Introduce BPF_PROG_TYPE_PERF_EVENT programs that can be attached to
HW and SW perf events (PERF_TYPE_HARDWARE and PERF_TYPE_SOFTWARE
correspondingly in uapi/linux/perf_event.h)

The program visible context meta structure is
struct bpf_perf_event_data {
    struct pt_regs regs;
     __u64 sample_period;
};
which is accessible directly from the program:
int bpf_prog(struct bpf_perf_event_data *ctx)
{
  ... ctx->sample_period ...
  ... ctx->regs.ip ...
}

The bpf verifier rewrites the accesses into kernel internal
struct bpf_perf_event_data_kern which allows changing
struct perf_sample_data without affecting bpf programs.
New fields can be added to the end of struct bpf_perf_event_data
in the future.
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The verifier supported only 4-byte metafields in
struct __sk_buff and struct xdp_md. The metafields in upcoming
struct bpf_perf_event are 8-byte to match register width in struct pt_regs.
Teach verifier to recognize 8-byte metafield access.
The patch doesn't affect safety of sockets and xdp programs.
They check for 4-byte only ctx access before these conditions are hit.
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We get a few warnings when building kernel with W=1:
drivers/isdn/hardware/mISDN/hfcmulti.c:568:1: warning: no previous declaration for 'enablepcibridge' [-Wmissing-declarations]
drivers/isdn/hardware/mISDN/hfcmulti.c:574:1: warning: no previous declaration for 'disablepcibridge' [-Wmissing-declarations]
drivers/isdn/hardware/mISDN/hfcmulti.c:580:1: warning: no previous declaration for 'readpcibridge' [-Wmissing-declarations]
drivers/isdn/hardware/mISDN/hfcmulti.c:608:1: warning: no previous declaration for 'writepcibridge' [-Wmissing-declarations]
drivers/isdn/hardware/mISDN/hfcmulti.c:638:1: warning: no previous declaration for 'cpld_set_reg' [-Wmissing-declarations]
drivers/isdn/hardware/mISDN/hfcmulti.c:645:1: warning: no previous declaration for 'cpld_write_reg' [-Wmissing-declarations]
drivers/isdn/hardware/mISDN/hfcmulti.c:657:1: warning: no previous declaration for 'cpld_read_reg' [-Wmissing-declarations]
drivers/isdn/hardware/mISDN/hfcmulti.c:674:1: warning: no previous declaration for 'vpm_write_address' [-Wmissing-declarations]
drivers/isdn/hardware/mISDN/hfcmulti.c:681:1: warning: no previous declaration for 'vpm_read_address' [-Wmissing-declarations]
drivers/isdn/hardware/mISDN/hfcmulti.c:695:1: warning: no previous declaration for 'vpm_in' [-Wmissing-declarations]
drivers/isdn/hardware/mISDN/hfcmulti.c:716:1: warning: no previous declaration for 'vpm_out' [-Wmissing-declarations]
drivers/isdn/hardware/mISDN/hfcmulti.c:1028:1: warning: no previous declaration for 'plxsd_checksync' [-Wmissing-declarations]
....

In fact, these functions are only used in the file in which they are
declared and don't need a declaration, but can be made static.
so this patch marks these functions with 'static'.
Signed-off-by: NBaoyou Xie <baoyou.xie@linaro.org>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add support for the Qualcomm Technologies, Inc. EMAC gigabit Ethernet
controller.

This driver supports the following features:
1) Checksum offload.
2) Interrupt coalescing support.
3) SGMII phy.
4) phylib interface for external phy

Based on original work by
	Niranjana Vishwanathapura <nvishwan@codeaurora.org>
	Gilad Avidov <gavidov@codeaurora.org>
Signed-off-by: NTimur Tabi <timur@codeaurora.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Access the priv member of the dsa_switch structure directly, instead of
having an unnecessary helper.
Signed-off-by: NVivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Nikolay Aleksandrov says:

====================
net: bridge: add per-port unknown multicast flood control

The first patch prepares the forwarding path by having the exact packet
type passed down so we can later filter based on it and the per-port
unknown mcast flood flag introduced in the second patch. It is similar to
how the per-port unknown unicast flood flag works.
Nice side-effects of patch 01 are the slight reduction of tests in the
fast-path and a few minor checkpatch fixes.

