Ben Hutchings says:

====================
ksz8795 VLAN fixes

This series fixes a number of bugs in the ksz8795 driver that affect
VLAN filtering, tag insertion, and tag removal.

I've tested these on the KSZ8795CLXD evaluation board, and checked the
register usage against the datasheets for the other supported chips.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

The magic number 4 in VLAN table lookup was the number of entries we
can read and write at once.  Using phy_port_cnt here doesn't make
sense and presumably broke VLAN filtering for 3-port switches.  Change
it back to 4.

Fixes: 4ce2a984 ("net: dsa: microchip: ksz8795: use phy_port_cnt ...")
Signed-off-by: Ben Hutchings <ben.hutchings@mind.be>
Signed-off-by: David S. Miller <davem@davemloft.net>

Currently ksz8_port_vlan_filtering() sets or clears the VLAN Enable
hardware flag.  That controls discarding of packets with a VID that
has not been enabled for any port on the switch.

Since it is a global flag, set the dsa_switch::vlan_filtering_is_global
flag so that the DSA core understands this can't be controlled per
port.

When VLAN filtering is enabled, the switch should also discard packets
with a VID that's not enabled on the ingress port.  Set or clear each
external port's VLAN Ingress Filter flag in ksz8_port_vlan_filtering()
to make that happen.

Fixes: e66f840c ("net: dsa: ksz: Add Microchip KSZ8795 DSA driver")
Signed-off-by: Ben Hutchings <ben.hutchings@mind.be>
Signed-off-by: David S. Miller <davem@davemloft.net>

On the CPU port, we can support both tagged and untagged VLANs at the
same time by doing any necessary untagging in software rather than
hardware.  To enable that, keep the CPU port's Remove Tag flag cleared
and set the dsa_switch::untag_bridge_pvid flag.

Fixes: e66f840c ("net: dsa: ksz: Add Microchip KSZ8795 DSA driver")
Signed-off-by: Ben Hutchings <ben.hutchings@mind.be>
Signed-off-by: David S. Miller <davem@davemloft.net>

When a VLAN is deleted from a port, the flags in struct
switchdev_obj_port_vlan are always 0.  ksz8_port_vlan_del() copies the
BRIDGE_VLAN_INFO_UNTAGGED flag to the port's Tag Removal flag, and
therefore always clears it.

In case there are multiple VLANs configured as untagged on this port -
which seems useless, but is allowed - deleting one of them changes the
remaining VLANs to be tagged.

It's only ever necessary to change this flag when a VLAN is added to
the port, so leave it unchanged in ksz8_port_vlan_del().

Fixes: e66f840c ("net: dsa: ksz: Add Microchip KSZ8795 DSA driver")
Signed-off-by: Ben Hutchings <ben.hutchings@mind.be>
Signed-off-by: David S. Miller <davem@davemloft.net>

The switches supported by ksz8795 only have a per-port flag for Tag
Removal.  This means it is not possible to support both tagged and
untagged VLANs on the same port.  Reject attempts to add a VLAN that
requires the flag to be changed, unless there are no VLANs currently
configured.

VID 0 is excluded from this check since it is untagged regardless of
the state of the flag.

On the CPU port we could support tagged and untagged VLANs at the same
time.  This will be enabled by a later patch.

Fixes: e66f840c ("net: dsa: ksz: Add Microchip KSZ8795 DSA driver")
Signed-off-by: Ben Hutchings <ben.hutchings@mind.be>
Signed-off-by: David S. Miller <davem@davemloft.net>

ksz8795 has never actually enabled PVID tag insertion, and it also
programmed the PVID incorrectly.  To fix this:

* Allow tag insertion to be controlled per ingress port.  On most
  chips, set bit 2 in Global Control 19.  On KSZ88x3 this control
  flag doesn't exist.

* When adding a PVID:
  - Set the appropriate register bits to enable tag insertion on
    egress at every other port if this was the packet's ingress port.
  - Mask *out* the VID from the default tag, before or-ing in the new
    PVID.

