void)
return NULL;
spin_lock_init(&channel->lock);
+ init_completion(&channel->rescind_event);
INIT_LIST_HEAD(&channel->sc_list);
INIT_LIST_HEAD(&channel->percpu_list);
@@ -898,6 +899,7 @@ static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
/*
* Now wait for offer handling to complete.
*/
+ vmbus_rescind_cleanup(channel);
while (READ_ONCE(channel->probe_done) == false) {
/*
* We wait here until any channel offer is currently
@@ -913,7 +915,6 @@ 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);
- vmbus_rescind_cleanup(channel);
return;
}
/*
@@ -922,7 +923,6 @@ static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
*/
dev = get_device(&channel->device_obj->device);
if (dev) {
- vmbus_rescind_cleanup(channel);
vmbus_device_unregister(channel->device_obj);
put_device(dev);
}
@@ -936,13 +936,14 @@ static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
* 2. Then close the primary channel.
*/
mutex_lock(&vmbus_connection.channel_mutex);
- vmbus_rescind_cleanup(channel);
if (channel->state == CHANNEL_OPEN_STATE) {
/*
* The channel is currently not open;
* it is safe for us to cleanup the channel.
*/
hv_process_channel_removal(rescind->child_relid);
+ } else {
+ complete(&channel->rescind_event);
}
mutex_unlock(&vmbus_connection.channel_mutex);
}
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index f3e97c5f94c9..6c9336626592 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -708,6 +708,7 @@ struct vmbus_channel {
u8 monitor_bit;
bool rescind; /* got rescind msg */
+ struct completion rescind_event;
u32 ringbuffer_gpadlhandle;