Merge branch 'eth-bnxt-fix-irq-notifier-bugs'

Jakub Kicinski says:

====================
eth: bnxt: fix IRQ notifier bugs

I was trying to make bnxt preserve IRQ mappings across reconfiguration.
While hacking on that I noticed 2 bugs in the notifiers that should
probably be fixed before development work.

First one is simple - TPH recofig makes aARFs not work. There can only
be one notifier per IRQ and TPH "steals" the callback from the rmap
updates. Fix by patches 1 and 2.

Second one is a deadlock between the affinity notifier and reconfig.
This one is a bit more involved (patch 3 and 4).

Unfortunately, I can't really verify the problem or test the fix.
I managed to get my hands on a system with an AMD Venice CPU which
is supposed to support TPH, but the ACPI is missing some bits to
actually advertise it. pcie_tph_get_cpu_st() returns -EINVAL.
====================

Link: https://patch.msgid.link/20260803193135.2030368-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

2 files changed, 92 insertions, 42 deletions

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index 25099077fe4f..bc7b37cb74a7 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -11789,10 +11789,21 @@ static void bnxt_irq_affinity_notify(struct irq_affinity_notify *notify,
 {
 	struct bnxt_irq *irq;
 	u16 tag;
-	int err;
 
 	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) {
+		int err;
+
+		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;
 
@@ -11802,20 +11813,11 @@ static void bnxt_irq_affinity_notify(struct irq_affinity_notify *notify,
 		return;
 
 	if (pcie_tph_get_cpu_st(irq->bp->pdev, TPH_MEM_TYPE_VM,
-				cpumask_first(irq->cpu_mask), &tag))
+				cpumask_first(mask), &tag))
 		return;
 
-	if (pcie_tph_set_st_entry(irq->bp->pdev, irq->msix_nr, tag))
-		return;
-
-	netdev_lock(irq->bp->dev);
-	if (netif_running(irq->bp->dev)) {
-		err = netdev_rx_queue_restart(irq->bp->dev, irq->ring_nr);
-		if (err)
-			netdev_err(irq->bp->dev,
-				   "RX queue restart failed: err=%d\n", err);
-	}
-	netdev_unlock(irq->bp->dev);
+	WRITE_ONCE(irq->new_tag, tag);
+	bnxt_queue_sp_work(irq->bp, BNXT_TPH_UPDATE_SP_EVENT);
 }
 
 static void bnxt_irq_affinity_release(struct kref *ref)
@@ -11866,10 +11868,6 @@ 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;
 
@@ -11878,27 +11876,35 @@ static void bnxt_free_irq(struct bnxt *bp)
 
 		irq = &bp->irq_tbl[map_idx];
 		if (irq->requested) {
+			bnxt_release_irq_notifier(irq);
+
 			if (irq->have_cpumask) {
 				irq_update_affinity_hint(irq->vector, NULL);
 				free_cpumask_var(irq->cpu_mask);
 				irq->have_cpumask = 0;
 			}
 
-			bnxt_release_irq_notifier(irq);
-
 			free_irq(irq->vector, bp->bnapi[i]);
 		}
 
 		irq->requested = 0;
+		irq->tag = 0;
+		irq->new_tag = 0;
 	}
 
 	/* 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)
 {
+	const int numa_node = dev_to_node(&bp->pdev->dev);
 	struct cpu_rmap *rmap = NULL;
 	int i, j, rc = 0;
 	unsigned long flags = 0;
@@ -11921,6 +11927,8 @@ static int bnxt_request_irq(struct bnxt *bp)
 	for (i = 0, j = 0; i < bp->cp_nr_rings; i++) {
 		int map_idx = bnxt_cp_num_to_irq_num(bp, i);
 		struct bnxt_irq *irq = &bp->irq_tbl[map_idx];
+		unsigned int cpu_num;
+		u16 tag;
 
 		if (IS_ENABLED(CONFIG_RFS_ACCEL) &&
 		    rmap && bp->bnapi[i]->rx_ring) {
@@ -11939,32 +11947,31 @@ static int bnxt_request_irq(struct bnxt *bp)
 		netif_napi_set_irq_locked(&bp->bnapi[i]->napi, irq->vector);
 		irq->requested = 1;
 
-		if (zalloc_cpumask_var(&irq->cpu_mask, GFP_KERNEL)) {
-			int numa_node = dev_to_node(&bp->pdev->dev);
-			u16 tag;
-
-			irq->have_cpumask = 1;
-			irq->msix_nr = map_idx;
-			irq->ring_nr = i;
-			cpumask_set_cpu(cpumask_local_spread(i, numa_node),
-					irq->cpu_mask);
-			rc = irq_update_affinity_hint(irq->vector, irq->cpu_mask);
-			if (rc) {
-				netdev_warn(bp->dev,
-					    "Update affinity hint failed, IRQ = %d\n",
-					    irq->vector);
-				break;
-			}
+		if (!zalloc_cpumask_var(&irq->cpu_mask, GFP_KERNEL))
+			continue;
 