* When removing a PVID:
  - Clear the same control bits to disable tag insertion.
  - Don't update the default tag.  This wasn't doing anything useful.

Fixes: e66f840c ("net: dsa: ksz: Add Microchip KSZ8795 DSA driver")
Signed-off-by: Ben Hutchings <ben.hutchings@mind.be>
Signed-off-by: David S. Miller <davem@davemloft.net>

ksz_read64() currently does some dubious byte-swapping on the two
halves of a 64-bit register, and then only returns the high bits.
Replace this with a straightforward expression.

Fixes: e66f840c ("net: dsa: ksz: Add Microchip KSZ8795 DSA driver")
Signed-off-by: Ben Hutchings <ben.hutchings@mind.be>
Signed-off-by: David S. Miller <davem@davemloft.net>

Merge tag 'linux-can-fixes-for-5.14-20210810' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can

linux-can-fixes-for-5.14-20210810

Marc Kleine-Budde says:

====================
pull-request: can 2021-08-10

this is a pull request of 2 patches for net/master.

Baruch Siach's patch fixes a typo for the Microchip CAN BUS Analyzer
Tool entry in the MAINTAINERS file.

Hussein Alasadi fixes the setting of the M_CAN_DBTP register in the
m_can driver. The regression git mainline in v5.14-rc1, so no backport
to stable is needed.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Saeed Mahameed says:

====================
mlx5 fixes 2021-08-09

This series introduces fixes to mlx5 driver.
Please pull and let me know if there is any problem.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Tony Nguyen says:

====================
Intel Wired LAN Driver Updates 2021-08-09

This series contains updates to ice and iavf drivers.

Ani prevents the ice driver from accidentally being probed to a virtual
function and stops processing of VF messages when VFs are being torn
down.

Brett prevents the ice driver from deleting is own MAC address.

Fahad ensures the RSS LUT and key are always set following reset for
iavf.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

This patch fixes the setting of the M_CAN_DBTP register contents:
- use DBTP_ (the data bitrate macros) instead of NBTP_ which area used
  for the nominal bitrate
- do not overwrite possibly-existing DBTP_TDC flag by ORing reg_btp
  instead of overwriting

Link: https://lore.kernel.org/r/FRYP281MB06140984ABD9994C0AAF7433D1F69@FRYP281MB0614.DEUP281.PROD.OUTLOOK.COM
Fixes: 20779943 ("can: m_can: use bits.h macros for all regmasks")
Cc: Torin Cooper-Bennun <torin@maxiluxsystems.com>
Cc: Chandrasekar Ramakrishnan <rcsekar@samsung.com>
Signed-off-by: Hussein Alasadi <alasadi@arecs.eu>
[mkl: update patch description, update indention]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

This patch fixes the abbreviated name of the Microchip CAN BUS
Analyzer Tool.

Fixes: 8a7b46fa ("MAINTAINERS: add Yasushi SHOJI as reviewer for the Microchip CAN BUS Analyzer Tool driver")
Link: https://lore.kernel.org/r/cc4831cb1c8759c15fb32c21fd326e831183733d.1627876781.git.baruch@tkos.co.ilSigned-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

Check return value of mlx5_fw_tracer_start(), set error path and fix
return value of mlx5_fw_tracer_init() accordingly.

Fixes: c71ad41c ("net/mlx5: FW tracer, events handling")
Signed-off-by: Aya Levin <ayal@nvidia.com>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

The CQ destroy is performed based on the IRQ number that is stored in
cq->irqn. That number wasn't set explicitly during CQ creation and as
expected some of the API users of mlx5_core_create_cq() forgot to update
it.

This caused to wrong synchronization call of the wrong IRQ with a number
0 instead of the real one.

As a fix, set the IRQ number directly in the mlx5_core_create_cq() and
update all users accordingly.

Fixes: 1a86b377 ("vdpa/mlx5: Add VDPA driver for supported mlx5 devices")
Fixes: ef1659ad ("IB/mlx5: Add DEVX support for CQ events")
Signed-off-by: Shay Drory <shayd@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

Free the offload sample action on error.

