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SubjectRe: [PATCH 2/2] signals: eventpoll: set ->saved_sigmask at the start
On 06/25, Al Viro wrote:
>
> On Tue, Jun 25, 2013 at 09:57:59PM +0200, Oleg Nesterov wrote:
> > + current->saved_sigmask = current->blocked;
> > set_current_blocked(&ksigmask);
> > }
> >
> > error = sys_epoll_wait(epfd, events, maxevents, timeout);
> > -
> > /*
> > * If we changed the signal mask, we need to restore the original one.
> > * In case we've got a signal while waiting, we do not restore the
> > @@ -1988,12 +1988,10 @@ SYSCALL_DEFINE6(epoll_pwait, int, epfd, struct epoll_event __user *, events,
> > * the way back to userspace, before the signal mask is restored.
> > */
> > if (sigmask) {
> > - if (error == -EINTR) {
> > - memcpy(&current->saved_sigmask, &sigsaved,
> > - sizeof(sigsaved));
> > + if (error == -EINTR)
> > set_restore_sigmask();
> > - } else
> > - set_current_blocked(&sigsaved);
> > + else
> > + __set_current_blocked(&current->saved_sigmask);
>
> I don't like that. If anything, we have
> static inline void restore_saved_sigmask(void)
> {
> if (test_and_clear_restore_sigmask())
> __set_current_blocked(&current->saved_sigmask);
> }
> which means that the last part can be turned into
> set_restore_sigmask();
> if (error != -EINTR)
> restore_saved_sigmask();

set_restore_sigmask() does WARN_ON(!TIF_SIGPENDING).

> and I'd pulled set_restore_sigmask() call next to setting the sucker.

Sorry, can't understand...

Anyway, I agree we can make this more clean. From 0/2

Perhaps it also makes sense to add the new helper which does
copy_from_user + set saved_sigmask + set_current_blocked() ?

and perhaps we can add another helper which does set_restore_sigmask()
_or_ set_current_blocked(saved_sigmask), this can simplify more callers.
I think we can do this on top of this change.

Or I misunderstood and you dislike the very fact we rely on the already
initialized ->saved_sigmask ?

Oleg.



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