Flowtable is destroyed when system boot

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1

In my test, lan and wan will up successively, so openwrt call "fw4 -q reload" twice, which calls
NFT_MSG_NEWFLOWTABLE/NFT_MSG_DELFLOWTABLE/NFT_MSG_NEWFLOWTABLE in the kernel as the following log shows.

But "NFT_MSG_DELFLOWTABLE" is committed after all msgs have been processed, which will call "nf_tables_trans_destroy_work" to destroy flowtable, then serial functions will be called, such as "nf_flow_table_offload_setup" will unbind lan1/lan2/lan3/lan4/wan finally.

Is this a bug or do I misunderstand the code ?

Thanks a lot

[   19.623963] [nfnetlink_find_client(147)] warning:cb_id=22, NFT_MSG_NEWFLOWTABLE
[   19.633808] [nf_tables_newflowtable(6791)] warning:flowtable->name=ft, type->family=1
[   19.672675] [nf_flow_table_offload_setup(1102)] warning:flowtable->type->family=1, cmd=0, dev->name=wan, bind
[   19.722649] [nf_flow_table_offload_setup(1102)] warning:flowtable->type->family=1, cmd=0, dev->name=lan4
[   19.768874] [nf_flow_table_offload_setup(1102)] warning:flowtable->type->family=1, cmd=0, dev->name=lan3
[   19.824991] [nf_flow_table_offload_setup(1102)] warning:flowtable->type->family=1, cmd=0, dev->name=lan2
[   19.863884] [nf_flow_table_offload_setup(1102)] warning:flowtable->type->family=1, cmd=0, dev->name=lan1
[   21.603257] [nfnetlink_find_client(147)] warning:cb_id=24, NFT_MSG_DELFLOWTABLE
[   21.608752] [nf_tables_delflowtable(6947)] warning:flowtable->name=ft
[   21.615466] [nfnetlink_find_client(147)] warning:cb_id=22, NFT_MSG_NEWFLOWTABLE
[   21.620851] [nf_tables_newflowtable(6791)] warning:flowtable->name=ft, type->family=1
[   21.628798] [nf_flow_table_offload_setup(1102)] warning:flowtable->type->family=1, cmd=0, dev->name=wlan1, bind
[   21.638441] [nf_flow_table_offload_setup(1102)] warning:flowtable->type->family=1, cmd=0, dev->name=wlan0
[   21.648064] [nf_flow_table_offload_setup(1102)] warning:flowtable->type->family=1, cmd=0, dev->name=wan
[   21.657538] [nf_flow_table_offload_setup(1102)] warning:flowtable->type->family=1, cmd=0, dev->name=lan4
[   21.667111] [nf_flow_table_offload_setup(1102)] warning:flowtable->type->family=1, cmd=0, dev->name=lan3
[   21.676580] [nf_flow_table_offload_setup(1102)] warning:flowtable->type->family=1, cmd=0, dev->name=lan2
[   21.686269] [nf_flow_table_offload_setup(1102)] warning:flowtable->type->family=1, cmd=0, dev->name=lan1
[   21.734706] [nf_tables_trans_destroy_work(7591)] warning: commit NFT_MSG_DELFLOWTABLE
[   21.742531] [nf_flow_table_offload_setup(1102)] warning:flowtable->type->family=1, cmd=1, dev->name=wan, unbind
[   21.764593] [nf_flow_table_offload_setup(1102)] warning:flowtable->type->family=1, cmd=1, dev->name=lan4
[   21.774149] [nf_flow_table_offload_setup(1102)] warning:flowtable->type->family=1, cmd=1, dev->name=lan3
[   21.783774] [nf_flow_table_offload_setup(1102)] warning:flowtable->type->family=1, cmd=1, dev->name=lan2
[   21.793260] [nf_flow_table_offload_setup(1102)] warning:flowtable->type->family=1, cmd=1, dev->name=lan1
2

I think I have found the answer from "build_dir\target-aarch64_cortex-a53_musl\linux-mediatek_mt7622\linux-5.10.138\drivers\net\ethernet\mediatek\mtk_ppe_offload.c"

In the function mtk_eth_setup_tc_block, bind will increase the refcnt, and unbind will decrease it.
So in the log, we bind twice and unbind once, the refcnt still be 1, so the flowtable still work.

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