> > In general, I tend to think that for this function to make any sense > (that is, to synchronize anything at all), it needs a barrier or you are > just making a decision based on a totally random value of desc->status > since it can have been re-ordered, speculatively loaded, pre-fetched, > whatever'ed... :-).
Take a real life example: drivers/message/fusion/mptbase.c /* Disable interrupts! */ CHIPREG_WRITE32(&ioc->chip->IntMask, 0xFFFFFFFF); ioc->active = 0; synchronize_irq(pdev->irq); And we aren't in a spinlock here. That's just a random example grepped.... I think I see a few more. Then, some drivers like tg3 actually do an smp_mb() before calling synchronize_irq(). But then, some don't. I think trying to have all drivers be correct here is asking for trouble, we'd rather have synchronize_irq() be uber-safe. It's not like it was used in hot path anyway. Ben. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev