Commit 5362855a authored by Vitaly Kuznetsov's avatar Vitaly Kuznetsov Committed by David S. Miller
Browse files

netvsc: get rid of completion timeouts 



I'm hitting 5 second timeout in rndis_filter_set_rss_param() while setting
RSS parameters for the device. When this happens we end up returning
-ETIMEDOUT from the function and rndis_filter_device_add() falls back to
setting

        net_device->max_chn = 1;
        net_device->num_chn = 1;
        net_device->num_sc_offered = 0;

but after a moment the rndis request succeeds and subchannels start to
appear. netvsc_sc_open() does unconditional nvscdev->num_sc_offered-- and
it becomes U32_MAX-1. Consequent rndis_filter_device_remove() will hang
while waiting for all U32_MAX-1 subchannels to appear and this is not
going to happen.

The immediate issue could be solved by adding num_sc_offered > 0 check to
netvsc_sc_open() but we're getting out of sync with the host and it's not
easy to adjust things later, e.g. in this particular case we'll be creating
queues without a user request for it and races are expected. Same applies
to other parts of the driver which have the same completion timeout.

Following the trend in drivers/hv/* code I suggest we remove all these
timeouts completely. As a guest we can always trust the host we're running
on and if the host screws things up there is no easy way to recover anyway.

Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: default avatarHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent adba931f

drivers/net/hyperv/netvsc.c

+3 −11
Original line number Diff line number Diff line
@@ -244,7 +244,6 @@ static int netvsc_destroy_buf(struct hv_device *device) 
static int netvsc_init_buf(struct hv_device *device)

{

	int ret = 0;

	unsigned long t;

	struct netvsc_device *net_device;

	struct nvsp_message *init_packet;

	struct net_device *ndev;
@@ -305,9 +304,7 @@ static int netvsc_init_buf(struct hv_device *device) 
		goto cleanup;

	}



	t = wait_for_completion_timeout(&net_device->channel_init_wait, 5*HZ);

	BUG_ON(t == 0);



	wait_for_completion(&net_device->channel_init_wait);



	/* Check the response */

	if (init_packet->msg.v1_msg.
@@ -390,8 +387,7 @@ static int netvsc_init_buf(struct hv_device *device) 
		goto cleanup;

	}



	t = wait_for_completion_timeout(&net_device->channel_init_wait, 5*HZ);

	BUG_ON(t == 0);

	wait_for_completion(&net_device->channel_init_wait);



	/* Check the response */

	if (init_packet->msg.v1_msg.
@@ -445,7 +441,6 @@ static int negotiate_nvsp_ver(struct hv_device *device, 
{

	struct net_device *ndev = hv_get_drvdata(device);

	int ret;

	unsigned long t;



	memset(init_packet, 0, sizeof(struct nvsp_message));

	init_packet->hdr.msg_type = NVSP_MSG_TYPE_INIT;
@@ -462,10 +457,7 @@ static int negotiate_nvsp_ver(struct hv_device *device, 
	if (ret != 0)

		return ret;



	t = wait_for_completion_timeout(&net_device->channel_init_wait, 5*HZ);



	if (t == 0)

		return -ETIMEDOUT;

	wait_for_completion(&net_device->channel_init_wait);



	if (init_packet->msg.init_msg.init_complete.status !=

	    NVSP_STAT_SUCCESS)

drivers/net/hyperv/rndis_filter.c

+28 −89
Original line number Diff line number Diff line
@@ -466,7 +466,6 @@ static int rndis_filter_query_device(struct rndis_device *dev, u32 oid, 
	struct rndis_query_request *query;

	struct rndis_query_complete *query_complete;

	int ret = 0;

	unsigned long t;



	if (!result)

		return -EINVAL;
@@ -503,11 +502,7 @@ static int rndis_filter_query_device(struct rndis_device *dev, u32 oid, 
	if (ret != 0)

		goto cleanup;



	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);

	if (t == 0) {

		ret = -ETIMEDOUT;

		goto cleanup;

	}

	wait_for_completion(&request->wait_event);



	/* Copy the response back */

	query_complete = &request->response_msg.msg.query_complete;
@@ -556,7 +551,6 @@ int rndis_filter_set_device_mac(struct net_device *ndev, char *mac) 
	u32 extlen = sizeof(struct rndis_config_parameter_info) +

		2*NWADR_STRLEN + 4*ETH_ALEN;

	int ret;

	unsigned long t;



	request = get_rndis_request(rdev, RNDIS_MSG_SET,

		RNDIS_MESSAGE_SIZE(struct rndis_set_request) + extlen);
@@ -597,22 +591,14 @@ int rndis_filter_set_device_mac(struct net_device *ndev, char *mac) 
	if (ret != 0)

		goto cleanup;



	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);

	if (t == 0) {

		netdev_err(ndev, "timeout before we got a set response...\n");

		/*

		 * can't put_rndis_request, since we may still receive a

		 * send-completion.

		 */

		return -EBUSY;

	} else {

	wait_for_completion(&request->wait_event);



	set_complete = &request->response_msg.msg.set_complete;

	if (set_complete->status != RNDIS_STATUS_SUCCESS) {

		netdev_err(ndev, "Fail to set MAC on host side:0x%x\n",

			   set_complete->status);

		ret = -EINVAL;

	}

	}



cleanup:

	put_rndis_request(rdev, request);
@@ -631,7 +617,6 @@ rndis_filter_set_offload_params(struct net_device *ndev, 
	struct rndis_set_complete *set_complete;

	u32 extlen = sizeof(struct ndis_offload_params);

	int ret;

	unsigned long t;

	u32 vsp_version = nvdev->nvsp_version;



	if (vsp_version <= NVSP_PROTOCOL_VERSION_4) {
@@ -665,21 +650,13 @@ rndis_filter_set_offload_params(struct net_device *ndev, 
	if (ret != 0)

		goto cleanup;



	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);

	if (t == 0) {

		netdev_err(ndev, "timeout before we got aOFFLOAD set response...\n");

		/* can't put_rndis_request, since we may still receive a

		 * send-completion.

