[PATCH net-next v3] netvsc: get rid of completion timeouts
From: Vitaly Kuznetsov <vkuznets@redhat.com>
Date: 2016-06-09 10:44:10
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: Vitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: Haiyang Zhang <haiyangz@microsoft.com>
---
Changes since v2:
- Rebase to current net-next [David Miller]
Changes since v1 RFC:
- Non-RFC
- Restore (net_dev->num_sc_offered > 0) condition in
rndis_filter_device_remove() as without it we may hang when there are no
subchannels at all.
- Remove now unused ndev in rndis_filter_set_packet_filter() to fix the build
warning reported by kbuild robot.
- Added Haiyang's ACK (hopefully it stands with the above mentioned
changes).
---
drivers/net/hyperv/netvsc.c | 14 +----
drivers/net/hyperv/rndis_filter.c | 117 +++++++++-----------------------------
2 files changed, 31 insertions(+), 100 deletions(-)
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 96f00c0..6909c32 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c@@ -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)
diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c
index 979fa44..8e830f7 100644
--- a/drivers/net/hyperv/rndis_filter.c
+++ b/drivers/net/hyperv/rndis_filter.c@@ -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);
@@ -597,21 +591,13 @@ 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 { - 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; - } + 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:
@@ -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) {
@@ -665,20 +650,12 @@ 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 { - 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; - } + 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:
@@ -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,
@@ -749,20 +725,12 @@ 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 { - 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; - } + 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:
@@ -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; - } + 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);
--
2.5.5