On Tue, 2015-06-23 at 11:05 +0200, Hannes Reinecke wrote: > On 06/23/2015 10:29 AM, Nicholas A. Bellinger wrote: > > On Fri, 2015-06-19 at 09:13 +0200, Hannes Reinecke wrote: > >> On 06/19/2015 08:48 AM, Christoph Hellwig wrote: > >>> What's the benefit of the SAS transport class writeout? I honestly > >>> always saw tcm_loop as a simple loopback driver, with the different > >>> transport IDs in the PR code as a gimmick. Note that vhost and > >>> xen-blkback copies that style and I did plan to consolidate it > >>> in common code. > >>> > >> The benefit is that tcm_loop will show up in the system as a 'real' > >> SAS hba; long-term goal is to simulate SAS multipathing here. > >> I was even planning on adding simlated FC infrastructure, too; > >> with that we could simulate FC multipathing, too, and our QA would > >> be _so_ happy... > >> > > > > Sounds like a reasonable use-case to support for loopback testing. > > > >> Again, these patches are mainly a collection of patches I've done to > >> test various scenarios, in the hope others might find them useful, > >> too. So I can easily hold off these patches until you've posted your > >> rework. > >> > > > > How different do you expect sas, fc, and iscsi transports to be..? > > > > Do you think this would this be better served by a simple tcm_loop LLD > > specific API for different multipath transports..? > > > Actually, I would split off the various transport functions into > separate files (tcm_loop_sas, tcm_loop_fc, etc), but keep a common > tcm_loop module. > We can even make transport classes optional by adding an explicit > 'sas.XXX' prefix scanning when creating the device similar to what > we do with the 'fc.XXX' prefix already. > With that we would have a 'sas.XXX', 'fc.XXX', and 'iqn.XXX' WWN > which would attach to the respective transport class, and any other > WWN (which would be the default) would be getting the standard > emulation without any transport class attached. I'm open to merging the tcm_loop patches #1-#6 as-is for the sas transport pieces, or wait until you've done a large split based on transport class types. It's really your call how the initial merge should look. --nab -- 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
