Merge: s390/pci: fix allocation of more than 1 MSI IRQ

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/5929

JIRA: https://issues.redhat.com/browse/RHEL-69123
Build-Info: https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=66090493
Tested: by IBM

Commits:
```
5fd11b9
ab42fcb
```

Signed-off-by: Mete Durlu <mdurlu@redhat.com>

Approved-by: Steve Best <sbest@redhat.com>
Approved-by: Tony Camuso <tcamuso@redhat.com>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>

Merged-by: Rado Vrbovsky <rvrbovsk@redhat.com>

Author: emmil

arch/s390/pci/pci_irq.c

@@ -268,61 +268,87 @@ static void zpci_floating_irq_handler(struct airq_struct *airq,
 	}
 }
 
-int arch_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
+static int __alloc_airq(struct zpci_dev *zdev, int msi_vecs,
+			unsigned long *bit)
 {
-	struct zpci_dev *zdev = to_zpci(pdev);
-	unsigned int hwirq, msi_vecs, cpu;
-	unsigned long bit;
-	struct msi_desc *msi;
-	struct msi_msg msg;
-	int cpu_addr;
-	int rc, irq;
-
-	zdev->aisb = -1UL;
-	zdev->msi_first_bit = -1U;
-	if (type == PCI_CAP_ID_MSI && nvec > 1)
-		return 1;
-	msi_vecs = min_t(unsigned int, nvec, zdev->max_msi);
-
 	if (irq_delivery == DIRECTED) {
 		/* Allocate cpu vector bits */
-		bit = airq_iv_alloc(zpci_ibv[0], msi_vecs);
-		if (bit == -1UL)
+		*bit = airq_iv_alloc(zpci_ibv[0], msi_vecs);
+		if (*bit == -1UL)
 			return -EIO;
 	} else {
 		/* Allocate adapter summary indicator bit */
-		bit = airq_iv_alloc_bit(zpci_sbv);
-		if (bit == -1UL)
+		*bit = airq_iv_alloc_bit(zpci_sbv);
+		if (*bit == -1UL)
 			return -EIO;
-		zdev->aisb = bit;
+		zdev->aisb = *bit;
 
 		/* Create adapter interrupt vector */
 		zdev->aibv = airq_iv_create(msi_vecs, AIRQ_IV_DATA | AIRQ_IV_BITLOCK, NULL);
 		if (!zdev->aibv)
 			return -ENOMEM;
 
 		/* Wire up shortcut pointer */
-		zpci_ibv[bit] = zdev->aibv;
+		zpci_ibv[*bit] = zdev->aibv;
 		/* Each function has its own interrupt vector */
-		bit = 0;
+		*bit = 0;
 	}
+	return 0;
+}
 
