bnxt_en: Do not adjust max_cp_rings by the ones used by RDMA.

Currently, the driver adjusts the bp->hw_resc.max_cp_rings by the number
of MSIX vectors used by RDMA.  There is one code path in open that needs
to check the true max_cp_rings including any used by RDMA.  This code
is now checking for the reduced max_cp_rings which will fail when the
number of cp rings is very small.

To fix this in a clean way, we don't adjust max_cp_rings anymore.
Instead, we add a helper bnxt_get_max_func_cp_rings_for_en() to get the
reduced max_cp_rings when appropriate.

Fixes: ec86f14ea506 ("bnxt_en: Add ULP calls to stop and restart IRQs.")
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -5913,9 +5913,9 @@ unsigned int bnxt_get_max_func_cp_rings(struct bnxt *bp)
 	return bp->hw_resc.max_cp_rings;
 }
 
-void bnxt_set_max_func_cp_rings(struct bnxt *bp, unsigned int max)
+unsigned int bnxt_get_max_func_cp_rings_for_en(struct bnxt *bp)
 {
-	bp->hw_resc.max_cp_rings = max;
+	return bp->hw_resc.max_cp_rings - bnxt_get_ulp_msix_num(bp);
 }
 
 static unsigned int bnxt_get_max_func_irqs(struct bnxt *bp)
@@ -8631,7 +8631,8 @@ static void _bnxt_get_max_rings(struct bnxt *bp, int *max_rx, int *max_tx,
 
 	*max_tx = hw_resc->max_tx_rings;
 	*max_rx = hw_resc->max_rx_rings;
-	*max_cp = min_t(int, hw_resc->max_irqs, hw_resc->max_cp_rings);
+	*max_cp = min_t(int, bnxt_get_max_func_cp_rings_for_en(bp),
+			hw_resc->max_irqs);
 	*max_cp = min_t(int, *max_cp, hw_resc->max_stat_ctxs);
 	max_ring_grps = hw_resc->max_hw_ring_grps;
 	if (BNXT_CHIP_TYPE_NITRO_A0(bp) && BNXT_PF(bp)) {

drivers/net/ethernet/broadcom/bnxt/bnxt.h

@@ -1481,7 +1481,7 @@ int bnxt_hwrm_set_coal(struct bnxt *);
 unsigned int bnxt_get_max_func_stat_ctxs(struct bnxt *bp);
 void bnxt_set_max_func_stat_ctxs(struct bnxt *bp, unsigned int max);
 unsigned int bnxt_get_max_func_cp_rings(struct bnxt *bp);
-void bnxt_set_max_func_cp_rings(struct bnxt *bp, unsigned int max);
+unsigned int bnxt_get_max_func_cp_rings_for_en(struct bnxt *bp);
 int bnxt_get_avail_msix(struct bnxt *bp, int num);
 int bnxt_reserve_rings(struct bnxt *bp);
 void bnxt_tx_disable(struct bnxt *bp);

drivers/net/ethernet/broadcom/bnxt/bnxt_sriov.c

@@ -451,7 +451,7 @@ static int bnxt_hwrm_func_vf_resc_cfg(struct bnxt *bp, int num_vfs)
 
 	bnxt_hwrm_cmd_hdr_init(bp, &req, HWRM_FUNC_VF_RESOURCE_CFG, -1, -1);
 
-	vf_cp_rings = hw_resc->max_cp_rings - bp->cp_nr_rings;
+	vf_cp_rings = bnxt_get_max_func_cp_rings_for_en(bp) - bp->cp_nr_rings;
 	vf_stat_ctx = hw_resc->max_stat_ctxs - bp->num_stat_ctxs;
 	if (bp->flags & BNXT_FLAG_AGG_RINGS)
 		vf_rx_rings = hw_resc->max_rx_rings - bp->rx_nr_rings * 2;
@@ -549,7 +549,8 @@ static int bnxt_hwrm_func_cfg(struct bnxt *bp, int num_vfs)
 	max_stat_ctxs = hw_resc->max_stat_ctxs;
 
 	/* Remaining rings are distributed equally amongs VF's for now */
-	vf_cp_rings = (hw_resc->max_cp_rings - bp->cp_nr_rings) / num_vfs;
+	vf_cp_rings = (bnxt_get_max_func_cp_rings_for_en(bp) -
+		       bp->cp_nr_rings) / num_vfs;
 	vf_stat_ctx = (max_stat_ctxs - bp->num_stat_ctxs) / num_vfs;
 	if (bp->flags & BNXT_FLAG_AGG_RINGS)
 		vf_rx_rings = (hw_resc->max_rx_rings - bp->rx_nr_rings * 2) /
@@ -643,7 +644,7 @@ static int bnxt_sriov_enable(struct bnxt *bp, int *num_vfs)
 	 */
 	vfs_supported = *num_vfs;
 
-	avail_cp = hw_resc->max_cp_rings - bp->cp_nr_rings;
+	avail_cp = bnxt_get_max_func_cp_rings_for_en(bp) - bp->cp_nr_rings;
 	avail_stat = hw_resc->max_stat_ctxs - bp->num_stat_ctxs;
 	avail_cp = min_t(int, avail_cp, avail_stat);
 

drivers/net/ethernet/broadcom/bnxt/bnxt_ulp.c

@@ -169,7 +169,6 @@ static int bnxt_req_msix_vecs(struct bnxt_en_dev *edev, int ulp_id,
 		edev->ulp_tbl[ulp_id].msix_requested = avail_msix;
 	}
 	bnxt_fill_msix_vecs(bp, ent);
-	bnxt_set_max_func_cp_rings(bp, max_cp_rings - avail_msix);
 	edev->flags |= BNXT_EN_FLAG_MSIX_REQUESTED;
 	return avail_msix;
 }
@@ -178,7 +177,6 @@ static int bnxt_free_msix_vecs(struct bnxt_en_dev *edev, int ulp_id)
 {
 	struct net_device *dev = edev->net;
 	struct bnxt *bp = netdev_priv(dev);
-	int max_cp_rings, msix_requested;
 
 	ASSERT_RTNL();
 	if (ulp_id != BNXT_ROCE_ULP)
@@ -187,9 +185,6 @@ static int bnxt_free_msix_vecs(struct bnxt_en_dev *edev, int ulp_id)
 	if (!(edev->flags & BNXT_EN_FLAG_MSIX_REQUESTED))
 		return 0;
 
-	max_cp_rings = bnxt_get_max_func_cp_rings(bp);
-	msix_requested = edev->ulp_tbl[ulp_id].msix_requested;
-	bnxt_set_max_func_cp_rings(bp, max_cp_rings + msix_requested);
 	edev->ulp_tbl[ulp_id].msix_requested = 0;
 	edev->flags &= ~BNXT_EN_FLAG_MSIX_REQUESTED;
 	if (netif_running(dev)) {