Re: [PATCH v2] ata: sata_dwc_460ex: Check !irq instead of irq == NO_IRQ
From: Damien Le Moal
Date: Fri Nov 11 2022 - 21:11:22 EST
On 11/11/22 17:30, Christophe Leroy wrote:
> NO_IRQ is a relic from the old days. It is not used anymore in core
> functions. By the way, function irq_of_parse_and_map() returns value 0
> on error.
>
> In some drivers, NO_IRQ is erroneously used to check the return of
> irq_of_parse_and_map().
>
> It is not a real bug today because the only architectures using the
> drivers being fixed by this patch define NO_IRQ as 0, but there are
> architectures which define NO_IRQ as -1. If one day those
> architectures start using the non fixed drivers, there will be a
> problem.
>
> Long time ago Linus advocated for not using NO_IRQ, see
> https://lkml.org/lkml/2005/11/21/221 . He re-iterated the same view
> recently in https://lkml.org/lkml/2022/10/12/622
>
> So test !irq instead of tesing irq == NO_IRQ.
>
> And remove the fallback definition of NO_IRQ at the top of the file.
>
> Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Applied to for-6.2. Thanks !
> ---
> v2: Also removed the #ifndef NO_IRQ #define NO_IRQ 0 at the top
> ---
> drivers/ata/sata_dwc_460ex.c | 8 ++------
> 1 file changed, 2 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/ata/sata_dwc_460ex.c b/drivers/ata/sata_dwc_460ex.c
> index e3263e961045..7b7e1516dbdd 100644
> --- a/drivers/ata/sata_dwc_460ex.c
> +++ b/drivers/ata/sata_dwc_460ex.c
> @@ -42,10 +42,6 @@
> #define sata_dwc_writel(a, v) writel_relaxed(v, a)
> #define sata_dwc_readl(a) readl_relaxed(a)
>
> -#ifndef NO_IRQ
> -#define NO_IRQ 0
> -#endif
> -
> #define AHB_DMA_BRST_DFLT 64 /* 16 data items burst length */
>
> enum {
> @@ -242,7 +238,7 @@ static int sata_dwc_dma_init_old(struct platform_device *pdev,
>
> /* Get SATA DMA interrupt number */
> hsdev->dma->irq = irq_of_parse_and_map(np, 1);
> - if (hsdev->dma->irq == NO_IRQ) {
> + if (!hsdev->dma->irq) {
> dev_err(dev, "no SATA DMA irq\n");
> return -ENODEV;
> }
> @@ -1180,7 +1176,7 @@ static int sata_dwc_probe(struct platform_device *ofdev)
>
> /* Get SATA interrupt number */
> irq = irq_of_parse_and_map(np, 0);
> - if (irq == NO_IRQ) {
> + if (!irq) {
> dev_err(dev, "no SATA DMA irq\n");
> return -ENODEV;
> }
--
Damien Le Moal
Western Digital Research