Commit Graph

234 Commits

Author SHA1 Message Date
Vitaly Kuznetsov
e8f0a89cd7 hv_netvsc: fix a race between netvsc_send() and netvsc_init_buf()
Fix in commit 8809883482 ("hv_netvsc: set nvdev link after populating
chn_table") turns out to be incomplete. A crash in
netvsc_get_next_send_section() is observed on mtu change when the device
is under load. The race I identified is: if we get to netvsc_send() after
we set net_device_ctx->nvdev link in netvsc_device_add() but before we
finish netvsc_connect_vsp()->netvsc_init_buf() send_section_map is not
allocated and we crash. Unfortunately we can't set net_device_ctx->nvdev
link after the netvsc_init_buf() call as during the negotiation we need
to receive packets and on the receive path we check for it. It would
probably be possible to split nvdev into a pair of nvdev_in and nvdev_out
links and check them accordingly in get_outbound_net_device()/
get_inbound_net_device() but this looks like an overkill.

Check that send_section_map is allocated in netvsc_send().

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-21 11:27:31 -04:00
Jarod Wilson
d0c2c9973e net: use core MTU range checking in virt drivers
hyperv_net:
- set min/max_mtu, per Haiyang, after rndis_filter_device_add

virtio_net:
- set min/max_mtu
- remove virtnet_change_mtu

vmxnet3:
- set min/max_mtu

xen-netback:
- min_mtu = 0, max_mtu = 65517

xen-netfront:
- min_mtu = 0, max_mtu = 65535

unisys/visor:
- clean up defines a little to not clash with network core or add
  redundat definitions

CC: netdev@vger.kernel.org
CC: virtualization@lists.linux-foundation.org
CC: "K. Y. Srinivasan" <kys@microsoft.com>
CC: Haiyang Zhang <haiyangz@microsoft.com>
CC: "Michael S. Tsirkin" <mst@redhat.com>
CC: Shrikrishna Khare <skhare@vmware.com>
CC: "VMware, Inc." <pv-drivers@vmware.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Paul Durrant <paul.durrant@citrix.com>
CC: David Kershner <david.kershner@unisys.com>
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-20 14:51:09 -04:00
David S. Miller
3f2b0a5a35 netvsc: Remove mistaken udp.h inclusion.
Based upon v2 of Stephen's patch.

Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-13 11:04:07 -04:00
stephen hemminger
ad19bc8a95 netvsc: fix checksum on UDP IPV6
The software calculation of UDP checksum in Netvsc driver was
only handling IPv4 case. By using skb_checksum_help() instead
all protocols can be handled. Rearrange code to eliminate goto
and look like other drivers.

This is a temporary solution; recent versions of Window Server etc
do support UDP checksum offload, just need to do the appropriate negotiation
with host to validate before using. This will be done in later patch.

Please queue this for -stable as well.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-13 10:48:17 -04:00
Stephen Hemminger
c6a77ff82f hv_netvsc: fix comments
Typo's and spelling errors. Also remove old comment from staging era.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-24 09:36:12 -04:00
Stephen Hemminger
f7ad75b753 hv_netvsc: count multicast packets received
Useful for debugging issues with multicast and SR-IOV to keep track
of number of received multicast packets.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-23 08:39:49 -04:00
Stephen Hemminger
9cbcc42806 hv_netvsc: remove VF in flight counters
Since VF reference is now protected by RCU, no longer need the VF usage
counter and can use device flags to see whether to inject or not.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-23 08:39:49 -04:00
Stephen Hemminger
f207c10d98 hv_netvsc: use RCU to protect vf_netdev
The vf_netdev pointer in the netvsc device context can simply be protected
by RCU because network device destruction is already RCU synchronized.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-23 08:39:49 -04:00
Stephen Hemminger
e8ff40d4bf hv_netvsc: improve VF device matching
The code to associate netvsc and VF devices can be made less error prone
by using a better matching algorithms.