v3: don't change br_auto_mask as that will change user-visible behaviour
v2: make pkt_type an enum as per Stephen's comment
====================
Acked-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add a per-port flag to control the unknown multicast flood, similar to the
unknown unicast flood flag and break a few long lines in the netlink flag
exports.
Signed-off-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Remove the unicast flag and introduce an exact pkt_type. That would help us
for the upcoming per-port multicast flood flag and also slightly reduce the
tests in the input fast path.
Signed-off-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

fdb dumps spanning multiple skb's currently restart from the first
interface again for every skb. This results in unnecessary
iterations on the already visited interfaces and their fdb
entries. In large scale setups, we have seen this to slow
down fdb dumps considerably. On a system with 30k macs we
see fdb dumps spanning across more than 300 skbs.

To fix the problem, this patch replaces the existing single fdb
marker with three markers: netdev hash entries, netdevs and fdb
index to continue where we left off instead of restarting from the
first netdev. This is consistent with link dumps.

In the process of fixing the performance issue, this patch also
re-implements fix done by
commit 472681d5 ("net: ndo_fdb_dump should report -EMSGSIZE to rtnl_fdb_dump")
(with an internal fix from Wilson Kok) in the following ways:
- change ndo_fdb_dump handlers to return error code instead
of the last fdb index
- use cb->args strictly for dump frag markers and not error codes.
This is consistent with other dump functions.

Below results were taken on a system with 1000 netdevs
and 35085 fdb entries:
before patch:
$time bridge fdb show | wc -l
15065

real    1m11.791s
user    0m0.070s
sys 1m8.395s

(existing code does not return all macs)

after patch:
$time bridge fdb show | wc -l
35085

real    0m2.017s
user    0m0.113s
sys 0m1.942s
Signed-off-by: NRoopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: NWilson Kok <wkok@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add the const for the parameter of flow_keys_have_l4 for the readability.
Signed-off-by: NGao Feng <fgao@ikuai8.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Don't expose skbs to in-kernel users, such as the AFS filesystem, but
instead provide a notification hook the indicates that a call needs
attention and another that indicates that there's a new call to be
collected.

This makes the following possibilities more achievable:

 (1) Call refcounting can be made simpler if skbs don't hold refs to calls.

 (2) skbs referring to non-data events will be able to be freed much sooner
     rather than being queued for AFS to pick up as rxrpc_kernel_recv_data
     will be able to consult the call state.

 (3) We can shortcut the receive phase when a call is remotely aborted
     because we don't have to go through all the packets to get to the one
     cancelling the operation.

 (4) It makes it easier to do encryption/decryption directly between AFS's
     buffers and sk_buffs.

 (5) Encryption/decryption can more easily be done in the AFS's thread
     contexts - usually that of the userspace process that issued a syscall
     - rather than in one of rxrpc's background threads on a workqueue.

 (6) AFS will be able to wait synchronously on a call inside AF_RXRPC.

To make this work, the following interface function has been added:

     int rxrpc_kernel_recv_data(
		struct socket *sock, struct rxrpc_call *call,
		void *buffer, size_t bufsize, size_t *_offset,
		bool want_more, u32 *_abort_code);

This is the recvmsg equivalent.  It allows the caller to find out about the
state of a specific call and to transfer received data into a buffer
piecemeal.

afs_extract_data() and rxrpc_kernel_recv_data() now do all the extraction
logic between them.  They don't wait synchronously yet because the socket
lock needs to be dealt with.

Five interface functions have been removed:

	rxrpc_kernel_is_data_last()
    	rxrpc_kernel_get_abort_code()
    	rxrpc_kernel_get_error_number()
    	rxrpc_kernel_free_skb()
    	rxrpc_kernel_data_consumed()

As a temporary hack, sk_buffs going to an in-kernel call are queued on the
rxrpc_call struct (->knlrecv_queue) rather than being handed over to the
in-kernel user.  To process the queue internally, a temporary function,
temp_deliver_data() has been added.  This will be replaced with common code
between the rxrpc_recvmsg() path and the kernel_rxrpc_recv_data() path in a
future patch.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The workqueue "pegasus_workqueue" queues a single work item per pegasus
instance and hence it doesn't require execution ordering. Hence,
alloc_workqueue has been used to replace the deprecated
create_singlethread_workqueue instance.

