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path: root/drivers/net/hyperv/netvsc_drv.c
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2016-08-23hv_netvsc: add ethtool statistics for tx packet issuesStephen Hemminger
Printing console messages is not helpful when system is out of memory; and can be disastrous with netconsole. Instead keep statistics of these anomalous conditions. Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-23hv_netvsc: report vmbus name in ethtoolStephen Hemminger
Make netvsc on vmbus behave more like PCI. Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-23hv_netvsc: rearrange start_xmitStephen Hemminger
Rearrange the transmit routine to eliminate goto's and unnecessary boolean variables. Use standard functions to test for vlan tag. Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-23hv_netvsc: style cleanupsStephen Hemminger
Fix most of the complaints about the style of the code. Things like extra blank lines and return statements. Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-23hv_netvsc: fix rtnl locking in callbackStephen Hemminger
The function get_netvsc_net_device had conditional locking. This was unnecessary, incorrect, but harmless. It was unnecessary since the code is only called from netlink netdev event callback where RTNL is always acquired before the callbacks are run. It was incorrect because of use of trylock and then continuing. Fix by replacing with proper assertion. Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-18Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
Minor overlapping changes for both merge conflicts. Resolution work done by Stephen Rothwell was used as a reference. Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-15hv_netvsc: fix bonding devices check in netvsc_netdev_event()Vitaly Kuznetsov
Bonding driver sets IFF_BONDING on both master (the bonding device) and slave (the real NIC) devices and in netvsc_netdev_event() we want to skip master devices only. Currently, there is an uncertainty when a slave interface is removed: if bonding module comes first in netdev_chain it clears IFF_BONDING flag on the netdev and netvsc_netdev_event() correctly handles NETDEV_UNREGISTER event, but in case netvsc comes first on the chain it sees the device with IFF_BONDING still attached and skips it. As we still hold vf_netdev pointer to the device we crash on the next inject. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Acked-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-15hv_netvsc: protect module refcount by checking net_device_ctx->vf_netdevVitaly Kuznetsov
We're not guaranteed to see NETDEV_REGISTER/NETDEV_UNREGISTER notifications only once per VF but we increase/decrease module refcount unconditionally. Check vf_netdev to make sure we don't take/release it twice. We presume that only one VF per netvsc device may exist. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Acked-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-15hv_netvsc: reset vf_inject on VF removalVitaly Kuznetsov
We reset vf_inject on VF going down (netvsc_vf_down()) but we don't on VF removal (netvsc_unregister_vf()) so vf_inject stays 'true' while vf_netdev is already NULL and we're trying to inject packets into NULL net device in netvsc_recv_callback() causing kernel to crash. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Acked-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-15hv_netvsc: avoid deadlocks between rtnl lock and vf_use_cnt waitVitaly Kuznetsov
Here is a deadlock scenario: - netvsc_vf_up() schedules netvsc_notify_peers() work and quits. - netvsc_vf_down() runs before netvsc_notify_peers() gets executed. As it is being executed from netdev notifier chain we hold rtnl lock when we get here. - we enter while (atomic_read(&net_device_ctx->vf_use_cnt) != 0) loop and wait till netvsc_notify_peers() drops vf_use_cnt. - netvsc_notify_peers() starts on some other CPU but netdev_notify_peers() will hang on rtnl_lock(). - deadlock! Instead of introducing additional synchronization I suggest we drop gwrk.dwrk completely and call NETDEV_NOTIFY_PEERS directly. As we're acting under rtnl lock this is legitimate. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Acked-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-15hv_netvsc: don't lose VF informationVitaly Kuznetsov
struct netvsc_device is not suitable for storing VF information as this structure is being destroyed on MTU change / set channel operation (see rndis_filter_device_remove()). Move all VF related stuff to struct net_device_context which is persistent. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Acked-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-08hv_netvsc: Add handler for physical link speed changeHaiyang Zhang
On Hyper-V host 2016 and later, VMs gets an event message of the physical link speed when vSwitch is changed. This patch handles this message, so the updated link speed can be reported by ethtool. Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com> Reviewed-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-08hv_netvsc: Add query for initial physical link speedHaiyang Zhang
