On Tue, 2011-06-14 at 04:12 -0400, Christoph Hellwig wrote: > On Mon, Jun 13, 2011 at 08:44:05PM -0700, Roland Dreier wrote: > > From: Roland Dreier <roland@xxxxxxxxxxxxxxx> > > > > transport_lookup_cmd_lun() may be called from interrupt context (eg > > tcm_loop_allocate_core_cmd() calls it, and it has a comment that says, > > "Can be called from interrupt context"), so it needs to use > > spin_lock_irqsave() instead of spin_lock_irq() to avoid enabling > > interrupts at the wrong time. > > > > (And indeed the last set of lock operations, on lun_cmd_lock, were > > already using spin_lock_irqsave(), so we just need to fix the other > > two locks we take) > > It currently is, but I think we'd better be off stopping to call it from > IRQ context. Soon after we offload the work to thread context anyway. > By moving the point of offloading a little earlier we can simply the > calling conventions a lot, and keep the amount of code that needs > IRQ-safe locking minimal. > The thing here is that the new descriptor can't be offloaded into thread context for TFO->new_cmd_map() processing until the se_cmd->se_dev assignment has occured, because we don't know which backend it's destined for. So, I think we at least need this patch.. --nab -- 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
