The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Ido Schimmel says:

====================
mlxsw: Offload FIFO

Petr says:

If an ETS or PRIO band contains an offloaded qdisc, it is possible to
obtain offloaded counters for that band. However, some of the bands will
likely simply contain the default invisible FIFO qdisc, which does not
present the counters.

To remedy this situation, make FIFO offloadable, and offload it by mlxsw
when below PRIO and ETS for the sole purpose of providing counters for the
bands that do not include other qdiscs.

- In patch #1, FIFO is extended to support offloading.
- Patches #2 and #3 restructure bits of mlxsw to facilitate
  the offload logic.
- Patch #4 then implements the offload itself.
- Patch #5 changes the ETS selftest to use the new counters.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Currently the SW-datapath ETS selftests use "ip link" stats to obtain the
number of packets that went through a given band. mlxsw then uses ethtool
per-priority counters.

Instead, change both to use qdiscs. In SW datapath this is the obvious
choice, and now that mlxsw offloads FIFO, this should work on the offloaded
datapath as well. This has the effect of verifying that the FIFO offload
works.
Signed-off-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

There are two peculiarities about offloading FIFO:

- sometimes the qdisc has an unspecified handle (it is "invisible")
- it may be created before the qdisc that it will be a child of

These features make the offload a bit more tricky. The approach chosen in
this patch is to make note of all the FIFOs that needed to be rejected
because their parents were not known. Later when the parent is created,
they are offloaded

FIFO is only offloaded for its counters, queue length is ignored.
Signed-off-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

PRIO and ETS will need to check the value of qdisc handle in their
handlers. Add it to the callback and propagate through.
Signed-off-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

In order to have a tidy structure where to put information related to Qdisc
offloads, introduce a new structure. Move there the two existing pieces of
data: root_qdisc and tclass_qdiscs. Embed them directly, because there's no
reason to go through pointer anymore. Convert users, update init/fini
functions.
Signed-off-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Invoke ndo_setup_tc() as appropriate to signal init / replacement,
destroying and dumping of pFIFO / bFIFO Qdisc.

A lot of the FIFO logic is used for pFIFO_head_drop as well, but that's a
semantically very different Qdisc that isn't really in the same boat as
pFIFO / bFIFO. Split some of the functions to keep the Qdisc intact.
Signed-off-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Jakub Kicinski says:

====================
ethtool: consolidate parameter checking for irq coalescing

This set aims to simplify and unify the unsupported irq
coalescing parameter handling.

First patch adds a bitmask which drivers should fill in
in their ethtool_ops structs to declare which parameters
they support. Core will then ensure that driver callback
won't see any parameter outside of that set.

This allows us to save some LoC and make sure all drivers
respond the same to unsupported parameters.

If any parameter driver does not support is set to a value
other than 0 core will return -EINVAL. In the future we can
reject any present but unsupported netlink attribute, without
assuming 0 means unset. We can also add some prints or extack,
perhaps a'la Intel's current code.

I started converting the drivers alphabetically but then
realized that for the first set it's probably best to
address a representative mix of actively developed drivers.

According to my unreliable math there are roughly 69 drivers
in the tree which support some form of interrupt coalescing
settings via ethtool. Of these roughly 17 reject parameters
they don't support.

I hope drivers which ignore the parameters don't care, and
won't care about the slight change in behavior. Once all
drivers are converted we can make the checking mandatory.

I've only tested the e1000e and virtio patches, the rest builds.

v2: fix up ice and virtio conversions
v3: (patch 1)
    - move the (temporary) check if driver defines types
      earlier (Michal)
    - rename used_types -> nonzero_params, and
      coalesce_types -> supported_coalesce_params (Alex)
    - use EOPNOTSUPP instead of EINVAL (Andrew, Michal)
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Set ethtool_ops->supported_coalesce_params to let
the core reject unsupported coalescing parameters.

This driver correctly rejects all unsupported parameters.
As a side effect of these changes the error code for
unsupported params changes from EINVAL to EOPNOTSUPP.

v2: correctly handle rx-frames (and adjust the commit msg)
v3: adjust commit message for new error code and member name
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Set ethtool_ops->supported_coalesce_params to let
the core reject unsupported coalescing parameters.

