linux-kernel - Re: [PATCH 3/8] signal: make may_ptrace

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Date:   Mon, 28 May 2018 20:30:12 +0200
From:   Christian Brauner <christian@...uner.io>
To:     Al Viro <viro@...IV.linux.org.uk>
Cc:     linux-kernel@...r.kernel.org, ebiederm@...ssion.com,
        gregkh@...uxfoundation.org, mingo@...nel.org,
        james.morris@...rosoft.com, keescook@...omium.org,
        peterz@...radead.org, sds@...ho.nsa.gov, akpm@...ux-foundation.org,
        oleg@...hat.com
Subject: Re: [PATCH 3/8] signal: make may_ptrace_stop() return bool

On Mon, May 28, 2018 at 03:12:19PM +0100, Al Viro wrote:
> On Mon, May 28, 2018 at 03:49:11PM +0200, Christian Brauner wrote:
> > may_ptrace_stop() already behaves like a boolean function. Let's actually
> > declare it as such too.
> > 
> > Signed-off-by: Christian Brauner <christian@...uner.io>
> > ---
> >  kernel/signal.c | 8 ++++----
> >  1 file changed, 4 insertions(+), 4 deletions(-)
> > 
> > diff --git a/kernel/signal.c b/kernel/signal.c
> > index 81be01d193f4..6c2e7b45cba1 100644
> > --- a/kernel/signal.c
> > +++ b/kernel/signal.c
> > @@ -1889,10 +1889,10 @@ static void do_notify_parent_cldstop(struct task_struct *tsk,
> >  	spin_unlock_irqrestore(&sighand->siglock, flags);
> >  }
> >  
> > -static inline int may_ptrace_stop(void)
> > +static inline bool may_ptrace_stop(void)
> >  {
> >  	if (!likely(current->ptrace))
> > -		return 0;
> > +		return false;
> >  	/*
> >  	 * Are we in the middle of do_coredump?
> >  	 * If so and our tracer is also part of the coredump stopping
> > @@ -1908,9 +1908,9 @@ static inline int may_ptrace_stop(void)
> >  	 */
> >  	if (unlikely(current->mm->core_state) &&
> >  	    unlikely(current->mm == current->parent->mm))
> > -		return 0;
> > +		return false;
> >  
> > -	return 1;
> > +	return true;
> 
> 	return !current->mm->core_state || current->mm != current->parent->mm;
> 
> or, if it gives any measurably better code generation,
> 
> 	return likely(!current->mm->core_state ||
> 			current->mm != current->parent->mm);

Makes sense. I put this in v1.

Thanks!
Christian