1. Added module parameters sr_iov and probe_vf for controlling enablement of
   SRIOV mode.
2. Increased default max num-qps, num-mpts and log_num_macs to accomodate
   SRIOV mode
3. Added port_type_array as a module parameter to allow driver startup with
   ports configured as desired.
   In SRIOV mode, only ETH is supported, and this array is ignored; otherwise,
   for the case where the FW supports both port types (ETH and IB), the
   port_type_array parameter is used.
   By default, the port_type_array is set to configure both ports as IB.
4. When running in sriov mode, the master needs to initialize the ICM eq table
   to hold the eq's for itself and also for all the slaves.
5. mlx4_set_port_mask() now invoked from mlx4_init_hca, instead of in mlx4_dev_cap.
6. Introduced sriov VF (slave) device startup/teardown logic (mainly procedures
   mlx4_init_slave, mlx4_slave_exit, mlx4_slave_cap, mlx4_slave_exit and flow
   modifications in __mlx4_init_one, mlx4_init_hca, and mlx4_setup_hca).
   VFs obtain their startup information from the PF (master) device via the
   comm channel.
7. In SRIOV mode (both PF and VF), MSI_X must be enabled, or the driver
   aborts loading the device.
8. Do not allow setting port type via sysfs when running in SRIOV mode.
9. mlx4_get_ownership:  Currently, only one PF is supported by the driver.
   If the HCA is burned with FW which enables more than one PF, only one
   of the PFs is allowed to run.  The first one up grabs a FW ownership
   semaphone -- all other PFs will find that semaphore taken, and the
   driver will not allow them to run.
Signed-off-by: NJack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: NYevgeny Petrilin <yevgenyp@mellanox.co.il>
Signed-off-by: NLiran Liss <liranl@mellanox.co.il>
Signed-off-by: NMarcel Apfelbaum <marcela@mellanox.co.il>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When running in SRIOV mode, driver should not automatically start/stop
the mlx4_core upon sensing an HCA internal error -- doing this disables/enables
sriov, which will cause the hypervisor to hang if there are running VMs with
attached VFs.

In addition, on VMs the catas process should not run at all, since the HCA
error buffer is not available to VMs in the BARs.
Signed-off-by: NJack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In the previous implementation mtts are managed by:
1. order     - log(mtt segments), 'mtt segment' groups several mtts together.
2. first_seg - segment location relative to mtt table.
In the current implementation:
1. order     - log(mtts) rather than segments
2. offset    - mtt index in mtt table

Note: The actual mtt allocation is made in segments but it is
      transparent to callers.

Rational: The mtt resource holders are not interested on how the allocation
          of mtt is done, but rather on how they will use it.
Signed-off-by: NMarcel Apfelbaum <marcela@dev.mellanox.co.il>
Reviewed-by: NJack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

To enable internal loopback, always fill DMAC in control segment
when transmitting the packet, once this is done, the packet is subject
for loopback for if the DMAC mathces one of the multicast/unicast addresses
registered on the physical port.
In receive path if source MAC is our own MAC and we are not in selftest,
or not in force LB mode - drop this packet.
Signed-off-by: NEugenia Emantayev <eugenia@mellanox.co.il>
Signed-off-by: NYevgeny Petrilin <yevgenyp@mellanox.co.il>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The physical port is now common to the PF and VFs.
The port resources and configuration is managed by the PF, VFs can
only influence the MTU of the port, it is set as max among all functions,
Each function allocates RX buffers of required size to meet it's MTU enforcement.
Port management code was moved to mlx4_core, as the mlx4_en module is
virtualization unaware

Move handling qp functionality to mlx4_get_eth_qp/mlx4_put_eth_qp
including reserve/release range and add/release unicast steering.
Let mlx4_register/unregister_mac deal only with MAC (un)registration.
Signed-off-by: NEugenia Emantayev <eugenia@mellanox.co.il>
Signed-off-by: NYevgeny Petrilin <yevgenyp@mellanox.co.il>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Let multicast/unicast attaching flow go through resource tracker.
The PF is the one responsible for managing all the steering entries.
Define and use module parameter that determines the number of qps
per multicast group.
Minor changes in function calls according to changed prototype.
Signed-off-by: NEugenia Emantayev <eugenia@mellanox.co.il>
Signed-off-by: NYevgeny Petrilin <yevgenyp@mellanox.co.il>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NJack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The resource tracker is used to track usage of HCA resources by the different
guests.

