Re: [PATCH] atm: firestream: avoid conversion error during build

[Andrew Lunn <andrew@lunn.ch>]

On Tue, Nov 16, 2021 at 01:38:25PM +0100, Helge Deller wrote:
> Although the firestream driver isn't relevant for the parisc
> architecture, but it generates this compile error when CONFIG_TEST is
> defined:
> 
>  drivers/atm/firestream.c: In function ‘top_off_fp’:
>  arch/parisc/include/asm/io.h:8:25: error: conversion from ‘long unsigned int’ to ‘u32’ {aka ‘unsigned int’} changes value
>      from ‘18446744072635809792’ to ‘3221225472’ [-Werror=overflow]
>  drivers/atm/firestream.c:1494:29: note: in expansion of macro ‘virt_to_bus’
>             ne->next  = virt_to_bus (NULL);
> 
> ne->next is of type u32, so this patch avoids the error by casting
> the return value of virt_to_bus() to u32.
> 
> Signed-off-by: Helge Deller <deller@gmx.de>
> 
> ---
> 
> diff --git a/drivers/atm/firestream.c b/drivers/atm/firestream.c
> index 3bc3c314a467..8148a4ea194c 100644
> --- a/drivers/atm/firestream.c
> +++ b/drivers/atm/firestream.c
> @@ -1491,7 +1491,7 @@ static void top_off_fp (struct fs_dev *dev, struct freepool *fp,
>  			    skb, ne, skb->data, skb->head);
>  		n++;
>  		ne->flags = FP_FLAGS_EPI | fp->bufsize;
> -		ne->next  = virt_to_bus (NULL);
> +		ne->next  = (u32)virt_to_bus (NULL);
>  		ne->bsa   = virt_to_bus (skb->data);
>  		ne->aal_bufsize = fp->bufsize;
>  		ne->skb = skb;

Does virt_to_bus() make any sense on NULL? Maybe just assign NULL?

     Andrew