[PATCH net-next] hv_netvsc: Add error handling while switching data path

[PATCH net-next] hv_netvsc: Add error handling while switching data path

[Haiyang Zhang]

Add error handling in case of failure to send switching data path message
to the host.

Reported-by: Shachar Raindel <shacharr@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>

---
 drivers/net/hyperv/hyperv_net.h |  6 +++++-
 drivers/net/hyperv/netvsc.c     | 35 +++++++++++++++++++++++++++++----
 drivers/net/hyperv/netvsc_drv.c | 18 +++++++++++------
 3 files changed, 48 insertions(+), 11 deletions(-)

diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index 59ac04a610ad..442c520ab8f3 100644
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -269,7 +269,7 @@ int rndis_filter_receive(struct net_device *ndev,
 int rndis_filter_set_device_mac(struct netvsc_device *ndev,
 				const char *mac);
 
-void netvsc_switch_datapath(struct net_device *nv_dev, bool vf);
+int netvsc_switch_datapath(struct net_device *nv_dev, bool vf);
 
 #define NVSP_INVALID_PROTOCOL_VERSION	((u32)0xFFFFFFFF)
 
@@ -1718,4 +1718,8 @@ struct rndis_message {
 #define TRANSPORT_INFO_IPV6_TCP 0x10
 #define TRANSPORT_INFO_IPV6_UDP 0x20
 
+#define RETRY_US_LO	5000
+#define RETRY_US_HI	10000
+#define RETRY_MAX	2000	/* >10 sec */
+
 #endif /* _HYPERV_NET_H */
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 5bce24731502..9d07c9ce4be2 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -31,12 +31,13 @@
  * Switch the data path from the synthetic interface to the VF
  * interface.
  */
-void netvsc_switch_datapath(struct net_device *ndev, bool vf)
+int netvsc_switch_datapath(struct net_device *ndev, bool vf)
 {
 	struct net_device_context *net_device_ctx = netdev_priv(ndev);
 	struct hv_device *dev = net_device_ctx->device_ctx;
 	struct netvsc_device *nv_dev = rtnl_dereference(net_device_ctx->nvdev);
 	struct nvsp_message *init_pkt = &nv_dev->channel_init_pkt;
+	int ret, retry = 0;
 
 	/* Block sending traffic to VF if it's about to be gone */
 	if (!vf)
@@ -51,15 +52,41 @@ void netvsc_switch_datapath(struct net_device *ndev, bool vf)
 		init_pkt->msg.v4_msg.active_dp.active_datapath =
 			NVSP_DATAPATH_SYNTHETIC;
 
+again:
 	trace_nvsp_send(ndev, init_pkt);
 
-	vmbus_sendpacket(dev->channel, init_pkt,
+	ret = vmbus_sendpacket(dev->channel, init_pkt,
 			       sizeof(struct nvsp_message),
-			       (unsigned long)init_pkt,
-			       VM_PKT_DATA_INBAND,
+			       (unsigned long)init_pkt, VM_PKT_DATA_INBAND,
 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
+
+	/* If failed to switch to/from VF, let data_path_is_vf stay false,
+	 * so we use synthetic path to send data.
+	 */
+	if (ret) {
+		if (ret != -EAGAIN) {
+			netdev_err(ndev,
+				   "Unable to send sw datapath msg, err: %d\n",
+				   ret);
+			return ret;
+		}
+
+		if (retry++ < RETRY_MAX) {
+			usleep_range(RETRY_US_LO, RETRY_US_HI);
+			goto again;
+		} else {
+			netdev_err(
+				ndev,
+				"Retry failed to send sw datapath msg, err: %d\n",
+				ret);
+			return ret;
+		}
+	}
+
 	wait_for_completion(&nv_dev->channel_init_wait);
 	net_device_ctx->data_path_is_vf = vf;
+
+	return 0;
 }
 
 /* Worker to setup sub channels on initial setup
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 97b5c9b60503..7349a70af083 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -38,9 +38,6 @@
 #include "hyperv_net.h"
 
 #define RING_SIZE_MIN	64
-#define RETRY_US_LO	5000
-#define RETRY_US_HI	10000
-#define RETRY_MAX	2000	/* >10 sec */
 
 #define LINKCHANGE_INT (2 * HZ)
 #define VF_TAKEOVER_INT (HZ / 10)
@@ -2402,6 +2399,7 @@ static int netvsc_vf_changed(struct net_device *vf_netdev, unsigned long event)
 	struct netvsc_device *netvsc_dev;
 	struct net_device *ndev;
 	bool vf_is_up = false;
+	int ret;
 
 	if (event != NETDEV_GOING_DOWN)
 		vf_is_up = netif_running(vf_netdev);
@@ -2418,9 +2416,17 @@ static int netvsc_vf_changed(struct net_device *vf_netdev, unsigned long event)
 	if (net_device_ctx->data_path_is_vf == vf_is_up)
 		return NOTIFY_OK;
 
