scsi: hisi_sas: Use pci_irq_get_affinity() for v3 hw as experimental

For auto-control irq affinity mode, choose the dq to deliver IO according
to the current CPU.

Then it decreases the performance regression that fio and CQ interrupts are
processed on different node.

For user control irq affinity mode, keep it as before.

To realize it, also need to distinguish the usage of dq lock and sas_dev
lock.

We mark as experimental due to ongoing discussion on managed MSI IRQ
during hotplug:
https://marc.info/?l=linux-scsi&m=154876335707751&w=2

We're almost at the point where we can expose multiple queues to the upper
layer for SCSI MQ, but we need to sort out the per-HBA tags performance
issue.
Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/hisi_sas/hisi_sas.h

@@ -173,6 +173,7 @@ struct hisi_sas_port {
 
 struct hisi_sas_cq {
 	struct hisi_hba *hisi_hba;
+	const struct cpumask *pci_irq_mask;
 	struct tasklet_struct tasklet;
 	int	rd_point;
 	int	id;
@@ -195,6 +196,7 @@ struct hisi_sas_device {
 	enum sas_device_type	dev_type;
 	int device_id;
 	int sata_idx;
+	spinlock_t lock; /* For protecting slots */
 };
 
 struct hisi_sas_tmf_task {
@@ -217,6 +219,7 @@ struct hisi_sas_slot {
 	int	cmplt_queue_slot;
 	int	abort;
 	int	ready;
+	int	device_id;
 	void	*cmd_hdr;
 	dma_addr_t cmd_hdr_dma;
 	struct timer_list internal_abort_timer;
@@ -366,6 +369,7 @@ struct hisi_hba {
 	u32 intr_coal_count;	/* Interrupt count to coalesce */
 
 	int cq_nvecs;
+	unsigned int *reply_map;
 
 	/* debugfs memories */
 	u32 *debugfs_global_reg;

drivers/scsi/hisi_sas/hisi_sas_main.c

@@ -241,8 +241,9 @@ static void hisi_sas_slot_index_init(struct hisi_hba *hisi_hba)
 void hisi_sas_slot_task_free(struct hisi_hba *hisi_hba, struct sas_task *task,
 			     struct hisi_sas_slot *slot)
 {
-	struct hisi_sas_dq *dq = &hisi_hba->dq[slot->dlvry_queue];
 	unsigned long flags;
+	int device_id = slot->device_id;
+	struct hisi_sas_device *sas_dev = &hisi_hba->devices[device_id];
 
 	if (task) {
 		struct device *dev = hisi_hba->dev;
@@ -267,10 +268,9 @@ void hisi_sas_slot_task_free(struct hisi_hba *hisi_hba, struct sas_task *task,
 		}
 	}
 
-
-	spin_lock_irqsave(&dq->lock, flags);
+	spin_lock_irqsave(&sas_dev->lock, flags);
 	list_del_init(&slot->entry);
-	spin_unlock_irqrestore(&dq->lock, flags);
+	spin_unlock_irqrestore(&sas_dev->lock, flags);
 
 	memset(slot, 0, offsetof(struct hisi_sas_slot, buf));
 
@@ -471,7 +471,14 @@ static int hisi_sas_task_prep(struct sas_task *task,
 		return -ECOMM;
 	}
 
-	*dq_pointer = dq = sas_dev->dq;
+	if (hisi_hba->reply_map) {
+		int cpu = raw_smp_processor_id();
+		unsigned int dq_index = hisi_hba->reply_map[cpu];
+
+		*dq_pointer = dq = &hisi_hba->dq[dq_index];
+	} else {
+		*dq_pointer = dq = sas_dev->dq;
+	}
 
 	port = to_hisi_sas_port(sas_port);
 	if (port && !port->port_attached) {
@@ -526,12 +533,15 @@ static int hisi_sas_task_prep(struct sas_task *task,
 	}
 
 	list_add_tail(&slot->delivery, &dq->list);
-	list_add_tail(&slot->entry, &sas_dev->list);
 	spin_unlock_irqrestore(&dq->lock, flags);
+	spin_lock_irqsave(&sas_dev->lock, flags);
+	list_add_tail(&slot->entry, &sas_dev->list);
+	spin_unlock_irqrestore(&sas_dev->lock, flags);
 
 	dlvry_queue = dq->id;
 	dlvry_queue_slot = wr_q_index;
 
