Root flow table is dynamically changed by the underlying flow steering
layer, and IPoIB/ULPs have no idea what will be the root flow table in
the future, hence we need a dynamic infrastructure to move Underlay QPs
with the root flow table.

Fixes: b3ba5149 ("net/mlx5: Refactor create flow table method to accept underlay QP")
Signed-off-by: NErez Shitrit <erezsh@mellanox.com>
Signed-off-by: NMaor Gottlieb <maorg@mellanox.com>
Signed-off-by: NYishai Hadas <yishaih@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

IPoIB doesn't support striding RQ at the moment, for this
we need to explicitly choose non striding RQ in IPoIB init,
even if the HW supports it.

Fixes: 8f493ffd ("net/mlx5e: IPoIB, RX steering RSS RQTs and TIRs")
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

Fail-safe support patches introduced a trivial bug,
setup tc callback is doing a wrong check of the netdevice state,
the fix is simply to invert the condition.

Fixes: 6f9485af ("net/mlx5e: Fail safe tc setup")
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

Pause bit should set when RX pause is on, not TX pause.
Also, setting Asym_Pause is incorrect, and should be turned off.

Fixes: 665bc539 ("net/mlx5e: Use new ethtool get/set link ksettings API")
Signed-off-by: NGal Pressman <galp@mellanox.com>
Cc: kernel-team@fb.com
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

Query the operational pause from firmware (PFCC register) instead of
always passing zeros.

Fixes: 665bc539 ("net/mlx5e: Use new ethtool get/set link ksettings API")
Signed-off-by: NGal Pressman <galp@mellanox.com>
Cc: kernel-team@fb.com
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

There are several paths in vmxnet3, where settings changes cause the
adapter to be brought down and back up (vmxnet3_set_ringparam among
them).  Should part of the reset operation fail, these paths call
vmxnet3_force_close, which enables all napi instances prior to calling
dev_close (with the expectation that vmxnet3_close will then properly
disable them again).  However, vmxnet3_force_close neglects to clear
VMXNET3_STATE_BIT_QUIESCED prior to calling dev_close.  As a result
vmxnet3_quiesce_dev (called from vmxnet3_close), returns early, and
leaves all the napi instances in a enabled state while the device itself
is closed.  If a device in this state is activated again, napi_enable
will be called on already enabled napi_instances, leading to a BUG halt.

The fix is to simply enausre that the QUIESCED bit is cleared in
vmxnet3_force_close to allow quesence to be completed properly on close.
Signed-off-by: NNeil Horman <nhorman@tuxdriver.com>
CC: Shrikrishna Khare <skhare@vmware.com>
CC: "VMware, Inc." <pv-drivers@vmware.com>
CC: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The revision enum values (eg EFX_REV_HUNT_A0) form part of our API,
 and are included in ethtool. If these are inconsistent then ethtool
 will print garbage for a register dump (ethtool -d).

Fixes: 5a6681e2 ("sfc: separate out SFC4000 ("Falcon") support into new sfc-falcon driver")
Signed-off-by: NEdward Cree <ecree@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add the missing endianness conversions to a debug statement printing
the USB device-descriptor idVendor and idProduct fields during probe.
Signed-off-by: NJohan Hovold <johan@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add missing endianness conversion when using the USB device-descriptor
bcdDevice field to construct a firmware file name.

Fixes: 8ef80aef ("[IRDA]: irda-usb.c: STIR421x cleanups")
Cc: stable <stable@vger.kernel.org>     # 2.6.18
Cc: Nick Fedchik <nfedchik@atlantic-link.com.ua>
Signed-off-by: NJohan Hovold <johan@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add default case to switch in order to avoid any chance of using an
uninitialized variable _low_, in case s->type does not match any of
the listed case values.

Addresses-Coverity-ID: 1398130
Suggested-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NGustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 0ca50d12 ("sctp: fix src address selection if using secondary
addresses") has fixed a src address selection issue when using secondary
addresses for ipv4.

