linux-kernel - Re: [PATCH v6 6/8] PCI: endpoint: pci-epf-test: Don't free doorbell IRQ unless requested

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Message-ID: <aYoD3V9X9H0sQpdY@lizhi-Precision-Tower-5810>
Date: Mon, 9 Feb 2026 10:57:17 -0500
From: Frank Li <Frank.li@....com>
To: Koichiro Den <den@...inux.co.jp>
Cc: vkoul@...nel.org, mani@...nel.org, cassel@...nel.org,
	jingoohan1@...il.com, lpieralisi@...nel.org, kwilczynski@...nel.org,
	robh@...nel.org, bhelgaas@...gle.com, kishon@...nel.org,
	jdmason@...zu.us, allenbh@...il.com, dmaengine@...r.kernel.org,
	linux-pci@...r.kernel.org, ntb@...ts.linux.dev,
	linux-kselftest@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6 6/8] PCI: endpoint: pci-epf-test: Don't free doorbell
 IRQ unless requested

On Mon, Feb 09, 2026 at 09:53:14PM +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.
>
> 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@...inux.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;

Prevous patch clean up epf->num_db = 0 at doorbell_free(). can you check
epf->num_db ?

Frank

>  	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
>