Similar to the existing helpers for the Clause 22 registers add helper
mii_10gbt_stat_mod_linkmode_lpa_t.

Note that this helper is defined in linux/mdio.h, not like the
Clause 22 helpers in linux/mii.h. Reason is that the Clause 45 register
constants are defined in uapi/linux/mdio.h. And uapi/linux/mdio.h
includes linux/mii.h before defining the C45 register constants.

v2:
- remove helpers that don't have users in this series
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Remove duplicated include.
Signed-off-by: NYueHaibing <yuehaibing@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

C45 configuration of 10/100 and multi-giga bit auto negotiation
advertisement is standardized. Configuration of 1000Base-T however
appears to be vendor specific. Move the generic code out of the
Marvell driver into the common phy-c45.c file.

v2:
- change function name to genphy_c45_an_config_aneg
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
[hkallweit1@gmail.com: use new helper linkmode_adv_to_mii_10gbt_adv_t and split patch]
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add a helper linkmode_adv_to_mii_10gbt_adv_t(), similar to
linkmode_adv_to_mii_adv_t.
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

ECPF connects to the eswitch through vport 0xfffe. ECPF may or may
not be the eswitch manager depending on firmware configuration.

1. If ECPF is eswitch manager: ECPF will take over the eswitch manager
   responsibility. A rep of the host PF shall be created at the ECPF
   side for the eswitch manager to control.

2. If ECPF is not eswitch manager: host PF will be the eswitch manager,
   ECPF acts similar as a VF to the host PF. Host PF will be aware
   of the ECPF vport presence and control it's rep.
Signed-off-by: NBodong Wang <bodong@mellanox.com>
Reviewed-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

In offloads mode, the current implementation puts the uplink
representor at index zero of the vport reps array. It is not "natural"
to place it at index 0 since we want to put the representor for vport
0 at index 0 with the introduction of SmartNIC. A separate patch will
handle the case whether a rep is needed for vport 0 (PF vport).

So, we want to have a different placeholder for uplink vport and
representor. It was placed at the end of vport and rep array. Since
vport number can no longer act as an index into the vport or
representors arrays, use functions to map vport numbers to indices
when accessing the vports or representors arrays, and vice versa.
Signed-off-by: NBodong Wang <bodong@mellanox.com>
Signed-off-by: NEli Cohen <eli@mellanox.com>
Reviewed-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

Eswitch has two users: IB and ETH. They both register repersentors
when mlx5 interface is added, and unregister the repersentors when
mlx5 interface is removed. Ideally, each driver should only deal with
the entities which are unique to itself. However, current IB and ETH
drivers have to perform the following eswitch operations:

1. When registering, specify how many vports to register. This number
   is the same for both drivers which is the total available vport
   numbers.
2. When unregistering, specify the number of registered vports to do
   unregister. Also, unload the repersentors which are already loaded.

It's unnecessary for eswitch driver to hands out the control of above
operations to individual driver users, as they're not unique to each
driver. Instead, such operations should be centralized to eswitch
driver. This consolidates eswitch control flow, and simplified IB and
ETH driver.

This patch doesn't change any functionality.
Signed-off-by: NBodong Wang <bodong@mellanox.com>
Reviewed-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

Currently the eswitch vport reps have a valid indicator, which is
set on register and unset on unregister. However, a rep can be loaded
or not loaded when doing unregister, current driver checks if the
vport of that rep is enabled as a flag to imply the rep is loaded.
However, for ECPF, this is not valid as the host PF will enable the
vports for its VFs instead.

Add three states: {unregistered, registered, loaded}, with the
following state changes across different operations:

	create: (none)       -> unregistered
	reg:    unregistered -> registered
	load:   registered   -> loaded
	unload: loaded       -> registered
	unreg:  registered   -> unregistered

Note that the state shall only be updated inside eswitch driver rather
than individual drivers such as ETH or IB.
Signed-off-by: NBodong Wang <bodong@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Suggested-by: NMark Bloch <markb@mellanox.com>
Reviewed-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

When driver is entering offloads mode, there are two major tasks to
do: initialize flow steering and create representors. Flow steering
should make sure enough flow table/group spaces are reserved for all
reps. Representors will be created in a group, all or none.