Now sctp ipv6 also has the similar issue. When using a secondary address,
sctp_v6_get_dst tries to choose the saddr which has the most same bits
with the daddr by sctp_v6_addr_match_len. It may make some cases not work
as expected.

hostA:
  [1] fd21:356b:459a:cf10::11 (eth1)
  [2] fd21:356b:459a:cf20::11 (eth2)

hostB:
  [a] fd21:356b:459a:cf30::2  (eth1)
  [b] fd21:356b:459a:cf40::2  (eth2)

route from hostA to hostB:
  fd21:356b:459a:cf30::/64 dev eth1  metric 1024  mtu 1500

The expected path should be:
  fd21:356b:459a:cf10::11 <-> fd21:356b:459a:cf30::2
But addr[2] matches addr[a] more bits than addr[1] does, according to
sctp_v6_addr_match_len. It causes the path to be:
  fd21:356b:459a:cf20::11 <-> fd21:356b:459a:cf30::2

This patch is to fix it with the same way as Marcelo's fix for sctp ipv4.
As no ip_dev_find for ipv6, this patch is to use ipv6_chk_addr to check
if the saddr is in a dev instead.

Note that for backwards compatibility, it will still do the addr_match_len
check here when no optimal is found.
Reported-by: NPatrick Talbert <ptalbert@redhat.com>
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The API convention makes it that a given MDIO bus reset should be able
to access PHY devices in its reset() callback and perform additional
MDIO accesses in order to bring the bus and PHYs in a working state.

Commit 69226896 ("mdio_bus: Issue GPIO RESET to PHYs.") broke that
contract by first calling bus->reset() and then release all PHYs from
reset using their shared GPIO line, so restore the expected
functionality here.

Fixes: 69226896 ("mdio_bus: Issue GPIO RESET to PHYs.")
Signed-off-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We must accumulate into reg->aux_off rather than use a plain assignment.

Add a test for this situation to test_align.
Reported-by: NAlexei Starovoitov <ast@fb.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The macro tipc_wait_for_cond() is embedding the macro sk_wait_event()
to fulfil its task. The latter, in turn, is evaluating the stated
condition outside the socket lock context. This is problematic if
the condition is accessing non-trivial data structures which may be
altered by incoming interrupts, as is the case with the cong_links()
linked list, used by socket to keep track of the current set of
congested links. We sometimes see crashes when this list is accessed
by a condition function at the same time as a SOCK_WAKEUP interrupt
is removing an element from the list.

We fix this by expanding selected parts of sk_wait_event() into the
outer macro, while ensuring that all evaluations of a given condition
are performed under socket lock protection.

Fixes: commit 365ad353 ("tipc: reduce risk of user starvation during link congestion")
Reviewed-by: NParthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>
Signed-off-by: NJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Shahid Habib noticed that when xdp1 was killed from a different console the xdp
program was not cleaned-up properly in the kernel and it continued to forward
traffic.

Most of the applications in samples/bpf cleanup properly, but only when getting
SIGINT.  Since kill defaults to using SIGTERM, add support to cleanup when the
application receives either SIGINT or SIGTERM.
Signed-off-by: NAndy Gospodarek <andy@greyhouse.net>
Reported-by: NShahid Habib <shahid.habib@broadcom.com>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The error status err is initialized as zero and then being checked
several times to see if it is less than zero even when it has not
been updated.  It may seem that the err should be assigned to the
return code of the call to the various *offload_en_set calls and
then we check for failure, however, these functions are void and
never actually return any status.

Since these error checks are redundant we can remove these
as well as err and the error exit label err_exit.

Detected by CoverityScan, CID#1398313 and CID#1398306 ("Logically
dead code")
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Reviewed-by: NLino Sanfilippo <LinoSanfilippo@gmx.de>
Acked-by: NPavel Belous <pavel.belous@aquantia.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Reported-by: NAlexander Alemayhu <alexander@alemayhu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Manish Chopra says:

====================
qlcnic: Bug fix and update version

This series has one fix and bumps up driver version.
Please consider applying to "net"
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Bumping up the version as couple of fixes added after 5.3.65
Signed-off-by: NManish Chopra <manish.chopra@cavium.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently driver returns error on speed configurations
for 83xx adapter's non XGBE ports, due to this link doesn't
come up on the ports using 1000Base-T as a connector with
autoneg disabled. This patch fixes this with initializing
appropriate port type based on queried module/connector
types from hardware before any speed/autoneg configuration.
Signed-off-by: NManish Chopra <manish.chopra@cavium.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Unavoidable crashes in netfront_resume() and netback_changed() after a
previous fail in talk_to_netback() (e.g. when we fail to read MAC from
xenstore) were discovered. The failure path in talk_to_netback() does
unregister/free for netdev but we don't reset drvdata and we try accessing
it after resume.