On registration, use the permanent address which avoids any possible
issues caused by device MAC address being changed. For all other callbacks,
search by the netdevice pointer value to ensure getting the correct
network device.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-23 08:39:49 -04:00
Stephen Hemminger
ee837a1373 hv_netvsc: simplify callback event code
The callback handler for netlink events can be simplified:
 * Consolidate check for netlink callback events about this driver itself.
 * Ignore non-Ethernet devices.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-23 08:39:49 -04:00
Stephen Hemminger
07d0f0008c hv_netvsc: dev hold/put reference to VF
The netvsc driver holds a pointer to the virtual function network device if
managing SR-IOV association. In order to ensure that the VF network device
does not disappear, it should be using dev_hold/dev_put to get a reference
count.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-23 08:39:48 -04:00
Stephen Hemminger
17db4bcef3 hv_netvsc: use consume_skb
Packets that are transmitted in normal path should use consume_skb
instead of kfree_skb. This allows for better tracing of packet drops.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-23 08:39:48 -04:00
Stephen Hemminger
3a8963acc7 Revert "hv_netvsc: make inline functions static"
These functions are used by other code misc-next tree.

This reverts commit 30d1de08c8.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-10 21:23:00 -07:00
Stephen Hemminger
4323b47cf8 hv_netvsc: add ethtool statistics for tx packet issues
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>
2016-08-23 12:05:38 -07:00
Stephen Hemminger
e3f74b841d hv_netvsc: report vmbus name in ethtool
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>
2016-08-23 12:05:38 -07:00
Stephen Hemminger
6c4c137e50 hv_netvsc: make variable local
The variable m_ret is only used in one basic block.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-23 12:05:37 -07:00
Stephen Hemminger
7a2a0a84fd hv_netvsc: make netvsc_destroy_buf void
No caller checks the return value.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-23 12:05:37 -07:00
Stephen Hemminger
bc304dd3b4 hv_netvsc: refactor completion function
Break the different cases, code is cleaner if broken up

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-23 12:05:37 -07:00
Stephen Hemminger
0ab05141f9 hv_netvsc: rearrange start_xmit
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>
2016-08-23 12:05:37 -07:00
Stephen Hemminger
fd612602d6 hv_netvsc: init completion during alloc
Move initialization to allocate where other fields are initialized.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-23 12:05:37 -07:00
Stephen Hemminger
e08f3ea586 hv_netvsc: make device_remove void
Always returns 0 and no callers check.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-23 12:05:37 -07:00
Stephen Hemminger
e5a78fad4f hv_netvsc: use ARRAY_SIZE() for NDIS versions
Don't hard code size of array of NDIS versions.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-23 12:05:36 -07:00
Stephen Hemminger
30d1de08c8 hv_netvsc: make inline functions static
Several new functions were introduced into hyperv.h but only used in one file.
Move them and let compiler decide on inline.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-23 12:05:36 -07:00
Stephen Hemminger
796cc88c32 hv_netvsc: style cleanups
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>
2016-08-23 12:05:36 -07:00
Stephen Hemminger
e53a9c2a5a hv_netvsc: use kcalloc
Better to use kcalloc rather than kzalloc and multiply for an array.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-23 12:05:36 -07:00
Stephen Hemminger
9477386687 hv_netvsc: make RSS hash key static
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-23 12:05:36 -07:00
Stephen Hemminger
8737caafd1 hv_netvsc: fix rtnl locking in callback
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>
2016-08-23 12:05:35 -07:00
Haiyang Zhang
c0b558e5a3 hv_netvsc: Implement batching of receive completions
The existing code uses busy retry when unable to send out receive
completions due to full ring buffer. It also gives up retrying after limit
is reached, and causes receive buffer slots not being recycled.
This patch implements batching of receive completions. It also prevents
dropping receive completions due to full ring buffer.

Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Reviewed-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-19 22:41:19 -07:00
David S. Miller
60747ef4d1 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
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>
2016-08-18 01:17:32 -04:00
Vitaly Kuznetsov
0dbff144a1 hv_netvsc: fix bonding devices check in netvsc_netdev_event()
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>
2016-08-15 13:48:07 -07:00
Vitaly Kuznetsov
0f20d795f7 hv_netvsc: protect module refcount by checking net_device_ctx->vf_netdev
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>
2016-08-15 13:48:07 -07:00
Vitaly Kuznetsov
57c1826b99 hv_netvsc: reset vf_inject on VF removal
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>
2016-08-15 13:48:07 -07:00
Vitaly Kuznetsov
d072218f21 hv_netvsc: avoid deadlocks between rtnl lock and vf_use_cnt wait
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>
2016-08-15 13:48:07 -07:00
Vitaly Kuznetsov
f9a7da9130 hv_netvsc: don't lose VF information
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>
2016-08-15 13:48:07 -07:00
Haiyang Zhang
7f5d5af0b2 hv_netvsc: Add handler for physical link speed change
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>
2016-08-08 16:14:07 -07:00
Haiyang Zhang
b37879e6ca hv_netvsc: Add query for initial physical link speed
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>
2016-08-08 16:14:07 -07:00
Haiyang Zhang
e2b9f1f7af hv_netvsc: Fix VF register on bonding devices
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>
2016-07-25 11:19:22 -07:00
K. Y. Srinivasan
99a50bb11c netvsc: Use the new in-place consumption APIs in the rx path
Use the new APIs for eliminating a copy on the receive path. These new APIs also
help in minimizing the number of memory barriers we end up issuing (in the
ringbuffer code) since we can better control when we want to expose the ring
state to the host.

The patch is being resent to address earlier email issues.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-08 23:11:20 -04:00
Vitaly Kuznetsov
5362855aba netvsc: get rid of completion timeouts
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>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-09 11:40:05 -07:00
Vitaly Kuznetsov
426d95417e hv_netvsc: pass struct net_device to rndis_filter_set_offload_params()
The only caller rndis_filter_device_add() has 'struct net_device' pointer
already.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-05 23:16:36 -04:00
Vitaly Kuznetsov
e834da9a40 hv_netvsc: pass struct net_device to rndis_filter_set_device_mac()
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>
2016-06-05 23:16:36 -04:00
Vitaly Kuznetsov
2f5fa6c869 hv_netvsc: pass struct netvsc_device to rndis_filter_{open, close}()
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>
2016-06-05 23:16:36 -04:00
Vitaly Kuznetsov
2625466d6d hv_netvsc: introduce {net, hv}_device_to_netvsc_device() helpers
Make it easier to get 'struct netvsc_device' from 'struct net_device' and
'struct hv_device' by introducing inline helpers.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-05 23:16:35 -04:00
Vitaly Kuznetsov
4baa994dc9 hv_netvsc: remove redundant assignment in netvsc_recv_callback()
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>
2016-06-05 23:16:35 -04:00
Haiyang Zhang
cb2911fed6 hv_netvsc: Fix VF register on vlan devices
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>
2016-06-03 19:40:05 -04:00
Vitaly Kuznetsov
8809883482 hv_netvsc: set nvdev link after populating chn_table
Crash in netvsc_send() is observed when netvsc device is re-created on
mtu change/set channels. The crash is caused by dereferencing of NULL
channel pointer which comes from chn_table. The root cause is a mixture
of two facts:
- we set nvdev pointer in net_device_context in alloc_net_device()
  before we populate chn_table.
- we populate chn_table[0] only.

The issue could be papered over by checking channel != NULL in
netvsc_send() but populating the whole chn_table and writing the
nvdev pointer afterwards seems more appropriate.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-16 13:26:01 -04:00
Vitaly Kuznetsov
6da7225f5a hv_netvsc: synchronize netvsc_change_mtu()/netvsc_set_channels() with 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>
2016-05-16 13:26:01 -04:00
Vitaly Kuznetsov
0a1275ca51 hv_netvsc: get rid of struct net_device pointer in struct netvsc_device
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>
2016-05-16 13:26:00 -04:00
Vitaly Kuznetsov
3d541ac5a9 hv_netvsc: untangle the pointer mess
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>
2016-05-16 13:26:00 -04:00
Vitaly Kuznetsov
1bdcec8a5f hv_netvsc: use start_remove flag to protect netvsc_link_change()
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>
2016-05-16 13:26:00 -04:00