With the introduction of ECPF, flow steering should still reserve the
same spaces. But, the representors are not always loaded/unloaded in a
single piece. Once ECPF is in offloads mode, it will get the number
of VF changing event from host PF. In such scenario, only the VF reps
should be loaded/unloaded, not the reps for special vports (such as
the uplink vport).

Thus, when entering offloads mode, driver should specify the total
number of reps, and the number of VF reps separately. When leaving
offloads mode, the cleanup should use the information self-contained
in eswitch such as number of VFs.

This patch doesn't change any functionality.
Signed-off-by: NBodong Wang <bodong@mellanox.com>
Reviewed-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

Commands referring to vports use the following scheme:

1. When referring to my own vport, put 0 in vport and 0 in other_vport.
2. When referring to another vport, put the vport number of the
   referred vport and put 1 in other_vport. It was assumed that driver
   is accessing other vport when vport number is greater than 0.

With the above scheme, the case that ECPF eswitch manager is trying
to access host PF vport will fall over with scheme 1 as the vport
number is 0. This is apparently wrong as driver is trying to refer
other vport.

As such usage can only happen in the eswitch context, change relevant
functions to provide other vport input properly.
Signed-off-by: NBodong Wang <bodong@mellanox.com>
Signed-off-by: NEli Cohen <eli@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

In SmartNIC mode, the eswitch manager is not necessarily the PF
(vport 0). Use a helper function to get the correct eswitch manager
vport number and cache on the eswitch instance for fast reference.
Signed-off-by: NBodong Wang <bodong@mellanox.com>
Signed-off-by: NEli Cohen <eli@mellanox.com>
Reviewed-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

Commit c9b47cc1 ("xsk: fix bug when trying to use both copy and
zero-copy on one queue id") moved the umem query code to the AF_XDP
core, and therefore removed the need to query the netdevice for a
umem.

This patch removes XDP_QUERY_XSK_UMEM and all code that implement that
behavior, which is just dead code.
Signed-off-by: NJan Sokolowski <jan.sokolowski@intel.com>
Acked-by: NBjörn Töpel <bjorn.topel@intel.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>

This patch exposes new link modes (including 50Gbps per lane), and ext_*
fields which describes the new link modes in Port Type and Speed
register (PTYS).
Access functions, translation functions (speed <-> HW bits) and
link max speed function were modified.
Signed-off-by: NAya Levin <ayal@mellanox.com>
Reviewed-by: NEran Ben Elisha <eranbe@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

Register Port Type and Speed (PTYS) introduces three new fields
extending the speed/protocols the can be reported and configured.
Signed-off-by: NAya Levin <ayal@mellanox.com>
Reviewed-by: NEran Ben Elisha <eranbe@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

This patch fascicles queries to speed related fields in Port Type and
Speed register (PTYS) into a single API. I addition, this patch
refactors functions which serves only Ethernet driver: remove the
protocol type as an input parameter, move code from 'core' directory
into 'en' directory and add 'eth' prefix to the function's name. The
patch also encapsulates functions that are not used outside the Ethernet
driver removes redundant include files.
Signed-off-by: NAya Levin <ayal@mellanox.com>
Reviewed-by: NEran Ben Elisha <eranbe@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

When dealing with the offloads mode initialization, driver refers to
the number of VFs and add magic number one (1) to take account of the
uplink. This is not clear and will make the code less readable after
adding other vports (e.g. host PF). As these are special vports
compared to VF vports, add a helper macro to denote such special
vports and eliminate the use of magic number.

Moreover, when creating offloads flow table and groups, the driver
reserves two more slots for UC and MC miss rules. Replace this magic
number with a helper macro as well.

This patch doesn't change any functionality.
Signed-off-by: NBodong Wang <bodong@mellanox.com>
Reviewed-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

These are two macros in the driver general header which deal with the
number of total vports and if a vport is vport manager. Such macros
are vport entities, better to place them at the vport header file.

This patch doesn't change any functionality.
Signed-off-by: NBodong Wang <bodong@mellanox.com>
Reviewed-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

Driver used to name uplink vport as FDB_UPLINK_VPORT, it's hard to
comply with the same naming convention along with the introduction of
other vports. Use MLX5_VPORT as the prefix for such vports and
relocate the uplink vport definition to public header file for the
benefits of both net and IB drivers.

