From 6407a4b7b4052e5e524380ca185d08aee9a8a85a Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Wed, 11 May 2022 12:50:19 +0300 Subject: [PATCH] net: dsa: felix: dynamically determine tag_8021q CPU port for traps Ocelot switches support a single active CPU port at a time (at least as a trapping destination, i.e. for control traffic). This is true regardless of whether we are using the native copy-to-CPU-port-module functionality, or a redirect action towards the software-defined tag_8021q CPU port. Currently we assume that the trapping destination in tag_8021q mode is the first CPU port, yet in the future we may want to migrate the user ports to the second CPU port. For that to work, we need to make sure that the tag_8021q trapping destination is a CPU port that is active, i.e. is used by at least some user port on which the trap was added. Otherwise, we may end up redirecting the traffic to a CPU port which isn't even up. Note that due to the current design where we simply choose the CPU port of the first port from the trap's ingress port mask, it may be that a CPU port absorbes control traffic from user ports which aren't affine to it as per user space's request. This isn't ideal, but is the lesser of two evils. Following the user-configured affinity for traps would mean that we can no longer reuse a single TCAM entry for multiple traps, which is what we actually do for e.g. PTP. Either we duplicate and deduplicate TCAM entries on the fly when user-to-CPU-port mappings change (which is unnecessarily complicated), or we redirect trapped traffic to all tag_8021q CPU ports if multiple such ports are in use. The latter would have actually been nice, if it actually worked, but it doesn't, since a OCELOT_MASK_MODE_REDIRECT action towards multiple ports would not take PGID_SRC into consideration, and it would just duplicate the packet towards each (CPU) port, leading to duplicates in software. Signed-off-by: Vladimir Oltean Signed-off-by: Jakub Kicinski --- drivers/net/dsa/ocelot/felix.c | 26 +++++++++++++++++--------- 1 file changed, 17 insertions(+), 9 deletions(-) diff --git a/drivers/net/dsa/ocelot/felix.c b/drivers/net/dsa/ocelot/felix.c index 0edec7c2b847e..e76a5d4346267 100644 --- a/drivers/net/dsa/ocelot/felix.c +++ b/drivers/net/dsa/ocelot/felix.c @@ -313,6 +313,21 @@ static void felix_8021q_cpu_port_deinit(struct ocelot *ocelot, int port) mutex_unlock(&ocelot->fwd_domain_lock); } +static int felix_trap_get_cpu_port(struct dsa_switch *ds, + const struct ocelot_vcap_filter *trap) +{ + struct dsa_port *dp; + int first_port; + + if (WARN_ON(!trap->ingress_port_mask)) + return -1; + + first_port = __ffs(trap->ingress_port_mask); + dp = dsa_to_port(ds, first_port); + + return dp->cpu_dp->index; +} + /* On switches with no extraction IRQ wired, trapped packets need to be * replicated over Ethernet as well, otherwise we'd get no notification of * their arrival when using the ocelot-8021q tagging protocol. @@ -326,19 +341,12 @@ static int felix_update_trapping_destinations(struct dsa_switch *ds, struct ocelot_vcap_filter *trap; enum ocelot_mask_mode mask_mode; unsigned long port_mask; - struct dsa_port *dp; bool cpu_copy_ena; - int cpu = -1, err; + int err; if (!felix->info->quirk_no_xtr_irq) return 0; - /* Figure out the current CPU port */ - dsa_switch_for_each_cpu_port(dp, ds) { - cpu = dp->index; - break; - } - /* We are sure that "cpu" was found, otherwise * dsa_tree_setup_default_cpu() would have failed earlier. */ @@ -356,7 +364,7 @@ static int felix_update_trapping_destinations(struct dsa_switch *ds, * port module. */ mask_mode = OCELOT_MASK_MODE_REDIRECT; - port_mask = BIT(cpu); + port_mask = BIT(felix_trap_get_cpu_port(ds, trap)); cpu_copy_ena = !!trap->take_ts; } else { /* Trap packets only to the CPU port module, which is -- 2.39.5