On Mon, Jan 16, 2023 at 11:57:08PM -0800, Christoph Hellwig wrote: > On Mon, Jan 16, 2023 at 11:08:24PM +0000, David Howells wrote: > > Define FOLL_SOURCE_BUF and FOLL_DEST_BUF to indicate to get_user_pages*() > > and iov_iter_get_pages*() how the buffer is intended to be used in an I/O > > operation. Don't use READ and WRITE as a read I/O writes to memory and > > vice versa - which causes confusion. > > > > The direction is checked against the iterator's data_source. > > Why can't we use the existing FOLL_WRITE? I'm really not fond of passing FOLL_... stuff into iov_iter primitives. That space contains things like FOLL_PIN, which makes no sense whatsoever for non-user-backed iterators; having the callers pass it in makes them automatically dependent upon the iov_iter flavour.
