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
Acked-by: Haiyang Zhang
---
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 719cb35..89e0dea 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -249,7 +249,6 @@ 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;
@@ -310,9 +309,7 @@ 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.
@@ -395,8 +392,7 @@ 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.
@@ -450,7 +446,6 @@ 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;
@@ -467,10 +462,7 @@ 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 97c292b..f5bf267 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;
@@ -558,7 +553,6 @@ int rndis_filter_set_device_mac(struct hv_device *hdev,
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,