-	netvsc_switch_datapath(ndev, vf_is_up);
-	netdev_info(ndev, "Data path switched %s VF: %s\n",
-		    vf_is_up ? "to" : "from", vf_netdev->name);
+	ret = netvsc_switch_datapath(ndev, vf_is_up);
+
+	if (ret) {
+		netdev_err(ndev,
+			   "Data path failed to switch %s VF: %s, err: %d\n",
+			   vf_is_up ? "to" : "from", vf_netdev->name, ret);
+		return NOTIFY_DONE;
+	} else {
+		netdev_info(ndev, "Data path switched %s VF: %s\n",
+			    vf_is_up ? "to" : "from", vf_netdev->name);
+	}
 
 	return NOTIFY_OK;
 }
-- 
2.25.1

Re: [PATCH net-next] hv_netvsc: Add error handling while switching data path

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (refs/heads/master):

On Mon, 29 Mar 2021 16:21:35 -0700 you wrote:
> Add error handling in case of failure to send switching data path message
> to the host.
> 
> Reported-by: Shachar Raindel <shacharr@microsoft.com>
> Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
> 
> 
> [...]

Here is the summary with links:
  - [net-next] hv_netvsc: Add error handling while switching data path
    https://git.kernel.org/netdev/net-next/c/d0922bf79817

You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html

Re: [PATCH net-next] hv_netvsc: Add error handling while switching data path

[Vitaly Kuznetsov]

Haiyang Zhang <haiyangz@microsoft.com> writes:

> Add error handling in case of failure to send switching data path message
> to the host.
>
> Reported-by: Shachar Raindel <shacharr@microsoft.com>
> Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
>
> ---
>  drivers/net/hyperv/hyperv_net.h |  6 +++++-
>  drivers/net/hyperv/netvsc.c     | 35 +++++++++++++++++++++++++++++----
>  drivers/net/hyperv/netvsc_drv.c | 18 +++++++++++------
>  3 files changed, 48 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
> index 59ac04a610ad..442c520ab8f3 100644
> --- a/drivers/net/hyperv/hyperv_net.h
> +++ b/drivers/net/hyperv/hyperv_net.h
> @@ -269,7 +269,7 @@ int rndis_filter_receive(struct net_device *ndev,
>  int rndis_filter_set_device_mac(struct netvsc_device *ndev,
>  				const char *mac);
>  
> -void netvsc_switch_datapath(struct net_device *nv_dev, bool vf);
> +int netvsc_switch_datapath(struct net_device *nv_dev, bool vf);
>  
>  #define NVSP_INVALID_PROTOCOL_VERSION	((u32)0xFFFFFFFF)
>  
> @@ -1718,4 +1718,8 @@ struct rndis_message {
>  #define TRANSPORT_INFO_IPV6_TCP 0x10
>  #define TRANSPORT_INFO_IPV6_UDP 0x20
>  
> +#define RETRY_US_LO	5000
> +#define RETRY_US_HI	10000
> +#define RETRY_MAX	2000	/* >10 sec */
> +
>  #endif /* _HYPERV_NET_H */
> diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
> index 5bce24731502..9d07c9ce4be2 100644
> --- a/drivers/net/hyperv/netvsc.c
> +++ b/drivers/net/hyperv/netvsc.c
> @@ -31,12 +31,13 @@
>   * Switch the data path from the synthetic interface to the VF
>   * interface.
>   */
> -void netvsc_switch_datapath(struct net_device *ndev, bool vf)
> +int netvsc_switch_datapath(struct net_device *ndev, bool vf)
>  {
>  	struct net_device_context *net_device_ctx = netdev_priv(ndev);
>  	struct hv_device *dev = net_device_ctx->device_ctx;
>  	struct netvsc_device *nv_dev = rtnl_dereference(net_device_ctx->nvdev);
>  	struct nvsp_message *init_pkt = &nv_dev->channel_init_pkt;
> +	int ret, retry = 0;
>  
>  	/* Block sending traffic to VF if it's about to be gone */
>  	if (!vf)
> @@ -51,15 +52,41 @@ void netvsc_switch_datapath(struct net_device *ndev, bool vf)
>  		init_pkt->msg.v4_msg.active_dp.active_datapath =
>  			NVSP_DATAPATH_SYNTHETIC;
>  
> +again:
>  	trace_nvsp_send(ndev, init_pkt);
>  
> -	vmbus_sendpacket(dev->channel, init_pkt,
> +	ret = vmbus_sendpacket(dev->channel, init_pkt,
>  			       sizeof(struct nvsp_message),
> -			       (unsigned long)init_pkt,
> -			       VM_PKT_DATA_INBAND,
> +			       (unsigned long)init_pkt, VM_PKT_DATA_INBAND,
>  			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
> +
> +	/* If failed to switch to/from VF, let data_path_is_vf stay false,
> +	 * so we use synthetic path to send data.
> +	 */
> +	if (ret) {
> +		if (ret != -EAGAIN) {
> +			netdev_err(ndev,
> +				   "Unable to send sw datapath msg, err: %d\n",
> +				   ret);
> +			return ret;
> +		}
> +
> +		if (retry++ < RETRY_MAX) {
> +			usleep_range(RETRY_US_LO, RETRY_US_HI);
> +			goto again;
> +		} else {
> +			netdev_err(
> +				ndev,
> +				"Retry failed to send sw datapath msg, err: %d\n",
> +				ret);