		 */

		return -EBUSY;

	} else {

	wait_for_completion(&request->wait_event);

	set_complete = &request->response_msg.msg.set_complete;

	if (set_complete->status != RNDIS_STATUS_SUCCESS) {

		netdev_err(ndev, "Fail to set offload on host side:0x%x\n",

			   set_complete->status);

		ret = -EINVAL;

	}

	}



cleanup:

	put_rndis_request(rdev, request);
@@ -706,7 +683,6 @@ static int rndis_filter_set_rss_param(struct rndis_device *rdev, int num_queue) 
	u32 *itab;

	u8 *keyp;

	int i, ret;

	unsigned long t;



	request = get_rndis_request(

			rdev, RNDIS_MSG_SET,
@@ -749,21 +725,13 @@ static int rndis_filter_set_rss_param(struct rndis_device *rdev, int num_queue) 
	if (ret != 0)

		goto cleanup;



	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);

	if (t == 0) {

		netdev_err(ndev, "timeout before we got a set response...\n");

		/* can't put_rndis_request, since we may still receive a

		 * send-completion.

		 */

		return -ETIMEDOUT;

	} else {

	wait_for_completion(&request->wait_event);

	set_complete = &request->response_msg.msg.set_complete;

	if (set_complete->status != RNDIS_STATUS_SUCCESS) {

		netdev_err(ndev, "Fail to set RSS parameters:0x%x\n",

			   set_complete->status);

		ret = -EINVAL;

	}

	}



cleanup:

	put_rndis_request(rdev, request);
@@ -791,8 +759,6 @@ int rndis_filter_set_packet_filter(struct rndis_device *dev, u32 new_filter) 
	struct rndis_set_complete *set_complete;

	u32 status;

	int ret;

	unsigned long t;

	struct net_device *ndev = dev->ndev;



	request = get_rndis_request(dev, RNDIS_MSG_SET,

			RNDIS_MESSAGE_SIZE(struct rndis_set_request) +
@@ -815,26 +781,14 @@ int rndis_filter_set_packet_filter(struct rndis_device *dev, u32 new_filter) 
	if (ret != 0)

		goto cleanup;



	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);

	wait_for_completion(&request->wait_event);



	if (t == 0) {

		netdev_err(ndev,

			"timeout before we got a set response...\n");

		ret = -ETIMEDOUT;

		/*

		 * We can't deallocate the request since we may still receive a

		 * send completion for it.

		 */

		goto exit;

	} else {

	set_complete = &request->response_msg.msg.set_complete;

	status = set_complete->status;

	}



cleanup:

	if (request)

		put_rndis_request(dev, request);

exit:

	return ret;

}
@@ -846,7 +800,6 @@ static int rndis_filter_init_device(struct rndis_device *dev) 
	struct rndis_initialize_complete *init_complete;

	u32 status;

	int ret;

	unsigned long t;

	struct netvsc_device *nvdev = net_device_to_netvsc_device(dev->ndev);



	request = get_rndis_request(dev, RNDIS_MSG_INIT,
@@ -870,12 +823,7 @@ static int rndis_filter_init_device(struct rndis_device *dev) 
		goto cleanup;

	}



	t = wait_for_completion_timeout(&request->wait_event, 5*HZ);



	if (t == 0) {

		ret = -ETIMEDOUT;

		goto cleanup;

	}

	wait_for_completion(&request->wait_event);



	init_complete = &request->response_msg.msg.init_complete;

	status = init_complete->status;
@@ -1008,7 +956,6 @@ int rndis_filter_device_add(struct hv_device *dev, 
	struct netvsc_device_info *device_info = additional_info;

	struct ndis_offload_params offloads;

	struct nvsp_message *init_packet;

	unsigned long t;

	struct ndis_recv_scale_cap rsscap;

	u32 rsscap_size = sizeof(struct ndis_recv_scale_cap);

	u32 mtu, size;
@@ -1151,11 +1098,8 @@ int rndis_filter_device_add(struct hv_device *dev, 
			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);

	if (ret)

		goto out;

	t = wait_for_completion_timeout(&net_device->channel_init_wait, 5*HZ);

	if (t == 0) {

		ret = -ETIMEDOUT;

		goto out;

	}

	wait_for_completion(&net_device->channel_init_wait);



	if (init_packet->msg.v5_msg.subchn_comp.status !=

	    NVSP_STAT_SUCCESS) {

		ret = -ENODEV;
@@ -1192,17 +1136,12 @@ void rndis_filter_device_remove(struct hv_device *dev) 
{

	struct netvsc_device *net_dev = hv_device_to_netvsc_device(dev);

	struct rndis_device *rndis_dev = net_dev->extension;

	unsigned long t;



	/* If not all subchannel offers are complete, wait for them until

	 * completion to avoid race.

	 */

	while (net_dev->num_sc_offered > 0) {

		t = wait_for_completion_timeout(&net_dev->channel_init_wait,

						10 * HZ);

		if (t == 0)

			WARN(1, "Netvsc: Waiting for sub-channel processing");

	}

	if (net_dev->num_sc_offered > 0)

		wait_for_completion(&net_dev->channel_init_wait);



	/* Halt and release the rndis device */

	rndis_filter_halt_device(rndis_dev);

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