The WQ_MEM_RECLAIM flag has been set to ensure forward progress under
memory pressure since it's a network driver.

Since there are fixed number of work items, explicit concurrency
limit is unnecessary here.
Signed-off-by: NBhaktipriya Shridhar <bhaktipriya96@gmail.com>
Acked-by: NTejun Heo <tj@kernel.org>
Acked-by: NPetko Manolov <petkan@mip-labs.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

alloc_ordered_workqueue() with WQ_MEM_RECLAIM set, replaces
deprecated create_singlethread_workqueue(). This is the identity
conversion.

The workqueue "wq" queues multiple work items viz
&bond->mcast_work, &nnw->work, &bond->mii_work, &bond->arp_work,
&bond->alb_work, &bond->mii_work, &bond->ad_work, &bond->slave_arr_work
which require strict execution ordering. Hence, an ordered dedicated
workqueue has been used.

Since, it is a network driver, WQ_MEM_RECLAIM has been set to
ensure forward progress under memory pressure.
Signed-off-by: NBhaktipriya Shridhar <bhaktipriya96@gmail.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Update the sky2 driver to pass number of packets done to NAPI.
The driver was never updated when napi_complete_done was added.
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Alexandre TORGUE says:

====================
Add Ethernet support on STM32F429

STM32F429 Chip embeds a Synopsys 3.50a MAC IP.

This series enhance current stmmac driver to control it (code already
available) and adds basic glue for STM32F429 chip.

Changes since v5:
 -Fix typo in bindings documentation patch.
 -Change clocks names in stm32-dwmac glue driver / Documentation.
 -After rebase, stm32 ethernet node is now available. It has to be updated
according to new clocks names.

Changes since v4:
 -Fix dirty copy/past in bindings documentation patch.

Changes since v3:
 -Fix "tx-clk" and "rx-clk" as required clocks. Driver and bindings are
modified.

Changes since v2:
 -Fix alphabetic order in Kconfig and Makefile.
 -Improve code according to Joachim review.
 -Binding: remove useless entry.

Changes since v1:
 -Fix Kbuild issue in Kconfig.
 -Remove init/exit callbacks. Suspend/Resume and remove driver is no more
driven in stmmac_pltfr but directly in dwmac-stm32 glue driver.
 -Take into account Joachim review.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Adds support of Synopsys 3.50a MAC IP in stmmac driver.
Acked-by: NGiuseppe Cavallaro <peppe.cavallaro@st.com>
Tested-by: NMaxime Coquelin <maxime.coquelin@st.com>
Signed-off-by: NAlexandre TORGUE <alexandre.torgue@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NAlexandre TORGUE <alexandre.torgue@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

stm324xx family chips support Synopsys MAC 3.510 IP.
This patch adds settings for logical glue logic:
-clocks
-mode selection MII or RMII.
Reviewed-by: NJoachim Eastwood <manabian@gmail.com>
Acked-by: NGiuseppe Cavallaro <peppe.cavallaro@st.com>
Tested-by: NMaxime Coquelin <maxime.coquelin@st.com>
Signed-off-by: NAlexandre TORGUE <alexandre.torgue@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

return at end of function is useless.
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A bugfix for backward compatibility handling introduced undefined
behavior for the case that of_parse_phandle() does not return
a valid entry, as "gcc -Wmaybe-unused" reports:

drivers/net/ethernet/apm/xgene/xgene_enet_hw.c: In function 'xgene_enet_phy_connect':
drivers/net/ethernet/apm/xgene/xgene_enet_hw.c:776:6: error: 'phy_dev' may be used uninitialized in this function [-Werror=maybe-uninitialized]
drivers/net/ethernet/apm/xgene/xgene_enet_hw.c: In function 'xgene_enet_mdio_config':
drivers/net/ethernet/apm/xgene/xgene_enet_hw.c:776:6: error: 'phy_dev' may be used uninitialized in this function [-Werror=maybe-uninitialized]

We can work around this by removing the check for zero "np", as
of_phy_connect() will correctly handle a NULL argument so we fall
back into the normal error handling case.

