Merge branch 'mlxsw-Add-support-for-buffer-drops-mirroring'

Petr Machata says:

====================
mlxsw: Add support for buffer drops mirroring

This set offloads the recently introduced qevent infrastructure in TC and
allows mlxsw to support mirroring of packets that were dropped due to
buffer related reasons (e.g., early drops) during forwarding.

Up until now mlxsw only supported mirroring that was either triggered by
per-port triggers (i.e., via matchall) or by the policy engine (i.e.,
via flower). Packets that are dropped due to buffer related reasons are
mirrored using a third type of trigger, a global trigger.

Global triggers are bound once to a mirroring (SPAN) agent and enabled
on a per-{port, TC} basis. This allows users, for example, to request
that only packets that were early dropped on a specific netdev to be
mirrored.

Patch set overview:

Patch #1 extends flow_block_offload and indirect offload structure to pass
a scheduler instead of a netdevice. That is necessary, because binding type
and netdevice are not a unique identifier of the block anymore.

Patches #2-#3 add the required registers to support above mentioned
functionality.

Patches #4-#6 gradually add support for global mirroring triggers.

Patch #7 adds support for enablement of global mirroring triggers.

Patches #8-#11 are cleanups in the flow offload code and shuffle some
code around to make the qevent offload easier.

Patch #12 implements offload of RED early_drop qevent.

Patch #13 extends the RED selftest for offloaded datapath to cover
early_drop qevent.

v2:
- Patch #1:
    - In struct flow_block_indr, track both sch and dev.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 122 insertions, 3 deletions

diff --git a/tools/testing/selftests/drivers/net/mlxsw/sch_red_core.sh b/tools/testing/selftests/drivers/net/mlxsw/sch_red_core.sh
index 0d347d48c112..45042105ead7 100644
--- a/tools/testing/selftests/drivers/net/mlxsw/sch_red_core.sh
+++ b/tools/testing/selftests/drivers/net/mlxsw/sch_red_core.sh
@@ -121,6 +121,7 @@ h1_destroy()
 h2_create()
 {
 	host_create $h2 2
+	tc qdisc add dev $h2 clsact
 
 	# Some of the tests in this suite use multicast traffic. As this traffic
 	# enters BR2_10 resp. BR2_11, it is flooded to all other ports. Thus
@@ -141,6 +142,7 @@ h2_create()
 h2_destroy()
 {
 	ethtool -s $h2 autoneg on
+	tc qdisc del dev $h2 clsact
 	host_destroy $h2
 }
 
@@ -336,6 +338,17 @@ get_qdisc_npackets()
 		qdisc_stats_get $swp3 $(get_qdisc_handle $vlan) .packets
 }
 
+send_packets()
+{
+	local vlan=$1; shift
+	local proto=$1; shift
+	local pkts=$1; shift
+
+	$MZ $h2.$vlan -p 8000 -a own -b $h3_mac \
+	    -A $(ipaddr 2 $vlan) -B $(ipaddr 3 $vlan) \
+	    -t $proto -q -c $pkts "$@"
+}
+
 # This sends traffic in an attempt to build a backlog of $size. Returns 0 on
 # success. After 10 failed attempts it bails out and returns 1. It dumps the
 # backlog size to stdout.
@@ -364,9 +377,7 @@ build_backlog()
 			return 1
 		fi
 
-		$MZ $h2.$vlan -p 8000 -a own -b $h3_mac \
-		    -A $(ipaddr 2 $vlan) -B $(ipaddr 3 $vlan) \
-		    -t $proto -q -c $pkts "$@"
+		send_packets $vlan $proto $pkts "$@"
 	done
 }
 
@@ -531,3 +542,92 @@ do_mc_backlog_test()
 