+	slot->device_id = sas_dev->device_id;
 	slot->n_elem = n_elem;
 	slot->n_elem_dif = n_elem_dif;
 	slot->dlvry_queue = dlvry_queue;
@@ -701,6 +711,7 @@ static struct hisi_sas_device *hisi_sas_alloc_dev(struct domain_device *device)
 			sas_dev->hisi_hba = hisi_hba;
 			sas_dev->sas_device = device;
 			sas_dev->dq = dq;
+			spin_lock_init(&sas_dev->lock);
 			INIT_LIST_HEAD(&hisi_hba->devices[i].list);
 			break;
 		}
@@ -1913,10 +1924,14 @@ hisi_sas_internal_abort_task_exec(struct hisi_hba *hisi_hba, int device_id,
 	}
 	list_add_tail(&slot->delivery, &dq->list);
 	spin_unlock_irqrestore(&dq->lock, flags_dq);
+	spin_lock_irqsave(&sas_dev->lock, flags);
+	list_add_tail(&slot->entry, &sas_dev->list);
+	spin_unlock_irqrestore(&sas_dev->lock, flags);
 
 	dlvry_queue = dq->id;
 	dlvry_queue_slot = wr_q_index;
 
+	slot->device_id = sas_dev->device_id;
 	slot->n_elem = n_elem;
 	slot->dlvry_queue = dlvry_queue;
 	slot->dlvry_queue_slot = dlvry_queue_slot;
@@ -1940,7 +1955,6 @@ hisi_sas_internal_abort_task_exec(struct hisi_hba *hisi_hba, int device_id,
 	WRITE_ONCE(slot->ready, 1);
 	/* send abort command to the chip */
 	spin_lock_irqsave(&dq->lock, flags);
-	list_add_tail(&slot->entry, &sas_dev->list);
 	hisi_hba->hw->start_delivery(dq);
 	spin_unlock_irqrestore(&dq->lock, flags);
 
@@ -2070,6 +2084,11 @@ hisi_sas_internal_task_abort(struct hisi_hba *hisi_hba,
 						     abort_flag, tag, dq);
 	case HISI_SAS_INT_ABT_DEV:
 		for (i = 0; i < hisi_hba->cq_nvecs; i++) {
+			struct hisi_sas_cq *cq = &hisi_hba->cq[i];
+			const struct cpumask *mask = cq->pci_irq_mask;
+
+			if (mask && !cpumask_intersects(cpu_online_mask, mask))
+				continue;
 			dq = &hisi_hba->dq[i];
 			rc = _hisi_sas_internal_task_abort(hisi_hba, device,
 							   abort_flag, tag,

drivers/scsi/hisi_sas/hisi_sas_v2_hw.c

@@ -873,6 +873,7 @@ hisi_sas_device *alloc_dev_quirk_v2_hw(struct domain_device *device)
 			sas_dev->sas_device = device;
 			sas_dev->sata_idx = sata_idx;
 			sas_dev->dq = dq;
+			spin_lock_init(&sas_dev->lock);
 			INIT_LIST_HEAD(&hisi_hba->devices[i].list);
 			break;
 		}

drivers/scsi/hisi_sas/hisi_sas_v3_hw.c

@@ -403,6 +403,7 @@ struct hisi_sas_err_record_v3 {
 #define T10_CHK_APP_TAG_MSK (0xc << T10_CHK_MSK_OFF)
 
