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SubjectRe: [PATCH v1 05/20] signal: flatten do_send_sig_info()
On Tue, May 29, 2018 at 07:28:27AM -0500, Eric W. Biederman wrote:
> Christian Brauner <christian@brauner.io> writes:
>
> > Let's return early when lock_task_sighand() fails and move send_signal()
> > and unlock_task_sighand() out of the if block.
>
> Introducing multiple exits into a function. Ick.
> You do know that is what Dijkstra was arguing against in his paper
> "Goto Considered Harmful"
>
> That introduces mutiple exits and makes the function harder to analyze.
> It is especially a pain as I have something in my queue that will
> shuffle things around and remove the possibility of lock_task_sighand
> failing.

I'm happy to drop this one if you have a fix for this in your tree
anyway.

Aside from that, I think it might make sense to route this patch series
through your tree though since you're doing the siginfo rework
currently.(?)

Christian

>
> Eric
>
> > Signed-off-by: Christian Brauner <christian@brauner.io>
> > ---
> > v0->v1:
> > * patch unchanged
> > ---
> > kernel/signal.c | 10 +++++-----
> > 1 file changed, 5 insertions(+), 5 deletions(-)
> >
> > diff --git a/kernel/signal.c b/kernel/signal.c
> > index baae137455eb..a628b56415e6 100644
> > --- a/kernel/signal.c
> > +++ b/kernel/signal.c
> > @@ -1167,16 +1167,16 @@ specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t)
> > }
> >
> > int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p,
> > - bool group)
> > + bool group)
> > {
> > unsigned long flags;
> > int ret = -ESRCH;
> >
> > - if (lock_task_sighand(p, &flags)) {
> > - ret = send_signal(sig, info, p, group);
> > - unlock_task_sighand(p, &flags);
> > - }
> > + if (!lock_task_sighand(p, &flags))
> > + return ret;
> >
> > + ret = send_signal(sig, info, p, group);
> > + unlock_task_sighand(p, &flags);
> > return ret;
> > }

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