Note that I had previously fixed another bug that resulted in the
exact same warning, but this is a different problem that was
introduced after my original fix.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Fixes: 03377e38 ("drivers: net: xgene: Fix backward compatibility")
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

check the coding style with checkpatch.pl and fix the warnings and errors.
Signed-off-by: NHayes Wang <hayeswang@realtek.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Robert Foss says:

====================
net/usb: asix driver improvements

This is a resubmission of v3, since the netdev
mailinlist was not sent the previous submission.

This series improves power management of the asix driver.

 - Suspend/resume support is improved to save needed registers.
 - Device disconnection is improved.
 - Fixes AX88772x resume failures
 - Implementes IEEE 802.3 spec section "22.2.4.1.1 Reset" correctly
 - Fixes AX_CMD_WRITE_MEDIUM_MODE being set incorrectly

Changes since v1:
- Added proper metadata tags to series.
- Added two more patches to series.

Changes since v2:
- Added coverletter
- Tested patches on AX88772A/AX88772B/AX88178/AX88179 hardware
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

From: Grant Grundler <grundler@chromium.org>

The miii_nway_restart() causes a PHY link change activity and
ax88772_link_reset will be called. link_reset will set
AX_CMD_WRITE_MEDIUM_MODE register correctly.

The asix_write_medium_mode in reset() fills in a default value to the register
which may be different from the negotiation result. So do this first.

Ignore the ret value since it's ignored in XXX_link_reset() functions.
Signed-off-by: NGrant Grundler <grundler@google.com>
Signed-off-by: NRobert Foss <robert.foss@collabora.com>
Tested-by: NRobert Foss <robert.foss@collabora.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

From: Grant Grundler <grundler@chromium.org>

https://lkml.org/lkml/2014/11/11/947

Ben Hutchings is correct. IEEE 802.3 spec section "22.2.4.1.1 Reset" requires
up to 500ms delay. Mitigate the "max" delay by polling the phy until BCM_RESET
bit is clear.
Signed-off-by: NGrant Grundler <grundler@chromium.org>
Signed-off-by: NRobert Foss <robert.foss@collabora.com>
Tested-by: NRobert Foss <robert.foss@collabora.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

From: Allan Chou <allan@asix.com.tw>

The change fixes AX88772x resume failure by
- Restore incorrect AX88772A PHY registers when resetting
- Need to stop MAC operation when suspending
- Need to restart MII when restoring PHY
Signed-off-by: NAllan Chou <allan@asix.com.tw>
Signed-off-by: NRobert Foss <robert.foss@collabora.com>
Tested-by: NRobert Foss <robert.foss@collabora.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

From: Vincent Palatin <vpalatin@chromium.org>

Check the answers from the USB stack and avoid re-sending multiple times
the request if the device has disappeared.
Signed-off-by: NVincent Palatin <vpalatin@chromium.org>
Signed-off-by: NRobert Foss <robert.foss@collabora.com>
Tested-by: NRobert Foss <robert.foss@collabora.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

From: Freddy Xin <freddy@asix.com.tw>

In order to R/W registers in suspend/resume functions, in_pm flags are
added to some functions to determine whether the nopm version of usb
functions is called.

Save BMCR and ANAR PHY registers in suspend function and restore them
in resume function.

Reset HW in resume function to ensure the PHY works correctly.
Signed-off-by: NFreddy Xin <freddy@asix.com.tw>
Signed-off-by: NRobert Foss <robert.foss@collabora.com>
Tested-by: NRobert Foss <robert.foss@collabora.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Check for ethtool_ops structures that are only stored in the ethtool_ops
field of a net_device structure or passed as the second argument to
netdev_set_default_ethtool_ops.  These contexts are declared const, so
ethtool_ops structures that have these properties can be declared as const
also.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r disable optional_qualifier@
identifier i;
position p;
@@
static struct ethtool_ops i@p = { ... };

@ok1@
identifier r.i;
struct net_device e;
position p;
@@
e.ethtool_ops = &i@p;

@ok2@
identifier r.i;
expression e;
position p;
@@
netdev_set_default_ethtool_ops(e, &i@p)

