i40iw: Account for IPv6 header when setting MSS

The IPv6 header size is not subtracted from MTU when MSS is
set for QPs.

Save MTU opposed to MSS in the vsi struct during
initialization and calculate the MSS based on IPv4 vs
IPv6 connection.

Fixes: f27b4746 ("i40iw: add connection management code")
Signed-off-by: Shiraz Saleem <shiraz.saleem@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/i40iw/i40iw.h

@@ -119,9 +119,6 @@
 #define I40IW_CQP_COMPL_SQ_WQE_FLUSHED    3
 #define I40IW_CQP_COMPL_RQ_SQ_WQE_FLUSHED 4
 
-#define I40IW_MTU_TO_MSS		40
-#define I40IW_DEFAULT_MSS		1460
-
 struct i40iw_cqp_compl_info {
 	u32 op_ret_val;
 	u16 maj_err_code;

drivers/infiniband/hw/i40iw/i40iw_cm.c

@@ -2193,7 +2193,8 @@ static struct i40iw_cm_node *i40iw_make_cm_node(
 			I40IW_CM_DEFAULT_RCV_WND_SCALED >> I40IW_CM_DEFAULT_RCV_WND_SCALE;
 	ts = current_kernel_time();
 	cm_node->tcp_cntxt.loc_seq_num = ts.tv_nsec;
-	cm_node->tcp_cntxt.mss = iwdev->vsi.mss;
+	cm_node->tcp_cntxt.mss = (cm_node->ipv4) ? (iwdev->vsi.mtu - I40IW_MTU_TO_MSS_IPV4) :
+				 (iwdev->vsi.mtu - I40IW_MTU_TO_MSS_IPV6);
 
 	cm_node->iwdev = iwdev;
 	cm_node->dev = &iwdev->sc_dev;

drivers/infiniband/hw/i40iw/i40iw_ctrl.c

@@ -348,7 +348,7 @@ void i40iw_change_l2params(struct i40iw_sc_vsi *vsi, struct i40iw_l2params *l2pa
 	u16 qs_handle;
 	int i;
 
-	vsi->mss = l2params->mss;
+	vsi->mtu = l2params->mtu;
 
 	i40iw_fill_qos_list(l2params->qs_handle_list);
 	for (i = 0; i < I40IW_MAX_USER_PRIORITY; i++) {
@@ -4582,9 +4582,8 @@ void i40iw_sc_vsi_init(struct i40iw_sc_vsi *vsi, struct i40iw_vsi_init_info *inf
 
 	vsi->dev = info->dev;
 	vsi->back_vsi = info->back_vsi;
-	vsi->mss = info->params->mss;
+	vsi->mtu = info->params->mtu;
 	vsi->exception_lan_queue = info->exception_lan_queue;
-
 	i40iw_fill_qos_list(info->params->qs_handle_list);
 
 	for (i = 0; i < I40IW_MAX_USER_PRIORITY; i++) {

drivers/infiniband/hw/i40iw/i40iw_d.h

@@ -73,6 +73,10 @@
 #define I40IW_FIRST_NON_PF_STAT	4
 
 
+#define I40IW_MTU_TO_MSS_IPV4		40
+#define I40IW_MTU_TO_MSS_IPV6		60
+#define I40IW_DEFAULT_MTU		1500
+
 #define LS_64_1(val, bits)      ((u64)(uintptr_t)val << bits)
 #define RS_64_1(val, bits)      ((u64)(uintptr_t)val >> bits)
 #define LS_32_1(val, bits)      (u32)(val << bits)

drivers/infiniband/hw/i40iw/i40iw_main.c

@@ -1327,8 +1327,8 @@ static enum i40iw_status_code i40iw_initialize_dev(struct i40iw_device *iwdev,
 	info.bar0 = ldev->hw_addr;
 	info.hw = &iwdev->hw;
 	info.debug_mask = debug;
-	l2params.mss =
-		(ldev->params.mtu) ? ldev->params.mtu - I40IW_MTU_TO_MSS : I40IW_DEFAULT_MSS;
+	l2params.mtu =
+		(ldev->params.mtu) ? ldev->params.mtu : I40IW_DEFAULT_MTU;
 	for (i = 0; i < I40E_CLIENT_MAX_USER_PRIORITY; i++) {
 		qset = ldev->params.qos.prio_qos[i].qs_handle;
 		l2params.qs_handle_list[i] = qset;
@@ -1748,7 +1748,7 @@ static void i40iw_l2param_change(struct i40e_info *ldev, struct i40e_client *cli
 	for (i = 0; i < I40E_CLIENT_MAX_USER_PRIORITY; i++)
 		l2params->qs_handle_list[i] = params->qos.prio_qos[i].qs_handle;
 
-	l2params->mss = (params->mtu) ? params->mtu - I40IW_MTU_TO_MSS : iwdev->vsi.mss;
+	l2params->mtu = (params->mtu) ? params->mtu : iwdev->vsi.mtu;
 
 	INIT_WORK(&work->work, i40iw_l2params_worker);
 	queue_work(iwdev->param_wq, &work->work);

drivers/infiniband/hw/i40iw/i40iw_puda.c

@@ -1401,7 +1401,8 @@ static void i40iw_ieq_handle_exception(struct i40iw_puda_rsrc *ieq,
 		pfpdu->rcv_nxt = fps;
 		pfpdu->fps = fps;
 		pfpdu->mode = true;
-		pfpdu->max_fpdu_data = ieq->vsi->mss;
+		pfpdu->max_fpdu_data = (buf->ipv4) ? (ieq->vsi->mtu - I40IW_MTU_TO_MSS_IPV4) :
+				       (ieq->vsi->mtu - I40IW_MTU_TO_MSS_IPV6);
 		pfpdu->pmode_count++;
 		INIT_LIST_HEAD(rxlist);
 		i40iw_ieq_check_first_buf(buf, fps);

drivers/infiniband/hw/i40iw/i40iw_type.h

@@ -460,7 +460,7 @@ struct i40iw_sc_vsi {
 	struct i40iw_virt_mem ieq_mem;
 	struct i40iw_puda_rsrc *ieq;
 	u16 exception_lan_queue;
-	u16 mss;
+	u16 mtu;
 	u8 fcn_id;
 	bool stats_fcn_id_alloc;
 	struct i40iw_qos qos[I40IW_MAX_USER_PRIORITY];
@@ -566,7 +566,7 @@ struct i40iw_ccq_cqe_info {
 
 struct i40iw_l2params {
 	u16 qs_handle_list[I40IW_MAX_USER_PRIORITY];
-	u16 mss;
+	u16 mtu;
 };
 
 struct i40iw_vsi_init_info {