From: Alex Estrin <alex.estrin@intel.com>
Date: Mon, 24 Jul 2017 07:46:36 -0700
Subject: IB/hfi1: Verify port data VLs credits on transition to Armed
Patch-mainline: v4.14-rc1
Git-commit: 5e2d6764a729bf8d43894b0368b0ae11a19485c0
References: bsc#1060463 FATE#323043

There is a window where the FM can read the buffer control table
and decide not to program buffers. When a port goes down, the code
clears the table and if it is not programmed, posted SDMA descriptors
will never complete due to no buffer credits.

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Alex Estrin <alex.estrin@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/infiniband/hw/hfi1/chip.c |   16 +++++++++++++++-
 drivers/infiniband/hw/hfi1/intr.c |    1 +
 2 files changed, 16 insertions(+), 1 deletion(-)

--- a/drivers/infiniband/hw/hfi1/chip.c
+++ b/drivers/infiniband/hw/hfi1/chip.c
@@ -10490,6 +10490,14 @@ void set_link_down_reason(struct hfi1_pp
 }
 
 /*
+ * Verify if BCT for data VLs is non-zero.
+ */
+static inline bool data_vls_operational(struct hfi1_pportdata *ppd)
+{
+	return !!ppd->actual_vls_operational;
+}
+
+/*
  * Change the physical and/or logical link state.
  *
  * Do not call this routine while inside an interrupt.  It contains
@@ -10587,6 +10595,13 @@ int set_link_state(struct hfi1_pportdata
 		if (ppd->host_link_state != HLS_UP_INIT)
 			goto unexpected;
 
+		if (!data_vls_operational(ppd)) {
+			dd_dev_err(dd,
+				   "%s: data VLs not operational\n", __func__);
+			ret = -EINVAL;
+			break;
+		}
+
 		ppd->host_link_state = HLS_UP_ARMED;
 		set_logical_state(dd, LSTATE_ARMED);
 		ret = wait_logical_linkstate(ppd, IB_PORT_ARMED, 1000);
@@ -14832,7 +14847,6 @@ struct hfi1_devdata *hfi1_init_dd(struct
 		}
 		ppd->vls_supported = num_vls;
 		ppd->vls_operational = ppd->vls_supported;
-		ppd->actual_vls_operational = ppd->vls_supported;
 		/* Set the default MTU. */
 		for (vl = 0; vl < num_vls; vl++)
 			dd->vld[vl].mtu = hfi1_max_mtu;
--- a/drivers/infiniband/hw/hfi1/intr.c
+++ b/drivers/infiniband/hw/hfi1/intr.c
@@ -164,6 +164,7 @@ void handle_linkup_change(struct hfi1_de
 		ppd->linkup = 0;
 
 		/* clear HW details of the previous connection */
+		ppd->actual_vls_operational = 0;
 		reset_link_credits(dd);
 
 		/* freeze after a link down to guarantee a clean egress */