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authorStephen Hemminger <stephen@networkplumber.org>2017-09-06 13:53:05 -0700
committerDavid S. Miller <davem@davemloft.net>2017-09-11 14:21:30 -0700
commit8195b1396ec86dddbba443c74b2188b423556c74 (patch)
treea09b122fb16f158c00385cfc07bcea9e88722d59
parent4400081b631af69abc63cea3352680e3d85e0c39 (diff)
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hv_netvsc: fix deadlock on hotplug
When a virtual device is added dynamically (via host console), then the vmbus sends an offer message for the primary channel. The processing of this message for networking causes the network device to then initialize the sub channels. The problem is that setting up the sub channels needs to wait until the subsequent subchannel offers have been processed. These offers come in on the same ring buffer and work queue as where the primary offer is being processed; leading to a deadlock. This did not happen in older kernels, because the sub channel waiting logic was broken (it wasn't really waiting). The solution is to do the sub channel setup in its own work queue context that is scheduled by the primary channel setup; and then happens later. Fixes: 732e49850c5e ("netvsc: fix race on sub channel creation") Reported-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/hyperv/hyperv_net.h3
-rw-r--r--drivers/net/hyperv/netvsc.c3
-rw-r--r--drivers/net/hyperv/netvsc_drv.c11
-rw-r--r--drivers/net/hyperv/rndis_filter.c122
4 files changed, 94 insertions, 45 deletions
diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index ec546da86683..d98cdfb1536b 100644
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -204,6 +204,8 @@ int netvsc_recv_callback(struct net_device *net,
const struct ndis_pkt_8021q_info *vlan);
void netvsc_channel_cb(void *context);
int netvsc_poll(struct napi_struct *napi, int budget);
+
+void rndis_set_subchannel(struct work_struct *w);
bool rndis_filter_opened(const struct netvsc_device *nvdev);
int rndis_filter_open(struct netvsc_device *nvdev);
int rndis_filter_close(struct netvsc_device *nvdev);
@@ -782,6 +784,7 @@ struct netvsc_device {
u32 num_chn;
atomic_t open_chn;
+ struct work_struct subchan_work;
wait_queue_head_t subchan_open;
struct rndis_device *extension;
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 0062b802676f..a5511b7326af 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -81,6 +81,7 @@ static struct netvsc_device *alloc_net_device(void)
init_completion(&net_device->channel_init_wait);
init_waitqueue_head(&net_device->subchan_open);
+ INIT_WORK(&net_device->subchan_work, rndis_set_subchannel);
return net_device;
}
@@ -557,6 +558,8 @@ void netvsc_device_remove(struct hv_device *device)
= rtnl_dereference(net_device_ctx->nvdev);
int i;
+ cancel_work_sync(&net_device->subchan_work);
+
netvsc_disconnect_vsp(device);
RCU_INIT_POINTER(net_device_ctx->nvdev, NULL);
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 165ba4b3b423..c538a4f15f3b 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -853,10 +853,7 @@ static int netvsc_set_channels(struct net_device *net,
rndis_filter_device_remove(dev, nvdev);
nvdev = rndis_filter_device_add(dev, &device_info);
- if (!IS_ERR(nvdev)) {
- netif_set_real_num_tx_queues(net, nvdev->num_chn);
