Subject line should read "first_iovec_segment"
On Wed, 2022-06-22 at 05:15 +0100, Al Viro wrote:
> ... and calculate the offset in the caller
>
> Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> ---
> lib/iov_iter.c | 22 +++++++---------------
> 1 file changed, 7 insertions(+), 15 deletions(-)
>
> diff --git a/lib/iov_iter.c b/lib/iov_iter.c
> index fca66ecce7a0..f455b8ee0d76 100644
> --- a/lib/iov_iter.c
> +++ b/lib/iov_iter.c
> @@ -1306,33 +1306,23 @@ static ssize_t iter_xarray_get_pages(struct iov_iter *i,
> return min_t(size_t, nr * PAGE_SIZE - offset, maxsize);
> }
>
> -static unsigned long found_ubuf_segment(unsigned long addr, size_t *start)
> -{
> - *start = addr % PAGE_SIZE;
> - return addr & PAGE_MASK;
> -}
> -
> /* must be done on non-empty ITER_UBUF or ITER_IOVEC one */
> static unsigned long first_iovec_segment(const struct iov_iter *i,
> - size_t *size, size_t *start)
> + size_t *size)
> {
> size_t skip;
> long k;
>
> - if (iter_is_ubuf(i)) {
> - unsigned long addr = (unsigned long)i->ubuf + i->iov_offset;
> - return found_ubuf_segment(addr, start);
> - }
> + if (iter_is_ubuf(i))
> + return (unsigned long)i->ubuf + i->iov_offset;
>
> for (k = 0, skip = i->iov_offset; k < i->nr_segs; k++, skip = 0) {
> - unsigned long addr = (unsigned long)i->iov[k].iov_base + skip;
> size_t len = i->iov[k].iov_len - skip;
> -
> if (unlikely(!len))
> continue;
> if (*size > len)
> *size = len;
> - return found_ubuf_segment(addr, start);
> + return (unsigned long)i->iov[k].iov_base + skip;
> }
> BUG(); // if it had been empty, we wouldn't get called
> }
> @@ -1375,7 +1365,9 @@ static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i,
> if (i->nofault)
> gup_flags |= FOLL_NOFAULT;
>
> - addr = first_iovec_segment(i, &maxsize, start);
> + addr = first_iovec_segment(i, &maxsize);
> + *start = addr % PAGE_SIZE;
> + addr &= PAGE_MASK;
> n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE);
> if (n > maxpages)
> n = maxpages;
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