Fix the bug by removing the whole xen device completely with
device_unregister(), this guarantees we won't have any calls into netfront
after a failure.
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In commit 59cc1f61 ("net: sched: convert qdisc linked list to
hashtable") we missed the opportunity to considerably speed up
tc_dump_tclass_root() if a qdisc handle is provided by user.

Instead of iterating all the qdiscs, use qdisc_match_from_root()
to directly get the one we look for.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch fixes a bug in splitting an SKB during SACK
processing. Specifically if an skb contains multiple
packets and is only partially sacked in the higher sequences,
tcp_match_sack_to_skb() splits the skb and marks the second fragment
as SACKed.

The current code further attempts rounding up the first fragment
to MSS boundaries. But it misses a boundary condition when the
rounded-up fragment size (pkt_len) is exactly skb size.  Spliting
such an skb is pointless and causses a kernel warning and aborts
the SACK processing. This patch universally checks such over-split
before calling tcp_fragment to prevent these unnecessary warnings.

Fixes: adb92db8 ("tcp: Make SACK code to split only at mss boundaries")
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NSoheil Hassas Yeganeh <soheil@google.com>
Acked-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

I should have known that lowering skb->truesize was dangerous :/

In case packets are not leaving the host via a standard Ethernet device,
but looped back to local sockets, bad things can happen, as reported
by Michael Madsen ( https://bugzilla.kernel.org/show_bug.cgi?id=195713 )

So instead of tweaking skb->truesize, lets change skb->destructor
and keep a reference on the owner socket via its sk_refcnt.

Fixes: f2f872f9 ("netem: Introduce skb_orphan_partial() helper")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: NMichael Madsen <mkm@nabto.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Daniel Borkmann says:

====================
Two generic xdp related follow-ups

Two follow-ups for the generic XDP API, would be great if
both could still be considered, since the XDP API is not
frozen yet. For details please see individual patches.

v1 -> v2:
  - Implemented feedback from Jakub Kicinski (reusing
    attribute on dump), thanks!
  - Rest as is.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

While working on the iproute2 generic XDP frontend, I noticed that
as of right now it's possible to have native *and* generic XDP
programs loaded both at the same time for the case when a driver
supports native XDP.

The intended model for generic XDP from b5cdae32 ("net: Generic
XDP") is, however, that only one out of the two can be present at
once which is also indicated as such in the XDP netlink dump part.
The main rationale for generic XDP is to ease accessibility (in
case a driver does not yet have XDP support) and to generically
provide a semantical model as an example for driver developers
wanting to add XDP support. The generic XDP option for an XDP
aware driver can still be useful for comparing and testing both
implementations.

However, it is not intended to have a second XDP processing stage
or layer with exactly the same functionality of the first native
stage. Only reason could be to have a partial fallback for future
XDP features that are not supported yet in the native implementation
and we probably also shouldn't strive for such fallback and instead
encourage native feature support in the first place. Given there's
currently no such fallback issue or use case, lets not go there yet
if we don't need to.

Therefore, change semantics for loading XDP and bail out if the
user tries to load a generic XDP program when a native one is
present and vice versa. Another alternative to bailing out would
be to handle the transition from one flavor to another gracefully,
but that would require to bring the device down, exchange both
types of programs, and bring it up again in order to avoid a tiny
window where a packet could hit both hooks. Given this complicates
the logic for just a debugging feature in the native case, I went
with the simpler variant.

For the dump, remove IFLA_XDP_FLAGS that was added with b5cdae32
and reuse IFLA_XDP_ATTACHED for indicating the mode. Dumping all
or just a subset of flags that were used for loading the XDP prog
is suboptimal in the long run since not all flags are useful for
dumping and if we start to reuse the same flag definitions for
load and dump, then we'll waste bit space. What we really just
want is to dump the mode for now.

