On Wed, Jul 27, 2022 at 12:10:33AM +0100, Al Viro wrote: > On Tue, Jul 26, 2022 at 10:38:11AM -0700, Keith Busch wrote: > > > +void iov_iter_dma_tag(struct iov_iter *i, unsigned int direction, > > + void *dma_tag, unsigned int dma_offset, > > + unsigned long nr_segs, size_t count) > > +{ > > + WARN_ON(direction & ~(READ | WRITE)); > > + *i = (struct iov_iter){ > > + .iter_type = ITER_DMA_TAG, > > + .data_source = direction, > > + .nr_segs = nr_segs, > > Could you can that cargo-culting? Just what the hell is nr_segs > here? Thanks for the catch. Setting nr_segs here is useless carry-over from an earlier version when I thought it would be used to build the request. Turns out it's not used at all.