Commit ccb61f8a authored by K. Y. Srinivasan's avatar K. Y. Srinivasan Committed by Greg Kroah-Hartman
Browse files

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guest and once the channel is rescinded, the host does not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: default avatarK. Y. Srinivasan <kys@microsoft.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 523b9408

drivers/hv/channel.c

+18 −0
Original line number Diff line number Diff line
@@ -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);

drivers/hv/channel_mgmt.c

+25 −0
Original line number Diff line number Diff line
@@ -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);

include/linux/hyperv.h

+1 −0
Original line number Diff line number Diff line
@@ -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;

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