Fixes: f94d6389 ("net/mlx5e: TC, Add support to offload sample action")
Signed-off-by: Chris Mi <cmi@nvidia.com>
Reviewed-by: Oz Shlomo <ozsh@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

Destroy pool->mutex when we destroy the pool.

Fixes: c36326d3 ("net/mlx5: Round-Robin EQs over IRQs")
Signed-off-by: Shay Drory <shayd@nvidia.com>
Reviewed-by: Parav Pandit <parav@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

Currently irq->pool is set after the irq is insert to the xarray.
Set irq->pool before the irq is inserted to the xarray.

Fixes: 71e084e2 ("net/mlx5: Allocating a pool of MSI-X vectors for SFs")
Signed-off-by: Shay Drory <shayd@nvidia.com>
Reviewed-by: Parav Pandit <parav@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

Change order of functions in mlx5_irq_detach_nb() so it will be
a mirror of mlx5_irq_attach_nb.

Fixes: 71e084e2 ("net/mlx5: Allocating a pool of MSI-X vectors for SFs")
Signed-off-by: Shay Drory <shayd@nvidia.com>
Reviewed-by: Parav Pandit <parav@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

Since switchdev mode can't support  devlink traps, verify there are
no active devlink traps before moving eswitch to switchdev mode. If
there are active traps, prevent the switchdev mode configuration.

Fixes: eb3862a0 ("net/mlx5e: Enable traps according to link state")
Signed-off-by: Aya Levin <ayal@nvidia.com>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

mlx5e_close_xdpsq does the cleanup: it calls mlx5e_free_xdpsq_descs to
free the outstanding descriptors, which relies on
mlx5e_page_release_dynamic and page_pool_release_page. However,
page_pool_destroy is already called by this point, because
mlx5e_close_rq runs before mlx5e_close_xdpsq.

This commit fixes the use-after-free by swapping mlx5e_close_xdpsq and
mlx5e_close_rq.

The commit cited below started calling page_pool_destroy directly from
the driver. Previously, the page pool was destroyed under a call_rcu
from xdp_rxq_info_unreg_mem_model, which would defer the deallocation
until after the XDPSQ is cleaned up.

Fixes: 1da4bbef ("net: core: page_pool: add user refcnt and reintroduce page_pool_destroy")
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

Ageing time is not converted from clock_t to jiffies which results
incorrect ageing timeout calculation in workqueue update task. Fix it by
applying clock_t_to_jiffies() to provided value.

Fixes: c636a0f0 ("net/mlx5: Bridge, dynamic entry ageing")
Signed-off-by: Vlad Buslov <vladbu@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

It could be local and remote are on the same machine and the route
result will be a local route which will result in creating encap id
with src/dst mac address of 0.

Fixes: a54e20b4 ("net/mlx5e: Add basic TC tunnel set action for SRIOV offloads")
Signed-off-by: Roi Dayan <roid@nvidia.com>
Reviewed-by: Maor Dickman <maord@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

While processing encapsulated packet on RX, one of the fields that is
checked is the inner packet length. If the length as specified in the header
doesn't match the actual inner packet length, the packet is invalid
and should be dropped. However, such packet caused the NIC to hang.

This patch turns on a 'fail_on_error' HW bit which allows HW to drop
such an invalid packet while processing RX packet and trying to decap it.

Fixes: ad17dc8c ("net/mlx5: DR, Move STEv0 action apply logic")
Signed-off-by: Alex Vesker <valex@nvidia.com>
Signed-off-by: Yevgeny Kliteynik <kliteyn@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

Clean SF resources if mlx5 eth failed to initialize.

Fixes: 1958fc2f ("net/mlx5: SF, Add auxiliary device driver")
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Reviewed-by: Parav Pandit <parav@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

Data beyond the UDP header might not be part of the skb's linear data.
Use skb_copy_bits() instead of direct access to skb->data+X, so that
we read the correct bytes even on a fragmented skb.

