ionic: Keep interrupt affinity up to date

Currently the driver either sets the initial interrupt affinity for its
adminq and tx/rx queues on probe or resets it on various
down/up/reconfigure flows. If any user and/or user process
(i.e. irqbalance) changes IRQ affinity for any of the driver's interrupts
that will be reset to driver defaults whenever any down/up/reconfigure
operation happens. This is incorrect and is fixed by making 2 changes:

1. Allocate an array of cpumasks that's only allocated on probe and
   destroyed on remove.
2. Update the cpumask(s) for interrupts that are in use by registering
   for affinity notifiers.

Signed-off-by: Brett Creeley <brett.creeley@amd.com>
Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
Link: https://lore.kernel.org/r/20240619003257.6138-3-shannon.nelson@amd.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: brettcreeley

drivers/net/ethernet/pensando/ionic/ionic.h

@@ -54,6 +54,7 @@ struct ionic {
 	unsigned int nrxqs_per_lif;
 	unsigned int nintrs;
 	DECLARE_BITMAP(intrs, IONIC_INTR_CTRL_REGS_MAX);
+	cpumask_var_t *affinity_masks;
 	struct work_struct nb_work;
 	struct notifier_block nb;
 	struct rw_semaphore vf_op_lock;	/* lock for VF operations */

drivers/net/ethernet/pensando/ionic/ionic_dev.h

@@ -280,9 +280,9 @@ struct ionic_intr_info {
 	u64 rearm_count;
 	unsigned int index;
 	unsigned int vector;
-	unsigned int cpu;
 	u32 dim_coal_hw;
-	cpumask_t affinity_mask;
+	cpumask_var_t *affinity_mask;
+	struct irq_affinity_notify aff_notify;
 };
 
 struct ionic_cq {

drivers/net/ethernet/pensando/ionic/ionic_lif.c

@@ -265,6 +265,18 @@ static void ionic_intr_free(struct ionic *ionic, int index)
 		clear_bit(index, ionic->intrs);
 }
 
+static void ionic_irq_aff_notify(struct irq_affinity_notify *notify,
+				 const cpumask_t *mask)
+{
+	struct ionic_intr_info *intr = container_of(notify, struct ionic_intr_info, aff_notify);
+
+	cpumask_copy(*intr->affinity_mask, mask);
+}
+
+static void ionic_irq_aff_release(struct kref __always_unused *ref)
+{
+}
+
 static int ionic_qcq_enable(struct ionic_qcq *qcq)
 {
 	struct ionic_queue *q = &qcq->q;
@@ -299,8 +311,10 @@ static int ionic_qcq_enable(struct ionic_qcq *qcq)
 
 	if (qcq->flags & IONIC_QCQ_F_INTR) {
 		napi_enable(&qcq->napi);
+		irq_set_affinity_notifier(qcq->intr.vector,
+					  &qcq->intr.aff_notify);
 		irq_set_affinity_hint(qcq->intr.vector,
-				      &qcq->intr.affinity_mask);
+				      *qcq->intr.affinity_mask);
 		ionic_intr_mask(idev->intr_ctrl, qcq->intr.index,
 				IONIC_INTR_MASK_CLEAR);
 	}
@@ -334,6 +348,7 @@ static int ionic_qcq_disable(struct ionic_lif *lif, struct ionic_qcq *qcq, int f
 		ionic_intr_mask(idev->intr_ctrl, qcq->intr.index,
 				IONIC_INTR_MASK_SET);
 		synchronize_irq(qcq->intr.vector);
+		irq_set_affinity_notifier(qcq->intr.vector, NULL);
 		irq_set_affinity_hint(qcq->intr.vector, NULL);
 		napi_disable(&qcq->napi);
 	}
@@ -474,6 +489,7 @@ static void ionic_link_qcq_interrupts(struct ionic_qcq *src_qcq,
 
 static int ionic_alloc_qcq_interrupt(struct ionic_lif *lif, struct ionic_qcq *qcq)
 {
+	cpumask_var_t *affinity_mask;
 	int err;
 
 	if (!(qcq->flags & IONIC_QCQ_F_INTR)) {
@@ -505,10 +521,19 @@ static int ionic_alloc_qcq_interrupt(struct ionic_lif *lif, struct ionic_qcq *qc
 	}
 
