On Wed, 2022-06-22 at 05:15 +0100, Al Viro wrote:
> now that we are advancing the iterator, there's no need to
> treat the first page separately - just call append_pipe()
> in a loop.
>
> Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> ---
> lib/iov_iter.c | 36 ++++++++----------------------------
> 1 file changed, 8 insertions(+), 28 deletions(-)
>
> diff --git a/lib/iov_iter.c b/lib/iov_iter.c
> index 70736b3e07c5..a8045c97b975 100644
> --- a/lib/iov_iter.c
> +++ b/lib/iov_iter.c
> @@ -1207,10 +1207,10 @@ static ssize_t pipe_get_pages(struct iov_iter *i,
> struct page ***pages, size_t maxsize, unsigned maxpages,
> size_t *start)
> {
> - struct pipe_inode_info *pipe = i->pipe;
> - unsigned int npages, off, count;
> + unsigned int npages, count;
> struct page **p;
> ssize_t left;
> + size_t off;
>
> if (!sanity(i))
> return -EFAULT;
> @@ -1222,38 +1222,18 @@ static ssize_t pipe_get_pages(struct iov_iter *i,
> if (!count)
> return -ENOMEM;
> p = *pages;
> - left = maxsize;
> - npages = 0;
> - if (off) {
> - struct pipe_buffer *buf = pipe_buf(pipe, pipe->head - 1);
> -
> - get_page(*p++ = buf->page);
> - left -= PAGE_SIZE - off;
> - if (left <= 0) {
> - buf->len += maxsize;
> - iov_iter_advance(i, maxsize);
> - return maxsize;
> - }
> - buf->len = PAGE_SIZE;
> - npages = 1;
> - }
> - for ( ; npages < count; npages++) {
> - struct page *page;
> - unsigned int size = min_t(ssize_t, left, PAGE_SIZE);
> -
> - if (pipe_full(pipe->head, pipe->tail, pipe->max_usage))
> - break;
> - page = push_anon(pipe, size);
> + for (npages = 0, left = maxsize ; npages < count; npages++) {
> + struct page *page = append_pipe(i, left, &off);
> if (!page)
> break;
> get_page(*p++ = page);
> - left -= size;
> + if (left <= PAGE_SIZE - off)
> + return maxsize;
> + left -= PAGE_SIZE - off;
> }
> if (!npages)
> return -EFAULT;
> - maxsize -= left;
> - iov_iter_advance(i, maxsize);
> - return maxsize;
> + return maxsize - left;
> }
>
> static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa,
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