This driver did not previously reject unsupported parameters.

v3: adjust commit message for new member name
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Set ethtool_ops->supported_coalesce_params to let
the core reject unsupported coalescing parameters.

This driver did not previously reject unsupported parameters.

v3: adjust commit message for new member name
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Set ethtool_ops->supported_coalesce_params to let
the core reject unsupported coalescing parameters.

This driver did not previously reject unsupported parameters.

v3: adjust commit message for new member name
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Set ethtool_ops->supported_coalesce_params to let
the core reject unsupported coalescing parameters.

This driver correctly rejects all unsupported parameters.
As a side effect of these changes the info message about
the bad parameter will no longer be printed. We also
always reject the tx_coalesce_usecs_high param, even
if the target queue pair does not have a TX queue.
Error code changes from EINVAL to EOPNOTSUPP.

v2: allow adaptive TX
v3: adjust commit message for new error code and member name
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Set ethtool_ops->supported_coalesce_params to let
the core reject unsupported coalescing parameters.

This driver correctly rejects all unsupported parameters.
No functional changes.

v3: adjust commit message for new error code and member name
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Set ethtool_ops->supported_coalesce_params to let
the core reject unsupported coalescing parameters.

This driver correctly rejects all unsupported parameters.
As a side effect of these changes the error code for
unsupported params changes from EINVAL to EOPNOTSUPP.

v3: adjust commit message for new error code and member name
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

Set ethtool_ops->supported_coalesce_params to let
the core reject unsupported coalescing parameters.

This driver correctly rejects all unsupported parameters.
No functional changes.

v3: adjust commit message for new error code and member name
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Set ethtool_ops->supported_coalesce_params to let
the core reject unsupported coalescing parameters.

This driver correctly rejects all unsupported parameters.
No functional changes.

v3: adjust commit message for new error code and member name
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Set ethtool_ops->supported_coalesce_params to let
the core reject unsupported coalescing parameters.

This driver correctly rejects all unsupported parameters.
The error code changes from EINVAL to EOPNOTSUPP.

v3: adjust commit message for new error code and member name
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Set ethtool_ops->supported_coalesce_params to let
the core reject unsupported coalescing parameters.

This driver correctly rejects all unsupported parameters.
We are only losing the error print.

v3: adjust commit message for new error code and member name
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Linux supports 22 different interrupt coalescing parameters.
No driver implements them all. Some drivers just ignore the
ones they don't support, while others have to carry a long
list of checks to reject unsupported settings.

To simplify the drivers add the ability to specify inside
ethtool_ops which parameters are supported and let the core
reject attempts to set any other one.

This commit makes the mechanism an opt-in, only drivers which
set ethtool_opts->coalesce_types to a non-zero value will have
the checks enforced.

The same mask is used for global and per queue settings.

v3: - move the (temporary) check if driver defines types
      earlier (Michal)
    - rename used_types -> nonzero_params, and
      coalesce_types -> supported_coalesce_params (Alex)
    - use EOPNOTSUPP instead of EINVAL (Andrew, Michal)

Leaving the long series of ifs for now, it seems nice to
be able to grep for the field and flag names. This will
probably have to be revisited once netlink support lands.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Michal Kubecek <mkubecek@suse.cz>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

In the commit e0a4b997 ("hsr: use upper/lower device infrastructure"),
dev_get() was removed but dev_put() in the error path wasn't removed.
So, if creating hsr interface command is failed, the reference counter leak
of lower interface would occur.

Test commands:
    ip link add dummy0 type dummy
    ip link add ipvlan0 link dummy0 type ipvlan mode l2
    ip link add ipvlan1 link dummy0 type ipvlan mode l2
    ip link add hsr0 type hsr slave1 ipvlan0 slave2 ipvlan1
    ip link del ipvlan0

Result:
[  633.271992][ T1280] unregister_netdevice: waiting for ipvlan0 to become free. Usage count = -1

Fixes: e0a4b997 ("hsr: use upper/lower device infrastructure")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Taehee Yoo says:

====================
net: rmnet: several code cleanup for rmnet module

This patchset is to cleanup rmnet module code.

1. The first patch is to add module alias
rmnet module can not be loaded automatically because there is no
alias name.

2. The second patch is to add extack error message code.
When rmnet netlink command fails, it doesn't print any error message.
So, users couldn't know the exact reason.
In order to tell the exact reason to the user, the extack error message
is used in this patch.

