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

Niklas Cassel
2026-02-16T11:36:01Z

On Mon, Feb 16, 2026 at 12:09:13AM +0900, Koichiro Den wrote:
> 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@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 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;

It would be nice if we could avoid this, it looks a bit odd.

> 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);
>

Can't we do something like:

-For all goto's after request_threaded_irq() success case:
jump to a label that also cleans up the IRQ.

For failures before or at request_threaded_irq(), jump to
a label that does not call free_irq().

pci_epf_test_disable_doorbell() should probably return error
if (!epf_test->db_bar.size)

(before pci_epf_test_disable_doorbell() calls free_irq())

pci_epf_test_disable_doorbell() should probably also memset
epf_test->db_bar.

Kind regards,
Niklas