@bad@
position p != {r.p,ok1.p,ok2.p};
identifier r.i;
@@
i@p

@depends on !bad disable optional_qualifier@
identifier r.i;
@@
static
+const
 struct ethtool_ops i = { ... };
// </smpl>
Suggested-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NJulia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Check for ethtool_ops structures that are only stored in the ethtool_ops
field of a net_device structure or passed as the second argument to
netdev_set_default_ethtool_ops.  These contexts are declared const, so
ethtool_ops structures that have these properties can be declared as const
also.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r disable optional_qualifier@
identifier i;
position p;
@@
static struct ethtool_ops i@p = { ... };

@ok1@
identifier r.i;
struct net_device e;
position p;
@@
e.ethtool_ops = &i@p;

@ok2@
identifier r.i;
expression e;
position p;
@@
netdev_set_default_ethtool_ops(e, &i@p)

@bad@
position p != {r.p,ok1.p,ok2.p};
identifier r.i;
@@
i@p

@depends on !bad disable optional_qualifier@
identifier r.i;
@@
static
+const
 struct ethtool_ops i = { ... };
// </smpl>
Suggested-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NJulia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Check for ethtool_ops structures that are only stored in the ethtool_ops
field of a net_device structure or passed as the second argument to
netdev_set_default_ethtool_ops.  These contexts are declared const, so
ethtool_ops structures that have these properties can be declared as const
also.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r disable optional_qualifier@
identifier i;
position p;
@@
static struct ethtool_ops i@p = { ... };

@ok1@
identifier r.i;
struct net_device e;
position p;
@@
e.ethtool_ops = &i@p;

@ok2@
identifier r.i;
expression e;
position p;
@@
netdev_set_default_ethtool_ops(e, &i@p)

@bad@
position p != {r.p,ok1.p,ok2.p};
identifier r.i;
@@
i@p

@depends on !bad disable optional_qualifier@
identifier r.i;
@@
static
+const
 struct ethtool_ops i = { ... };
// </smpl>
Suggested-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NJulia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Guillaume Nault says:

====================
ppp: fix deadlock upon recursive xmit

This series fixes the issue reported by Feng where packets looping
through a ppp device makes the module deadlock:
https://marc.info/?l=linux-netdev&m=147134567319038&w=2

The problem can occur on virtual interfaces (e.g. PPP over L2TP, or
PPPoE on vxlan devices), when a PPP packet is routed back to the PPP
interface.

PPP's xmit path isn't reentrant, so patch #1 uses a per-cpu variable
to detect and break recursion. Patch #2 sets the NETIF_F_LLTX flag to
avoid lock inversion issues between ppp and txqueue locks.

There are multiple entry points to the PPP xmit path. This series has
been tested with lockdep and should address recursion issues no matter
how the packet entered the path.

A similar issue in L2TP is not covered by this series:
l2tp_xmit_skb() also isn't reentrant, and it can be called as part of
PPP's xmit path (pppol2tp_xmit()), or directly from the L2TP socket
(l2tp_ppp_sendmsg()). If a packet is sent by l2tp_ppp_sendmsg() and
routed to the parent PPP interface, then it's going to hit
l2tp_xmit_skb() again.

Breaking recursion as done in ppp_generic is not enough, because we'd
still have a lock inversion issue (locking in l2tp_xmit_skb() can
happen before or after locking in ppp_generic). The best approach would
be to use the ip_tunnel functions and remove the socket locking in
l2tp_xmit_skb(). But that'd be something for net-next.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

ppp_xmit_process() already locks the xmit path. If HARD_TX_LOCK() tries
to hold the _xmit_lock we can get lock inversion.