-	/* Request MSI interrupts */
+int arch_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
+{
+	unsigned int hwirq, msi_vecs, irqs_per_msi, i, cpu;
+	struct zpci_dev *zdev = to_zpci(pdev);
+	struct msi_desc *msi;
+	struct msi_msg msg;
+	unsigned long bit;
+	int cpu_addr;
+	int rc, irq;
+
+	zdev->aisb = -1UL;
+	zdev->msi_first_bit = -1U;
+
+	msi_vecs = min_t(unsigned int, nvec, zdev->max_msi);
+	if (msi_vecs < nvec) {
+		pr_info("%s requested %d irqs, allocate system limit of %d",
+			pci_name(pdev), nvec, zdev->max_msi);
+	}
+
+	rc = __alloc_airq(zdev, msi_vecs, &bit);
+	if (rc < 0)
+		return rc;
+
+	/*
+	 * Request MSI interrupts:
+	 * When using MSI, nvec_used interrupt sources and their irq
+	 * descriptors are controlled through one msi descriptor.
+	 * Thus the outer loop over msi descriptors shall run only once,
+	 * while two inner loops iterate over the interrupt vectors.
+	 * When using MSI-X, each interrupt vector/irq descriptor
+	 * is bound to exactly one msi descriptor (nvec_used is one).
+	 * So the inner loops are executed once, while the outer iterates
+	 * over the MSI-X descriptors.
+	 */
 	hwirq = bit;
 	msi_for_each_desc(msi, &pdev->dev, MSI_DESC_NOTASSOCIATED) {
-		rc = -EIO;
 		if (hwirq - bit >= msi_vecs)
 			break;
-		irq = __irq_alloc_descs(-1, 0, 1, 0, THIS_MODULE,
-				(irq_delivery == DIRECTED) ?
-				msi->affinity : NULL);
+		irqs_per_msi = min_t(unsigned int, msi_vecs, msi->nvec_used);
+		irq = __irq_alloc_descs(-1, 0, irqs_per_msi, 0, THIS_MODULE,
+					(irq_delivery == DIRECTED) ?
+					msi->affinity : NULL);
 		if (irq < 0)
 			return -ENOMEM;
-		rc = irq_set_msi_desc(irq, msi);
-		if (rc)
-			return rc;
-		irq_set_chip_and_handler(irq, &zpci_irq_chip,
-					 handle_percpu_irq);
+
+		for (i = 0; i < irqs_per_msi; i++) {
+			rc = irq_set_msi_desc_off(irq, i, msi);
+			if (rc)
+				return rc;
+			irq_set_chip_and_handler(irq + i, &zpci_irq_chip,
+						 handle_percpu_irq);
+		}
+
 		msg.data = hwirq - bit;
 		if (irq_delivery == DIRECTED) {
 			if (msi->affinity)
@@ -335,31 +361,35 @@ int arch_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
 			msg.address_lo |= (cpu_addr << 8);
 
 			for_each_possible_cpu(cpu) {
-				airq_iv_set_data(zpci_ibv[cpu], hwirq, irq);
+				for (i = 0; i < irqs_per_msi; i++)
+					airq_iv_set_data(zpci_ibv[cpu],
+							 hwirq + i, irq + i);
 			}
 		} else {
 			msg.address_lo = zdev->msi_addr & 0xffffffff;
-			airq_iv_set_data(zdev->aibv, hwirq, irq);
+			for (i = 0; i < irqs_per_msi; i++)
+				airq_iv_set_data(zdev->aibv, hwirq + i, irq + i);
 		}
 		msg.address_hi = zdev->msi_addr >> 32;
 		pci_write_msi_msg(irq, &msg);
-		hwirq++;
+		hwirq += irqs_per_msi;
 	}
 
 	zdev->msi_first_bit = bit;
-	zdev->msi_nr_irqs = msi_vecs;
+	zdev->msi_nr_irqs = hwirq - bit;
 
 	rc = zpci_set_irq(zdev);
 	if (rc)
 		return rc;
 
-	return (msi_vecs == nvec) ? 0 : msi_vecs;
+	return (zdev->msi_nr_irqs == nvec) ? 0 : zdev->msi_nr_irqs;
 }
 
 void arch_teardown_msi_irqs(struct pci_dev *pdev)
 {
 	struct zpci_dev *zdev = to_zpci(pdev);
 	struct msi_desc *msi;
+	unsigned int i;
 	int rc;
 
 	/* Disable interrupts */
@@ -369,8 +399,10 @@ void arch_teardown_msi_irqs(struct pci_dev *pdev)
 
 	/* Release MSI interrupts */
 	msi_for_each_desc(msi, &pdev->dev, MSI_DESC_ASSOCIATED) {
-		irq_set_msi_desc(msi->irq, NULL);
-		irq_free_desc(msi->irq);
+		for (i = 0; i < msi->nvec_used; i++) {
+			irq_set_msi_desc(msi->irq + i, NULL);
+			irq_free_desc(msi->irq + i);
+		}
 		msi->msg.address_lo = 0;
 		msi->msg.address_hi = 0;
 		msi->msg.data = 0;