Re: [PATCH v2] alpha/PCI: Fix I/O port accessor argument order in pci_legacy_write()

On Mon, Jul 6, 2026 at 7:54=E2=80=AFPM Krzysztof Wilczy=C5=84ski
<[email protected]> wrote:
>
> pci_legacy_write() in arch/alpha/kernel/pci-sysfs.c passes its arguments
> to outb(), outw() and outl() in the wrong order:
>
>   outb(port, val);
>
> The Alpha I/O accessors in arch/alpha/include/asm/io.h take the value
> first and the port second:
>
>   extern void outb(u8 b, unsigned long port);
>
> So the port number is written as data to the I/O address taken from the
> user-supplied value, and the intended write to the requested port never
> happens.
>
> The arguments have been reversed since the file was added, and the
> function returns the access size regardless, so the caller sees success
> while the requested port is left untouched.
>
> Fixes: 10a0ef39fbd1 ("PCI/alpha: pci sysfs resources")
> Tested-by: Magnus Lindholm <[email protected]>
> Reviewed-by: Magnus Lindholm <[email protected]>
> Cc: [email protected]
> Signed-off-by: Krzysztof Wilczy=C5=84ski <[email protected]>
> ---
> Changes in v2:
>  https://lore.kernel.org/linux-pci/20260612232400.585195-1-kwilczynski@ke=
rnel.org/
>
>  - Collected Reviewed-by and Tested-by tags from Magnus Lindholm.
>
>  arch/alpha/kernel/pci-sysfs.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/alpha/kernel/pci-sysfs.c b/arch/alpha/kernel/pci-sysfs.=
c
> index 94dbc470cd6c..7050f0f7fe3d 100644
> --- a/arch/alpha/kernel/pci-sysfs.c
> +++ b/arch/alpha/kernel/pci-sysfs.c
> @@ -224,17 +224,17 @@ int pci_legacy_write(struct pci_bus *bus, loff_t po=
rt, u32 val, size_t size)
>
>         switch(size) {
>         case 1:
> -               outb(port, val);
> +               outb(val, port);
>                 return 1;
>         case 2:
>                 if (port & 1)
>                         return -EINVAL;
> -               outw(port, val);
> +               outw(val, port);
>                 return 2;
>         case 4:
>                 if (port & 3)
>                         return -EINVAL;
> -               outl(port, val);
> +               outl(val, port);
>                 return 4;
>         }
>         return -EINVAL;
> --
> 2.55.0
>

Thanks for doing this, this is just me acking the v2 version of this patch,
please go ahead and take this through your tree.

Acked-by: Magnus Lindholm <[email protected]>