Messages in this thread | | | Date | Thu, 24 Aug 2006 15:44:33 +0200 | From | Suleiman Souhlal <> | Subject | Re: [PATCH] Fix x86_64 _spin_lock_irqsave() |
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Arjan van de Ven wrote: > On Thu, 2006-08-24 at 14:33 +0200, Suleiman Souhlal wrote: > >>Andi Kleen wrote: >> >>>On Thursday 24 August 2006 13:04, Suleiman Souhlal wrote: >>> >>> >>>>Andi Kleen wrote: >>>> >>>> >>>>>Edward Falk <efalk@google.com> writes: >>>>> >>>>> >>>>> >>>>> >>>>>>Add spin_lock_string_flags and _raw_spin_lock_flags() to >>>>>>asm-x86_64/spinlock.h so that _spin_lock_irqsave() has the same >>>>>>semantics on x86_64 as it does on i386 and does *not* have interrupts >>>>>>disabled while it is waiting for the lock. >>>>> >>>>> >>>>>Did it fix anything for you? >>>> >>>>I think this was to work around the fact that some buggy drivers try to >>>>grab spinlocks without disabling interrupts when they should, which >>>>would cause deadlocks when trying to rendez-vous every cpu via IPIs. >>> >>> >>>That doesn't help them at all because they could then deadlock later. >> >>If the driver uses spin_lock() when it knows that the hardware won't >>generate the interrupt that would need to be masked, and >>spin_lock_irqsave() elsewhere, there shouldn't be any deadlocks unless >>IPIs are involved. > > > this still is bad practice and lockdep will also scream about it
Great.
> Can you point at ANY place that does this?
From a quick inspection, drivers/net/forcedeth.c appears to do this.
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