Messages in this thread | | | Date | Wed, 9 Dec 2009 10:29:22 +0100 | From | Ingo Molnar <> | Subject | Re: spinlock in completion_done() (was: Re: Async resume patch (was: Re: [GIT PULL] PM updates for 2.6.33)) |
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* Rafael J. Wysocki <rjw@sisk.pl> wrote:
> On Tuesday 08 December 2009, Alan Stern wrote: > > On Tue, 8 Dec 2009, Rafael J. Wysocki wrote: > > > > > BTW, is there a good reason why completion_done() doesn't use spin_lock_irqsave > > > and spin_unlock_irqrestore? complete() and complete_all() use them, so why not > > > here? > > > > And likewise in try_wait_for_completion(). It looks like a bug. Maybe > > these routines were not intended to be called with interrupts disabled, > > but that requirement doesn't seem to be documented. And it isn't a > > natural requirement anyway. > > OK, let's ask Ingo about that. > > Ingo, is there any particular reason why completion_done() and > try_wait_for_completion() don't use spin_lock_irqsave() and > spin_unlock_irqrestore()?
that's a bug that should be fixed - all the wakeup side (and atomic) variants of completetion API should be irq safe.
It appears that these new completion APIs were added via the XFS tree about a year ago:
39d2f1a: [XFS] extend completions to provide XFS object flush requirements
Please Cc: scheduler folks to all scheduler patches.
Ingo
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