On 12/23, Tomas Henzl wrote: > > On 12/23/2013 04:06 PM, Jack Wang wrote: > > On 12/23/2013 03:55 PM, Jason Seba wrote: > >> Why is this considered dangerous? I put some thought into it and > >> couldn't find any obvious reason why it wouldn't work, but I also > >> couldn't find any other drivers that work this way. Is there a > >> particular reason to avoid doing it this way? > >> > > If you use global flags, you may change interrupt state depends on context. > > The problem could show up when different threads try to store different > content to the flags.
Agreed. I have no idea if the patch is right or not, but at least the changelog should clearly explain that only one thread can do spin_lock_irqsave(&x->lock, x->lock_flags) at any time, otherwise the patch (and the code) _looks_ wrong even if it is correct. And if we can't use a local "unsigned long flags" because _unlock can happen in another function, imho this should be mentioned in the changelog as well. Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
