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Drivers: hv: vmbus: Fix a rescind handling bug 

The host can rescind a channel that has been offered to the
guest and once the channel is rescinded, the host does not
respond to any requests on that channel. Deal with the case where
the guest may be blocked waiting for a response from the host.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
K. Y. Srinivasan 2016-12-22 16:54:00 -08:00 committed by Greg Kroah-Hartman
parent 523b940870
commit ccb61f8a99
3 changed files with 44 additions and 0 deletions
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18
drivers/hv/channel.c
View File

@ -157,6 +157,7 @@ int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,
}
init_completion(&open_info->waitevent);
open_info->waiting_channel = newchannel;
open_msg = (struct vmbus_channel_open_channel *)open_info->msg;
open_msg->header.msgtype = CHANNELMSG_OPENCHANNEL;
@ -194,6 +195,11 @@ int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,
list_del(&open_info->msglistentry);
spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
if (newchannel->rescind) {
err = -ENODEV;
goto error_free_gpadl;
}
if (open_info->response.open_result.status) {
err = -EAGAIN;
goto error_free_gpadl;
@ -405,6 +411,7 @@ int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
return ret;
init_completion(&msginfo->waitevent);
msginfo->waiting_channel = channel;
gpadlmsg = (struct vmbus_channel_gpadl_header *)msginfo->msg;
gpadlmsg->header.msgtype = CHANNELMSG_GPADL_HEADER;
@ -441,6 +448,11 @@ int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
}
wait_for_completion(&msginfo->waitevent);
if (channel->rescind) {
ret = -ENODEV;
goto cleanup;
}
/* At this point, we received the gpadl created msg */
*gpadl_handle = gpadlmsg->gpadl;
@ -474,6 +486,7 @@ int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32 gpadl_handle)
return -ENOMEM;
init_completion(&info->waitevent);
info->waiting_channel = channel;
msg = (struct vmbus_channel_gpadl_teardown *)info->msg;
@ -493,6 +506,11 @@ int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32 gpadl_handle)
wait_for_completion(&info->waitevent);
if (channel->rescind) {
ret = -ENODEV;
goto post_msg_err;
}
post_msg_err:
spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
list_del(&info->msglistentry);

25
drivers/hv/channel_mgmt.c
View File

@ -147,6 +147,29 @@ static const struct {
{ HV_RDV_GUID },
};
/*
* The rescinded channel may be blocked waiting for a response from the host;
* take care of that.
*/
static void vmbus_rescind_cleanup(struct vmbus_channel *channel)
{
struct vmbus_channel_msginfo *msginfo;
unsigned long flags;
spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
msglistentry) {
if (msginfo->waiting_channel == channel) {
complete(&msginfo->waitevent);
break;
}
}
spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
}
static bool is_unsupported_vmbus_devs(const uuid_le *guid)
{
int i;
@ -825,6 +848,8 @@ static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
channel->rescind = true;
spin_unlock_irqrestore(&channel->lock, flags);
vmbus_rescind_cleanup(channel);
if (channel->device_obj) {
if (channel->chn_rescind_callback) {
channel->chn_rescind_callback(channel);

1
include/linux/hyperv.h
View File

@ -627,6 +627,7 @@ struct vmbus_channel_msginfo {
/* Synchronize the request/response if needed */
struct completion waitevent;
struct vmbus_channel *waiting_channel;
union {
struct vmbus_channel_version_supported version_supported;
struct vmbus_channel_open_result open_result;