Fixes: 4b5f6723 ("net: Special handling for IP & MPLS.")
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Link: https://lore.kernel.org/r/7741c46545c6ef02e70c80a9b32814b22d9616b3.1628264975.git.gnault@redhat.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Repair kernel-doc notation in a few places to make it conform to
the expected format.

Fixes the following kernel-doc warnings:

flow.c:296: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
 * Parse vlan tag from vlan header.
flow.c:296: warning: missing initial short description on line:
 * Parse vlan tag from vlan header.
flow.c:537: warning: No description found for return value of 'key_extract_l3l4'
flow.c:769: warning: No description found for return value of 'key_extract'
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Pravin B Shelar <pshelar@ovn.org>
Cc: dev@openvswitch.org
Link: https://lore.kernel.org/r/20210808190834.23362-1-rdunlap@infradead.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Without this there is a warning if source files include psample.h
before skbuff.h or doesn't include it at all.

Fixes: 6ae0a628 ("net: Introduce psample, a new genetlink channel for packet sampling")
Signed-off-by: Roi Dayan <roid@nvidia.com>
Link: https://lore.kernel.org/r/20210808065242.1522535-1-roid@nvidia.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

iavf driver should set RSS LUT and key unconditionally in reset
path. Currently, the driver does not do that. This patch fixes
this issue.

Fixes: 2c86ac3c ("i40evf: create a generic config RSS function")
Signed-off-by: Md Fahad Iqbal Polash <md.fahad.iqbal.polash@intel.com>
Tested-by: Konrad Jankowski <konrad0.jankowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

In some circumstances, such as with bridging, it's possible that the
stack will add the device's own MAC address to its unicast address list.

If, later, the stack deletes this address, the driver will receive a
request to remove this address.

The driver stores its current MAC address as part of the VSI MAC filter
list instead of separately. So, this causes a problem when the device's
MAC address is deleted unexpectedly, which results in traffic failure in
some cases.

The following configuration steps will reproduce the previously
mentioned problem:

> ip link set eth0 up
> ip link add dev br0 type bridge
> ip link set br0 up
> ip addr flush dev eth0
> ip link set eth0 master br0
> echo 1 > /sys/class/net/br0/bridge/vlan_filtering
> modprobe -r veth
> modprobe -r bridge
> ip addr add 192.168.1.100/24 dev eth0

The following ping command fails due to the netdev->dev_addr being
deleted when removing the bridge module.
> ping <link partner>

Fix this by making sure to not delete the netdev->dev_addr during MAC
address sync. After fixing this issue it was noticed that the
netdev_warn() in .set_mac was overly verbose, so make it at
netdev_dbg().

Also, there is a possibility of a race condition between .set_mac and
.set_rx_mode. Fix this by calling netif_addr_lock_bh() and
netif_addr_unlock_bh() on the device's netdev when the netdev->dev_addr
is going to be updated in .set_mac.

Fixes: e94d4478 ("ice: Implement filter sync, NDO operations and bump version")
Signed-off-by: Brett Creeley <brett.creeley@intel.com>
Tested-by: Liang Li <liali@redhat.com>
Tested-by: Gurucharan G <gurucharanx.g@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

When VFs are setup and torn down in quick succession, it is possible
that a VF is torn down by the PF while the VF's virtchnl requests are
still in the PF's mailbox ring. Processing the VF's virtchnl request
when the VF itself doesn't exist results in undefined behavior. Fix
this by adding a check to stop processing virtchnl requests when VF
teardown is in progress.

Fixes: ddf30f7f ("ice: Add handler to configure SR-IOV")
Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Konrad Jankowski <konrad0.jankowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

The userspace utility "driverctl" can be used to change/override the
system's default driver choices. This is useful in some situations
(buggy driver, old driver missing a device ID, trying a workaround,
etc.) where the user needs to load a different driver.

However, this is also prone to user error, where a driver is mapped
to a device it's not designed to drive. For example, if the ice driver
is mapped to driver iavf devices, the ice driver crashes.

Add a check to return an error if the ice driver is being used to
probe a virtual function.

