[PATCH] PCI: mvebu: Dispose INTx irqs prior to removing INTx domain

["Marek Behún" <kabel@kernel.org>]

From: Pali Rohár <pali@kernel.org>

Documentation for irq_domain_remove() says that all mapping within the
domain must be disposed prior to domain remove.

Currently INTx irqs are not disposed in pci-mvebu.c device unbind callback
which cause that kernel crashes after unloading driver and trying to read
/sys/kernel/debug/irq/irqs/<num> or /proc/interrupts.

Fixes: ec075262648f ("PCI: mvebu: Implement support for legacy INTx interrupts")
Reported-by: Hajo Noerenberg <hajo-linux-bugzilla@noerenberg.de>
Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Marek Behún <kabel@kernel.org>
[ refactored a little ]
Signed-off-by: Marek Behún <kabel@kernel.org>
---
This was discussed back in 2022
  https://lore.kernel.org/linux-arm-kernel/20220709161858.15031-1-pali@kernel.org/
IMO Pali gave good arguments about why it should be applied, and Lorenzo
agreed.

Can we get this applied?
---
 drivers/pci/controller/pci-mvebu.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/controller/pci-mvebu.c b/drivers/pci/controller/pci-mvebu.c
index 29fe09c99e7d..91a02b23aeb1 100644
--- a/drivers/pci/controller/pci-mvebu.c
+++ b/drivers/pci/controller/pci-mvebu.c
@@ -1683,8 +1683,15 @@ static void mvebu_pcie_remove(struct platform_device *pdev)
 			irq_set_chained_handler_and_data(irq, NULL, NULL);
 
 		/* Remove IRQ domains. */
-		if (port->intx_irq_domain)
+		if (port->intx_irq_domain) {
+			for (int j = 0; j < PCI_NUM_INTX; j++) {
+				int virq = irq_find_mapping(port->intx_irq_domain, j);
+
+				if (virq > 0)
+					irq_dispose_mapping(virq);
+			}
 			irq_domain_remove(port->intx_irq_domain);
+		}
 
 		/* Free config space for emulated root bridge. */
 		pci_bridge_emul_cleanup(&port->bridge);
-- 
2.44.2