Messages in this thread | | | Date | Mon, 22 Oct 2007 13:02:23 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH 1/2] irq_flags_t: intro and core annotations |
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On Mon, 22 Oct 2007 12:56:29 -0700 (PDT) Linus Torvalds <torvalds@linux-foundation.org> wrote:
> > > On Mon, 22 Oct 2007, Matthew Wilcox wrote: > > > > We certainly don't want to encourage people to blindly make those > > conversions ... and I've seen the results of encouraging kernel janitors > > to do things a certain way. > > There's another issue: the "irqsave/irqrestore" versions are much safer > than the plain "irq" versions, in case the caller already has interrupts > disabled. > > So anybody making the change not only would need to make the performance > argument, he'd better not be a janitor that blindly does the change > without thinking about all call-sites etc.. >
It's almost always a bug to do spin_lock_irq() when local interrupts are disabled. However iirc when we've tried to add runtime debugging to catch that, it triggered false-positives which made the idea unworkable. I forget where.
However what we could do is to add a new spin_lock_irq_tell_me_if_i_goofed() which would perform that runtime check.
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