On Wed, Mar 31, 2010 at 02:05:00PM -0700, H. Peter Anvin wrote: > What I note is that lib/rwsem-spinlock.c seems to be rather inconsistent > in its use of spin_lock_irqsave/spin_lock_irqrestore versus > spin_lock_irq/spin_unlock_irq... in fact, __down_read is the *only* > place where we use the latter as opposed to the former. > > Is that a bug? If so, it would certainly explain this behavior. It's based on down_read() and down_write() not being callable from interrupt context, or with interrupts disabled (since they can sleep). up_read(), up_write(), down_read_trylock(), down_write_trylock(), downgrade_write() can all be called from interrupt context since they cannot sleep. -- Matthew Wilcox Intel Open Source Technology Centre "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step." -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
