Messages in this thread | | | Date | Fri, 20 Oct 2006 11:46:40 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH 3/3] Enforce "unsigned long flags;" when spinlocking |
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On Fri, 20 Oct 2006 17:15:44 +0400 Alexey Dobriyan <adobriyan@gmail.com> wrote:
> Make it break or warn if you pass to spin_lock_irqsave() and friends > something different from "unsigned long flags;". Suprisingly large amount of > these was caught by recent commit c53421b18f205c5f97c604ae55c6a921f034b0f6 . > > Idea is largely from FRV typechecking. > > Note #1: checking with sparse is still needed, because a driver can save and > pass around flags or something. So far patch is very intrusive. > Note #2: techically, we should break only if sizeof(flags) < sizeof(unsigned long), > but hey, there is opportunity to escalate. Thus != > Note #3: yes, would break every single buggy out-of-tree module. >
This is a pretty ugly-looking patch.
> > + BUILD_BUG_ON(sizeof(flags) != sizeof(unsigned long)); \ > + typecheck(unsigned long, flags); \ > ... > + BUILD_BUG_ON(sizeof(flags) != sizeof(unsigned long)); \ > + typecheck(unsigned long, flags); \ > ... > + BUILD_BUG_ON(sizeof(flags) != sizeof(unsigned long)); \ > + typecheck(unsigned long, flags); \ > ... > + BUILD_BUG_ON(sizeof(flags) != sizeof(unsigned long)); \ > + typecheck(unsigned long, flags); \ > ... > + BUILD_BUG_ON(sizeof(flags) != sizeof(unsigned long)); \ > + typecheck(unsigned long, flags); \ > ...
starting to see a pattern here?
If we're going to do this then a helper macro build_check_irq_flags() would help clean things up. It will also allow us to centralise the warning-vs-error policy decision.
I'm not sure that we need both, do we? If it spits a warning then it'll get fixed soon enough. - 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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