nfp: flower: avoid rmmod nfp crash issues

When there are CT table entries, and you rmmod nfp, the following
events can happen:

task1：
    nfp_net_pci_remove
          ↓
    nfp_flower_stop->(asynchronous)tcf_ct_flow_table_cleanup_work(3)
          ↓
    nfp_zone_table_entry_destroy(1)

task2：
    nfp_fl_ct_handle_nft_flow(2)

When the execution order is (1)->(2)->(3), it will crash. Therefore, in
the function nfp_fl_ct_del_flow, nf_flow_table_offload_del_cb needs to
be executed synchronously.

At the same time, in order to solve the deadlock problem and the problem
of rtnl_lock sometimes failing, replace rtnl_lock with the private
nfp_fl_lock.

Fixes: 7cc93d888df7 ("nfp: flower-ct: remove callback delete deadlock")
Cc: stable@vger.kernel.org
Signed-off-by: Yanguo Li <yanguo.li@corigine.com>
Signed-off-by: Louis Peens <louis.peens@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/net/ethernet/netronome/nfp/flower/main.h b/drivers/net/ethernet/netronome/nfp/flower/main.h
index 40372545148e..2b7c947ff4f2 100644
--- a/drivers/net/ethernet/netronome/nfp/flower/main.h
+++ b/drivers/net/ethernet/netronome/nfp/flower/main.h
@@ -297,6 +297,7 @@ struct nfp_fl_internal_ports {
  * @predt_list:		List to keep track of decap pretun flows
  * @neigh_table:	Table to keep track of neighbor entries
  * @predt_lock:		Lock to serialise predt/neigh table updates
+ * @nfp_fl_lock:	Lock to protect the flow offload operation
  */
 struct nfp_flower_priv {
 	struct nfp_app *app;
@@ -339,6 +340,7 @@ struct nfp_flower_priv {
 	struct list_head predt_list;
 	struct rhashtable neigh_table;
 	spinlock_t predt_lock; /* Lock to serialise predt/neigh table updates */
+	struct mutex nfp_fl_lock; /* Protect the flow operation */
 };
 
 /**