On Wed, Aug 12, 2015 at 09:05:15AM -0700, Linus Torvalds wrote: > [ Again, I'm responding to one random patch - this pattern was in > other patches too. ] > > A question: do we actually expect to mix page-less and pageful SG > entries in the same SG list? > > How does that happen? Both for DAX and the video buffer case people could do direct I/O spanning the boundary between such a VMA and a normal one unless we add special code to prevent that. Right now I don't think it's all that useful, but then again it doesn't seem harmful either and adding those checks might add up.