3. The third patch is to use GFP_KERNEL instead of GFP_ATOMIC.
In the sleepable context, GFP_KERNEL can be used.
So, in this patch, GFP_KERNEL is used instead of GFP_ATOMIC.

Change log:
 - v1->v2: change error message in the second patch.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

In the current code, rmnet_register_real_device() and rmnet_newlink()
are using GFP_ATOMIC.
But, these functions are allowed to sleep.
So, GFP_KERNEL can be used.
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When rmnet netlink command fails, it doesn't print any error message.
So, users couldn't know the exact reason.
In order to tell the exact reason to the user, the extack error message
is used in this patch.
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

In the current rmnet code, there is no module alias.
So, RTNL couldn't load rmnet module automatically.

Test commands:
    ip link add dummy0 type dummy
    modprobe -rv rmnet
    ip link add rmnet0 link dummy0 type rmnet  mux_id 1
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Russell King says:

====================
marvell10g tunable and power saving support

This patch series adds support for:
- mdix configuration (auto, mdi, mdix)
- energy detect power down (edpd)
- placing in edpd mode at probe

for both the 88x3310 and 88x2110 PHYs.

Antione, could you test this for the 88x2110 PHY please?

v3: fix return code in get_tunable/set_tunable
v2: fix comments from Antione.
====================
Tested-by: Antoine Tenart <antoine.tenart@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Place the 88x3310 into powersaving mode when probing, which saves 600mW
per PHY. For both PHYs on the Macchiatobin double-shot, this saves
about 10% of the board idle power.
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add support for the energy detect power down tunable, which saves
around 600mW when the link is down. The 88x3310 supports off, rx-only
and NLP every second. Enable EDPD by default for 88x3310.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add support for controlling the MDI-X state of the PHY.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

Merge branch 'PCI-Add-and-use-constant-PCI_STATUS_ERROR_BITS-and-helper-pci_status_get_and_clear_errors'

Heiner Kallweit says:

====================
PCI: Add and use constant PCI_STATUS_ERROR_BITS and helper pci_status_get_and_clear_errors

Several drivers have own definitions for this constant, so move it
to the PCI core. In addition in multiple places the following code
sequence is used:
1. Read PCI_STATUS
2. Mask out non-error bits
3. Action based on set error bits
4. Write back set error bits to clear them

As this is a repeated pattern, add a helper to the PCI core.

Most affected drivers are network drivers. But as it's about core
PCI functionality, I suppose the series should go through the PCI
tree.

v2:
- fix formal issue with cover letter
v3:
- fix dumb typo in patch 7
v4:
- add patches 1-3
- move new constant PCI_STATUS_ERROR_BITS to include/linux/pci.h
- small improvements in commit messages
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Use new helper pci_status_get_and_clear_errors() to simplify the code.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use new constant PCI_STATUS_ERROR_BITS to simplify the code.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use new PCI core constant PCI_STATUS_ERROR_BITS to simplify the code.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use new helper pci_status_get_and_clear_errors() to simplify the code.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use new helper pci_status_get_and_clear_errors() to simplify the code.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Several drivers use the following code sequence:
1. Read PCI_STATUS
2. Mask out non-error bits
3. Action based on error bits set
4. Write back set error bits to clear them

As this is a repeated pattern, add a helper to the PCI core.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This collection of PCI error bits is used in more than one driver,
so move it to the PCI core.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

In preparation of factoring out PCI_STATUS error bit handling let drivers
use the same collection of error bits. To facilitate bisecting we do this
in a separate patch per affected driver. For the r8169 driver we have to
add PCI_STATUS_PARITY to the error bits.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

In preparation of factoring out PCI_STATUS error bit handling let drivers
use the same collection of error bits. To facilitate bisecting we do this
in a separate patch per affected driver. For the skfp driver we have to
add PCI_STATUS_REC_TARGET_ABORT to the error bits.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

In preparation of factoring out PCI_STATUS error bit handling let drivers
use the same collection of error bits. To facilitate bisecting we do this
in a separate patch per affected driver. For the Marvell drivers we have
to add PCI_STATUS_SIG_TARGET_ABORT to the error bits.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>