On Fri, Jun 07, 2019 at 08:19:08AM +0000, Yoshihiro Shimoda wrote: > Hi Christoph, > > > From: Christoph Hellwig, Sent: Friday, June 7, 2019 5:08 PM > > > > Looks good. And it seems like you've also found the solution to > > your usb storage problem, but I'm going to post the variant I just > > hacked up nevertheless. > > Thank you for your reply! I think this API is related to my problem, > but I don't have any actual solution (a patch) for now. So, I'll wait > for your patch! Turns out it isn't as simple as I thought, as there doesn't seem to be an easy way to get to the struct device used for DMA mapping from USB drivers. I'll need to think a bit more how to handle that best.