[PATCH net 2/4] eth: bnxt: keep the aRFS rmap updated when TPH is enabled

[Jakub Kicinski <kuba@kernel.org>]

The TPH support must have broken aRFS in bnxt. IRQ can only have one
notifier, so installing the TPH notifier is overriding the one implicitly
installed by irq_cpu_rmap_add().

Make sure we call cpu_rmap_update() from the TPH notifier.

We need to be careful with the ordering and not free the rmap
until we unregistered the notifier. Note that moving the rmap
freeing after the early return in bnxt_free_irq() is fine -
there's no path that could leave rmap with irq_tbl being NULL.

Fixes: c214410c47d6 ("bnxt_en: Add TPH support in BNXT driver")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 drivers/net/ethernet/broadcom/bnxt/bnxt.c | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index 4a2a44ffe669..47bea6d8ee3e 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -11774,6 +11774,16 @@ static void bnxt_irq_affinity_notify(struct irq_affinity_notify *notify,
 
 	irq = container_of(notify, struct bnxt_irq, affinity_notify);
 
+#ifdef CONFIG_RFS_ACCEL
+	if (irq->bp->dev->rx_cpu_rmap && irq->ring_nr < irq->bp->rx_nr_rings) {
+		err = cpu_rmap_update(irq->bp->dev->rx_cpu_rmap, irq->ring_nr,
+				      mask);
+		if (err)
+			netdev_warn(irq->bp->dev,
+				    "aRFS rmap update failed: %d\n", err);
+	}
+#endif
+
 	if (!irq->bp->tph_mode)
 		return;
 
@@ -11847,10 +11857,6 @@ static void bnxt_free_irq(struct bnxt *bp)
 	struct bnxt_irq *irq;
 	int i;
 
-#ifdef CONFIG_RFS_ACCEL
-	free_irq_cpu_rmap(bp->dev->rx_cpu_rmap);
-	bp->dev->rx_cpu_rmap = NULL;
-#endif
 	if (!bp->irq_tbl || !bp->bnapi)
 		return;
 
@@ -11876,6 +11882,11 @@ static void bnxt_free_irq(struct bnxt *bp)
 	/* Disable TPH support */
 	pcie_disable_tph(bp->pdev);
 	bp->tph_mode = 0;
+
+#ifdef CONFIG_RFS_ACCEL
+	free_irq_cpu_rmap(bp->dev->rx_cpu_rmap);
+	bp->dev->rx_cpu_rmap = NULL;
+#endif
 }
 
 static int bnxt_request_irq(struct bnxt *bp)
-- 
2.55.0