Re: [PATCH] autofs: fix the wrong usage of the deprecated task_pgrp_nr()

[Ian Kent <raven@themaw.net>]

On Sun, 2009-01-18 at 08:34 +0100, Oleg Nesterov wrote:
> parse_options(&pgid) sets pgid = task_pgrp_nr() which uses the global
> namespace. This is wrong, we use this pgid to find "struct pid" in the
> current's namespace. Change parse_options() to use task_pgrp_vnr().
> 
> Also do s/task_pgrp_nr/task_pgrp_vnr/ in the debugging printks.
> checkpatch.pl complains about "line over 80 characters", but it should
> blame the cuurent code, not the patch.

This changelog entry doesn't really have anything that I can use to work
out if this change might introduce regressions.

It would be helpful to me if you could include:
1) A brief statement about what your trying to achieve and why.
2) The reason why task_pgrp_nr() has changed to task_pgrp_vnr() since
you made the change (that is someone working on pid namespaces) to
task_pgrp_nr().
3) Why you believe this change won't introduce a regression.

> 
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
> 
> --- CUR/fs/autofs/inode.c~1_AUTOFS	2009-01-12 23:07:46.000000000 +0100
> +++ CUR/fs/autofs/inode.c	2009-01-18 06:18:49.000000000 +0100
> @@ -78,7 +78,7 @@ static int parse_options(char *options, 
>  
>  	*uid = current_uid();
>  	*gid = current_gid();
> -	*pgrp = task_pgrp_nr(current);
> +	*pgrp = task_pgrp_vnr(current);
>  
>  	*minproto = *maxproto = AUTOFS_PROTO_VERSION;
>  
> --- CUR/fs/autofs/root.c~1_AUTOFS	2008-10-10 00:13:53.000000000 +0200
> +++ CUR/fs/autofs/root.c	2009-01-18 06:15:42.000000000 +0100
> @@ -215,7 +215,7 @@ static struct dentry *autofs_root_lookup
>  	oz_mode = autofs_oz_mode(sbi);
>  	DPRINTK(("autofs_lookup: pid = %u, pgrp = %u, catatonic = %d, "
>  				"oz_mode = %d\n", task_pid_nr(current),
> -				task_pgrp_nr(current), sbi->catatonic,
> +				task_pgrp_vnr(current), sbi->catatonic,
>  				oz_mode));
>  
>  	/*
> @@ -550,7 +550,8 @@ static int autofs_root_ioctl(struct inod
>  	struct autofs_sb_info *sbi = autofs_sbi(inode->i_sb);
>  	void __user *argp = (void __user *)arg;
>  
> -	DPRINTK(("autofs_ioctl: cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u\n",cmd,arg,sbi,task_pgrp_nr(current)));
> +	DPRINTK(("autofs_ioctl: cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u\n",
> +		cmd, arg, sbi, task_pgrp_vnr(current)));
>  
>  	if (_IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) ||
>  	     _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT)
>