From 49f885b2d97093451410e7279aa29d81e094e108 Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Tue, 12 Oct 2021 14:40:41 +0300 Subject: net: dsa: tag_ocelot_8021q: break circular dependency with ocelot switch lib Michael reported that when using the "ocelot-8021q" tagging protocol, the switch driver module must be manually loaded before the tagging protocol can be loaded/is available. This appears to be the same problem described here: https://lore.kernel.org/netdev/20210908220834.d7gmtnwrorhharna@skbuf/ where due to the fact that DSA tagging protocols make use of symbols exported by the switch drivers, circular dependencies appear and this breaks module autoloading. The ocelot_8021q driver needs the ocelot_can_inject() and ocelot_port_inject_frame() functions from the switch library. Previously the wrong approach was taken to solve that dependency: shims were provided for the case where the ocelot switch library was compiled out, but that turns out to be insufficient, because the dependency when the switch lib _is_ compiled is problematic too. We cannot declare ocelot_can_inject() and ocelot_port_inject_frame() as static inline functions, because these access I/O functions like __ocelot_write_ix() which is called by ocelot_write_rix(). Making those static inline basically means exposing the whole guts of the ocelot switch library, not ideal... We already have one tagging protocol driver which calls into the switch driver during xmit but not using any exported symbol: sja1105_defer_xmit. We can do the same thing here: create a kthread worker and one work item per skb, and let the switch driver itself do the register accesses to send the skb, and then consume it. Fixes: 0a6f17c6ae21 ("net: dsa: tag_ocelot_8021q: add support for PTP timestamping") Reported-by: Michael Walle Signed-off-by: Vladimir Oltean Signed-off-by: Jakub Kicinski --- include/linux/dsa/ocelot.h | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'include/linux') diff --git a/include/linux/dsa/ocelot.h b/include/linux/dsa/ocelot.h index 50641a7529ad..8ae999f587c4 100644 --- a/include/linux/dsa/ocelot.h +++ b/include/linux/dsa/ocelot.h @@ -5,6 +5,7 @@ #ifndef _NET_DSA_TAG_OCELOT_H #define _NET_DSA_TAG_OCELOT_H +#include #include #include @@ -160,6 +161,17 @@ struct ocelot_skb_cb { * +------+------+------+------+------+------+------+------+ */ +struct felix_deferred_xmit_work { + struct dsa_port *dp; + struct sk_buff *skb; + struct kthread_work work; +}; + +struct felix_port { + void (*xmit_work_fn)(struct kthread_work *work); + struct kthread_worker *xmit_worker; +}; + static inline void ocelot_xfh_get_rew_val(void *extraction, u64 *rew_val) { packing(extraction, rew_val, 116, 85, OCELOT_TAG_LEN, UNPACK, 0); -- cgit v1.2.3