nfp: flower: split and limit cmsg skb lists

Introduce a second skb list for handling control messages and limit the
number of allowed messages. Some control messages are considered more
crucial than others, resulting in the need for a second skb list. By
splitting the list into a separate high and low priority list we can
ensure that messages on the high list get added to the head of the list
that gets processed, this however has no functional impact. Previously
there was no limit on the number of messages allowed on the queue, this
could result in the queue growing boundlessly and eventually the host
running out of memory.

Fixes: b985f870a5f0 ("nfp: process control messages in workqueue in flower app")
Signed-off-by: Pieter Jansen van Vuuren <pieter.jansenvanvuuren@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 2 deletions

diff --git a/drivers/net/ethernet/netronome/nfp/flower/main.h b/drivers/net/ethernet/netronome/nfp/flower/main.h
index e030b3ce4510..c67e1b54c614 100644
--- a/drivers/net/ethernet/netronome/nfp/flower/main.h
+++ b/drivers/net/ethernet/netronome/nfp/flower/main.h
@@ -107,7 +107,10 @@ struct nfp_mtu_conf {
  * @mask_table:		Hash table used to store masks
  * @flow_table:		Hash table used to store flower rules
  * @cmsg_work:		Workqueue for control messages processing
- * @cmsg_skbs:		List of skbs for control message processing
+ * @cmsg_skbs_high:	List of higher priority skbs for control message
+ *			processing
+ * @cmsg_skbs_low:	List of lower priority skbs for control message
+ *			processing
  * @nfp_mac_off_list:	List of MAC addresses to offload
  * @nfp_mac_index_list:	List of unique 8-bit indexes for non NFP netdevs
  * @nfp_ipv4_off_list:	List of IPv4 addresses to offload
@@ -136,7 +139,8 @@ struct nfp_flower_priv {
 	DECLARE_HASHTABLE(mask_table, NFP_FLOWER_MASK_HASH_BITS);
 	DECLARE_HASHTABLE(flow_table, NFP_FLOWER_HASH_BITS);
 	struct work_struct cmsg_work;
-	struct sk_buff_head cmsg_skbs;
+	struct sk_buff_head cmsg_skbs_high;
+	struct sk_buff_head cmsg_skbs_low;
 	struct list_head nfp_mac_off_list;
 	struct list_head nfp_mac_index_list;
 	struct list_head nfp_ipv4_off_list;