The physical link speed value will be reported by ethtool command. The real speed is available from Windows 2016 host or later. Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com> Reviewed-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-25hv_netvsc: Fix VF register on bonding devicesHaiyang Zhang
Added a condition to avoid bonding devices with same MAC registering as VF. Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com> Reviewed-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-05hv_netvsc: pass struct net_device to rndis_filter_set_device_mac()Vitaly Kuznetsov
We unpack 'struct net_device' in netvsc_set_mac_addr() to get to 'struct hv_device' pointer which we use in rndis_filter_set_device_mac() to get back to 'struct net_device'. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-05hv_netvsc: pass struct netvsc_device to rndis_filter_{open, close}()Vitaly Kuznetsov
Both rndis_filter_open()/rndis_filter_close() use struct hv_device to reach to struct netvsc_device only and all callers have it already. While on it, rename net_device to nvdev in rndis_filter_open() as net_device is misleading. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-05hv_netvsc: remove redundant assignment in netvsc_recv_callback()Vitaly Kuznetsov
net_device_ctx is assigned in the very beginning of the function and 'net' pointer doesn't change. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-03hv_netvsc: Fix VF register on vlan devicesHaiyang Zhang
Added a condition to avoid vlan devices with same MAC registering as VF. Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com> Reviewed-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-16hv_netvsc: synchronize netvsc_change_mtu()/netvsc_set_channels() with ↵Vitaly Kuznetsov
netvsc_remove() When netvsc device is removed during mtu change or channels setup we get into troubles as both paths are trying to remove the device. Synchronize them with start_remove flag and rtnl lock. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-16hv_netvsc: get rid of struct net_device pointer in struct netvsc_deviceVitaly Kuznetsov
Simplify netvsvc pointer graph by getting rid of the redundant ndev pointer. We can always get a pointer to struct net_device from somewhere else. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-16hv_netvsc: untangle the pointer messVitaly Kuznetsov
We have the following structures keeping netvsc adapter state: - struct net_device - struct net_device_context - struct netvsc_device - struct rndis_device - struct hv_device and there are pointers/dependencies between them: - struct net_device_context is contained in struct net_device - struct hv_device has driver_data pointer which points to 'struct net_device' OR 'struct netvsc_device' depending on driver's state (!). - struct net_device_context has a pointer to 'struct hv_device'. - struct netvsc_device has pointers to 'struct hv_device' and 'struct net_device_context'. - struct rndis_device has a pointer to 'struct netvsc_device'. Different functions get different structures as parameters and use these pointers for traveling. The problem is (in addition to keeping in mind this complex graph) that some of these structures (struct netvsc_device and struct rndis_device) are being removed and re-created on mtu change (as we implement it as re-creation of hyper-v device) so our travel using these pointers is dangerous. Simplify this to a the following: - add struct netvsc_device pointer to struct net_device_context (which is a part of struct net_device and thus never disappears) - remove struct hv_device and struct net_device_context pointers from struct netvsc_device - replace pointer to 'struct netvsc_device' with pointer to 'struct net_device'. - always keep 'struct net_device' in hv_device driver_data. We'll end up with the following 'circular' structure: net_device: [net_device_context] -> netvsc_device -> rndis_device -> net_device -> hv_device -> net_device On MTU change we'll be removing the 'netvsc_device -> rndis_device' branch and re-creating it making the synchronization easier. There is one additional redundant pointer left, it is struct net_device link in struct netvsc_device, it is going to be removed in a separate commit. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-16hv_netvsc: use start_remove flag to protect netvsc_link_change()Vitaly Kuznetsov
netvsc_link_change() can race with netvsc_change_mtu() or netvsc_set_channels() as these functions destroy struct netvsc_device and rndis filter. Use start_remove flag for syncronization. As netvsc_change_mtu()/netvsc_set_channels() are called with rtnl lock held we need to take it before checking start_remove value in netvsc_link_change(). Reported-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-16hv_netvsc: move start_remove flag to net_device_contextVitaly Kuznetsov