This patch doesn't change any functionality.
Signed-off-by: NBodong Wang <bodong@mellanox.com>
Reviewed-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

ECPF doesn't support SR-IOV, but an ECPF E-Switch manager shall know
the max VFs supported by its peer host PF in order to control those
VF vports.

The current driver implementation uses the total vfs quantity as
provided by the pci sub-system for an upper bound of the VF vports
the e-switch code needs to deal with. This obviously can't work as
is on ECPF e-switch manager. For now, we use a hard coded value of
128 on such systems.
Signed-off-by: NBodong Wang <bodong@mellanox.com>
Reviewed-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

In Embedded CPU (EC) configurations, the EC driver needs to know when
the number of virtual functions change on the corresponding PF at the
host side. This is required so the EC driver can create or destroy
representor net devices that represent the VFs ports.

Whenever a change in the number of VFs occurs, firmware will generate an
event towards the EC which will trigger a work to complete the rest of
the handling. The specifics of the handling will be introduced in a
downstream patch.
Signed-off-by: NBodong Wang <bodong@mellanox.com>
Signed-off-by: NEli Cohen <eli@mellanox.com>
Reviewed-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

The QUERY_HOST_PARAMS command is used by an Embedded CPU Physical
Function (ECPF) driver to identify and retrieve information about the
PF on the host side. E.g, number of virtual functions and PCI BDF.

The number of VFs can be changed on the fly, a function is added to
query current number of VFs and will be used in downstream patches.
Signed-off-by: NBodong Wang <bodong@mellanox.com>
Signed-off-by: NEli Cohen <eli@mellanox.com>
Reviewed-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

With the introduction of ECPF, we require that the ECPF driver will
aways call enable/disable HCA for that PF in the same way a PF does
this for its VFs. The PF is still responsible for calling enable and
disable HCA for its VFs.

To distinguish between the ECPF executing enable/disable HCA for
itself or for the PF, it sets the embedded CPU function bit in the
input params struct of these commands. When the bit is cleared and
function ID is zero, it refers to the peer PF.
Signed-off-by: NBodong Wang <bodong@mellanox.com>
Signed-off-by: NEli Cohen <eli@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

Mellanox's SmartNIC combines embedded CPU(e.g, ARM) processing power
with advanced network offloads to accelerate a multitude of security,
networking and storage applications.

With the introduction of the SmartNIC, there is a new PCI function
called Embedded CPU Physical Function(ECPF). And it's possible for a
PF to get its ICM pages from the ECPF PCI function. Driver shall
identify if it is running on such a function by reading a bit in
the initialization segment.

When firmware asks for pages, it would issue a page request event
specifying how many pages it requests and for which function. That
driver responds with a manage_pages command providing the requested
pages along with an indication for which function it is providing these
pages.

The encoding before this patch was as follows:
    function_id == 0: pages are requested for the function receiving
                      the EQE.
    function_id != 0: pages are requested for VF identified by the
                      function_id value

A new one bit field in the EQE identifies that pages are requested for
the ECPF.

The notion of page_supplier can be introduced here and to support that,
manage pages and query pages were modified so firmware can distinguish
the following cases:

1. Function provides pages for itself
2. PF provides pages for its VF
3. ECPF provides pages to itself
4. ECPF provides pages for another function

This distinction is possible through the introduction of the bit
"embedded_cpu_function" in query_pages, manage_pages and page request
EQE.
Signed-off-by: NBodong Wang <bodong@mellanox.com>
Signed-off-by: NEli Cohen <eli@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

Use u16 for vport number, which matches how hardware refers to this
argument throughout commands.

This patch doesn't change any functionality.
Signed-off-by: NBodong Wang <bodong@mellanox.com>
Signed-off-by: NEli Cohen <eli@mellanox.com>
Reviewed-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

Better to use void * and avoid unnecessary casts.

This patch doesn't change any functionality.
Signed-off-by: NBodong Wang <bodong@mellanox.com>
Signed-off-by: NEli Cohen <eli@mellanox.com>
Reviewed-by: NOr Gerlitz <ogerlitz@mellanox.com>
Reviewed-by: NDaniel Jurgens <danielj@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

Russell suggested to remove the locking from phy_is_started() because
the read is atomic anyway and actually the locking may be more
misleading.