[  973.726130] ======================================================
[  973.727311] [ INFO: possible circular locking dependency detected ]
[  973.728546] 4.8.0-rc2 #1 Tainted: G           O
[  973.728986] -------------------------------------------------------
[  973.728986] accel-pppd/1806 is trying to acquire lock:
[  973.728986]  (&qdisc_xmit_lock_key){+.-...}, at: [<ffffffff8146f6fe>] sch_direct_xmit+0x8d/0x221
[  973.728986]
[  973.728986] but task is already holding lock:
[  973.728986]  (l2tp_sock){+.-...}, at: [<ffffffffa0202c4a>] l2tp_xmit_skb+0x1e8/0x5d7 [l2tp_core]
[  973.728986]
[  973.728986] which lock already depends on the new lock.
[  973.728986]
[  973.728986]
[  973.728986] the existing dependency chain (in reverse order) is:
[  973.728986]
-> #3 (l2tp_sock){+.-...}:
[  973.728986]        [<ffffffff810b3130>] lock_acquire+0x150/0x217
[  973.728986]        [<ffffffff815752f4>] _raw_spin_lock+0x2d/0x3c
[  973.728986]        [<ffffffffa0202c4a>] l2tp_xmit_skb+0x1e8/0x5d7 [l2tp_core]
[  973.728986]        [<ffffffffa01b2466>] pppol2tp_xmit+0x1f2/0x25e [l2tp_ppp]
[  973.728986]        [<ffffffffa0184f59>] ppp_channel_push+0xb5/0x14a [ppp_generic]
[  973.728986]        [<ffffffffa01853ed>] ppp_write+0x104/0x11c [ppp_generic]
[  973.728986]        [<ffffffff811b2ec6>] __vfs_write+0x56/0x120
[  973.728986]        [<ffffffff811b3f4c>] vfs_write+0xbd/0x11b
[  973.728986]        [<ffffffff811b4cb2>] SyS_write+0x5e/0x96
[  973.728986]        [<ffffffff81575ba5>] entry_SYSCALL_64_fastpath+0x18/0xa8
[  973.728986]
-> #2 (&(&pch->downl)->rlock){+.-...}:
[  973.728986]        [<ffffffff810b3130>] lock_acquire+0x150/0x217
[  973.728986]        [<ffffffff81575334>] _raw_spin_lock_bh+0x31/0x40
[  973.728986]        [<ffffffffa01808e2>] ppp_push+0xa7/0x82d [ppp_generic]
[  973.728986]        [<ffffffffa0184675>] __ppp_xmit_process+0x48/0x877 [ppp_generic]
[  973.728986]        [<ffffffffa018505b>] ppp_xmit_process+0x4b/0xaf [ppp_generic]
[  973.728986]        [<ffffffffa01853f7>] ppp_write+0x10e/0x11c [ppp_generic]
[  973.728986]        [<ffffffff811b2ec6>] __vfs_write+0x56/0x120
[  973.728986]        [<ffffffff811b3f4c>] vfs_write+0xbd/0x11b
[  973.728986]        [<ffffffff811b4cb2>] SyS_write+0x5e/0x96
[  973.728986]        [<ffffffff81575ba5>] entry_SYSCALL_64_fastpath+0x18/0xa8
[  973.728986]
-> #1 (&(&ppp->wlock)->rlock){+.-...}:
[  973.728986]        [<ffffffff810b3130>] lock_acquire+0x150/0x217
[  973.728986]        [<ffffffff81575334>] _raw_spin_lock_bh+0x31/0x40
[  973.728986]        [<ffffffffa0184654>] __ppp_xmit_process+0x27/0x877 [ppp_generic]
[  973.728986]        [<ffffffffa018505b>] ppp_xmit_process+0x4b/0xaf [ppp_generic]
[  973.728986]        [<ffffffffa01852da>] ppp_start_xmit+0x21b/0x22a [ppp_generic]
[  973.728986]        [<ffffffff8143f767>] dev_hard_start_xmit+0x1a9/0x43d
