Messages in this thread | | | Date | Tue, 3 Feb 2009 12:24:09 -0800 (PST) | From | Davide Libenzi <> | Subject | Re: [patch 2/6] epoll keyed wakeups v2 - introduce new *_poll() wakeup macros |
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On Tue, 3 Feb 2009, Andrew Morton wrote:
> On Tue, 3 Feb 2009 11:20:46 -0800 (PST) > Davide Libenzi <davidel@xmailserver.org> wrote: > > > On Tue, 3 Feb 2009, Davide Libenzi wrote: > > > > > On Tue, 3 Feb 2009, Andrew Morton wrote: > > > > > > > On Sun, 01 Feb 2009 12:04:23 -0800 Davide Libenzi <davidel@xmailserver.org> wrote: > > > > > > > > > +#define wake_up_nested_poll(x, m, s) \ > > > > > +do { \ > > > > > + unsigned long flags; \ > > > > > + \ > > > > > + spin_lock_irqsave_nested(&(x)->lock, flags, (s)); \ > > > > > + wake_up_locked_poll(x, m); \ > > > > > + spin_unlock_irqrestore(&(x)->lock, flags); \ > > > > > +} while (0) > > > > > > > > I had to go and find the callsite to work out the type of `x' :( > > > > > > > > - this macro can be passed the address of any structure which has a > > > > `spinlock_t lock;' in it, which seems strange. > > > > > > > > - It references its first arg three times. > > > > > > > > Is there any reason why we can't implement this in C? > > > > > > I don't see any reason why these two couldn't be normal functions (I > > > just referenced wake_up_nested(), that was a macro in the first place). > > > > Actually reading the comments helps :) It triggers an include-hell, if you > > make them inline. Since they're lockdep debug thingies, I think it's kinda > > wasted turn them into non-inline real functions, so they'd better remain > > macros IMO. > > > > ho hum. I think it'd be worth at least renaming the arguments to > something less daft, for readability reasons. > > One could also do > > do { > wait_queue_head_t *__wqh = x; > <use __wqh> > } > > which would provide typechecking of the first arg (so people can no > longer "pass the address of any structure which has a `spinlock_t > lock;' in it") and which fixes the multiple-references-to-an-argument > issue.
OK, you've got my arg-rename bits already. Another version using a typecheck() in there? Or you prefer the explicit instantiation?
- Davide
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