Current IFLA_XDP_ATTACHED semantics are: nothing was installed (0),
a program is running at the native driver layer (1). Thus, add a
mode that says that a program is running at generic XDP layer (2).
Applications will handle this fine in that older binaries will
just indicate that something is attached at XDP layer, effectively
this is similar to IFLA_XDP_FLAGS attr that we would have had
modulo the redundancy.
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After commit b5cdae32 ("net: Generic XDP") we automatically fall
back to a generic XDP variant if the driver does not support native
XDP. Allow for an option where the user can specify that always the
native XDP variant should be selected and in case it's not supported
by a driver, just bail out.
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We do not want to use the architecture's type.h header when
building BPF programs which are always 64-bit.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

David S. Miller says:

====================
bpf: Add alignment tracker to verifier.

First we add the alignment tracking logic to the verifier.

Next, we work on building up infrastructure to facilitate regression
testing of this facility.

Finally, we add the "test_align" test case.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>

This allows a test case to load a BPF program and unconditionally
acquire the verifier log.

It also allows specification of the strict alignment flag.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>

Add a new field, "prog_flags", and an initial flag value
BPF_F_STRICT_ALIGNMENT.

When set, the verifier will enforce strict pointer alignment
regardless of the setting of CONFIG_EFFICIENT_UNALIGNED_ACCESS.

The verifier, in this mode, will also use a fixed value of "2" in
place of NET_IP_ALIGN.

This facilitates test cases that will exercise and validate this part
of the verifier even when run on architectures where alignment doesn't
matter.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>

If log_level > 1, do a state dump every instruction and emit it in
a more compact way (without a leading newline).

This will facilitate more sophisticated test cases which inspect the
verifier log for register state.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>

Currently if we add only constant values to pointers we can fully
validate the alignment, and properly check if we need to reject the
program on !CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS architectures.

However, once an unknown value is introduced we only allow byte sized
memory accesses which is too restrictive.

Add logic to track the known minimum alignment of register values,
and propagate this state into registers containing pointers.

The most common paradigm that makes use of this new logic is computing
the transport header using the IP header length field.  For example:

	struct ethhdr *ep = skb->data;
	struct iphdr *iph = (struct iphdr *) (ep + 1);
	struct tcphdr *th;
 ...
	n = iph->ihl;
	th = ((void *)iph + (n * 4));
	port = th->dest;

The existing code will reject the load of th->dest because it cannot
validate that the alignment is at least 2 once "n * 4" is added the
the packet pointer.

In the new code, the register holding "n * 4" will have a reg->min_align
value of 4, because any value multiplied by 4 will be at least 4 byte
aligned.  (actually, the eBPF code emitted by the compiler in this case
is most likely to use a shift left by 2, but the end result is identical)

At the critical addition:

	th = ((void *)iph + (n * 4));

The register holding 'th' will start with reg->off value of 14.  The
pointer addition will transform that reg into something that looks like:

	reg->aux_off = 14
	reg->aux_off_align = 4

Next, the verifier will look at the th->dest load, and it will see
a load offset of 2, and first check:

	if (reg->aux_off_align % size)

which will pass because aux_off_align is 4.  reg_off will be computed:

	reg_off = reg->off;
 ...
		reg_off += reg->aux_off;

plus we have off==2, and it will thus check:

	if ((NET_IP_ALIGN + reg_off + off) % size != 0)

which evaluates to:

	if ((NET_IP_ALIGN + 14 + 2) % size != 0)

On strict alignment architectures, NET_IP_ALIGN is 2, thus:

	if ((2 + 14 + 2) % size != 0)

which passes.

These pointer transformations and checks work regardless of whether
the constant offset or the variable with known alignment is added
first to the pointer register.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>

Shubham was recently asking on netdev why in arm64 JIT we don't multiply
the index for accessing the tail call map by 8. That led me into testing
out arm64 JIT wrt tail calls and it turned out I got a NULL pointer
dereference on the tail call.

The buggy access is at:

  prog = array->ptrs[index];
  if (prog == NULL)
      goto out;

  [...]
  00000060:  d2800e0a  mov x10, #0x70 // #112
  00000064:  f86a682a  ldr x10, [x1,x10]
  00000068:  f862694b  ldr x11, [x10,x2]
  0000006c:  b40000ab  cbz x11, 0x00000080
  [...]

