Hi, On 08/28/2014 02:17 PM, Paolo Bonzini wrote: > Il 28/08/2014 14:04, Hannes Reinecke ha scritto: >>> >>> Setting TASK ABORTED aside, the important part is that an abort can do >>> one of two things: >>> >>> - complete the command, and then eh_abort should return after the driver >>> has noticed the completion and called the ->scsi_done callback for the >>> Scsi_Cmnd*. >>> >>> - abort the command, and then the driver should never call the >>> ->scsi_done callback for the Scsi_Cmnd*. >>> >> In practice we rely on the latter behaviour; when ->scsi_done is called >> while the command is under eh_abort _really bad things_ >> will happen. >> As soon as eh_abort is called control is transferred back to the >> SCSI midlayer, so any LLDD should never send completions for these >> commands back to the midlayer. > > No, this is wrong. I think we have sorted it out a couple of months > ago. virtio-scsi for example (due to QEMU quirks) will do the former > more often than not. > > Ignoring scsi_eh_done which is just as harmless, scsi_eh_done is new to me. Should I ever use that, and if so when ? > ->scsi_done does > nothing more than calling blk_complete_request. If the command is under > abort, it has already been marked as complete by the block layer's > timeout timer---see blk_rq_timed_out_timer and blk_rq_check_expired---or > by blk_abort_request. > > Then, blk_complete_request will do nothing because its call to > blk_mark_rq_complete returns true. > > All this, of course, as long as ->scsi_done is called _before_ eh_abort > returns. What about calling scsi_done after eh_abort if eh_abort returned FAILED? Regards, Hans -- 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
