On Thu, 03 Apr 2008, James Bottomley wrote: > On Thu, 2008-04-03 at 13:13 -0700, Andrew Vasquez wrote: > > There's no need to use the heavier (albiet safer) > > *_irq[save|restore]() locking primitives within the driver's > > interrupt handlers, interrupts are guaranteed to be > > non-reentrant. Use lightweight spin_lock() and spin_unlock() > > primitives while acquiring the hardware_lock. > > The above statement isn't entirely true: interrupts are not guaranteed > to be non re-entrant. They are guaranteed not to be re-entered from the > *same* interrupt, but if you've got more than one card, the interrupt > routine can be executing simultaneously on an SMP system which is in > contravention of the classical definition of re-entrancy. > > So, the rules for locks in interrupt is that as long as the lock is > unique per interrupting instance (which it looks like yours are) They are... > you can > get away with not requiring interrupt disables within critical sections > but if you have a more global lock which could be taken by different > interrupting entities then you must do interrupt disables still. Thanks for the clarification. Would you like me to resubmit with an altered changelog or can the current one glide in? Thanks, av -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
