[PATCH v4 07/12] dmaengine: switchtec-dma: fix chan_status_irq cleanup on create() error

chan_status_irq stores an MSI-X vector index, but err_exit freed it
with plain free_irq() instead of pci_free_irq(), which would free the
wrong Linux IRQ. The guard also treated a valid vector index of 0 as
unset, skipping the free entirely in that case and leaving the handler
registered against soon-to-be-freed swdma_dev.

Initialize chan_status_irq to -1 and use the value being non-negative
to signal when to free it with pci_free_irq().

Reported-by: Sashiko <[email protected]>
Link: https://lore.kernel.org/dmaengine/[email protected]
Reviewed-by: Frank Li <[email protected]>
Signed-off-by: Logan Gunthorpe <[email protected]>
---
 drivers/dma/switchtec_dma.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/switchtec_dma.c b/drivers/dma/switchtec_dma.c
index 63e60de9f86d..6ab2c62b52fd 100644
--- a/drivers/dma/switchtec_dma.c
+++ b/drivers/dma/switchtec_dma.c
@@ -1262,6 +1262,8 @@ static int switchtec_dma_create(struct pci_dev *pdev)
 	if (!swdma_dev)
 		return -ENOMEM;
 
+	swdma_dev->chan_status_irq = -1;
+
 	swdma_dev->bar = ioremap(pci_resource_start(pdev, 0),
 				 pci_resource_len(pdev, 0));
 
@@ -1336,8 +1338,8 @@ static int switchtec_dma_create(struct pci_dev *pdev)
 	switchtec_dma_chans_free(swdma_dev);
 
 err_exit:
-	if (swdma_dev->chan_status_irq)
-		free_irq(swdma_dev->chan_status_irq, swdma_dev);
+	if (swdma_dev->chan_status_irq >= 0)
+		pci_free_irq(pdev, swdma_dev->chan_status_irq, swdma_dev);
 
 	iounmap(swdma_dev->bar);
 	kfree(swdma_dev);
-- 
2.47.3