struct netvsc_device is destroyed on mtu change so keeping the protection flag there is not a good idea. Move it to struct net_device_context which is preserved. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-24hv_netvsc: Fix the list processing for network change eventHaiyang Zhang
RNDIS_STATUS_NETWORK_CHANGE event is handled as two "half events" -- media disconnect & connect. The second half should be added to the list head, not to the tail. So all events are processed in normal order. Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com> Reviewed-by: K. Y. Srinivasan <kys@microsoft.com> Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-18hv_netvsc: Implement support for VF drivers on Hyper-VKY Srinivasan
Support VF drivers on Hyper-V. On Hyper-V, each VF instance presented to the guest has an associated synthetic interface that shares the MAC address with the VF instance. Typically these are bonded together to support live migration. By default, the host delivers all the incoming packets on the synthetic interface. Once the VF is up, we need to explicitly switch the data path on the host to divert traffic onto the VF interface. Even after switching the data path, broadcast and multicast packets are always delivered on the synthetic interface and these will have to be injected back onto the VF interface (if VF is up). This patch implements the necessary support in netvsc to support Linux VF drivers. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-03-23hv_netvsc: Fix accessing freed memory in netvsc_change_mtu()Haiyang Zhang
struct netvsc_device is freed in rndis_filter_device_remove(). So we save the nvdev->num_chn into a temp variable for later usage. (Please also include this patch into stable branch.) Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com> Reviewed-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-29hv_netvsc: add ethtool support for set and get of settingssixiao@microsoft.com
This patch allows the user to set and retrieve speed and duplex of the hv_netvsc device via ethtool. Example: $ ethtool eth0 Settings for eth0: ... Speed: Unknown! Duplex: Unknown! (255) ... $ ethtool -s eth0 speed 1000 duplex full $ ethtool eth0 Settings for eth0: ... Speed: 1000Mb/s Duplex: Full ... This is based on patches by Roopa Prabhu and Nikolay Aleksandrov. Signed-off-by: Simon Xiao <sixiao@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-23Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
Conflicts: drivers/net/phy/bcm7xxx.c drivers/net/phy/marvell.c drivers/net/vxlan.c All three conflicts were cases of simple overlapping changes. Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-19hv_netvsc: add software transmit timestamp supportsixiao@microsoft.com
Enable skb_tx_timestamp in hyperv netvsc. Signed-off-by: Simon Xiao <sixiao@microsoft.com> Reviewed-by: K. Y. Srinivasan <kys@microsoft.com> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-13hv_netvsc: Restore needed_headroom requestVitaly Kuznetsov
Commit c0eb454034aa ("hv_netvsc: Don't ask for additional head room in the skb") got rid of needed_headroom setting for the driver. With the change I hit the following issue trying to use ptkgen module: [ 57.522021] kernel BUG at net/core/skbuff.c:1128! [ 57.522021] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC ... [ 58.721068] Call Trace: [ 58.721068] [<ffffffffa0144e86>] netvsc_start_xmit+0x4c6/0x8e0 [hv_netvsc] ... [ 58.721068] [<ffffffffa02f87fc>] ? pktgen_finalize_skb+0x25c/0x2a0 [pktgen] [ 58.721068] [<ffffffff814f5760>] ? __netdev_alloc_skb+0xc0/0x100 [ 58.721068] [<ffffffffa02f9907>] pktgen_thread_worker+0x257/0x1920 [pktgen] Basically, we're calling skb_cow_head(skb, RNDIS_AND_PPI_SIZE) and crash on if (skb_shared(skb)) BUG(); We probably need to restore needed_headroom setting (but shrunk to RNDIS_AND_PPI_SIZE as we don't need more) to request the required headroom space. In theory, it should not give us performance penalty. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-11hv_netvsc: cleanup netdev feature flags for netvscsixiao@microsoft.com
1. Adding NETIF_F_TSO6 feature flag; 2. Adding NETIF_F_HW_CSUM. NETIF_F_IPV6_CSUM and NETIF_F_IP_CSUM are being deprecated; 3. Cleanup the coding style of flag assignment by using macro. Signed-off-by: Simon Xiao <sixiao@microsoft.com> Reviewed-by: K. Y. Srinivasan <kys@microsoft.com> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-01-25hv_netvsc: use skb_get_hash() instead of a homegrown implementationVitaly Kuznetsov
Recent changes to 'struct flow_keys' (e.g commit d34af823ff40 ("net: Add VLAN ID to flow_keys")) introduced a performance regression in netvsc driver. Is problem is, however, not the above mentioned commit but the fact that netvsc_set_hash() function did some assumptions on the struct flow_keys data layout and this is wrong. Get rid of netvsc_set_hash() by switching to skb_get_hash(). This change will also imply switching to Jenkins hash from the currently used Toeplitz but it seems there is no good excuse for Toeplitz to stay. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-02hv_netvsc: Eliminate vlan_tci from struct hv_netvsc_packetKY Srinivasan
