PCI/MSI: Move descriptor counting on allocation fail to the legacy code

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2151246
Upstream Status: 60bf9b3

commit 60bf9b3
Author: Thomas Gleixner <tglx@linutronix.de>
Date:   Mon Dec 6 23:28:00 2021 +0100

    PCI/MSI: Move descriptor counting on allocation fail to the legacy code

    The irqdomain code already returns the information. Move the loop to the
    legacy code.

    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    Tested-by: Juergen Gross <jgross@suse.com>
    Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
    Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Link: https://lore.kernel.org/r/20211206210225.101336873@linutronix.de

Signed-off-by: Myron Stowe <mstowe@redhat.com>

Author: Myron Stowe

drivers/pci/msi/legacy.c

@@ -50,9 +50,27 @@ void __weak arch_teardown_msi_irqs(struct pci_dev *dev)
 	}
 }
 
+static int pci_msi_setup_check_result(struct pci_dev *dev, int type, int ret)
+{
+	struct msi_desc *entry;
+	int avail = 0;
+
+	if (type != PCI_CAP_ID_MSIX || ret >= 0)
+		return ret;
+
+	/* Scan the MSI descriptors for successfully allocated ones. */
+	for_each_pci_msi_entry(entry, dev) {
+		if (entry->irq != 0)
+			avail++;
+	}
+	return avail ? avail : ret;
+}
+
 int pci_msi_legacy_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
 {
-	return arch_setup_msi_irqs(dev, nvec, type);
+	int ret = arch_setup_msi_irqs(dev, nvec, type);
+
+	return pci_msi_setup_check_result(dev, type, ret);
 }
 
 void pci_msi_legacy_teardown_msi_irqs(struct pci_dev *dev)

drivers/pci/msi/msi.c

@@ -606,7 +606,7 @@ static int msix_capability_init(struct pci_dev *dev, struct msix_entry *entries,
 
 	ret = pci_msi_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX);
 	if (ret)
-		goto out_avail;
+		goto out_free;
 
 	/* Check if all MSI entries honor device restrictions */
 	ret = msi_verify_entries(dev);
@@ -641,23 +641,6 @@ static int msix_capability_init(struct pci_dev *dev, struct msix_entry *entries,
 	pcibios_free_irq(dev);
 	return 0;
 
-out_avail:
-	if (ret < 0) {
-		/*
-		 * If we had some success, report the number of IRQs
-		 * we succeeded in setting up.
-		 */
-		struct msi_desc *entry;
-		int avail = 0;
-
-		for_each_pci_msi_entry(entry, dev) {
-			if (entry->irq != 0)
-				avail++;
-		}
-		if (avail != 0)
-			ret = avail;
-	}
-
 out_free:
 	free_msi_irqs(dev);