From 886f8e26f5397827f031bce48f3138040d88ffb3 Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Fri, 29 Jan 2021 03:00:04 +0200 Subject: net: dsa: document the existing switch tree notifiers and add a new one The existence of dsa_broadcast has generated some confusion in the past: https://www.mail-archive.com/netdev@vger.kernel.org/msg365042.html So let's document the existing dsa_port_notify and dsa_broadcast functions and explain when each of them should be used. Also, in fact, the in-between function has always been there but was lacking a name, and is the main reason for this patch: dsa_tree_notify. Refactor dsa_broadcast to use it. This patch also moves dsa_broadcast (a top-level function) to dsa2.c, where it really belonged in the first place, but had no companion so it stood with dsa_port_notify. Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: Jakub Kicinski --- net/dsa/dsa2.c | 43 +++++++++++++++++++++++++++++++++++++++++++ net/dsa/dsa_priv.h | 2 ++ net/dsa/port.c | 36 +++++++++++++----------------------- 3 files changed, 58 insertions(+), 23 deletions(-) (limited to 'net/dsa') diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c index cc13549120e5..2953d0c1c7bc 100644 --- a/net/dsa/dsa2.c +++ b/net/dsa/dsa2.c @@ -21,6 +21,49 @@ static DEFINE_MUTEX(dsa2_mutex); LIST_HEAD(dsa_tree_list); +/** + * dsa_tree_notify - Execute code for all switches in a DSA switch tree. + * @dst: collection of struct dsa_switch devices to notify. + * @e: event, must be of type DSA_NOTIFIER_* + * @v: event-specific value. + * + * Given a struct dsa_switch_tree, this can be used to run a function once for + * each member DSA switch. The other alternative of traversing the tree is only + * through its ports list, which does not uniquely list the switches. + */ +int dsa_tree_notify(struct dsa_switch_tree *dst, unsigned long e, void *v) +{ + struct raw_notifier_head *nh = &dst->nh; + int err; + + err = raw_notifier_call_chain(nh, e, v); + + return notifier_to_errno(err); +} + +/** + * dsa_broadcast - Notify all DSA trees in the system. + * @e: event, must be of type DSA_NOTIFIER_* + * @v: event-specific value. + * + * Can be used to notify the switching fabric of events such as cross-chip + * bridging between disjoint trees (such as islands of tagger-compatible + * switches bridged by an incompatible middle switch). + */ +int dsa_broadcast(unsigned long e, void *v) +{ + struct dsa_switch_tree *dst; + int err = 0; + + list_for_each_entry(dst, &dsa_tree_list, list) { + err = dsa_tree_notify(dst, e, v); + if (err) + break; + } + + return err; +} + /** * dsa_lag_map() - Map LAG netdev to a linear LAG ID * @dst: Tree in which to record the mapping. diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h index 2ce46bb87703..3cc1e6d76e3a 100644 --- a/net/dsa/dsa_priv.h +++ b/net/dsa/dsa_priv.h @@ -283,6 +283,8 @@ void dsa_switch_unregister_notifier(struct dsa_switch *ds); /* dsa2.c */ void dsa_lag_map(struct dsa_switch_tree *dst, struct net_device *lag); void dsa_lag_unmap(struct dsa_switch_tree *dst, struct net_device *lag); +int dsa_tree_notify(struct dsa_switch_tree *dst, unsigned long e, void *v); +int dsa_broadcast(unsigned long e, void *v); extern struct list_head dsa_tree_list; diff --git a/net/dsa/port.c b/net/dsa/port.c index f5b0f72ee7cd..a8886cf40160 100644 --- a/net/dsa/port.c +++ b/net/dsa/port.c @@ -13,31 +13,21 @@ #include "dsa_priv.h" -static int dsa_broadcast(unsigned long e, void *v) -{ - struct dsa_switch_tree *dst; - int err = 0; - - list_for_each_entry(dst, &dsa_tree_list, list) { - struct raw_notifier_head *nh = &dst->nh; - - err = raw_notifier_call_chain(nh, e, v); - err = notifier_to_errno(err); - if (err) - break; - } - - return err; -} - +/** + * dsa_port_notify - Notify the switching fabric of changes to a port + * @dp: port on which change occurred + * @e: event, must be of type DSA_NOTIFIER_* + * @v: event-specific value. + * + * Notify all switches in the DSA tree that this port's switch belongs to, + * including this switch itself, of an event. Allows the other switches to + * reconfigure themselves for cross-chip operations. Can also be used to + * reconfigure ports without net_devices (CPU ports, DSA links) whenever + * a user port's state changes. + */ static int dsa_port_notify(const struct dsa_port *dp, unsigned long e, void *v) { - struct raw_notifier_head *nh = &dp->ds->dst->nh; - int err; - - err = raw_notifier_call_chain(nh, e, v); - - return notifier_to_errno(err); + return dsa_tree_notify(dp->ds->dst, e, v); } int dsa_port_set_state(struct dsa_port *dp, u8 state) -- cgit v1.2.3-58-ga151