 	/* try to get the irq on the local numa node first */
-	qcq->intr.cpu = cpumask_local_spread(qcq->intr.index,
-					     dev_to_node(lif->ionic->dev));
-	if (qcq->intr.cpu != -1)
-		cpumask_set_cpu(qcq->intr.cpu, &qcq->intr.affinity_mask);
+	affinity_mask = &lif->ionic->affinity_masks[qcq->intr.index];
+	if (cpumask_empty(*affinity_mask)) {
+		unsigned int cpu;
+
+		cpu = cpumask_local_spread(qcq->intr.index,
+					   dev_to_node(lif->ionic->dev));
+		if (cpu != -1)
+			cpumask_set_cpu(cpu, *affinity_mask);
+	}
+
+	qcq->intr.affinity_mask = affinity_mask;
+	qcq->intr.aff_notify.notify = ionic_irq_aff_notify;
+	qcq->intr.aff_notify.release = ionic_irq_aff_release;
 
 	netdev_dbg(lif->netdev, "%s: Interrupt index %d\n", qcq->q.name, qcq->intr.index);
 	return 0;
@@ -3120,6 +3145,44 @@ int ionic_reconfigure_queues(struct ionic_lif *lif,
 	return err;
 }
 
+static int ionic_affinity_masks_alloc(struct ionic *ionic)
+{
+	cpumask_var_t *affinity_masks;
+	int nintrs = ionic->nintrs;
+	int i;
+
+	affinity_masks = kcalloc(nintrs, sizeof(cpumask_var_t), GFP_KERNEL);
+	if (!affinity_masks)
+		return -ENOMEM;
+
+	for (i = 0; i < nintrs; i++) {
+		if (!zalloc_cpumask_var_node(&affinity_masks[i], GFP_KERNEL,
+					     dev_to_node(ionic->dev)))
+			goto err_out;
+	}
+
+	ionic->affinity_masks = affinity_masks;
+
+	return 0;
+
+err_out:
+	for (--i; i >= 0; i--)
+		free_cpumask_var(affinity_masks[i]);
+	kfree(affinity_masks);
+
+	return -ENOMEM;
+}
+
+static void ionic_affinity_masks_free(struct ionic *ionic)
+{
+	int i;
+
+	for (i = 0; i < ionic->nintrs; i++)
+		free_cpumask_var(ionic->affinity_masks[i]);
+	kfree(ionic->affinity_masks);
+	ionic->affinity_masks = NULL;
+}
+
 int ionic_lif_alloc(struct ionic *ionic)
 {
 	struct device *dev = ionic->dev;
@@ -3211,11 +3274,15 @@ int ionic_lif_alloc(struct ionic *ionic)
 
 	ionic_debugfs_add_lif(lif);
 
+	err = ionic_affinity_masks_alloc(ionic);
+	if (err)
+		goto err_out_free_lif_info;
+
 	/* allocate control queues and txrx queue arrays */
 	ionic_lif_queue_identify(lif);
 	err = ionic_qcqs_alloc(lif);
 	if (err)
-		goto err_out_free_lif_info;
+		goto err_out_free_affinity_masks;
 
 	/* allocate rss indirection table */
 	tbl_sz = le16_to_cpu(lif->ionic->ident.lif.eth.rss_ind_tbl_sz);
@@ -3237,6 +3304,8 @@ int ionic_lif_alloc(struct ionic *ionic)
 
 err_out_free_qcqs:
 	ionic_qcqs_free(lif);
+err_out_free_affinity_masks:
+	ionic_affinity_masks_free(lif->ionic);
 err_out_free_lif_info:
 	dma_free_coherent(dev, lif->info_sz, lif->info, lif->info_pa);
 	lif->info = NULL;
@@ -3410,6 +3479,8 @@ void ionic_lif_free(struct ionic_lif *lif)
 	if (!test_bit(IONIC_LIF_F_FW_RESET, lif->state))
 		ionic_lif_reset(lif);
 
+	ionic_affinity_masks_free(lif->ionic);
+
 	/* free lif info */
 	kfree(lif->identity);
 	dma_free_coherent(dev, lif->info_sz, lif->info, lif->info_pa);
@@ -3487,7 +3558,7 @@ static int ionic_lif_adminq_init(struct ionic_lif *lif)
 
 	if (qcq->flags & IONIC_QCQ_F_INTR) {
 		irq_set_affinity_hint(qcq->intr.vector,
-				      &qcq->intr.affinity_mask);
+				      *qcq->intr.affinity_mask);
 		ionic_intr_mask(idev->intr_ctrl, qcq->intr.index,
 				IONIC_INTR_MASK_CLEAR);
 	}