Add a helper to change the owner of sysfs objects.
This function will be used to correctly account for kobject ownership
changes, e.g. when moving network devices between network namespaces.

This mirrors how a kobject is added through driver core which in its guts is
done via kobject_add_internal() which in summary creates the main directory via
create_dir(), populates that directory with the groups associated with the
ktype of the kobject (if any) and populates the directory with the basic
attributes associated with the ktype of the kobject (if any). These are the
basic steps that are associated with adding a kobject in sysfs.
Any additional properties are added by the specific subsystem itself (not by
driver core) after it has registered the device. So for the example of network
devices, a network device will e.g. register a queue subdirectory under the
basic sysfs directory for the network device and than further subdirectories
within that queues subdirectory.  But that is all specific to network devices
and they call the corresponding sysfs functions to do that directly when they
create those queue objects. So anything that a subsystem adds outside of what
driver core does must also be changed by it (That's already true for removal of
files it created outside of driver core.) and it's the same for ownership
changes.
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChristian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add helpers to change the owner of sysfs groups.
This function will be used to correctly account for kobject ownership
changes, e.g. when moving network devices between network namespaces.
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChristian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add a helper to change the owner of a sysfs link.
This function will be used to correctly account for kobject ownership
changes, e.g. when moving network devices between network namespaces.
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChristian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add helpers to change the owner of a sysfs files.
This function will be used to correctly account for kobject ownership
changes, e.g. when moving network devices between network namespaces.
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChristian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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]

Lastly, fix the following checkpatch warning:
CHECK: Prefer kernel type 'u32' over 'u_int32_t'
#61: FILE: drivers/net/ethernet/cisco/enic/vnic_devcmd.h:653:
+	u_int32_t val[];

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: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NGustavo A. R. Silva <gustavo@embeddedor.com>
Acked-by: NMartin Habets <mhabets@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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 detected 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: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This reverts commit 7458bd54 ("net: dsa:
bcm_sf2: Also configure Port 5 for 2Gb/sec on 7278") as it causes
advanced congestion buffering issues with 7278 switch devices when using
their internal Giabit PHY. While this is being debugged, continue with
conservative defaults that work and do not cause packet loss.

Fixes: 7458bd54 ("net: dsa: bcm_sf2: Also configure Port 5 for 2Gb/sec on 7278")
Signed-off-by: NFlorian Fainelli <f.fainelli@gmail.com>
Reviewed-by: NVivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Looks like the iavf code actually experienced a race condition, when a
developer took code before the check for chain 0 was put to helper.
So use tc_cls_can_offload_and_chain0() helper instead of direct check and
move the check to _cb() so this is similar to i40e code.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Jiri Pirko says:

====================
mlxsw: Implement ACL-dropped packets identification

mlxsw hardware allows to insert a ACL-drop action with a value defined
by user that would be later on passed with a dropped packet.

To implement this, use the existing TC action cookie and pass it to the
driver. As the cookie format coming down from TC and the mlxsw HW cookie
format is different, do the mapping of these two using idr and rhashtable.

The cookie is passed up from the HW through devlink_trap_report() to
drop_monitor code. A new metadata type is used for that.

Example:
$ tc qdisc add dev enp0s16np1 clsact
$ tc filter add dev enp0s16np1 ingress protocol ip pref 10 flower skip_sw dst_ip 192.168.1.2 action drop cookie 3b45fa38c8
                                                                                                                ^^^^^^^^^^
$ devlink trap set pci/0000:00:10.0 trap acl action trap
$ dropwatch
Initializing null lookup method
dropwatch> set hw true
setting hardware drops monitoring to 1
dropwatch> set alertmode packet
Setting alert mode
Alert mode successfully set
dropwatch> start
Enabling monitoring...
Kernel monitoring activated.
Issue Ctrl-C to stop monitoring
drop at: ingress_flow_action_drop (acl_drops)
origin: hardware
input port ifindex: 30
input port name: enp0s16np1
cookie: 3b45fa38c8    <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
timestamp: Fri Jan 24 17:10:53 2020 715387671 nsec
protocol: 0x800
length: 98
original length: 98