Eliminate vlan_tci from struct hv_netvsc_packet. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-02hv_netvsc: Eliminate status from struct hv_netvsc_packetKY Srinivasan
Eliminate status from struct hv_netvsc_packet. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-02hv_netvsc: Eliminate xmit_more from struct hv_netvsc_packetKY Srinivasan
Eliminate xmit_more from struct hv_netvsc_packet. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-02hv_netvsc: Eliminate completion_func from struct hv_netvsc_packetKY Srinivasan
Eliminate completion_func from struct hv_netvsc_packet. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-02hv_netvsc: Eliminate is_data_pkt from struct hv_netvsc_packetKY Srinivasan
Eliminate is_data_pkt from struct hv_netvsc_packet. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-02hv_netvsc: Eliminate send_completion_tid from struct hv_netvsc_packetKY Srinivasan
Eliminate send_completion_tid from struct hv_netvsc_packet. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-02hv_netvsc: Eliminate page_buf from struct hv_netvsc_packetKY Srinivasan
Eliminate page_buf from struct hv_netvsc_packet. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-02hv_netvsc: move subchannel existence check to netvsc_select_queue()Vitaly Kuznetsov
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-02hv_netvsc: Don't ask for additional head room in the skbKY Srinivasan
The rndis header is 116 bytes big and can be placed in the default head room that will be available in the skb. Since the netvsc packet is less than 48 bytes, we can use the skb control buffer for the netvsc packet. With these changes we don't need to ask for additional head room. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-02hv_netvsc: Eliminate send_completion_ctx from struct hv_netvsc_packetKY Srinivasan
Eliminate send_completion_ctx from struct hv_netvsc_packet. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-02hv_netvsc: Eliminate send_completion from struct hv_netvsc_packetKY Srinivasan
Eliminate send_completion from struct hv_netvsc_packet. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-02hv_netvsc: Eliminatte the data field from struct hv_netvsc_packetKY Srinivasan
Eliminatte the data field from struct hv_netvsc_packet. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-02hv_netvsc: Eliminate rndis_msg pointer from hv_netvsc_packet structureKY Srinivasan
Eliminate rndis_msg pointer from hv_netvsc_packet structure. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-02hv_netvsc: Eliminate the channel field in hv_netvsc_packet structureKY Srinivasan
Eliminate the channel field in hv_netvsc_packet structure. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-01hv_netvsc: rework link status change handlingVitaly Kuznetsov
There are several issues in hv_netvsc driver with regards to link status change handling: - RNDIS_STATUS_NETWORK_CHANGE results in calling userspace helper doing '/etc/init.d/network restart' and this is inappropriate and broken for many reasons. - link_watch infrastructure only sends one notification per second and in case of e.g. paired disconnect/connect events we get only one notification with last status. This makes it impossible to handle such situations in userspace. Redo link status changes handling in the following way: - Create a list of reconfig events in network device context. - On a reconfig event add it to the list of events and schedule netvsc_link_change(). - In netvsc_link_change() ensure 2-second delay between link status changes. - Handle RNDIS_STATUS_NETWORK_CHANGE as a paired disconnect/connect event. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-09-01flow_dissector: Add flags argument to skb_flow_dissector functionsTom Herbert
The flags argument will allow control of the dissection process (for instance whether to parse beyond L3). Signed-off-by: Tom Herbert <tom@herbertland.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-08-18hv_netvsc: Fix dereference of nvdev before checkAndrew Schwartzmeyer
Passes static analysis by Smatch. Signed-off-by: Andrew Schwartzmeyer <andschwa@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-08-12hv_netvsc: Implement set_channels ethtool opAndrew Schwartzmeyer
This enables the use of ethtool --set-channels devname combined N to change the number of vRSS queues. Separate rx, tx, and other parameters are not supported. The maximum is rsscap.num_recv_que. It passes the given value to rndis_filter_device_add through the device_info->num_chn field. If the procedure fails, it attempts to recover to the prior state. If the recovery fails, it logs an error and aborts. Current num_chn is saved and restored when changing the MTU. Signed-off-by: Andrew Schwartzmeyer <andschwa@microsoft.com> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>