On Mon, Dec 17, 2018 at 08:49:49AM -0800, Christoph Hellwig wrote: > > > > Given that you alread use an ioctl as the interface what is the problem > > > of passing this data through the ioctl? > > > > Do you mean pass the verity metadata in a buffer? That cannot work in general, > > because it may be too large to fit into memory. > > Have a pointer in the ioctl and do get_user_pages on it. I don't see how that helps. The Merkle tree can still be too large to fit in memory. In the worst case, it might not even fit in the address space. And I don't see how get_user_pages() helps either over just copy_from_user(); what are you proposing to do with the pages after getting them, exactly? - Eric