err is always -EAGAIN here, right?

> +			return ret;
> +		}

Nitpicking: I think we can simplify the above a bit:

	if (ret) {
		if (ret == -EAGAIN && retry++ < RETRY_MAX) {
			usleep_range(RETRY_US_LO, RETRY_US_HI);
			goto again;
		}
		netdev_err(ndev, "Unable to send sw datapath msg, err: %d\n", ret);
		return ret;
	}

> +	}
> +
>  	wait_for_completion(&nv_dev->channel_init_wait);
>  	net_device_ctx->data_path_is_vf = vf;
> +
> +	return 0;
>  }
>  
>  /* Worker to setup sub channels on initial setup
> diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
> index 97b5c9b60503..7349a70af083 100644
> --- a/drivers/net/hyperv/netvsc_drv.c
> +++ b/drivers/net/hyperv/netvsc_drv.c
> @@ -38,9 +38,6 @@
>  #include "hyperv_net.h"
>  
>  #define RING_SIZE_MIN	64
> -#define RETRY_US_LO	5000
> -#define RETRY_US_HI	10000
> -#define RETRY_MAX	2000	/* >10 sec */
>  
>  #define LINKCHANGE_INT (2 * HZ)
>  #define VF_TAKEOVER_INT (HZ / 10)
> @@ -2402,6 +2399,7 @@ static int netvsc_vf_changed(struct net_device *vf_netdev, unsigned long event)
>  	struct netvsc_device *netvsc_dev;
>  	struct net_device *ndev;
>  	bool vf_is_up = false;
> +	int ret;
>  
>  	if (event != NETDEV_GOING_DOWN)
>  		vf_is_up = netif_running(vf_netdev);
> @@ -2418,9 +2416,17 @@ static int netvsc_vf_changed(struct net_device *vf_netdev, unsigned long event)
>  	if (net_device_ctx->data_path_is_vf == vf_is_up)
>  		return NOTIFY_OK;
>  
> -	netvsc_switch_datapath(ndev, vf_is_up);
> -	netdev_info(ndev, "Data path switched %s VF: %s\n",
> -		    vf_is_up ? "to" : "from", vf_netdev->name);
> +	ret = netvsc_switch_datapath(ndev, vf_is_up);
> +
> +	if (ret) {
> +		netdev_err(ndev,
> +			   "Data path failed to switch %s VF: %s, err: %d\n",
> +			   vf_is_up ? "to" : "from", vf_netdev->name, ret);
> +		return NOTIFY_DONE;
> +	} else {
> +		netdev_info(ndev, "Data path switched %s VF: %s\n",
> +			    vf_is_up ? "to" : "from", vf_netdev->name);
> +	}
>  
>  	return NOTIFY_OK;
>  }

-- 
Vitaly

RE: [PATCH net-next] hv_netvsc: Add error handling while switching data path

[Haiyang Zhang]

