i40e: Fix errors resulted while turning off TSO

BugLink: http://bugs.launchpad.net/bugs/1626782

On systems with 128 CPUs, turning off TSO results in errors,

i40e 0000:03:00.0: failed to get tracking for 1 vectors for VSI 400, err=-12
i40e 0000:03:00.0: Couldn't create FDir VSI
i40e 0000:03:00.0: i40e_ptp_init: PTP not supported on eth0
i40e 0000:03:00.0: couldn't add VEB, err I40E_ERR_ADMIN_QUEUE_ERROR aq_err I40E_AQ_RC_ENOENT
i40e 0000:03:00.0: rebuild of switch failed: -1, will try to set up simple PF connection
i40e 0000:03:00.0 eth0: adding 00:10:e0:8a:24:b6 vid=0

Enabling FD_SB without checking availability of MSI-X vector is the
root cause. This change adds necessary check.
Signed-off-by: Tushar Dave <tushar.n.dave@oracle.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
(cherry picked from commit a70e407f)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

 Conflicts:
	drivers/net/ethernet/intel/i40e/i40e.h
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

drivers/net/ethernet/intel/i40e/i40e.h

@@ -282,6 +282,7 @@ struct i40e_pf {
 #endif /* I40E_FCOE */
 	u16 num_lan_qps;           /* num lan queues this PF has set up */
 	u16 num_lan_msix;          /* num queue vectors for the base PF vsi */
+	u16 num_fdsb_msix;         /* num queue vectors for sideband Fdir */
 	int queues_left;           /* queues left unclaimed */
 	u16 alloc_rss_size;        /* allocated RSS queues */
 	u16 rss_size_max;          /* HW defined max RSS queues */

drivers/net/ethernet/intel/i40e/i40e_main.c

@@ -7193,7 +7193,7 @@ static int i40e_set_num_rings_in_vsi(struct i40e_vsi *vsi)
 		vsi->alloc_queue_pairs = 1;
 		vsi->num_desc = ALIGN(I40E_FDIR_RING_COUNT,
 				      I40E_REQ_DESCRIPTOR_MULTIPLE);
-		vsi->num_q_vectors = 1;
+		vsi->num_q_vectors = pf->num_fdsb_msix;
 		break;
 
 	case I40E_VSI_VMDQ2:
@@ -7579,9 +7579,11 @@ static int i40e_init_msix(struct i40e_pf *pf)
 	/* reserve one vector for sideband flow director */
 	if (pf->flags & I40E_FLAG_FD_SB_ENABLED) {
 		if (vectors_left) {
+			pf->num_fdsb_msix = 1;
 			v_budget++;
 			vectors_left--;
 		} else {
+			pf->num_fdsb_msix = 0;
 			pf->flags &= ~I40E_FLAG_FD_SB_ENABLED;
 		}
 	}
@@ -8546,7 +8548,9 @@ bool i40e_set_ntuple(struct i40e_pf *pf, netdev_features_t features)
 		/* Enable filters and mark for reset */
 		if (!(pf->flags & I40E_FLAG_FD_SB_ENABLED))
 			need_reset = true;
-		pf->flags |= I40E_FLAG_FD_SB_ENABLED;
+		/* enable FD_SB only if there is MSI-X vector */
+		if (pf->num_fdsb_msix > 0)
+			pf->flags |= I40E_FLAG_FD_SB_ENABLED;
 	} else {
 		/* turn off filters, mark for reset and clear SW filter list */
 		if (pf->flags & I40E_FLAG_FD_SB_ENABLED) {