[  973.728986]        [<ffffffff8146f747>] sch_direct_xmit+0xd6/0x221
[  973.728986]        [<ffffffff814401e4>] __dev_queue_xmit+0x62a/0x912
[  973.728986]        [<ffffffff814404d7>] dev_queue_xmit+0xb/0xd
[  973.728986]        [<ffffffff81449978>] neigh_direct_output+0xc/0xe
[  973.728986]        [<ffffffff8150e62b>] ip6_finish_output2+0x5a9/0x623
[  973.728986]        [<ffffffff81512128>] ip6_output+0x15e/0x16a
[  973.728986]        [<ffffffff8153ef86>] dst_output+0x76/0x7f
[  973.728986]        [<ffffffff8153f737>] mld_sendpack+0x335/0x404
[  973.728986]        [<ffffffff81541c61>] mld_send_initial_cr.part.21+0x99/0xa2
[  973.728986]        [<ffffffff8154441d>] ipv6_mc_dad_complete+0x42/0x71
[  973.728986]        [<ffffffff8151c4bd>] addrconf_dad_completed+0x1cf/0x2ea
[  973.728986]        [<ffffffff8151e4fa>] addrconf_dad_work+0x453/0x520
[  973.728986]        [<ffffffff8107a393>] process_one_work+0x365/0x6f0
[  973.728986]        [<ffffffff8107aecd>] worker_thread+0x2de/0x421
[  973.728986]        [<ffffffff810816fb>] kthread+0x121/0x130
[  973.728986]        [<ffffffff81575dbf>] ret_from_fork+0x1f/0x40
[  973.728986]
-> #0 (&qdisc_xmit_lock_key){+.-...}:
[  973.728986]        [<ffffffff810b28d6>] __lock_acquire+0x1118/0x1483
[  973.728986]        [<ffffffff810b3130>] lock_acquire+0x150/0x217
[  973.728986]        [<ffffffff815752f4>] _raw_spin_lock+0x2d/0x3c
[  973.728986]        [<ffffffff8146f6fe>] sch_direct_xmit+0x8d/0x221
[  973.728986]        [<ffffffff814401e4>] __dev_queue_xmit+0x62a/0x912
[  973.728986]        [<ffffffff814404d7>] dev_queue_xmit+0xb/0xd
[  973.728986]        [<ffffffff81449978>] neigh_direct_output+0xc/0xe
[  973.728986]        [<ffffffff81487811>] ip_finish_output2+0x5db/0x609
[  973.728986]        [<ffffffff81489590>] ip_finish_output+0x152/0x15e
[  973.728986]        [<ffffffff8148a0d4>] ip_output+0x8c/0x96
[  973.728986]        [<ffffffff81489652>] ip_local_out+0x41/0x4a
[  973.728986]        [<ffffffff81489e7d>] ip_queue_xmit+0x5a5/0x609
[  973.728986]        [<ffffffffa0202fe4>] l2tp_xmit_skb+0x582/0x5d7 [l2tp_core]
[  973.728986]        [<ffffffffa01b2466>] pppol2tp_xmit+0x1f2/0x25e [l2tp_ppp]
[  973.728986]        [<ffffffffa0184f59>] ppp_channel_push+0xb5/0x14a [ppp_generic]
[  973.728986]        [<ffffffffa01853ed>] ppp_write+0x104/0x11c [ppp_generic]
[  973.728986]        [<ffffffff811b2ec6>] __vfs_write+0x56/0x120
[  973.728986]        [<ffffffff811b3f4c>] vfs_write+0xbd/0x11b
[  973.728986]        [<ffffffff811b4cb2>] SyS_write+0x5e/0x96
[  973.728986]        [<ffffffff81575ba5>] entry_SYSCALL_64_fastpath+0x18/0xa8
[  973.728986]
[  973.728986] other info that might help us debug this:
[  973.728986]
[  973.728986] Chain exists of:
  &qdisc_xmit_lock_key --> &(&pch->downl)->rlock --> l2tp_sock