Fixes: 837f08fd ("ice: Add basic driver framework for Intel(R) E800 Series")
Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Gurucharan G <gurucharanx.g@intel.com>
Tested-by: Konrad Jankowski <konrad0.jankowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

When mirror/redirect a skb to a different port, the ct info should be reset
for reclassification. Or the pkts will match unexpected rules. For example,
with following topology and commands:

    -----------
              |
       veth0 -+-------
              |
       veth1 -+-------
              |
   ------------

 tc qdisc add dev veth0 clsact
 # The same with "action mirred egress mirror dev veth1" or "action mirred ingress redirect dev veth1"
 tc filter add dev veth0 egress chain 1 protocol ip flower ct_state +trk action mirred ingress mirror dev veth1
 tc filter add dev veth0 egress chain 0 protocol ip flower ct_state -inv action ct commit action goto chain 1
 tc qdisc add dev veth1 clsact
 tc filter add dev veth1 ingress chain 0 protocol ip flower ct_state +trk action drop

 ping <remove ip via veth0> &
 tc -s filter show dev veth1 ingress

With command 'tc -s filter show', we can find the pkts were dropped on
veth1.

Fixes: b57dc7c1 ("net/sched: Introduce action ct")
Signed-off-by: Roi Dayan <roid@nvidia.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Guvenc Gulce says:

====================
net/smc: fixes 2021-08-09

please apply the following patch series for smc to netdev's net tree.
One patch fixes invalid connection counting for links and the other
one fixes an access to an already cleared link.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

SMC clients may be assigned to a different link after the initial
connection between two peers was established. In such a case,
the connection counter was not correctly set.

Update the connection counter correctly when a smc client connection
is assigned to a different smc link.

Fixes: 07d51580 ("net/smc: Add connection counters for links")
Signed-off-by: Guvenc Gulce <guvenc@linux.ibm.com>
Tested-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

There can be a race between the waiters for a tx work request buffer
and the link down processing that finally clears the link. Although
all waiters are woken up before the link is cleared there might be
waiters which did not yet get back control and are still waiting.
This results in an access to a cleared wait queue head.

Fix this by introducing atomic reference counting around the wait calls,
and wait with the link clear processing until all waiters have finished.
Move the work request layer related calls into smc_wr.c and set the
link state to INACTIVE before calling smcr_link_clear() in
smc_llc_srv_add_link().

Fixes: 15e1b99a ("net/smc: no WR buffer wait for terminating link group")
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Guvenc Gulce <guvenc@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The CPSW switchdev driver inherited fix from commit 9421c901 ("net:
ethernet: ti: cpsw: fix min eth packet size") which changes min TX packet
size to 64bytes (VLAN_ETH_ZLEN, excluding ETH_FCS). It was done to fix HW
packed drop issue when packets are sent from Host to the port with PVID and
un-tagging enabled. Unfortunately this breaks some other non-switch
specific use-cases, like:
- [1] CPSW port as DSA CPU port with DSA-tag applied at the end of the
packet
- [2] Some industrial protocols, which expects min TX packet size 60Bytes
(excluding FCS).

Fix it by configuring min TX packet size depending on driver mode
 - 60Bytes (ETH_ZLEN) for multi mac (dual-mac) mode
 - 64Bytes (VLAN_ETH_ZLEN) for switch mode
and update it during driver mode change and annotate with
READ_ONCE()/WRITE_ONCE() as it can be read by napi while writing.

[1] https://lore.kernel.org/netdev/20210531124051.GA15218@cephalopod/
[2] https://e2e.ti.com/support/arm/sitara_arm/f/791/t/701669

Cc: stable@vger.kernel.org
Fixes: ed3525ed ("net: ethernet: ti: introduce cpsw switchdev based driver part 1 - dual-emac")
Reported-by: Ben Hutchings <ben.hutchings@essensium.com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

As mentioned in commit c07aea3e ("mm: add a signature in
struct page"):
"The page->signature field is aliased to page->lru.next and
page->compound_head."

