On Sun, 2013-06-23 at 20:21 -0500, Mike Christie wrote: > On 6/12/13 7:57 AM, Bart Van Assche wrote: > > A SCSI LLD may overwrite host_scribble in its queuecommand() > > implementation. Several drivers need that field to process > > requests and aborts correctly. Hence this field must be saved > > by scsi_eh_prep_cmnd() and must be restored by > > scsi_eh_restore_cmnd(). > > > > Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx> > > Cc: James Bottomley <JBottomley@xxxxxxxxxxxxx> > > Cc: Mike Christie <michaelc@xxxxxxxxxxx> > > Cc: Hannes Reinecke <hare@xxxxxxx> > > Cc: Tejun Heo <tj@xxxxxxxxxx> > > > How have we not hit this before :) ? Well, because the patch is making bogus assumptions and then acting on them. host_scribble may only exist for the lifetime of the command ... meaning from when we pass the command into the hba to when it comes back. When we begin error recovery, that lifetime is over, so host_scribble should be cleared at this point to reuse the command because that's how it is on a pristine command, so this patch, if applied, would cause us to violate that assumption. Fortunately, I don't think any HBA driver expects host_scribble to be NULL, so they all unconditionally overwrite the value in their queuecommand routines if they use it, so I think the net effect of applying this would have been zero, but it could easily have been unfortunate. > Looks ok. Oops, minus 10 review kudos points for you. However, you seem to have a stock of several million of these built up over the years, so the net effect on your maintainer trust rating for reviews is zero. James -- 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