This way the user may insert multiple drop rules and monitor the dropped
packets with the information of which action caused the drop.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Extend existing devlink trap test to include metadata type for flow
action cookie.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add new trap ACL which reports flow action cookie in a metadata. Allow
used to setup the cookie using debugfs file.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Reviewed-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use the cookie index received along with the packet to lookup original
flow_offload cookie binary and pass it down to devlink_trap_report().
Add "fa_cookie" metadata to the ACL trap.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In case the received packet comes in due to one of ACL discard traps,
take the user_def_val_orig_pkt_len field from CQE and store it
in skb->cb as ACL cookie index.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Track cookies coming down to driver by flow_offload.
Assign a cookie_index to each unique cookie binary. Use previously
defined "Trap with userdef" flex action to ask HW to pass cookie_index
alongside with the dropped packets.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Expose "Trap action with userdef". It is the same as already
defined "Trap action" with a difference that it would ask the policy
engine to pass arbitrary value (userdef) alongside with received packets.
This would be later on used to carry cookie index.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add cookie argument to devlink_trap_report() allowing driver to pass in
the user cookie. Pass on the cookie down to drop monitor code.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Reviewed-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If driver passed along the cookie, push it through Netlink.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Allow driver to indicate cookie metadata for registered traps.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Reviewed-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Extend struct flow_action_entry in order to hold TC action cookie
specified by user inserting the action.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Reviewed-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Merge tag 'mac80211-next-for-net-next-2020-02-24' of git://git.kernel.org/pub/scm/linux/kernel/git/jberg/mac80211-next

Johannes Berg says:

====================
A new set of changes:
 * lots of small documentation fixes, from Jérôme Pouiller
 * beacon protection (BIGTK) support from Jouni Malinen
 * some initial code for TID configuration, from Tamizh chelvam
 * I reverted some new API before it's actually used, because
   it's wrong to mix controlled port and preauth
 * a few other cleanups/fixes
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There is a spelling mistake in a pr_err message. Fix it.
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The "stm32_pwr_wakeup" is optional per the binding and the driver
handles its absence gracefully. Request it with
platform_get_irq_byname_optional, so its absence doesn't needlessly
clutter the log.
Signed-off-by: NAhmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The specification of a "eth-ck" and a "ptp_ref" clock is optional per
the binding and the driver handles them gracefully.
Demote the output to an info message accordingly.
Signed-off-by: NAhmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Jeremy Linton says:

====================
Add ACPI bindings to the genet

This patch series allows the BCM GENET, as used on the RPi4,
to attach when booted in an ACPI environment. The DSDT entry to
trigger this is seen below. Of note, the first patch adds a
small extension to the mdio layer which allows drivers to find
the mii_bus without firmware assistance. The fifth patch in
the set retrieves the MAC address from the umac registers
rather than carrying it directly in the DSDT. This of course
requires the firmware to pre-program it, so we continue to fall
back on a random one if it appears to be garbage.

v1 -> v2:
     fail on missing phy-mode property
     replace phy-mode internal property read string with
     	     device_get_phy_mode() equivalent
     rework mac address detection logic so that it merges
     	    the acpi/DT case into device_get_mac_address()
	    allowing _DSD mac address properties.
     some commit messages justifying why phy_find_first()
     	    isn't the worst choice for this driver.

+    Device (ETH0)
+    {
+      Name (_HID, "BCM6E4E")
+      Name (_UID, 0)
+      Name (_CCA, 0x0)
+      Method (_STA)
+      {
+        Return (0xf)
+      }
+      Method (_CRS, 0x0, Serialized)
+      {
+        Name (RBUF, ResourceTemplate ()
+        {
+          Memory32Fixed (ReadWrite, 0xFd580000, 0x10000, )
+          Interrupt (ResourceConsumer, Level, ActiveHigh, Exclusive) { 0xBD }
+          Interrupt (ResourceConsumer, Level, ActiveHigh, Exclusive) { 0xBE }
+        })
+        Return (RBUF)
+      }
+      Name (_DSD, Package () {
+        ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+          Package () {
+          Package () { "phy-mode", "rgmii-rxid" },
+        }
+      })
+    }
====================
Tested-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If one types "failed to get enet clock" or similar into google
there are ~370k hits. The vast majority are people debugging
problems unrelated to this adapter, or bragging about their
rpi's. Further, the DT clock bindings here are optional.

