On Wed, Aug 21, 2013 at 07:38:21AM -0700, Roland Dreier wrote: > I don't understand this. In fact the whole patch series looks quite > confused. COMPARE AND WRITE is a normal Data-Out command, with no > requirement for special bidirectional handling or anything like that. > The only slightly unusual thing is that a CAW command with a NUMBER OF > LOGICAL BLOCKS equal to N will actually transfer 2*N worth of data -- > one set of data for the compare operation and a second set to write if > the compare succeeds. But just to be clear, the transfer of those 2*N > blocks happens as a single transfer during the Data-Out phase. I think the confusion is that the implementation of COMPARE AND WRITE obviously requires a read and a write phase, and the implementation tries to mix this up with an actual bidirectional scsi command. If the core stopped keying off t_bidi_data_sg and used better flag this could be easily solved. -- 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
