[PATCH 3/4] PCI: endpoint: pci-epf-test: Don't free doorbell IRQ unless requested

[Koichiro Den]

pci_epf_test_enable_doorbell() allocates a doorbell and then installs
the interrupt handler with request_threaded_irq(). On failures before
the IRQ is successfully requested (e.g. no free BAR,
request_threaded_irq() failure), the error path jumps to
err_doorbell_cleanup and calls pci_epf_test_doorbell_cleanup().

pci_epf_test_doorbell_cleanup() unconditionally calls free_irq() for the
doorbell virq, which can trigger "Trying to free already-free IRQ"
warnings when the IRQ was never requested or when request_threaded_irq()
failed.

Track whether the doorbell IRQ has been successfully requested and only
call free_irq() when it has.

Fixes: eff0c286aa91 ("PCI: endpoint: pci-epf-test: Add doorbell test support")
Signed-off-by: Koichiro Den <den@xxxxxxxxxxxxx>
---
 drivers/pci/endpoint/functions/pci-epf-test.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
index 148a34e51f6b..defe1e2ea427 100644
--- a/drivers/pci/endpoint/functions/pci-epf-test.c
+++ b/drivers/pci/endpoint/functions/pci-epf-test.c
@@ -86,6 +86,7 @@ struct pci_epf_test {
 	bool			dma_private;
 	const struct pci_epc_features *epc_features;
 	struct pci_epf_bar	db_bar;
+	bool			db_irq_requested;
 	size_t			bar_size[PCI_STD_NUM_BARS];
 };
 
@@ -715,7 +716,10 @@ static void pci_epf_test_doorbell_cleanup(struct pci_epf_test *epf_test)
 	struct pci_epf_test_reg *reg = epf_test->reg[epf_test->test_reg_bar];
 	struct pci_epf *epf = epf_test->epf;
 
-	free_irq(epf->db_msg[0].virq, epf_test);
+	if (epf_test->db_irq_requested && epf->db_msg) {
+		free_irq(epf->db_msg[0].virq, epf_test);
+		epf_test->db_irq_requested = false;
+	}
 	reg->doorbell_bar = cpu_to_le32(NO_BAR);
 
 	pci_epf_free_doorbell(epf);
@@ -732,6 +736,8 @@ static void pci_epf_test_enable_doorbell(struct pci_epf_test *epf_test,
 	size_t offset;
 	int ret;
 
+	epf_test->db_irq_requested = false;
+
 	ret = pci_epf_alloc_doorbell(epf, 1);
 	if (ret)
 		goto set_status_err;
@@ -751,6 +757,7 @@ static void pci_epf_test_enable_doorbell(struct pci_epf_test *epf_test,
 		goto err_doorbell_cleanup;
 	}
 
+	epf_test->db_irq_requested = true;
 	reg->doorbell_data = cpu_to_le32(msg->data);
 	reg->doorbell_bar = cpu_to_le32(bar);
 
-- 
2.51.0