[PATCH RFC net-next 2/3] crypto: caam/qi2 - skip isolated CPUs when setting up queue pairs

[Josua Mayer]

The driver looks up the affine DPIO and sets up one Rx/Tx queue pair for
each online CPU, up to the number of queues. Response notifications and
NAPI polling are handled on the DPIO object's assigned CPU. All online
may enqueue requests.

When isolcpus=managed_irq is used to reserve CPUs for latency-sensitive
applications, those CPUs are expected to be free of routine device
interrupts.

The DPIO driver assigns affine CPUs only from the HK_TYPE_MANAGED_IRQ
housekeeping mask, leaving isolated CPUs without an affine DPIO. This
defers caam qi2 probe indefinitely once DPIO setup reaches an isolated
CPU.

Restrict queue pairs, notifications and NAPI polling to the online CPUs
in the HK_TYPE_MANAGED_IRQ housekeeping mask, so that isolated CPUs are
skipped and don't defer probe. Isolated CPUs may still enqueue requests,
with responses handled on housekeeping CPUs.

As the dequeuing CPUs are no longer necessarily CPUs 0 to num_pairs - 1,
enable and disable NAPI based on the bookkeeping in clean_mask instead.

Signed-off-by: Josua Mayer <josua@xxxxxxxxxxxxx>
---
 drivers/crypto/caam/caamalg_qi2.c | 26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/drivers/crypto/caam/caamalg_qi2.c b/drivers/crypto/caam/caamalg_qi2.c
index 6b47bcc16a506..e9faaee009b74 100644
--- a/drivers/crypto/caam/caamalg_qi2.c
+++ b/drivers/crypto/caam/caamalg_qi2.c
@@ -25,6 +25,7 @@
 #include <soc/fsl/dpaa2-fd.h>
 #include <crypto/xts.h>
 #include <linux/unaligned.h>
+#include <linux/sched/isolation.h>
 
 #define CAAM_CRA_PRIORITY	2000
 
@@ -4683,9 +4684,10 @@ static int __cold dpaa2_dpseci_dpio_setup(struct dpaa2_caam_priv *priv)
 	struct device *dev = priv->dev;
 	struct dpaa2_io_notification_ctx *nctx;
 	struct dpaa2_caam_priv_per_cpu *ppriv;
+	const struct cpumask *hk_mask = housekeeping_cpumask(HK_TYPE_MANAGED_IRQ);
 	int err, i = 0, cpu;
 
-	for_each_online_cpu(cpu) {
+	for_each_cpu_and(cpu, cpu_online_mask, hk_mask) {
 		ppriv = per_cpu_ptr(priv->ppriv, cpu);
 		ppriv->priv = priv;
 		nctx = &ppriv->nctx;
@@ -4725,14 +4727,14 @@ static int __cold dpaa2_dpseci_dpio_setup(struct dpaa2_caam_priv *priv)
 	return 0;
 
 err:
-	for_each_online_cpu(cpu) {
+	for_each_cpu_and(cpu, cpu_online_mask, hk_mask) {
 		ppriv = per_cpu_ptr(priv->ppriv, cpu);
 		if (!ppriv->nctx.cb)
 			break;
 		dpaa2_io_service_deregister(ppriv->dpio, &ppriv->nctx, dev);
 	}
 
-	for_each_online_cpu(cpu) {
+	for_each_cpu_and(cpu, cpu_online_mask, hk_mask) {
 		ppriv = per_cpu_ptr(priv->ppriv, cpu);
 		if (!ppriv->store)
 			break;
@@ -4745,9 +4747,10 @@ static int __cold dpaa2_dpseci_dpio_setup(struct dpaa2_caam_priv *priv)
 static void __cold dpaa2_dpseci_dpio_free(struct dpaa2_caam_priv *priv)
 {
 	struct dpaa2_caam_priv_per_cpu *ppriv;
+	const struct cpumask *hk_mask = housekeeping_cpumask(HK_TYPE_MANAGED_IRQ);
 	int i = 0, cpu;
 
-	for_each_online_cpu(cpu) {
+	for_each_cpu_and(cpu, cpu_online_mask, hk_mask) {
 		ppriv = per_cpu_ptr(priv->ppriv, cpu);
 		dpaa2_io_service_deregister(ppriv->dpio, &ppriv->nctx,
 					    priv->dev);
@@ -4764,10 +4767,11 @@ static int dpaa2_dpseci_bind(struct dpaa2_caam_priv *priv)
 	struct device *dev = priv->dev;
 	struct fsl_mc_device *ls_dev = to_fsl_mc_device(dev);
 	struct dpaa2_caam_priv_per_cpu *ppriv;
+	const struct cpumask *hk_mask = housekeeping_cpumask(HK_TYPE_MANAGED_IRQ);
 	int err = 0, i = 0, cpu;
 
 	/* Configure Rx queues */
-	for_each_online_cpu(cpu) {
+	for_each_cpu_and(cpu, cpu_online_mask, hk_mask) {
 		ppriv = per_cpu_ptr(priv->ppriv, cpu);
 
 		rx_queue_cfg.options = DPSECI_QUEUE_OPT_DEST |
@@ -5012,6 +5016,8 @@ static int __cold dpaa2_dpseci_setup(struct fsl_mc_device *ls_dev)
 	struct device *dev = &ls_dev->dev;
 	struct dpaa2_caam_priv *priv;
 	struct dpaa2_caam_priv_per_cpu *ppriv;
+	const struct cpumask *hk_mask = housekeeping_cpumask(HK_TYPE_MANAGED_IRQ);
+	unsigned int num_online_hk_cpus = cpumask_weight_and(cpu_online_mask, hk_mask);
 	int err, cpu;
 	u8 i;
 
@@ -5070,10 +5076,10 @@ static int __cold dpaa2_dpseci_setup(struct fsl_mc_device *ls_dev)
 
 	priv->num_pairs = min(priv->dpseci_attr.num_rx_queues,
 			      priv->dpseci_attr.num_tx_queues);
-	if (priv->num_pairs > num_online_cpus()) {
+	if (priv->num_pairs > num_online_hk_cpus) {
 		dev_warn(dev, "%d queues won't be used\n",
-			 priv->num_pairs - num_online_cpus());
-		priv->num_pairs = num_online_cpus();
+			 priv->num_pairs - num_online_hk_cpus);
+		priv->num_pairs = num_online_hk_cpus;
 	}
 
 	for (i = 0; i < priv->dpseci_attr.num_rx_queues; i++) {
@@ -5151,7 +5157,7 @@ static int dpaa2_dpseci_enable(struct dpaa2_caam_priv *priv)
 	struct dpaa2_caam_priv_per_cpu *ppriv;
 	int i;
 
-	for (i = 0; i < priv->num_pairs; i++) {
+	for_each_cpu(i, priv->clean_mask) {
 		ppriv = per_cpu_ptr(priv->ppriv, i);
 		napi_enable(&ppriv->napi);
 	}
@@ -5180,7 +5186,7 @@ static int __cold dpaa2_dpseci_disable(struct dpaa2_caam_priv *priv)
 
 	dev_dbg(dev, "disable: %s\n", str_false_true(enabled));
 
-	for (i = 0; i < priv->num_pairs; i++) {
+	for_each_cpu(i, priv->clean_mask) {
 		ppriv = per_cpu_ptr(priv->ppriv, i);
 		napi_disable(&ppriv->napi);
 		netif_napi_del(&ppriv->napi);

-- 
2.51.0