Fixes: 2b3e88ea ("net: phy: improve phy state checking")
Suggested-by: NRussell King - ARM Linux admin <linux@armlinux.org.uk>
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The page_pool API is using page->private to store DMA addresses.
As pointed out by David Miller we can't use that on 32-bit architectures
with 64-bit DMA

This patch adds a new dma_addr_t struct to allow storing DMA addresses
Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: NIlias Apalodimas <ilias.apalodimas@linaro.org>
Acked-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Marvell 10G PHY driver has a generic way of initializing the supported
link modes by reading the PHY's C45 PMA abilities. This can be made
generic, since these registers are part of the 802.3 specifications.

This commit extracts the config_init link_mode initialization code from
marvell10g and uses it to introduce the genphy_c45_pma_read_abilities
function.

Only PMA modes are read, it's still up to the caller to set the Pause
parameters.
Signed-off-by: NMaxime Chevallier <maxime.chevallier@bootlin.com>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since of_set_phy_supported was moved to phy-core.c, we can also move
of_set_phy_eee_broken to the same location, so that we have all OF
functions in the same place.

This patch doesn't intend to introduce any change in behaviour.
Signed-off-by: NMaxime Chevallier <maxime.chevallier@bootlin.com>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When setting a PHY's max speed using either the max-speed DT property
or ethtool, we should mask-out all non-compatible modes according to the
settings table, instead of just the 10/100BASET modes.
Signed-off-by: NMaxime Chevallier <maxime.chevallier@bootlin.com>
Suggested-by: NRussell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The 1588 timer on eTSEC Ethernet controller uses different
register memory map with DPAA Ethernet controller.
Now the new ENETC Ethernet controller uses same reigster
memory map with DPAA. To support ENETC, let's use register
memory map of DPAA/ENETC in default.
Signed-off-by: NYangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There is QorIQ 1588 timer IP block on the new ENETC Ethernet
controller. However it uses little endian mode which is different
with before. This patch is to add little endian support for the
driver by using "little-endian" dts node property.
Signed-off-by: NYangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Moved QorIQ PTP clock initialization/free into new functions
ptp_qoriq_init()/ptp_qoriq_free(). These functions could also
be reused by ENETC PTP drvier which is a PCI driver for same
1588 timer IP block.
Signed-off-by: NYangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch is to make functions of ptp operations global,
so that ENETC PTP driver which is a PCI driver for same
1588 timer IP block could reuse them.
Signed-off-by: NYangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Strings containing "ptp_qoriq" or "qoriq_ptp" which were used for
structure/function names were complained by users. Let's just use
the unique "ptp_qoriq" to make these names more consistent.
This patch is just to unify the names using "ptp_qoriq". It hasn't
changed any functions.
Signed-off-by: NYangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There are several skb_* functions where the locked and unlocked
functions are confusingly documented. For several of them, the
kernel-doc for the unlocked version is placed above the locked version,
which to the casual reader makes it seems like the locked version "takes
no locks and you must therefore hold required locks before calling it."

One can see, for example, that this link claims to document
skb_queue_head(), while instead describing __skb_queue_head().

https://www.kernel.org/doc/html/latest/networking/kapi.html#c.skb_queue_head

The correct documentation for skb_queue_head() is also included further
down the page.

This diff tested via:

  $ scripts/kernel-doc -rst include/linux/skbuff.h net/core/skbuff.c

No new warnings were seen, and the output makes a little more sense.
Signed-off-by: NBrian Norris <briannorris@chromium.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Provide phylink_init_eee() to allow MAC drivers to initialise PHY EEE
from within the ethtool set_eee() method.
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently bpf_offload_dev does not have any priv pointer, forcing
the drivers to work backwards from the netdev in program metadata.
This is not great given programs are conceptually associated with
the offload device, and it means one or two unnecessary deferences.
Add a priv pointer to bpf_offload_dev.
Signed-off-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: NQuentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>

This patch adds a helper function BPF_FUNC_tcp_sock and it
is currently available for cg_skb and sched_(cls|act):

struct bpf_tcp_sock *bpf_tcp_sock(struct bpf_sock *sk);

int cg_skb_foo(struct __sk_buff *skb) {
	struct bpf_tcp_sock *tp;
	struct bpf_sock *sk;
	__u32 snd_cwnd;

	sk = skb->sk;
	if (!sk)
		return 1;

	tp = bpf_tcp_sock(sk);
	if (!tp)
		return 1;

	snd_cwnd = tp->snd_cwnd;
	/* ... */

	return 1;
}

A 'struct bpf_tcp_sock' is also added to the uapi bpf.h to provide
read-only access.  bpf_tcp_sock has all the existing tcp_sock's fields
that has already been exposed by the bpf_sock_ops.
i.e. no new tcp_sock's fields are exposed in bpf.h.

