On 11/30/18 12:21 PM, Al Viro wrote: > On Fri, Nov 30, 2018 at 09:56:43AM -0700, Jens Axboe wrote: >> For an ITER_KVEC, we can just iterate the iov and add the pages >> to the bio directly. > >> + page = virt_to_page(kv->iov_base); >> + size = bio_add_page(bio, page, kv->iov_len, >> + offset_in_page(kv->iov_base)); > > Who said that you *can* do virt_to_page() on those? E.g. vmalloc()'ed > addresses are fine for ITER_KVEC, etc. Then how do you set up a kvec based iter with memory you can safely DMA to/from? -- Jens Axboe
