[PATCH net-next 5/7] nfp: abm: don't set negative threshold

[Jakub Kicinski]

Turns out the threshold value is used in signed compares in the FW,
so we should avoid setting the top bit.

Signed-off-by: Jakub Kicinski <jakub.kicin...@netronome.com>
Reviewed-by: John Hurley <john.hur...@netronome.com>
Reviewed-by: Quentin Monnet <quentin.mon...@netronome.com>
---
 drivers/net/ethernet/netronome/nfp/abm/main.h  |  3 +++
 drivers/net/ethernet/netronome/nfp/abm/qdisc.c | 10 ++++++++--
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/netronome/nfp/abm/main.h 
b/drivers/net/ethernet/netronome/nfp/abm/main.h
index c617d213e406..3774c063e419 100644
--- a/drivers/net/ethernet/netronome/nfp/abm/main.h
+++ b/drivers/net/ethernet/netronome/nfp/abm/main.h
@@ -4,9 +4,12 @@
 #ifndef __NFP_ABM_H__
 #define __NFP_ABM_H__ 1
 
+#include <linux/bits.h>
 #include <net/devlink.h>
 #include <net/pkt_cls.h>
 
+#define NFP_ABM_LVL_INFINITY           S32_MAX
+
 struct nfp_app;
 struct nfp_net;
 
diff --git a/drivers/net/ethernet/netronome/nfp/abm/qdisc.c 
b/drivers/net/ethernet/netronome/nfp/abm/qdisc.c
index 04b91cc12434..979afb3ea855 100644
--- a/drivers/net/ethernet/netronome/nfp/abm/qdisc.c
+++ b/drivers/net/ethernet/netronome/nfp/abm/qdisc.c
@@ -31,7 +31,7 @@ static void
 nfp_abm_reset_root(struct net_device *netdev, struct nfp_abm_link *alink,
                   u32 handle, unsigned int qs)
 {
-       __nfp_abm_reset_root(netdev, alink, handle, qs, ~0);
+       __nfp_abm_reset_root(netdev, alink, handle, qs, NFP_ABM_LVL_INFINITY);
 }
 
 static int
@@ -67,7 +67,7 @@ nfp_abm_red_destroy(struct net_device *netdev, struct 
nfp_abm_link *alink,
        if (alink->parent == TC_H_ROOT) {
                nfp_abm_reset_root(netdev, alink, TC_H_ROOT, 0);
        } else {
-               nfp_abm_ctrl_set_q_lvl(alink, i, ~0);
+               nfp_abm_ctrl_set_q_lvl(alink, i, NFP_ABM_LVL_INFINITY);
                memset(&alink->qdiscs[i], 0, sizeof(*alink->qdiscs));
        }
 }
@@ -88,6 +88,12 @@ nfp_abm_red_check_params(struct nfp_abm_link *alink,
                         opt->parent, opt->handle);
                return false;
        }
+       if (opt->set.min > NFP_ABM_LVL_INFINITY) {
+               nfp_warn(cpp, "RED offload failed - threshold too large %d > %d 
(p:%08x h:%08x)\n",
+                        opt->set.min, NFP_ABM_LVL_INFINITY, opt->parent,
+                        opt->handle);
+               return false;
+       }
 
        return true;
 }
-- 
2.17.1