Virtual functions (VFs) are attached to guest operating systems but
resources are allocated from the same pool and are assigned to VFs. It is
essential that hostile/buggy guests not be able to affect the operation of
other VFs, possibly attached to other guest OSs since ConnectX firmware is not
tolerant to misuse of resources.

The resource tracker module associates each resource with a VF and maintains
state information for the allocated object. It also defines allowed state
transitions and enforces them.

Relationships between resources are also referred to. For example, CQs are
pointed to by QPs, so it is forbidden to destroy a CQ if a QP refers to it.

ICM memory is always accessible through the primary function and hence it is
allocated by the owner of the primary function.

When a guest dies, an FLR is generated for all the VFs it owns and all the
resources it used are freed.

The tracked resource types are: QPs, CQs, SRQs, MPTs, MTTs, MACs, RES_EQs,
and XRCDNs.
Signed-off-by: NEli Cohen <eli@mellanox.co.il>
Signed-off-by: NJack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Passing async events to slaves:
In SRIOV mode, each slave creates its own async EQ, but only the master can
register directly with the FW to receive async events.  Async events which
should be passed to slaves (such as a WQ_ACCESS_ERROR for a QP owned by a slave)
are generated at the slave by the master using the GEN_EQE FW command.

Wrapper functions: mlx4_MAP_EQ_wrapper
Only the master can map an EQ. The slave commands to map their EQs arrive
at the master via the comm channel.  The master then invokes the wrapper
function to do the work (and enter the resource in the tracking database).

New events: COMM_CHANNEL and FLR
The COMM_CHANNEL event arrives only at the master, and signals that
a slave has posted a command on the comm channel.
The FLR event is generated by the FW when a guest operating a VF
unexpectedly goes down.
Signed-off-by: NJack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

MTTs are resources which are allocated and tracked by the PF driver.
In multifunction mode, the allocation and icm mapping is done in
the resource tracker (later patch in this sequence).

To accomplish this, we have "work" functions whose names start with
"__", and "request" functions (same name, no __). If we are operating
in multifunction mode, the request function actually results in
comm-channel commands being sent (ALLOC_RES or FREE_RES).
The PF-driver comm-channel handler will ultimately invoke the
"work" (__) function and return the result.

If we are not in multifunction mode, the "work" handler is invoked
immediately.
Signed-off-by: NJack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

CQs are resources which are allocated and tracked by the PF driver.
In multifunction mode, the allocation and icm mapping is done in
the resource tracker (later patch in this sequence).

To accomplish this, we have "work" functions whose names start with
"__", and "request" functions (same name, no __). If we are operating
in multifunction mode, the request function actually results in
comm-channel commands being sent (ALLOC_RES or FREE_RES).
The PF-driver comm-channel handler will ultimately invoke the
"work" (__) function and return the result.

If we are not in multifunction mode, the "work" handler is invoked
immediately.
Signed-off-by: NJack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

QPs are resources which are allocated and tracked by the PF driver.
In multifunction mode, the allocation and icm mapping is done in
the resource tracker (later patch in this sequence).

To accomplish this, we have "work" functions whose names start with
"__", and "request" functions (same name, no __). If we are operating
in multifunction mode, the request function actually results in
comm-channel commands being sent (ALLOC_RES or FREE_RES).
The PF-driver comm-channel handler will ultimately invoke the
"work" (__) function and return the result.