Given that its not a fatal situation with common DT based
systems, lets reduce the severity so people aren't seeing failure
messages in everyday operation.
Signed-off-by: NJeremy Linton <jeremy.linton@arm.com>
Reviewed-by: NNicolas Saenz Julienne <nsaenzjulienne@suse.de>
Acked-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

ARM/ACPI machines should utilize self describing hardware
when possible. The MAC address on the BCMGENET can be
read from the adapter if a full featured firmware has already
programmed it. Lets try using the address already programmed,
if it appears to be valid.

It should be noted that while we move the macaddr logic below
the clock and power logic in the driver, none of that code will
ever be active in an ACPI environment as the device will be
attached to the acpi power domain, and brought to full power
with all clocks enabled immediately before the device probe
routine is called.

One side effect of the above tweak is that while its now
possible to read the MAC address via _DSD properties, it should
be avoided.
Signed-off-by: NJeremy Linton <jeremy.linton@arm.com>
Acked-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The rpi4 is capable of booting in ACPI mode with the latest
edk2-platform commits. As such it would be helpful if the genet
platform device were usable.

To achieve this we add a new MODULE_DEVICE_TABLE, and convert
a few dt specific methods to their generic device_ calls. Until
the next patch, ACPI based machines will fallback on random
mac addresses.
Signed-off-by: NJeremy Linton <jeremy.linton@arm.com>
Acked-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The unimac mdio driver falls back to scanning the
entire bus if its given an appropriate mask. In ACPI
mode we expect that the system is well behaved and
conforms to recent versions of the specification.

We then utilize phy_find_first(), and
phy_connect_direct() to find and attach to the
discovered phy during net_device open. While its
apparently possible to build a genet based device
with multiple phys on a single mdio bus, this works
for current machines. Further, this driver makes
a number of assumptions about the platform device,
mac, mdio and phy all being 1:1. Lastly, It also
avoids having to create references across the ACPI
namespace hierarchy.
Signed-off-by: NJeremy Linton <jeremy.linton@arm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The DT phy mode is similar to what we want for ACPI
lets factor it out of the of path, and change the
of_ call to device_.
Signed-off-by: NJeremy Linton <jeremy.linton@arm.com>
Acked-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It appears most ethernet drivers follow one of two main strategies
for mdio bus/phy management. A monolithic model where the net driver
itself creates, probes and uses the phy, and one where an external
mdio/phy driver instantiates the mdio bus/phy and the net driver
only attaches to a known phy. Usually in this latter model the phys
are discovered via DT relationships or simply phy name/address
hardcoding.

This is a shame because modern well behaved mdio buses are self
describing and can be probed. The mdio layer itself is fully capable
of this, yet there isn't a clean way for a standalone net driver
to attach and enumerate the discovered devices. This is because
outside of of_mdio_find_bus() there isn't a straightforward way
to acquire the mii_bus pointer.

So, lets add a mdio_find_bus which can return the mii_bus based
only on its name.
Signed-off-by: NJeremy Linton <jeremy.linton@arm.com>
Acked-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Vladimir Oltean says:

====================
Remainder for "DT bindings for Felix DSA switch on LS1028A"

This series is the remainder of patchset [0] which has been merged
through Shawn Guo's devicetree tree.

It contains changes to the PHY mode validation in the Felix driver
("gmii" to "internal") and the documentation for the DT bindings.

[0]: https://patchwork.ozlabs.org/cover/1242716/
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds the required documentation for the embedded L2 switch
inside the NXP LS1028A chip.

I've submitted it in the legacy format instead of yaml schema, because
DSA itself has not yet been converted to yaml, and this driver defines
no custom bindings.
Signed-off-by: NVladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>