linux-kernel - Re: [PATCH v2 2/5] dma: mcf-edma: Add per-channel IRQ naming for debugging

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <aUF8/r6FZcPraINk@lizhi-Precision-Tower-5810>
Date: Tue, 16 Dec 2025 10:38:38 -0500
From: Frank Li <Frank.li@....com>
To: Vinod Koul <vkoul@...nel.org>
Cc: jeanmichel.hautbois@...eli.org, Angelo Dureghello <angelo@...am.it>,
	Greg Ungerer <gerg@...ux-m68k.org>, imx@...ts.linux.dev,
	dmaengine@...r.kernel.org, linux-m68k@...ts.linux-m68k.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/5] dma: mcf-edma: Add per-channel IRQ naming for
 debugging

On Tue, Dec 16, 2025 at 08:56:01PM +0530, Vinod Koul wrote:
> On 26-11-25, 11:12, Frank Li wrote:
> > On Wed, Nov 26, 2025 at 09:36:03AM +0100, Jean-Michel Hautbois via B4 Relay wrote:
> > > From: Jean-Michel Hautbois <jeanmichel.hautbois@...eli.org>
> > >
> > > Add dynamic per-channel IRQ naming to make DMA interrupt identification
> > > easier in /proc/interrupts and debugging tools.
> > >
> > > Instead of all channels showing "eDMA", they now show:
> > > - "eDMA-0" through "eDMA-15" for channels 0-15
> > > - "eDMA-16" through "eDMA-55" for channels 16-55
> > > - "eDMA-tx-56" for the shared channel 56-63 interrupt
> > > - "eDMA-err" for the error interrupt
> > >
> > > This aids debugging DMA issues by making it clear which channel's
> > > interrupt is being serviced.
> > >
> > > Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@...eli.org>
> > > ---
> > >  drivers/dma/mcf-edma-main.c | 26 ++++++++++++++++++--------
> > >  1 file changed, 18 insertions(+), 8 deletions(-)
> > >
> > > diff --git a/drivers/dma/mcf-edma-main.c b/drivers/dma/mcf-edma-main.c
> > > index f95114829d80..6a7d88895501 100644
> > > --- a/drivers/dma/mcf-edma-main.c
> > > +++ b/drivers/dma/mcf-edma-main.c
> > > @@ -81,8 +81,14 @@ static int mcf_edma_irq_init(struct platform_device *pdev,
> > >  	if (!res)
> > >  		return -1;
> > >
> > > -	for (ret = 0, i = res->start; i <= res->end; ++i)
> > > -		ret |= request_irq(i, mcf_edma_tx_handler, 0, "eDMA", mcf_edma);
> > > +	for (ret = 0, i = res->start; i <= res->end; ++i) {
> > > +		char *irq_name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
> > > +						"eDMA-%d", (int)(i - res->start));
> > > +		if (!irq_name)
> > > +			return -ENOMEM;
> > > +
> > > +		ret |= request_irq(i, mcf_edma_tx_handler, 0, irq_name, mcf_edma);
> > > +	}
> > >  	if (ret)
> > >  		return ret;
> >
> > The existing code have problem, it should use devm_request_irq(). if one
> > irq request failure, return here,  requested irq will not free.
>
> Why is that an error!

        ret = fsl_edma->drvdata->setup_irq(pdev, fsl_edma);
        if (ret)
                return ret;

if last one of request_irq() failure, mcf_edma_irq_init() return failure.
probe will return failure also without free irq.

So previous irq by request_irq() is never free at this case.

Frank

>
> >
> > You'd better add patch before this one to change to use devm_request_irq()
>
> Not really, devm_ is a not always good option.
>
> --
> ~Vinod