If we are not in multifunction mode, the "work" handler is invoked
immediately.
Signed-off-by: NJack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

SRQs are resources which are allocated and tracked by the PF driver.
In multifunction mode, the allocation and icm mapping is done in
the resource tracker (later patch in this sequence).

To accomplish this, we have "work" functions whose names start with
"__", and "request" functions (same name, no __). If we are operating
in multifunction mode, the request function actually results in
comm-channel commands being sent (ALLOC_RES or FREE_RES).
The PF-driver comm-channel handler will ultimately invoke the
"work" (__) function and return the result.

If we are not in multifunction mode, the "work" handler is invoked
immediately.
Signed-off-by: NJack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The following commands are added here:
1. QUERY_FUNC_CAP and its wrapper.  This function is used by VFs when
   they start up to receive configuration information from the PF, such
   as resource quotas for this VF, which ports should be used (currently
   two), what protocol is running on the port (currently Ethernet ONLY,
   or port not active).

2. QUERY_PORT and its wrapper. Previously, this FW command was invoked directly
   by the ETH driver (en_port.c) using mlx4_cmd_box. Virtualization is now
   required here (the VF's MAC address must be substituted for the PFs
   MAC address returned by the FW). We changed the invocation
   in the ETH driver to use mlx4_QUERY_PORT, and added the wrapper.

3. QUERY_HCA. Used by the VF to determine how the HCA was initialized.
   For now, we need only the multicast table member entry size
   (log2_mc_table_entry_sz, in the ConnectX PRM).  No wrapper is needed
   here, because the data may be passed as is to the VF without modification).

   In this command, we have added a GLOBAL_CAPS field for passing required
   configuration information from FW to a VF (this field is to allow safely
                   adding new SRIOV capabilities which require support in VF drivers, too).
   Bits will set here by FW in response to PF-driver configuration commands which
   will activate as yet undefined new SRIOV features. The VF will test to see that
   all required capabilities indicated by this field are supported (i.e., if a bit
   is set and the VF driver does not recognize that bit, it must abort
   its initialization).  Currently, no bits are set.

4. Added a CLOSE_PORT wrapper.  The PF context needs to keep track of how many VF contexts
   have the port open.  The PF context will not actually issue the FW close port command
   until the last port user issues a CLOSE_PORT request.
Signed-off-by: NJack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: NYevgeny Petrilin <yevgenyp@mellanox.co.il>
Signed-off-by: NMarcel Apfelbaum <marcela@mellanox.co.il>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When SRIOV is enabled, pf and vfs communicate via shared comm channel.
The vf gets its side of the comm channel via a VF BAR.
Each VF (slave) creates its vHCR (virtual HCA Command Register),
Its DMA address is passed to the PF (master) using Communication Channel Register.
The same Register is used to notify the master of commands posted by the
slaves and for the master to pass events to the slaves, such as command completions
and asynchronous events.

The vHCR format is identical to the HCR format, except for the 'go' and 't' bits,
which are reserved in the vHCR. Posting commands to the vHCR is identical to
the way it is done with the HCR, albeit that the function/PF token fields are
used instead of the HCR go bit.
Specifically:
- When the function prepares a new command in the vHCR, it issues the Post_vHCR_cmd
  communication channel command and toggles the value of the function token;
  when PF token has an equal value, the command has been accepted and a new command may be posted.
- When the PF detects a Post_vHCR_cmd command, it concludes that a new command is available in the vHCR;
  after processing the command, the PF toggles the PF token to match the function token.

When the 'e' bit is not set, the completion of a Post_vHCR_cmd command also indicates
the completion the vHCR command. If, however, the 'e' bit is set, the completion of a
Post_vHCR_cmd command only indicates that the vHCR command has been accepted for execution by the PF.