- netif_set_real_num_rx_queues(net, nvdev->num_chn);
- } else {
+ if (IS_ERR(nvdev)) {
ret = PTR_ERR(nvdev);
device_info.num_chn = orig;
nvdev = rndis_filter_device_add(dev, &device_info);
@@ -1954,9 +1951,6 @@ static int netvsc_probe(struct hv_device *dev,
NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX;
net->vlan_features = net->features;
- netif_set_real_num_tx_queues(net, nvdev->num_chn);
- netif_set_real_num_rx_queues(net, nvdev->num_chn);
-
netdev_lockdep_set_classes(net);
/* MTU range: 68 - 1500 or 65521 */
@@ -2012,9 +2006,10 @@ static int netvsc_remove(struct hv_device *dev)
if (vf_netdev)
netvsc_unregister_vf(vf_netdev);
+ unregister_netdevice(net);
+
rndis_filter_device_remove(dev,
rtnl_dereference(ndev_ctx->nvdev));
- unregister_netdevice(net);
rtnl_unlock();
hv_set_drvdata(dev, NULL);
diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c
index 69c40b8fccc3..731bc7cc6f43 100644
--- a/drivers/net/hyperv/rndis_filter.c
+++ b/drivers/net/hyperv/rndis_filter.c
@@ -1039,8 +1039,6 @@ static void netvsc_sc_open(struct vmbus_channel *new_sc)
/* Set the channel before opening.*/
nvchan->channel = new_sc;
- netif_napi_add(ndev, &nvchan->napi,
- netvsc_poll, NAPI_POLL_WEIGHT);
ret = vmbus_open(new_sc, nvscdev->ring_size * PAGE_SIZE,
nvscdev->ring_size * PAGE_SIZE, NULL, 0,
@@ -1048,12 +1046,88 @@ static void netvsc_sc_open(struct vmbus_channel *new_sc)
if (ret == 0)
napi_enable(&nvchan->napi);
else
- netif_napi_del(&nvchan->napi);
+ netdev_notice(ndev, "sub channel open failed: %d\n", ret);
atomic_inc(&nvscdev->open_chn);
wake_up(&nvscdev->subchan_open);
}
+/* Open sub-channels after completing the handling of the device probe.
+ * This breaks overlap of processing the host message for the
+ * new primary channel with the initialization of sub-channels.
+ */
+void rndis_set_subchannel(struct work_struct *w)
+{
+ struct netvsc_device *nvdev
+ = container_of(w, struct netvsc_device, subchan_work);
+ struct nvsp_message *init_packet = &nvdev->channel_init_pkt;
+ struct net_device_context *ndev_ctx;
+ struct rndis_device *rdev;
+ struct net_device *ndev;
+ struct hv_device *hv_dev;
+ int i, ret;
+
+ if (!rtnl_trylock()) {
+ schedule_work(w);
+ return;
+ }
+
+ rdev = nvdev->extension;
+ if (!rdev)
+ goto unlock; /* device was removed */
+
+ ndev = rdev->ndev;
+ ndev_ctx = netdev_priv(ndev);
+ hv_dev = ndev_ctx->device_ctx;
+
+ memset(init_packet, 0, sizeof(struct nvsp_message));
+ init_packet->hdr.msg_type = NVSP_MSG5_TYPE_SUBCHANNEL;
+ init_packet->msg.v5_msg.subchn_req.op = NVSP_SUBCHANNEL_ALLOCATE;
+ init_packet->msg.v5_msg.subchn_req.num_subchannels =
+ nvdev->num_chn - 1;
+ ret = vmbus_sendpacket(hv_dev->channel, init_packet,
+ sizeof(struct nvsp_message),
+ (unsigned long)init_packet,
+ VM_PKT_DATA_INBAND,
+ VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
+ if (ret) {
+ netdev_err(ndev, "sub channel allocate send failed: %d\n", ret);
+ goto failed;
+ }
+
+ wait_for_completion(&nvdev->channel_init_wait);
+ if (init_packet->msg.v5_msg.subchn_comp.status != NVSP_STAT_SUCCESS) {
+ netdev_err(ndev, "sub channel request failed\n");
+ goto failed;
+ }
+
+ nvdev->num_chn = 1 +
+ init_packet->msg.v5_msg.subchn_comp.num_subchannels;
+
+ /* wait for all sub channels to open */