The code triggering the crash is f862694b. x1 at the time contains the
address of the bpf array, x10 offsetof(struct bpf_array, ptrs). Meaning,
above we load the pointer to the program at map slot 0 into x10. x10
can then be NULL if the slot is not occupied, which we later on try to
access with a user given offset in x2 that is the map index.

Fix this by emitting the following instead:

  [...]
  00000060:  d2800e0a  mov x10, #0x70 // #112
  00000064:  8b0a002a  add x10, x1, x10
  00000068:  d37df04b  lsl x11, x2, #3
  0000006c:  f86b694b  ldr x11, [x10,x11]
  00000070:  b40000ab  cbz x11, 0x00000084
  [...]

This basically adds the offset to ptrs to the base address of the bpf
array we got and we later on access the map with an index * 8 offset
relative to that. The tail call map itself is basically one large area
with meta data at the head followed by the array of prog pointers.
This makes tail calls working again, tested on Cavium ThunderX ARMv8.

Fixes: ddb55992 ("arm64: bpf: implement bpf_tail_call() helper")
Reported-by: NShubham Bansal <illusionist.neo@gmail.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fix error path while dma open channel issue. Also, no need to check output
on NULL if it's never returned.
Signed-off-by: NIvan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Julian Wiedmann says:

====================
s390/net fixes

some qeth fixes for -net, the OSM/OSN one being the most crucial.
Please also queue these up for stable.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

commit 5f78e29c ("qeth: optimize IP handling in rx_mode callback")
added new hash tables, but missed to initialize them.

Fixes: 5f78e29c ("qeth: optimize IP handling in rx_mode callback")
Signed-off-by: NUrsula Braun <ubraun@linux.vnet.ibm.com>
Reviewed-by: NJulian Wiedmann <jwi@linux.vnet.ibm.com>
Signed-off-by: NJulian Wiedmann <jwi@linux.vnet.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Access card->dev only after checking whether's its valid.
Signed-off-by: NJulian Wiedmann <jwi@linux.vnet.ibm.com>
Reviewed-by: NUrsula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

commit b4d72c08 ("qeth: bridgeport support - basic control")
broke the support for OSM and OSN devices as follows:

As OSM and OSN are L2 only, qeth_core_probe_device() does an early
setup by loading the l2 discipline and calling qeth_l2_probe_device().
In this context, adding the l2-specific bridgeport sysfs attributes
via qeth_l2_create_device_attributes() hits a BUG_ON in fs/sysfs/group.c,
since the basic sysfs infrastructure for the device hasn't been
established yet.

Note that OSN actually has its own unique sysfs attributes
(qeth_osn_devtype), so the additional attributes shouldn't be created
at all.
For OSM, add a new qeth_l2_devtype that contains all the common
and l2-specific sysfs attributes.
When qeth_core_probe_device() does early setup for OSM or OSN, assign
the corresponding devtype so that the ccwgroup probe code creates the
full set of sysfs attributes.
This allows us to skip qeth_l2_create_device_attributes() in case
of an early setup.

Any device that can't do early setup will initially have only the
generic sysfs attributes, and when it's probed later
qeth_l2_probe_device() adds the l2-specific attributes.

If an early-setup device is removed (by calling ccwgroup_ungroup()),
device_unregister() will - using the devtype - delete the
l2-specific attributes before qeth_l2_remove_device() is called.
So make sure to not remove them twice.

What complicates the issue is that qeth_l2_probe_device() and
qeth_l2_remove_device() is also called on a device when its
layer2 attribute changes (ie. its layer mode is switched).
For early-setup devices this wouldn't work properly - we wouldn't
remove the l2-specific attributes when switching to L3.
But switching the layer mode doesn't actually make any sense;
we already decided that the device can only operate in L2!
So just refuse to switch the layer mode on such devices. Note that
OSN doesn't have a layer2 attribute, so we only need to special-case
OSM.

Based on an initial patch by Ursula Braun.

Fixes: b4d72c08 ("qeth: bridgeport support - basic control")
Signed-off-by: NJulian Wiedmann <jwi@linux.vnet.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>