 	log_test "TC $((vlan - 10)): Qdisc reports MC backlog"
 }
+
+do_drop_test()
+{
+	local vlan=$1; shift
+	local limit=$1; shift
+	local trigger=$1; shift
+	local subtest=$1; shift
+	local fetch_counter=$1; shift
+	local backlog
+	local base
+	local now
+	local pct
+
+	RET=0
+
+	start_traffic $h1.$vlan $(ipaddr 1 $vlan) $(ipaddr 3 $vlan) $h3_mac
+
+	# Create a bit of a backlog and observe no mirroring due to drops.
+	qevent_rule_install_$subtest
+	base=$($fetch_counter)
+
+	build_backlog $vlan $((2 * limit / 3)) udp >/dev/null
+
+	busywait 1100 until_counter_is ">= $((base + 1))" $fetch_counter >/dev/null
+	check_fail $? "Spurious packets observed without buffer pressure"
+
+	qevent_rule_uninstall_$subtest
+
+	# Push to the queue until it's at the limit. The configured limit is
+	# rounded by the qdisc and then by the driver, so this is the best we
+	# can do to get to the real limit of the system. Do this with the rules
+	# uninstalled so that the inevitable drops don't get counted.
+	build_backlog $vlan $((3 * limit / 2)) udp >/dev/null
+
+	qevent_rule_install_$subtest
+	base=$($fetch_counter)
+
+	send_packets $vlan udp 11
+
+	now=$(busywait 1100 until_counter_is ">= $((base + 10))" $fetch_counter)
+	check_err $? "Dropped packets not observed: 11 expected, $((now - base)) seen"
+
+	# When no extra traffic is injected, there should be no mirroring.
+	busywait 1100 until_counter_is ">= $((base + 20))" $fetch_counter >/dev/null
+	check_fail $? "Spurious packets observed"
+
+	# When the rule is uninstalled, there should be no mirroring.
+	qevent_rule_uninstall_$subtest
+	send_packets $vlan udp 11
+	busywait 1100 until_counter_is ">= $((base + 20))" $fetch_counter >/dev/null
+	check_fail $? "Spurious packets observed after uninstall"
+
+	log_test "TC $((vlan - 10)): ${trigger}ped packets $subtest'd"
+
+	stop_traffic
+	sleep 1
+}
+
+qevent_rule_install_mirror()
+{
+	tc filter add block 10 pref 1234 handle 102 matchall skip_sw \
+	   action mirred egress mirror dev $swp2 hw_stats disabled
+}
+
+qevent_rule_uninstall_mirror()
+{
+	tc filter del block 10 pref 1234 handle 102 matchall
+}
+
+qevent_counter_fetch_mirror()
+{
+	tc_rule_handle_stats_get "dev $h2 ingress" 101
+}
+
+do_drop_mirror_test()
+{
+	local vlan=$1; shift
+	local limit=$1; shift
+	local qevent_name=$1; shift
+
+	tc filter add dev $h2 ingress pref 1 handle 101 prot ip \
+	   flower skip_sw ip_proto udp \
+	   action drop
+
+	do_drop_test "$vlan" "$limit" "$qevent_name" mirror \
+		     qevent_counter_fetch_mirror
+
+	tc filter del dev $h2 ingress pref 1 handle 101 flower
+}
diff --git a/tools/testing/selftests/drivers/net/mlxsw/sch_red_ets.sh b/tools/testing/selftests/drivers/net/mlxsw/sch_red_ets.sh
index 1c36c576613b..c8968b041bea 100755
--- a/tools/testing/selftests/drivers/net/mlxsw/sch_red_ets.sh
+++ b/tools/testing/selftests/drivers/net/mlxsw/sch_red_ets.sh
@@ -7,6 +7,7 @@ ALL_TESTS="
 	ecn_nodrop_test
 	red_test
 	mc_backlog_test
+	red_mirror_test
 "
 : ${QDISC:=ets}
 source sch_red_core.sh
@@ -83,6 +84,16 @@ mc_backlog_test()
 	uninstall_qdisc
 }
 
+red_mirror_test()
+{
+	install_qdisc qevent early_drop block 10
+
+	do_drop_mirror_test 10 $BACKLOG1 early_drop
+	do_drop_mirror_test 11 $BACKLOG2 early_drop
+
+	uninstall_qdisc
+}
+
 trap cleanup EXIT
 
 setup_prepare
diff --git a/tools/testing/selftests/drivers/net/mlxsw/sch_red_root.sh b/tools/testing/selftests/drivers/net/mlxsw/sch_red_root.sh
index 558667ea11ec..ede9c38d3eff 100755
--- a/tools/testing/selftests/drivers/net/mlxsw/sch_red_root.sh
+++ b/tools/testing/selftests/drivers/net/mlxsw/sch_red_root.sh
@@ -7,6 +7,7 @@ ALL_TESTS="
 	ecn_nodrop_test
 	red_test
 	mc_backlog_test
+	red_mirror_test
 "
 source sch_red_core.sh
 
@@ -57,6 +58,13 @@ mc_backlog_test()
 	uninstall_qdisc
 }
 
+red_mirror_test()
+{
+	install_qdisc qevent early_drop block 10
+	do_drop_mirror_test 10 $BACKLOG
+	uninstall_qdisc
+}
+
 trap cleanup EXIT
 
 setup_prepare