This helper returns a pointer to the tcp_sock.  If it is not a tcp_sock
or it cannot be traced back to a tcp_sock by sk_to_full_sk(), it
returns NULL.  Hence, the caller needs to check for NULL before
accessing it.

The current use case is to expose members from tcp_sock
to allow a cg_skb_bpf_prog to provide per cgroup traffic
policing/shaping.
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NMartin KaFai Lau <kafai@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>

In kernel, it is common to check "skb->sk && sk_fullsock(skb->sk)"
before accessing the fields in sock.  For example, in __netdev_pick_tx:

static u16 __netdev_pick_tx(struct net_device *dev, struct sk_buff *skb,
			    struct net_device *sb_dev)
{
	/* ... */

	struct sock *sk = skb->sk;

		if (queue_index != new_index && sk &&
		    sk_fullsock(sk) &&
		    rcu_access_pointer(sk->sk_dst_cache))
			sk_tx_queue_set(sk, new_index);

	/* ... */

	return queue_index;
}

This patch adds a "struct bpf_sock *sk" pointer to the "struct __sk_buff"
where a few of the convert_ctx_access() in filter.c has already been
accessing the skb->sk sock_common's fields,
e.g. sock_ops_convert_ctx_access().

"__sk_buff->sk" is a PTR_TO_SOCK_COMMON_OR_NULL in the verifier.
Some of the fileds in "bpf_sock" will not be directly
accessible through the "__sk_buff->sk" pointer.  It is limited
by the new "bpf_sock_common_is_valid_access()".
e.g. The existing "type", "protocol", "mark" and "priority" in bpf_sock
     are not allowed.

The newly added "struct bpf_sock *bpf_sk_fullsock(struct bpf_sock *sk)"
can be used to get a sk with all accessible fields in "bpf_sock".
This helper is added to both cg_skb and sched_(cls|act).

int cg_skb_foo(struct __sk_buff *skb) {
	struct bpf_sock *sk;

	sk = skb->sk;
	if (!sk)
		return 1;

	sk = bpf_sk_fullsock(sk);
	if (!sk)
		return 1;

	if (sk->family != AF_INET6 || sk->protocol != IPPROTO_TCP)
		return 1;

	/* some_traffic_shaping(); */

	return 1;
}

(1) The sk is read only

(2) There is no new "struct bpf_sock_common" introduced.

(3) Future kernel sock's members could be added to bpf_sock only
    instead of repeatedly adding at multiple places like currently
    in bpf_sock_ops_md, bpf_sock_addr_md, sk_reuseport_md...etc.

(4) After "sk = skb->sk", the reg holding sk is in type
    PTR_TO_SOCK_COMMON_OR_NULL.

(5) After bpf_sk_fullsock(), the return type will be in type
    PTR_TO_SOCKET_OR_NULL which is the same as the return type of
    bpf_sk_lookup_xxx().

    However, bpf_sk_fullsock() does not take refcnt.  The
    acquire_reference_state() is only depending on the return type now.
    To avoid it, a new is_acquire_function() is checked before calling
    acquire_reference_state().

(6) The WARN_ON in "release_reference_state()" is no longer an
    internal verifier bug.

    When reg->id is not found in state->refs[], it means the
    bpf_prog does something wrong like
    "bpf_sk_release(bpf_sk_fullsock(skb->sk))" where reference has
    never been acquired by calling "bpf_sk_fullsock(skb->sk)".

    A -EINVAL and a verbose are done instead of WARN_ON.  A test is
    added to the test_verifier in a later patch.

    Since the WARN_ON in "release_reference_state()" is no longer
    needed, "__release_reference_state()" is folded into
    "release_reference_state()" also.
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NMartin KaFai Lau <kafai@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>