Re: [PATCH 1/3] net: add a CMSG_USER_DATA macro

[Sergei Shtylyov]

Hello!

On 11.05.2020 14:59, Christoph Hellwig wrote:

> Add a variant of CMSG_DATA that operates on user pointer to avoid
> sparse warnings about casting to/from user pointers.  Also fix up
> CMSG_DATA to rely on the gcc extension that allows void pointer
> arithmetics to cut down on the amount of casts.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
[...]
> diff --git a/net/core/scm.c b/net/core/scm.c
> index dc6fed1f221c4..abfdc85a64c1b 100644
> --- a/net/core/scm.c
> +++ b/net/core/scm.c
[...]
> @@ -300,7 +300,7 @@ void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm)
>   	if (fdnum < fdmax)
>   		fdmax = fdnum;
>   
> -	for (i=0, cmfptr=(__force int __user *)CMSG_DATA(cm); i<fdmax;
> +	for (i=0, cmfptr =(int __user *)CMSG_USER_DATA(cm); i<fdmax;

   Perhaps it's time to add missing spaces consistently, not just one that 
you added?

>   	     i++, cmfptr++)
>   	{
>   		struct socket *sock;

MBR, Sergei