 #define BASE_VECTORS_V3_HW  16
+#define MIN_AFFINE_VECTORS_V3_HW  (BASE_VECTORS_V3_HW + 1)
 
 static bool hisi_sas_intr_conv;
 MODULE_PARM_DESC(intr_conv, "interrupt converge enable (0-1)");
@@ -412,6 +413,11 @@ static int prot_mask;
 module_param(prot_mask, int, 0);
 MODULE_PARM_DESC(prot_mask, " host protection capabilities mask, def=0x0 ");
 
+static bool auto_affine_msi_experimental;
+module_param(auto_affine_msi_experimental, bool, 0444);
+MODULE_PARM_DESC(auto_affine_msi_experimental, "Enable auto-affinity of MSI IRQs as experimental:\n"
+		 "default is off");
+
 static u32 hisi_sas_read32(struct hisi_hba *hisi_hba, u32 off)
 {
 	void __iomem *regs = hisi_hba->regs + off;
@@ -2037,19 +2043,64 @@ static irqreturn_t cq_interrupt_v3_hw(int irq_no, void *p)
 	return IRQ_HANDLED;
 }
 
+static void setup_reply_map_v3_hw(struct hisi_hba *hisi_hba, int nvecs)
+{
+	const struct cpumask *mask;
+	int queue, cpu;
+
+	for (queue = 0; queue < nvecs; queue++) {
+		struct hisi_sas_cq *cq = &hisi_hba->cq[queue];
+
+		mask = pci_irq_get_affinity(hisi_hba->pci_dev, queue +
+					    BASE_VECTORS_V3_HW);
+		if (!mask)
+			goto fallback;
+		cq->pci_irq_mask = mask;
+		for_each_cpu(cpu, mask)
+			hisi_hba->reply_map[cpu] = queue;
+	}
+	return;
+
+fallback:
+	for_each_possible_cpu(cpu)
+		hisi_hba->reply_map[cpu] = cpu % hisi_hba->queue_count;
+	/* Don't clean all CQ masks */
+}
+
 static int interrupt_init_v3_hw(struct hisi_hba *hisi_hba)
 {
 	struct device *dev = hisi_hba->dev;
 	struct pci_dev *pdev = hisi_hba->pci_dev;
 	int vectors, rc;
 	int i, k;
-	int max_msi = HISI_SAS_MSI_COUNT_V3_HW;
-
-	vectors = pci_alloc_irq_vectors(hisi_hba->pci_dev, 1,
-					max_msi, PCI_IRQ_MSI);
-	if (vectors < max_msi) {
-		dev_err(dev, "could not allocate all msi (%d)\n", vectors);
-		return -ENOENT;
+	int max_msi = HISI_SAS_MSI_COUNT_V3_HW, min_msi;
+
+	if (auto_affine_msi_experimental) {
+		struct irq_affinity desc = {
+			.pre_vectors = BASE_VECTORS_V3_HW,
+		};
+
+		min_msi = MIN_AFFINE_VECTORS_V3_HW;
+
+		hisi_hba->reply_map = devm_kcalloc(dev, nr_cpu_ids,
+						   sizeof(unsigned int),
+						   GFP_KERNEL);
+		if (!hisi_hba->reply_map)
+			return -ENOMEM;
+		vectors = pci_alloc_irq_vectors_affinity(hisi_hba->pci_dev,
+							 min_msi, max_msi,
+							 PCI_IRQ_MSI |
+							 PCI_IRQ_AFFINITY,
+							 &desc);
+		if (vectors < 0)
+			return -ENOENT;
+		setup_reply_map_v3_hw(hisi_hba, vectors - BASE_VECTORS_V3_HW);
+	} else {
+		min_msi = max_msi;
+		vectors = pci_alloc_irq_vectors(hisi_hba->pci_dev, min_msi,
+						max_msi, PCI_IRQ_MSI);
+		if (vectors < 0)
+			return vectors;
 	}
 
 	hisi_hba->cq_nvecs = vectors - BASE_VECTORS_V3_HW;