powerpc/msi: Fix deassociation of MSI descriptors

Since 2f2940d16823 ("genirq/msi: Remove filter from
msi_free_descs_free_range()"), the core MSI code relies on the
msi_desc->irq field to have been cleared before the descriptor
can be freed, as it indicates that there is no association with
a device anymore.

The irq domain code provides this guarantee, and so does s390,
which is one of the two architectures not using irq domains for
MSIs.

Powerpc, however, is missing this particular requirements,
leading in a splat and leaked MSI descriptors.

Adding the now required irq reset to the handful of powerpc backends
that implement MSIs fixes that particular problem.

Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/70dab88e-6119-0c12-7c6a-61bcbe239f66@roeck-us.net

2 files changed, 2 insertions, 0 deletions

diff --git a/arch/powerpc/sysdev/fsl_msi.c b/arch/powerpc/sysdev/fsl_msi.c
index 73c2d70706c0..57978a44d55b 100644
--- a/arch/powerpc/sysdev/fsl_msi.c
+++ b/arch/powerpc/sysdev/fsl_msi.c
@@ -132,6 +132,7 @@ static void fsl_teardown_msi_irqs(struct pci_dev *pdev)
 		msi_data = irq_get_chip_data(entry->irq);
 		irq_set_msi_desc(entry->irq, NULL);
 		irq_dispose_mapping(entry->irq);
+		entry->irq = 0;
 		msi_bitmap_free_hwirqs(&msi_data->bitmap, hwirq, 1);
 	}
 }
diff --git a/arch/powerpc/sysdev/mpic_u3msi.c b/arch/powerpc/sysdev/mpic_u3msi.c
index 1d8cfdfdf115..492cb03c0b62 100644
--- a/arch/powerpc/sysdev/mpic_u3msi.c
+++ b/arch/powerpc/sysdev/mpic_u3msi.c
@@ -108,6 +108,7 @@ static void u3msi_teardown_msi_irqs(struct pci_dev *pdev)
 		hwirq = virq_to_hw(entry->irq);
 		irq_set_msi_desc(entry->irq, NULL);
 		irq_dispose_mapping(entry->irq);
+		entry->irq = 0;
 		msi_bitmap_free_hwirqs(&msi_mpic->msi_bitmap, hwirq, 1);
 	}
 }