Re: [PATCH 2/3] signals: introduce SIGQUEUE_CANCELLED

From: Roland McGrath
Date: Tue May 20 2008 - 22:25:26 EST


> Introduce SIGQUEUE_CANCELLED flag. If it is set, the pending signal should be
> ignored and collect_signal() should return 0.

Acked-by: Roland McGrath <roland@xxxxxxxxxx>

> Note that the new flag is completely orthogonal to SIGQUEUE_PREALLOC, and it
> can be set without ->siglock held.

I think to keep things easier to understand, we should say the rule is that
touching q->flags is always controlled by siglock when q is on a queue.
Before it's queued or after it's been dequeued (i.e. list_empty(&q->list)
with siglock held), then the "owner" of the struct sigqueue of course needs
noone's siglock.


Thanks,
Roland
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