Messages in this thread | | | From | Linus Torvalds <> | Date | Thu, 21 Jun 2012 20:33:38 -0700 | Subject | Re: [patch 3.5-rc3] mm, mempolicy: fix mbind() to do synchronous migration |
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On Thu, Jun 21, 2012 at 6:45 PM, Andrew Morton <akpm@linux-foundation.org> wrote: > >> I wonder if I should make sparse warn about any casts to/from enums. >> They tend to always be wrong. > > I think it would be worth trying, see how much fallout there is. Also > casts from "enum a" to "enum b". We've had a few of those, > unintentionally.
Ugh. We have this all over. Well, at least in multiple places.
Like <linux/personality.h>, which does things like
PER_LINUX_32BIT = 0x0000 | ADDR_LIMIT_32BIT,
where PER_LINUX_32BIT is one enum, and ADDR_LIMIT_32BIT is a different one.
And things like
WORK_STRUCT_PENDING = 1 << WORK_STRUCT_PENDING_BIT,
in <linux/workqueue.h> is similar.
Sure, my quick warning generator gives lots of extraneous warnings, and it complains about the above kind of "mixing enum with int" behavior, but the above is a very real example of casting an enum to an integer. And we *want* it to happen in the above cases.
I'll see what it looks like if I only warn about casting *to* an enum.
Linus -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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