Messages in this thread | | | Date | Fri, 2 Jul 2010 17:09:44 -0400 | From | Chris Metcalf <> | Subject | Re: [PATCH] Break out types from <linux/list.h> to <linux/list_types.h>. |
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On 7/2/2010 4:48 PM, Matthew Wilcox wrote: > On Fri, Jul 02, 2010 at 03:33:52PM -0400, Chris Metcalf wrote: > >> On 7/2/2010 3:19 PM, Matthew Wilcox wrote: >> >>> Why a new header file instead of linux/types.h? >>> >> I was working from analogy to kvm_types.h, mm_types.h, rwlock_types.h, >> spinlock_types.h. My impression is that linux/types.h is generally for >> basic (non-struct) types, with atomic_t/atomic64_t being added as >> "almost non-struct types", and of course the historical exception of >> "struct ustat", which has been there since the dawn of time (0.97 anyway). >> > I think list_head, hlist_head and hlist_node qualify as "almost non-struct > types", don't you? :-) >
I see the smiley, but to reply seriously, the distinction I was making was that atomic_t is really just an integer type, but with typing magic to protect it from implicit conversion -- unlike list_head, which really is a more complex type.
I suppose one could make a kind of "intent of the founders" constitutional law-type argument suggesting that the presence of "struct ustat" suggests more complex types are in fact appropriate in <linux/types.h>. :-)
> I wouldn't mind seeing kvm_types.h, rwlock_types.h and spinlock_types.h > merged into types.h, personally. They're all pretty fundamental kernel > kind of types. It's a matter of taste, and I'm not particularly fussed > one way or the other. >
Somehow it's hard to see kvm_ioapic_redirect_entry on a par with size_t :-)
> I just object to the unnecessary creation of tiny files like this. > Which is how we ended up with atomic_t and atomic64_t in there in the > first place :-) >
In any case, I think this either way is plausible, but in the absence of more folks weighing in, I think "avoid adding a complex type to <linux/types.h>" sounds more convincing to me than "avoid adding a new tiny file", though I certainly do buy the latter argument.
-- Chris Metcalf, Tilera Corp. http://www.tilera.com
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