[PATCH v6 6/8] 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.

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 <d...@valinux.co.jp>
---
 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 6952ee418622..23034f548c90 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);
@@ -741,6 +745,8 @@ static void pci_epf_test_enable_doorbell(struct 
pci_epf_test *epf_test,
        if (bar < BAR_0)
                goto err_doorbell_cleanup;
 
+       epf_test->db_irq_requested = false;
+
        ret = request_threaded_irq(epf->db_msg[0].virq, NULL,
                                   pci_epf_test_doorbell_handler, IRQF_ONESHOT,
                                   "pci-ep-test-doorbell", epf_test);
@@ -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