Il 26/07/2012 11:41, James Bottomley ha scritto: > On Thu, 2012-07-26 at 11:27 +0200, Paolo Bonzini wrote: >> Il 26/07/2012 11:21, James Bottomley ha scritto: >>>>> Because scsilun_to_int does not do the AND, so it would have exactly the >>>>> same bug I'm fixing. >>> It's not a bug ... it's the encoding. All the other devices use this >>> too. Ideally we should have switched to 64 bit lun numbers for the >>> encoding to be exact, but nothing so far has gone over 32 bits. If we >>> don't encode the Address method as part of the lun number, we don't get >>> the reverse transform right and the addressing often fails. >> >> But virtio-scsi gets it right even if you use method=0 and method=1 >> interchangeably. > > I don't actually understand this statement. LUNS < 256 may be encoded > either way (they should be encoded with address method=0 but they don't > have to be) if you address the array with the wrong method, it doesn't > have to give you your lun. But virtio-scsi does, LUN "16384" and LUN 0 are the same. If somebody wanted to add support for >16383 LUNs, we would do it with the 4-byte encoding that is in SAM, but I don't see that happening. > It's nothing to do with buggy hardware ... Hardware that knows about format=1 LUNs, and yet treats LUN 0 differently depending on the encoding sounds buggy. Of course some hardware may not know anything about format=1, so it is wrong to pass format=1 unconditionally, but virtio-scsi does. Paolo -- 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