Function commands are processed by the PF as follows:
-DMA (using the ACCESS_MEM command) the vHCR image into a shadow buffer.
-Validate that the opcode is non-privileged, and that the opcode- and input-modifiers are legal.
-DMA the in-box (if required) into a shadow buffer.
-Validate the command:
	o Resource ranges (e.g., QP ranges).
	o Partition key.
	o Ranges of referenced resources (e.g., CQs within QP contexts).
-If the 'e' bit is set
	o complete the Post_vHCR_cmd command
-Execute the command on the HCR.
-DMA the results to the vHCR out-box (if required).
-If the 'e' bit is set
	o Indicate command completion by generating a completion event using the GEN_EQE command
-Otherwise
	o DMA the command status to the vHCR
	o Complete the Post_vHCR_cmd command
Signed-off-by: NJack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: NYevgeny Petrillin <yevgenyp@mellanox.com>
Signed-off-by: NLiran Liss <liranl@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When SRIOV is enabled on the chip (at FW burning time),
the HCA uses only 17 bits for the PD. The remaining 7 high-order bits
are ignored.

Change the allocator to return only 17 bits for the PD.  The MSB 7
bits will be used to encode the slave number for consistency
checking later on in the resource tracker.
Signed-off-by: NJack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

For SRIOV, some Hypervisor commands can be executed directly (native = 1).
Others should go through the command wrapper flow (for tracking resource
usage, for example, or for changing some HCA configurations that slaves
need to be notified of).

This patch sets the groundwork for this capability -- adding the correct
value of "native" in each case.

Note that if SRIOV is not activated, this parameter has no effect.
Signed-off-by: NJack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Port mask now has additional state.
Port can be set as "none". In this case neither the mlx4_en or mlx4_ib
drivers take ownership of the port.
In multifunction mode there is an option to set the vfs as single ported devices.
(in single function mode, both physical ports belong to same function)
Signed-off-by: NJack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: NYevgeny Petrilin <yevgenyp@mellanox.co.il>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These changes will not affect module operation as yet. They
are only to get some structs and enums in place for use by
subsequent patches (making those smaller).

Added here:
* sriov state structs and inlines (mlx4_is_master/slave/mfunc)
* comm-channel and vhcr support structures
* enum values for new FW and comm-channel virtual commands
  (i.e., commands, passed via the comm channel to the PF-driver).
* prototypes for many command wrapper functions (used by the
  PF context for processing FW commands passed to it by the VFs).
* struct mlx4_eqe is moved from eq.c to mlx4.h (it will be used
  by other mlx4_core source files).
Signed-off-by: NJack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Reported-by: NChristoph Paasch <christoph.paasch@uclouvain.be>
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

- use adapter->num_vfs (and not the module param) to store the actual
number of vfs created. Use the same variable to reflect SRIOV
enable/disable state. So, drop the adapter->sriov_enabled field.

- use for_all_vfs() macro in VF configuration code

- drop the "vf_" prefix for the fields of be_vf_cfg; the prefix is
redundant and removing it helps reduce line wrap
Signed-off-by: NSathya Perla <sathya.perla@emulex.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The ethtool "-g" option is supposed to report the max queue length and
user modified queue length for RX and TX queues.  be2net doesn't support
user modification of queue lengths. So, the correct values for these
would be the max numbers.
be2net incorrectly reports the queue used values for these fields.
Signed-off-by: NSathya Perla <sathya.perla@emulex.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since commit e52fcb24 newly allocated
skb for small packets are not updated properly and dropped by stack.
Signed-off-by: NDmitry Kravkov <dmitry@broadcom.com>
Signed-off-by: NEilon Greenstein <eilong@broadcom.com>
Acked-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This extension can be used to simulate special link layer
characteristics. Simulate because packet data is not modified, only the
calculation base is changed to delay a packet based on the original
packet size and artificial cell information.

packet_overhead can be used to simulate a link layer header compression
scheme (e.g. set packet_overhead to -20) or with a positive
packet_overhead value an additional MAC header can be simulated. It is
also possible to "replace" the 14 byte Ethernet header with something
else.

cell_size and cell_overhead can be used to simulate link layer schemes,
based on cells, like some TDMA schemes. Another application area are MAC
schemes using a link layer fragmentation with a (small) header each.
Cell size is the maximum amount of data bytes within one cell. Cell
overhead is an additional variable to change the per-cell-overhead
(e.g.  5 byte header per fragment).