And as the comment in page_is_pfmemalloc():
"lru.next has bit 1 set if the page is allocated from the
pfmemalloc reserves. Callers may simply overwrite it if they
do not need to preserve that information."

The page->signature is OR’ed with PP_SIGNATURE when a page is
allocated in page pool, see __page_pool_alloc_pages_slow(),
and page->signature is checked directly with PP_SIGNATURE in
page_pool_return_skb_page(), which might cause resoure leaking
problem for a page from page pool if bit 1 of lru.next is set
for a pfmemalloc page. What happens here is that the original
pp->signature is OR'ed with PP_SIGNATURE after the allocation
in order to preserve any existing bits(such as the bit 1, used
to indicate a pfmemalloc page), so when those bits are present,
those page is not considered to be from page pool and the DMA
mapping of those pages will be left stale.

As bit 0 is for page->compound_head, So mask both bit 0/1 before
the checking in page_pool_return_skb_page(). And we will return
those pfmemalloc pages back to the page allocator after cleaning
up the DMA mapping.

Fixes: 6a5bcd84 ("page_pool: Allow drivers to hint on SKB recycling")
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

GCC complains about empty macros in an 'if' statement, so convert
them to 'do {} while (0)' macros.

Fixes these build warnings:

net/dccp/output.c: In function 'dccp_xmit_packet':
../net/dccp/output.c:283:71: warning: suggest braces around empty body in an 'if' statement [-Wempty-body]
  283 |                 dccp_pr_debug("transmit_skb() returned err=%d\n", err);
net/dccp/ackvec.c: In function 'dccp_ackvec_update_old':
../net/dccp/ackvec.c:163:80: warning: suggest braces around empty body in an 'else' statement [-Wempty-body]
  163 |                                               (unsigned long long)seqno, state);

Fixes: dc841e30 ("dccp: Extend CCID packet dequeueing interface")
Fixes: 38024086 ("dccp ccid-2: Update code for the Ack Vector input/registration routine")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: dccp@vger.kernel.org
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

When registering new ppp interface via PPPIOCNEWUNIT ioctl then kernel has
to choose interface name as this ioctl API does not support specifying it.

Kernel in this case register new interface with name "ppp<id>" where <id>
is the ppp unit id, which can be obtained via PPPIOCGUNIT ioctl. This
applies also in the case when registering new ppp interface via rtnl
without supplying IFLA_IFNAME.

PPPIOCNEWUNIT ioctl allows to specify own ppp unit id which will kernel
assign to ppp interface, in case this ppp id is not already used by other
ppp interface.

In case user does not specify ppp unit id then kernel choose the first free
ppp unit id. This applies also for case when creating ppp interface via
rtnl method as it does not provide a way for specifying own ppp unit id.

If some network interface (does not have to be ppp) has name "ppp<id>"
with this first free ppp id then PPPIOCNEWUNIT ioctl or rtnl call fails.

And registering new ppp interface is not possible anymore, until interface
which holds conflicting name is renamed. Or when using rtnl method with
custom interface name in IFLA_IFNAME.

As list of allocated / used ppp unit ids is not possible to retrieve from
kernel to userspace, userspace has no idea what happens nor which interface
is doing this conflict.

So change the algorithm how ppp unit id is generated. And choose the first
number which is not neither used as ppp unit id nor in some network
interface with pattern "ppp<id>".

This issue can be simply reproduced by following pppd call when there is no
ppp interface registered and also no interface with name pattern "ppp<id>":

    pppd ifname ppp1 +ipv6 noip noauth nolock local nodetach pty "pppd +ipv6 noip noauth nolock local nodetach notty"

Or by creating the one ppp interface (which gets assigned ppp unit id 0),
renaming it to "ppp1" and then trying to create a new ppp interface (which
will always fails as next free ppp unit id is 1, but network interface with
name "ppp1" exists).

This patch fixes above described issue by generating new and new ppp unit
id until some non-conflicting id with network interfaces is generated.
Signed-off-by: Pali Rohár <pali@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>