Hello, Jeff, Linus. On 11/17/2010 09:08 AM, Jeff Garzik wrote: > Looking solely at the SCSI code (ie. ignoring LLD code), it seems > like the magic number zero for serial_number is signaling a boolean > condition "are we an EH command?" > > EH tests this at the very beginning of the abort/reset/explode error > handling sequence, presumably to avoid recursive EH invocations > (scsi_try_to_abort_cmd). > > So maybe an EH expert (Tejun?) can correct me here, but I think we > may be able to completely the lock/get-serial/unlock sequence from > libata, as long as scsi_init_cmd_errh() reliably sets an "I am an EH > command" flag. > > Would be nice if true... Yeah, it's actually nice (for once). libata doesn't use or care about scmd->serial_number at all. The SCSI EH path you mentioned above is not applicable as libata implements its eh_strategy_handler and SCSI only calls scsi_try_to_abort_cmd() for the default EH handler, scsi_unjam_host(). We'll need to test a bit to make sure everything is okay but I'm fairly certain removing it won't break anything fundamental. If something breaks at all, it would be some silly easy-to-fix thing. Thanks. -- tejun -- 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