[  973.728986]  Possible unsafe locking scenario:
[  973.728986]
[  973.728986]        CPU0                    CPU1
[  973.728986]        ----                    ----
[  973.728986]   lock(l2tp_sock);
[  973.728986]                                lock(&(&pch->downl)->rlock);
[  973.728986]                                lock(l2tp_sock);
[  973.728986]   lock(&qdisc_xmit_lock_key);
[  973.728986]
[  973.728986]  *** DEADLOCK ***
[  973.728986]
[  973.728986] 6 locks held by accel-pppd/1806:
[  973.728986]  #0:  (&(&pch->downl)->rlock){+.-...}, at: [<ffffffffa0184efa>] ppp_channel_push+0x56/0x14a [ppp_generic]
[  973.728986]  #1:  (l2tp_sock){+.-...}, at: [<ffffffffa0202c4a>] l2tp_xmit_skb+0x1e8/0x5d7 [l2tp_core]
[  973.728986]  #2:  (rcu_read_lock){......}, at: [<ffffffff81486981>] rcu_lock_acquire+0x0/0x20
[  973.728986]  #3:  (rcu_read_lock_bh){......}, at: [<ffffffff81486981>] rcu_lock_acquire+0x0/0x20
[  973.728986]  #4:  (rcu_read_lock_bh){......}, at: [<ffffffff814340e3>] rcu_lock_acquire+0x0/0x20
[  973.728986]  #5:  (dev->qdisc_running_key ?: &qdisc_running_key#2){+.....}, at: [<ffffffff8144011e>] __dev_queue_xmit+0x564/0x912
[  973.728986]
[  973.728986] stack backtrace:
[  973.728986] CPU: 2 PID: 1806 Comm: accel-pppd Tainted: G           O    4.8.0-rc2 #1
[  973.728986] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014
[  973.728986]  ffff7fffffffffff ffff88003436f850 ffffffff812a20f4 ffffffff82156e30
[  973.728986]  ffffffff82156920 ffff88003436f890 ffffffff8115c759 ffff88003344ae00
[  973.728986]  ffff88003344b5c0 0000000000000002 0000000000000006 ffff88003344b5e8
[  973.728986] Call Trace:
[  973.728986]  [<ffffffff812a20f4>] dump_stack+0x67/0x90
[  973.728986]  [<ffffffff8115c759>] print_circular_bug+0x22e/0x23c
[  973.728986]  [<ffffffff810b28d6>] __lock_acquire+0x1118/0x1483
[  973.728986]  [<ffffffff810b3130>] lock_acquire+0x150/0x217
[  973.728986]  [<ffffffff810b3130>] ? lock_acquire+0x150/0x217
[  973.728986]  [<ffffffff8146f6fe>] ? sch_direct_xmit+0x8d/0x221
[  973.728986]  [<ffffffff815752f4>] _raw_spin_lock+0x2d/0x3c
[  973.728986]  [<ffffffff8146f6fe>] ? sch_direct_xmit+0x8d/0x221
[  973.728986]  [<ffffffff8146f6fe>] sch_direct_xmit+0x8d/0x221
[  973.728986]  [<ffffffff814401e4>] __dev_queue_xmit+0x62a/0x912
[  973.728986]  [<ffffffff814404d7>] dev_queue_xmit+0xb/0xd
[  973.728986]  [<ffffffff81449978>] neigh_direct_output+0xc/0xe
[  973.728986]  [<ffffffff81487811>] ip_finish_output2+0x5db/0x609
[  973.728986]  [<ffffffff81486853>] ? dst_mtu+0x29/0x2e
[  973.728986]  [<ffffffff81489590>] ip_finish_output+0x152/0x15e
[  973.728986]  [<ffffffff8148a0bc>] ? ip_output+0x74/0x96
[  973.728986]  [<ffffffff8148a0d4>] ip_output+0x8c/0x96
[  973.728986]  [<ffffffff81489652>] ip_local_out+0x41/0x4a
[  973.728986]  [<ffffffff81489e7d>] ip_queue_xmit+0x5a5/0x609
[  973.728986]  [<ffffffff814c559e>] ? udp_set_csum+0x207/0x21e
[  973.728986]  [<ffffffffa0202fe4>] l2tp_xmit_skb+0x582/0x5d7 [l2tp_core]
[  973.728986]  [<ffffffffa01b2466>] pppol2tp_xmit+0x1f2/0x25e [l2tp_ppp]
[  973.728986]  [<ffffffffa0184f59>] ppp_channel_push+0xb5/0x14a [ppp_generic]
[  973.728986]  [<ffffffffa01853ed>] ppp_write+0x104/0x11c [ppp_generic]
[  973.728986]  [<ffffffff811b2ec6>] __vfs_write+0x56/0x120
[  973.728986]  [<ffffffff8124c11d>] ? fsnotify_perm+0x27/0x95
[  973.728986]  [<ffffffff8124d41d>] ? security_file_permission+0x4d/0x54
[  973.728986]  [<ffffffff811b3f4c>] vfs_write+0xbd/0x11b
[  973.728986]  [<ffffffff811b4cb2>] SyS_write+0x5e/0x96
[  973.728986]  [<ffffffff81575ba5>] entry_SYSCALL_64_fastpath+0x18/0xa8
[  973.728986]  [<ffffffff810ae0fa>] ? trace_hardirqs_off_caller+0x121/0x12f
Signed-off-by: NGuillaume Nault <g.nault@alphalink.fr>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>