From: Leon Romanovsky <leonro@mellanox.com>
Date: Tue, 29 May 2018 14:56:13 +0300
Subject: RDMA/mlx4: Catch FW<->SW misalignment without machine crash
Patch-mainline: v4.18-rc1
Git-commit: f77f3036264b2e0d9abd2938b8999dc9d33819ed
References: bsc#1103988 FATE#326003

Any steering QP is supposed be above steering_qp_base,
see function mlx4_ib_steer_qp_alloc() for it, however in case
of misalignment between SW and FW, this qp_base can be wrong.

Use WARN() to catch such situation without killing the machine.

Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/infiniband/hw/mlx4/main.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/infiniband/hw/mlx4/main.c
+++ b/drivers/infiniband/hw/mlx4/main.c
@@ -3017,7 +3017,10 @@ void mlx4_ib_steer_qp_free(struct mlx4_i
 	    dev->steering_support != MLX4_STEERING_MODE_DEVICE_MANAGED)
 		return;
 
-	BUG_ON(qpn < dev->steer_qpn_base);
+	if (WARN(qpn < dev->steer_qpn_base, "qpn = %u, steer_qpn_base = %u\n",
+		 qpn, dev->steer_qpn_base))
+		/* not supposed to be here */
+		return;
 
 	bitmap_release_region(dev->ib_uc_qpns_bitmap,
 			      qpn - dev->steer_qpn_base,