> -----Original Message-----
> From: Vitaly Kuznetsov <vkuznets@redhat.com>
> Sent: Tuesday, March 30, 2021 7:43 AM
> To: Haiyang Zhang <haiyangz@microsoft.com>; linux-
> hyperv@vger.kernel.org; netdev@vger.kernel.org
> Cc: Haiyang Zhang <haiyangz@microsoft.com>; KY Srinivasan
> <kys@microsoft.com>; Stephen Hemminger <sthemmin@microsoft.com>;
> olaf@aepfle.de; davem@davemloft.net; linux-kernel@vger.kernel.org
> Subject: Re: [PATCH net-next] hv_netvsc: Add error handling while switching
> data path
> 
> Haiyang Zhang <haiyangz@microsoft.com> writes:
> 
> > Add error handling in case of failure to send switching data path message
> > to the host.
> >
> > Reported-by: Shachar Raindel <shacharr@microsoft.com>
> > Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
> >
> > ---
> >  drivers/net/hyperv/hyperv_net.h |  6 +++++-
> >  drivers/net/hyperv/netvsc.c     | 35 +++++++++++++++++++++++++++++-
> ---
> >  drivers/net/hyperv/netvsc_drv.c | 18 +++++++++++------
> >  3 files changed, 48 insertions(+), 11 deletions(-)
> >
> > diff --git a/drivers/net/hyperv/hyperv_net.h
> b/drivers/net/hyperv/hyperv_net.h
> > index 59ac04a610ad..442c520ab8f3 100644
> > --- a/drivers/net/hyperv/hyperv_net.h
> > +++ b/drivers/net/hyperv/hyperv_net.h
> > @@ -269,7 +269,7 @@ int rndis_filter_receive(struct net_device *ndev,
> >  int rndis_filter_set_device_mac(struct netvsc_device *ndev,
> >  				const char *mac);
> >
> > -void netvsc_switch_datapath(struct net_device *nv_dev, bool vf);
> > +int netvsc_switch_datapath(struct net_device *nv_dev, bool vf);
> >
> >  #define NVSP_INVALID_PROTOCOL_VERSION	((u32)0xFFFFFFFF)
> >
> > @@ -1718,4 +1718,8 @@ struct rndis_message {
> >  #define TRANSPORT_INFO_IPV6_TCP 0x10
> >  #define TRANSPORT_INFO_IPV6_UDP 0x20
> >
> > +#define RETRY_US_LO	5000
> > +#define RETRY_US_HI	10000
> > +#define RETRY_MAX	2000	/* >10 sec */
> > +
> >  #endif /* _HYPERV_NET_H */
> > diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
> > index 5bce24731502..9d07c9ce4be2 100644
> > --- a/drivers/net/hyperv/netvsc.c
> > +++ b/drivers/net/hyperv/netvsc.c
> > @@ -31,12 +31,13 @@
> >   * Switch the data path from the synthetic interface to the VF
> >   * interface.
> >   */
> > -void netvsc_switch_datapath(struct net_device *ndev, bool vf)
> > +int netvsc_switch_datapath(struct net_device *ndev, bool vf)
> >  {
> >  	struct net_device_context *net_device_ctx = netdev_priv(ndev);
> >  	struct hv_device *dev = net_device_ctx->device_ctx;
> >  	struct netvsc_device *nv_dev = rtnl_dereference(net_device_ctx-
> >nvdev);
> >  	struct nvsp_message *init_pkt = &nv_dev->channel_init_pkt;
> > +	int ret, retry = 0;
> >
> >  	/* Block sending traffic to VF if it's about to be gone */
> >  	if (!vf)
> > @@ -51,15 +52,41 @@ void netvsc_switch_datapath(struct net_device
> *ndev, bool vf)
> >  		init_pkt->msg.v4_msg.active_dp.active_datapath =
> >  			NVSP_DATAPATH_SYNTHETIC;
> >
> > +again:
> >  	trace_nvsp_send(ndev, init_pkt);
> >
> > -	vmbus_sendpacket(dev->channel, init_pkt,
> > +	ret = vmbus_sendpacket(dev->channel, init_pkt,
> >  			       sizeof(struct nvsp_message),
> > -			       (unsigned long)init_pkt,
> > -			       VM_PKT_DATA_INBAND,
> > +			       (unsigned long)init_pkt, VM_PKT_DATA_INBAND,
> >
> VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
> > +
> > +	/* If failed to switch to/from VF, let data_path_is_vf stay false,
> > +	 * so we use synthetic path to send data.
> > +	 */
> > +	if (ret) {
> > +		if (ret != -EAGAIN) {
> > +			netdev_err(ndev,
> > +				   "Unable to send sw datapath msg,
> err: %d\n",
> > +				   ret);
> > +			return ret;
> > +		}
> > +
> > +		if (retry++ < RETRY_MAX) {
> > +			usleep_range(RETRY_US_LO, RETRY_US_HI);
> > +			goto again;
> > +		} else {
> > +			netdev_err(
> > +				ndev,
> > +				"Retry failed to send sw datapath msg,
> err: %d\n",
> > +				ret);
> 
> err is always -EAGAIN here, right?
> 
> > +			return ret;
> > +		}
> 
> Nitpicking: I think we can simplify the above a bit:
> 
> 	if (ret) {
> 		if (ret == -EAGAIN && retry++ < RETRY_MAX) {
> 			usleep_range(RETRY_US_LO, RETRY_US_HI);
> 			goto again;
> 		}
> 		netdev_err(ndev, "Unable to send sw datapath msg,
> err: %d\n", ret);
> 		return ret;
> 	}
> 

Yes this looks cleaner.

Thanks,

Haiyang