Example (5 kbit/s, 20 byte per packet overhead, cell-size 100 byte, per
cell overhead 5 byte):

  tc qdisc add dev eth0 root netem rate 5kbit 20 100 5
Signed-off-by: NHagen Paul Pfeifer <hagen@jauu.net>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Acked-by: NStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch introduces kmem.tcp.max_usage_in_bytes file, living in the
kmem_cgroup filesystem. The root cgroup will display a value equal
to RESOURCE_MAX. This is to avoid introducing any locking schemes in
the network paths when cgroups are not being actively used.

All others, will see the maximum memory ever used by this cgroup.
Signed-off-by: NGlauber Costa <glommer@parallels.com>
Reviewed-by: NHiroyouki Kamezawa <kamezawa.hiroyu@jp.fujitsu.com>
CC: David S. Miller <davem@davemloft.net>
CC: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch introduces kmem.tcp.failcnt file, living in the
kmem_cgroup filesystem. Following the pattern in the other
memcg resources, this files keeps a counter of how many times
allocation failed due to limits being hit in this cgroup.
The root cgroup will always show a failcnt of 0.
Signed-off-by: NGlauber Costa <glommer@parallels.com>
Reviewed-by: NHiroyouki Kamezawa <kamezawa.hiroyu@jp.fujitsu.com>
CC: David S. Miller <davem@davemloft.net>
CC: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch introduces kmem.tcp.usage_in_bytes file, living in the
kmem_cgroup filesystem. It is a simple read-only file that displays the
amount of kernel memory currently consumed by the cgroup.
Signed-off-by: NGlauber Costa <glommer@parallels.com>
Reviewed-by: NHiroyouki Kamezawa <kamezawa.hiroyu@jp.fujitsu.com>
CC: David S. Miller <davem@davemloft.net>
CC: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch uses the "tcp.limit_in_bytes" field of the kmem_cgroup to
effectively control the amount of kernel memory pinned by a cgroup.

This value is ignored in the root cgroup, and in all others,
caps the value specified by the admin in the net namespaces'
view of tcp_sysctl_mem.

If namespaces are being used, the admin is allowed to set a
value bigger than cgroup's maximum, the same way it is allowed
to set pretty much unlimited values in a real box.
Signed-off-by: NGlauber Costa <glommer@parallels.com>
Reviewed-by: NHiroyouki Kamezawa <kamezawa.hiroyu@jp.fujitsu.com>
CC: David S. Miller <davem@davemloft.net>
CC: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch allows each namespace to independently set up
its levels for tcp memory pressure thresholds. This patch
alone does not buy much: we need to make this values
per group of process somehow. This is achieved in the
patches that follows in this patchset.
Signed-off-by: NGlauber Costa <glommer@parallels.com>
Reviewed-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
CC: David S. Miller <davem@davemloft.net>
CC: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch introduces memory pressure controls for the tcp
protocol. It uses the generic socket memory pressure code
introduced in earlier patches, and fills in the
necessary data in cg_proto struct.
Signed-off-by: NGlauber Costa <glommer@parallels.com>
Reviewed-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujtisu.com>
CC: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The goal of this work is to move the memory pressure tcp
controls to a cgroup, instead of just relying on global
conditions.

To avoid excessive overhead in the network fast paths,
the code that accounts allocated memory to a cgroup is
hidden inside a static_branch(). This branch is patched out
until the first non-root cgroup is created. So when nobody
is using cgroups, even if it is mounted, no significant performance
penalty should be seen.