-			bnxt_register_irq_notifier(bp, irq);
+		irq->have_cpumask = 1;
+		irq->msix_nr = map_idx;
+		irq->ring_nr = i;
+		cpu_num = cpumask_local_spread(i, numa_node);
+		cpumask_set_cpu(cpu_num, irq->cpu_mask);
+
+		/* Init ST table entry if we can get the mapping */
+		if (!pcie_tph_get_cpu_st(bp->pdev, TPH_MEM_TYPE_VM,
+					 cpu_num, &tag)) {
+			pcie_tph_set_st_entry(bp->pdev, irq->msix_nr, tag);
+			irq->tag = tag;
+			irq->new_tag = tag;
+		}
 
-			/* Init ST table entry */
-			if (pcie_tph_get_cpu_st(irq->bp->pdev, TPH_MEM_TYPE_VM,
-						cpumask_first(irq->cpu_mask),
-						&tag))
-				continue;
+		bnxt_register_irq_notifier(bp, irq);
 
-			pcie_tph_set_st_entry(irq->bp->pdev, irq->msix_nr, tag);
+		rc = irq_update_affinity_hint(irq->vector, irq->cpu_mask);
+		if (rc) {
+			netdev_warn(bp->dev,
+				    "Update affinity hint failed, IRQ = %d\n",
+				    irq->vector);
+			break;
 		}
 	}
 	return rc;
@@ -14468,6 +14475,43 @@ static void bnxt_rtnl_unlock_sp(struct bnxt *bp)
 	rtnl_unlock();
 }
 
+static void bnxt_tph_update(struct bnxt *bp)
+{
+	struct net_device *dev = bp->dev;
+	int i;
+
+	bnxt_lock_sp(bp);
+	if (!test_bit(BNXT_STATE_OPEN, &bp->state))
+		goto unlock;
+
+	for (i = 0; i < bp->rx_nr_rings; i++) {
+		struct bnxt_irq *irq;
+		int map_idx, err;
+		u16 tag;
+
+		map_idx = bnxt_cp_num_to_irq_num(bp, i);
+		irq = &bp->irq_tbl[map_idx];
+		tag = READ_ONCE(irq->new_tag);
+		if (irq->tag == tag)
+			continue;
+
+		if (pcie_tph_set_st_entry(bp->pdev, irq->msix_nr, tag))
+			continue;
+
+		err = netdev_rx_queue_restart(dev, irq->ring_nr);
+		if (err) {
+			netdev_err(dev, "RX queue restart failed: err=%d\n",
+				   err);
+			continue;
+		}
+
+		irq->tag = tag;
+	}
+
+unlock:
+	bnxt_unlock_sp(bp);
+}
+
 /* Only called from bnxt_sp_task() */
 static void bnxt_reset(struct bnxt *bp, bool silent)
 {
@@ -14892,6 +14936,9 @@ static void bnxt_sp_task(struct work_struct *work)
 			bnxt_devlink_health_fw_report(bp);
 	}
 
+	if (test_and_clear_bit(BNXT_TPH_UPDATE_SP_EVENT, &bp->sp_event))
+		bnxt_tph_update(bp);
+
 	smp_mb__before_atomic();
 	clear_bit(BNXT_STATE_IN_SP_TASK, &bp->state);
 }
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.h b/drivers/net/ethernet/broadcom/bnxt/bnxt.h
index 44ea8fc7b766..dc8ec5e5733e 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.h
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.h
@@ -1268,6 +1268,8 @@ struct bnxt_irq {
 	struct bnxt	*bp;
 	int		msix_nr;
 	int		ring_nr;
+	u16		tag;
+	u16		new_tag;
 	struct irq_affinity_notify affinity_notify;
 };
 
@@ -2642,6 +2644,7 @@ struct bnxt {
 #define BNXT_RING_COAL_NOW_SP_EVENT	17
 #define BNXT_FW_RESET_NOTIFY_SP_EVENT	18
 #define BNXT_FW_EXCEPTION_SP_EVENT	19
+#define BNXT_TPH_UPDATE_SP_EVENT	20
 #define BNXT_LINK_CFG_CHANGE_SP_EVENT	21
 #define BNXT_THERMAL_THRESHOLD_SP_EVENT	22
 #define BNXT_FW_ECHO_REQUEST_SP_EVENT	23