On Thu, May 28, 2020 at 07:40:38AM +0200, Christoph Hellwig wrote: > If we write to a file that implements ->write_iter there is no need > to change the address limit if we send a kvec down. Implement that > case, and prefer it over using plain ->write with a changed address > limit if available. Umm... It needs a comment along the lines of "weird shits like /dev/sg that currently check for uaccess_kernel() will just have to make sure they never switch to ->write_iter()"