This patch handles the generic part of the code, and has nothing
tcp-specific.
Signed-off-by: NGlauber Costa <glommer@parallels.com>
Reviewed-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujtsu.com>
CC: Kirill A. Shutemov <kirill@shutemov.name>
CC: David S. Miller <davem@davemloft.net>
CC: Eric W. Biederman <ebiederm@xmission.com>
CC: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch replaces all uses of struct sock fields' memory_pressure,
memory_allocated, sockets_allocated, and sysctl_mem to acessor
macros. Those macros can either receive a socket argument, or a mem_cgroup
argument, depending on the context they live in.

Since we're only doing a macro wrapping here, no performance impact at all is
expected in the case where we don't have cgroups disabled.
Signed-off-by: NGlauber Costa <glommer@parallels.com>
Reviewed-by: NHiroyouki Kamezawa <kamezawa.hiroyu@jp.fujitsu.com>
CC: David S. Miller <davem@davemloft.net>
CC: Eric W. Biederman <ebiederm@xmission.com>
CC: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch lays down the foundation for the kernel memory component
of the Memory Controller.

As of today, I am only laying down the following files:

 * memory.independent_kmem_limit
 * memory.kmem.limit_in_bytes (currently ignored)
 * memory.kmem.usage_in_bytes (always zero)
Signed-off-by: NGlauber Costa <glommer@parallels.com>
CC: Kirill A. Shutemov <kirill@shutemov.name>
CC: Paul Menage <paul@paulmenage.org>
CC: Greg Thelen <gthelen@google.com>
CC: Johannes Weiner <jweiner@redhat.com>
CC: Michal Hocko <mhocko@suse.cz>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After a guest is live migrated, the xen-netfront driver emits a gratuitous
ARP message, so that networking hardware on the target host's subnet can
take notice, and public routing to the guest is re-established. However,
if the packet appears on the backend interface before the backend is added
to the target host's bridge, the packet is lost, and the migrated guest's
peers become unable to talk to the guest.

A sufficient two-parts condition to prevent the above is:

(1) ensure that the backend only moves to Connected xenbus state after its
hotplug scripts completed, ie. the netback interface got added to the
bridge; and

(2) ensure the frontend only queues the gARP when it sees the backend move
to Connected.

These two together provide complete ordering. Sub-condition (1) is already
satisfied by commit f942dc25 in Linus' tree, based on commit
6b0b80ca7165 from [1].

In general, the full condition is sufficient, not necessary, because,
according to [2], live migration has been working for a long time without
satisfying sub-condition (2). However, after 6b0b80ca7165 was backported
to the RHEL-5 host to ensure (1), (2) still proved necessary in the RHEL-6
guest. This patch intends to provide (2) for upstream.

The Reviewed-by line comes from [3].

[1] git://xenbits.xen.org/people/ianc/linux-2.6.git#upstream/dom0/backend/netback-history
[2] http://old-list-archives.xen.org/xen-devel/2011-06/msg01969.html
[3] http://old-list-archives.xen.org/xen-devel/2011-07/msg00484.htmlSigned-off-by: NLaszlo Ersek <lersek@redhat.com>
Reviewed-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next into for-davem

Don't write more than the requested number of bytes of an batman-adv icmp
packet to the userspace buffer. Otherwise unrelated userspace memory might get
overridden by the kernel.
Signed-off-by: NSven Eckelmann <sven@narfation.org>
Signed-off-by: NMarek Lindner <lindner_marek@yahoo.de>

The access_ok read check can be directly done in copy_from_user since a failure
of access_ok is handled the same way as an error in __copy_from_user.
Signed-off-by: NSven Eckelmann <sven@narfation.org>
Signed-off-by: NMarek Lindner <lindner_marek@yahoo.de>

Writing a icmp_packet_rr and then reading icmp_packet can lead to kernel
memory corruption, if __user *buf is just below TASK_SIZE.
Signed-off-by: NPaul Kot <pawlkt@gmail.com>
[sven@narfation.org: made it checkpatch clean]
Signed-off-by: NSven Eckelmann <sven@narfation.org>
Signed-off-by: NMarek Lindner <lindner_marek@yahoo.de>

Instead of testing defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>