On Wed, Oct 01, 2014 at 02:51:31PM -0400, Webb Scales wrote: > Hannes, > > In megasas_change_queue_type(), is it possible for sdev->queue_depth to be > greater than 256? > > Unless I'm misunderstanding the SCSI code, we can request a > queue-depth/tag-map-size which is greater than 256, but, since the > scsi_cmnd::tag field is an unsigned char, depths greater than 256 may > overflow the field when high-numbered tags are used...do I have that right?
Yes, we really need to increase the size of the tag field. SAM allows a transport specific limit of up to 64 _bytes_ for it, although I don't know implementation that large. Given that the block layer can generate up to 32-bit tags both for the old blk-tag.c code and the new blk-mq-tag.c version it would be good to use a u32 there. Can you send me a patch? -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
