[PATCH AUTOSEL 5.10 28/47] PCI: xgene-msi: Fix race in installing chained irq handler

Sasha Levin
2021-03-02T13:22:47Z

From: Martin Kaiser <martin@kaiser.cx>

[ Upstream commit a93c00e5f975f23592895b7e83f35de2d36b7633 ]

Fix a race where a pending interrupt could be received and the handler
called before the handler's data has been setup, by converting to
irq_set_chained_handler_and_data().

See also 2cf5a03cb29d ("PCI/keystone: Fix race in installing chained IRQ
handler").

Based on the mail discussion, it seems ok to drop the error handling.

Link: https://lore.kernel.org/r/20210115212435.19940-3-martin@kaiser.cx
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/pci/controller/pci-xgene-msi.c | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/drivers/pci/controller/pci-xgene-msi.c b/drivers/pci/controller/pci-xgene-msi.c
index 2470782cb01a..1c34c897a7e2 100644
--- a/drivers/pci/controller/pci-xgene-msi.c
+++ b/drivers/pci/controller/pci-xgene-msi.c
@@ -384,13 +384,9 @@ static int xgene_msi_hwirq_alloc(unsigned int cpu)
if (!msi_group->gic_irq)
continue;

- irq_set_chained_handler(msi_group->gic_irq,
- xgene_msi_isr);
- err = irq_set_handler_data(msi_group->gic_irq, msi_group);
- if (err) {
- pr_err("failed to register GIC IRQ handler\n");
- return -EINVAL;
- }
+ irq_set_chained_handler_and_data(msi_group->gic_irq,
+ xgene_msi_isr, msi_group);
+
/*
* Statically allocate MSI GIC IRQs to each CPU core.
* With 8-core X-Gene v1, 2 MSI GIC IRQs are allocated
--
2.30.1