[PATCH AUTOSEL 5.4 5/7] powerpc/msi: Fix deassociation of MSI descriptors

[Sasha Levin]

From: Marc Zyngier <maz at kernel.org>

[ Upstream commit 4545c6a3d6ba71747eaa984c338ddd745e56e23f ]

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 at roeck-us.net>
Signed-off-by: Marc Zyngier <maz at kernel.org>
Link: https://lore.kernel.org/r/70dab88e-6119-0c12-7c6a-61bcbe239f66@roeck-us.net
Signed-off-by: Sasha Levin <sashal at kernel.org>
---
 arch/powerpc/platforms/4xx/hsta_msi.c  | 1 +
 arch/powerpc/platforms/cell/axon_msi.c | 1 +
 arch/powerpc/platforms/pasemi/msi.c    | 1 +
 arch/powerpc/sysdev/fsl_msi.c          | 1 +
 arch/powerpc/sysdev/mpic_u3msi.c       | 1 +
 5 files changed, 5 insertions(+)

diff --git a/arch/powerpc/platforms/4xx/hsta_msi.c b/arch/powerpc/platforms/4xx/hsta_msi.c
index c950fed43b32..4f65bd0cf111 100644
--- a/arch/powerpc/platforms/4xx/hsta_msi.c
+++ b/arch/powerpc/platforms/4xx/hsta_msi.c
@@ -117,6 +117,7 @@ static void hsta_teardown_msi_irqs(struct pci_dev *dev)
 		msi_bitmap_free_hwirqs(&ppc4xx_hsta_msi.bmp, irq, 1);
 		pr_debug("%s: Teardown IRQ %u (index %u)\n", __func__,
 			 entry->irq, irq);
+		entry->irq = 0;
 	}
 }
 
diff --git a/arch/powerpc/platforms/cell/axon_msi.c b/arch/powerpc/platforms/cell/axon_msi.c
index ba33140e671d..d141f64150e8 100644
--- a/arch/powerpc/platforms/cell/axon_msi.c
+++ b/arch/powerpc/platforms/cell/axon_msi.c
@@ -295,6 +295,7 @@ static void axon_msi_teardown_msi_irqs(struct pci_dev *dev)
 
 		irq_set_msi_desc(entry->irq, NULL);
 		irq_dispose_mapping(entry->irq);
+		entry->irq = 0;
 	}
 }
 
diff --git a/arch/powerpc/platforms/pasemi/msi.c b/arch/powerpc/platforms/pasemi/msi.c
index d38944a1e258..76393c158ada 100644
--- a/arch/powerpc/platforms/pasemi/msi.c
+++ b/arch/powerpc/platforms/pasemi/msi.c
@@ -69,6 +69,7 @@ static void pasemi_msi_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, ALLOC_CHUNK);
 	}
 
diff --git a/arch/powerpc/sysdev/fsl_msi.c b/arch/powerpc/sysdev/fsl_msi.c
index d276c5e96445..5c3f3173638e 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 3861023d378a..43686c82e483 100644
--- a/arch/powerpc/sysdev/mpic_u3msi.c
+++ b/arch/powerpc/sysdev/mpic_u3msi.c
@@ -111,6 +111,7 @@ 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);
 	}
 
-- 
2.35.1