>>>>> "Christof" == Christof Schmitt <christof.schmitt@xxxxxxxxxx> writes: Christof> While experimenting with the data integrity support in the Christof> Linux kernel, i found that the block layer integrity code can Christof> send integrity data segments for a request that do not adhere Christof> to the queue limits. The integrity data segment can be larger Christof> than queue_max_segment_size and the segment does not adhere to Christof> the queue_segment_boundary. Correct. That was a deliberate design decision. Modern HBAs allow essentially indefinite chaining and our block layer segmentation controls are to some extent legacy baggage. I did not want to put in a set of constraints on the DI scatterlist because I was afraid it would encourage vendors to actually them. Christof> It appears to me that the right way would be to apply the same Christof> restrictions that are in place for data segments also to Christof> integrity data segments. The patch works for my experiments Christof> and applies on top of the current Linux tree (2.6.35-rc5). Who says constraints on the integrity scatterlist are the same as on the data ditto? In my experience they are not. If you must do this, then the DI constraints should be separate from the data segmentation ones. But I'm interested in what motivated this change to begin with. Your change also has repercussions when merging requests and bios. We'd need to honor the DI segmentation constraints when merging. Otherwise we may end up going beyond the controller limits when mapping the sgl. -- Martin K. Petersen Oracle Linux Engineering -- 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
