net: sched: Merge Qdisc::bstats and Qdisc::cpu_bstats data types

The only factor differentiating per-CPU bstats data type (struct
gnet_stats_basic_cpu) from the packed non-per-CPU one (struct
gnet_stats_basic_packed) was a u64_stats sync point inside the former.
The two data types are now equivalent: earlier commits added a u64_stats
sync point to the latter.

Combine both data types into "struct gnet_stats_basic_sync". This
eliminates redundancy and simplifies the bstats read/write APIs.

Use u64_stats_t for bstats "packets" and "bytes" data types. On 64-bit
architectures, u64_stats sync points do not use sequence counter
protection.

Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfp: abm: add support for more threshold actions

Original FW only allowed us to perform ECN marking. Newer releases
also support plain old drop. Add the ability to configure drop
policy. This is particularly useful in combination with GRED,
because different bands can have different ECN marking setting.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: John Hurley <john.hurley@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfp: abm: add cls_u32 offload for simple band classification

Use offload of very simple u32 filters to direct packets to GRED
bands based on the DSCP marking. No u32 hashing is supported,
just plain simple filters matching on ToS or Priority with
appropriate mask device can support.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: John Hurley <john.hurley@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfp: abm: add GRED offload

Add support for GRED offload. It behaves much like RED, but
can apply different parameters to different bands. GRED operates
pretty much exactly like our HW/FW with a single FIFO and different
RED state instances.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: John Hurley <john.hurley@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfp: abm: wrap RED parameters in bands

Wrap RED parameters and stats into a structure, and a 1-element
array. Upcoming GRED offload will add the support for more bands.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: John Hurley <john.hurley@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfp: abm: pass band parameter to functions

In preparation for per-band RED offload pass band parameter to
functions. For now it will always be 0.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: John Hurley <john.hurley@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfp: abm: restructure Qdisc handling

In preparation of handling more Qdisc types switch to a different
offload strategy. We have now recreated the Qdisc hierarchy in
the driver. Every time the hierarchy changes parse it, and update
the configuration of the HW accordingly.

While at it drop the support of pretending that we can instantiate
a single queue on a multi-queue device in HW/FW. MQ is now required,
and each queue will have its own instance of RED.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: John Hurley <john.hurley@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfp: abm: save RED's parameters

Use the new driver Qdisc structure to keep track of parameters
of RED Qdiscs. This way as the Qdisc moves around in the hierarchy
we will be able to configure the HW appropriately.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: John Hurley <john.hurley@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfp: abm: reset RED's child based on limit

RED qdisc will replace its child Qdisc with a new FIFO queue if
it is reconfigured and the limit parameter is not 0.

This means that when it's created with limit of 0 it will have no FIFO,
and all packets will be dropped. If it's changed and limit is specified
it will loose its existing child (implicit graft). Make sure we mark
RED Qdisc child as NFP_QDISC_UNTRACKED if its not the expected FIFO.

nfp_abm_qdisc_replace() will return 1 if Qdisc already existed.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: John Hurley <john.hurley@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfp: abm: build full Qdisc hierarchy based on graft notifications

Using graft notifications recreate in the driver the full Qdisc
hierarchy. Keep track of how many times each Qdisc is attached
to the hierarchy to make sure we don't offload Qdiscs which are
attached multiple times (device queues can't be shared). For
graft events of Qdiscs we don't know exist make the child as
invalid/untracked.

Note that MQ Qdisc doesn't send destruction events reliably when
device is dismantled, so we need to manually clean out the
children otherwise we'd think Qdiscs which are still in use
are getting freed.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: John Hurley <john.hurley@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfp: abm: allocate Qdisc child table

To keep track of Qdisc hierarchy allocate a table for children
for each Qdisc. RED Qdisc can only have one child.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: John Hurley <john.hurley@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfp: abm: remember which Qdisc is root

Keep track of which Qdisc is currently root. We need to implement
TC_SETUP_ROOT_QDISC handling, and for completeness also clear the
root Qdisc pointer when it's freed. TC_SETUP_ROOT_QDISC isn't always
sent when device is dismantled.

Remembering the root Qdisc will allow us to build the entire hierarchy
in following patches.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: John Hurley <john.hurley@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfp: abm: track all offload-enabled qdiscs

Allocate an object corresponding to any offloaded qdisc we are
informed about by the kernel. Not only the qdiscs we have a
chance of offloading.

The count of created objects will be used to decide whether
the ethtool TC offload can be disabled, since otherwise we may
miss destroy commands.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: John Hurley <john.hurley@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfp: abm: keep track of all RED thresholds

Instead of writing the threshold out when Qdisc is configured
and not remembering it move to a scheme where we remember all
thresholds. When configuration changes parse the offloaded
Qdiscs and set thresholds appropriately.

This will help future extensions.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: John Hurley <john.hurley@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfp: abm: rename qdiscs -> red_qdiscs

Rename qdiscs member to red_qdiscs. One of following patches will
use the name qdiscs for tracking all qdisc types.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: John Hurley <john.hurley@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfp: abm: refuse RED offload with harddrop set

RED Qdisc will now inform the drivers about the state of the harddrop
flag. Refuse to offload in case harddrop is set.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: John Hurley <john.hurley@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfp: abm: don't set negative threshold

Turns out the threshold value is used in signed compares in the FW,
so we should avoid setting the top bit.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: John Hurley <john.hurley@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfp: abm: provide more precise info about offload parameter validation

Improve log messages printed when RED can't be offloaded because
of Qdisc parameters.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: John Hurley <john.hurley@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfp: abm: split qdisc offload code into a separate file

The Qdisc offload code is logically separate, and we will soon
do significant surgery on it to support more Qdiscs, so move
it to a separate file.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: John Hurley <john.hurley@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>