+ wait_event(nvdev->subchan_open,
+ atomic_read(&nvdev->open_chn) == nvdev->num_chn);
+
+ /* ignore failues from setting rss parameters, still have channels */
+ rndis_filter_set_rss_param(rdev, netvsc_hash_key);
+
+ netif_set_real_num_tx_queues(ndev, nvdev->num_chn);
+ netif_set_real_num_rx_queues(ndev, nvdev->num_chn);
+
+ rtnl_unlock();
+ return;
+
+failed:
+ /* fallback to only primary channel */
+ for (i = 1; i < nvdev->num_chn; i++)
+ netif_napi_del(&nvdev->chan_table[i].napi);
+
+ nvdev->max_chn = 1;
+ nvdev->num_chn = 1;
+unlock:
+ rtnl_unlock();
+}
+
struct netvsc_device *rndis_filter_device_add(struct hv_device *dev,
struct netvsc_device_info *device_info)
{
@@ -1063,7 +1137,6 @@ struct netvsc_device *rndis_filter_device_add(struct hv_device *dev,
struct rndis_device *rndis_device;
struct ndis_offload hwcaps;
struct ndis_offload_params offloads;
- struct nvsp_message *init_packet;
struct ndis_recv_scale_cap rsscap;
u32 rsscap_size = sizeof(struct ndis_recv_scale_cap);
unsigned int gso_max_size = GSO_MAX_SIZE;
@@ -1215,9 +1288,7 @@ struct netvsc_device *rndis_filter_device_add(struct hv_device *dev,
net_device->num_chn);
atomic_set(&net_device->open_chn, 1);
-
- if (net_device->num_chn == 1)
- return net_device;
+ vmbus_set_sc_create_callback(dev->channel, netvsc_sc_open);
for (i = 1; i < net_device->num_chn; i++) {
ret = netvsc_alloc_recv_comp_ring(net_device, i);
@@ -1228,38 +1299,15 @@ struct netvsc_device *rndis_filter_device_add(struct hv_device *dev,
}
}
- vmbus_set_sc_create_callback(dev->channel, netvsc_sc_open);
+ for (i = 1; i < net_device->num_chn; i++)
+ netif_napi_add(net, &net_device->chan_table[i].napi,
+ netvsc_poll, NAPI_POLL_WEIGHT);
- init_packet = &net_device->channel_init_pkt;
- memset(init_packet, 0, sizeof(struct nvsp_message));
- init_packet->hdr.msg_type = NVSP_MSG5_TYPE_SUBCHANNEL;
- init_packet->msg.v5_msg.subchn_req.op = NVSP_SUBCHANNEL_ALLOCATE;
- init_packet->msg.v5_msg.subchn_req.num_subchannels =
- net_device->num_chn - 1;
- ret = vmbus_sendpacket(dev->channel, init_packet,
- sizeof(struct nvsp_message),
- (unsigned long)init_packet,
- VM_PKT_DATA_INBAND,
- VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
- if (ret)
- goto out;
-
- wait_for_completion(&net_device->channel_init_wait);
- if (init_packet->msg.v5_msg.subchn_comp.status != NVSP_STAT_SUCCESS) {
- ret = -ENODEV;
- goto out;
- }
+ if (net_device->num_chn > 1)
+ schedule_work(&net_device->subchan_work);
- net_device->num_chn = 1 +
- init_packet->msg.v5_msg.subchn_comp.num_subchannels;
-
- /* wait for all sub channels to open */
- wait_event(net_device->subchan_open,
- atomic_read(&net_device->open_chn) == net_device->num_chn);
-
- /* ignore failues from setting rss parameters, still have channels */
- rndis_filter_set_rss_param(rndis_device, netvsc_hash_key);
out:
+ /* if unavailable, just proceed with one queue */
if (ret) {
net_device->max_chn = 1;
net_device->num_chn = 1;
@@ -1280,10 +1328,10 @@ void rndis_filter_device_remove(struct hv_device *dev,
/* Halt and release the rndis device */
rndis_filter_halt_device(rndis_dev);
- kfree(rndis_dev);
net_dev->extension = NULL;
netvsc_device_remove(dev);
+ kfree(rndis_dev);
}
int rndis_filter_open(struct netvsc_device *nvdev)