Merge branch 'mlxsw-Add-support-for-buffer-drop-traps'

Ido Schimmel says:

====================
mlxsw: Add support for buffer drop traps

Petr says:

A recent patch set added the ability to mirror buffer related drops
(e.g., early drops) through a netdev. This patch set adds the ability to
trap such packets to the local CPU for analysis.

The trapping towards the CPU is configured by using tc-trap action
instead of tc-mirred as was done when the packets were mirrored through
a netdev. A future patch set will also add the ability to sample the
dropped packets using tc-sample action.

The buffer related drop traps are added to devlink, which means that the
dropped packets can be reported to user space via the kernel's
drop_monitor module.

Patch set overview:

Patch #1 adds the early_drop trap to devlink

Patch #2 adds extack to a few devlink operations to facilitate better
error reporting to user space. This is necessary - among other things -
because the action of buffer drop traps cannot be changed in mlxsw

Patch #3 performs a small refactoring in mlxsw, patch #4 fixes a bug that
this patchset would trigger.

Patches #5-#6 add the infrastructure required to support different traps
/ trap groups in mlxsw per-ASIC. This is required because buffer drop
traps are not supported by Spectrum-1

Patch #7 extends mlxsw to register the early_drop trap

Patch #8 adds the offload logic for the "trap" action at a qevent block.

Patch #9 adds a mlxsw-specific selftest.
====================

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

2 files changed, 40 insertions, 6 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 45042105ead7..517297a14ecf 100644
--- a/tools/testing/selftests/drivers/net/mlxsw/sch_red_core.sh
+++ b/tools/testing/selftests/drivers/net/mlxsw/sch_red_core.sh
@@ -568,17 +568,12 @@ do_drop_test()
 	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.
+	# can do to get to the real limit of the system.
 	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)
@@ -631,3 +626,31 @@ do_drop_mirror_test()
 
 	tc filter del dev $h2 ingress pref 1 handle 101 flower
 }
+
+qevent_rule_install_trap()
+{
+	tc filter add block 10 pref 1234 handle 102 matchall skip_sw \
+	   action trap hw_stats disabled
+}
+
+qevent_rule_uninstall_trap()
+{
+	tc filter del block 10 pref 1234 handle 102 matchall
+}
+
+qevent_counter_fetch_trap()
+{
+	local trap_name=$1; shift
+
+	devlink_trap_rx_packets_get "$trap_name"
+}
+
+do_drop_trap_test()
+{
+	local vlan=$1; shift
+	local limit=$1; shift
+	local trap_name=$1; shift
+
+	do_drop_test "$vlan" "$limit" "$trap_name" trap \
+		     "qevent_counter_fetch_trap $trap_name"
+}
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 c8968b041bea..3f007c5f8361 100755
--- a/tools/testing/selftests/drivers/net/mlxsw/sch_red_ets.sh
+++ b/tools/testing/selftests/drivers/net/mlxsw/sch_red_ets.sh
@@ -8,6 +8,7 @@ ALL_TESTS="
 	red_test
 	mc_backlog_test
 	red_mirror_test
+	red_trap_test
 "
 : ${QDISC:=ets}
 source sch_red_core.sh
@@ -94,6 +95,16 @@ red_mirror_test()
 	uninstall_qdisc
 }
 
+red_trap_test()
+{
+	install_qdisc qevent early_drop block 10
+
+	do_drop_trap_test 10 $BACKLOG1 early_drop
+	do_drop_trap_test 11 $BACKLOG2 early_drop
+
+	uninstall_qdisc
+}
+
 trap cleanup EXIT
 
 setup_prepare