On Wed, 2022-06-22 at 05:15 +0100, Al Viro wrote:
> ... and untangle the cleanup on failure to add into pipe.
>
> Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> ---
> fs/splice.c | 47 ++++++++++++++++++++++++-----------------------
> 1 file changed, 24 insertions(+), 23 deletions(-)
>
> diff --git a/fs/splice.c b/fs/splice.c
> index 6645b30ec990..9f84bd21f64c 100644
> --- a/fs/splice.c
> +++ b/fs/splice.c
> @@ -1160,39 +1160,40 @@ static int iter_to_pipe(struct iov_iter *from,
> };
> size_t total = 0;
> int ret = 0;
> - bool failed = false;
>
> - while (iov_iter_count(from) && !failed) {
> + while (iov_iter_count(from)) {
> struct page *pages[16];
> - ssize_t copied;
> + ssize_t left;
> size_t start;
> - int n;
> + int i, n;
>
> - copied = iov_iter_get_pages(from, pages, ~0UL, 16, &start);
> - if (copied <= 0) {
> - ret = copied;
> + left = iov_iter_get_pages2(from, pages, ~0UL, 16, &start);
> + if (left <= 0) {
> + ret = left;
> break;
> }
>
> - for (n = 0; copied; n++, start = 0) {
> - int size = min_t(int, copied, PAGE_SIZE - start);
> - if (!failed) {
> - buf.page = pages[n];
> - buf.offset = start;
> - buf.len = size;
> - ret = add_to_pipe(pipe, &buf);
> - if (unlikely(ret < 0)) {
> - failed = true;
> - } else {
> - iov_iter_advance(from, ret);
> - total += ret;
> - }
> - } else {
> - put_page(pages[n]);
> + n = DIV_ROUND_UP(left + start, PAGE_SIZE);
> + for (i = 0; i < n; i++) {
> + int size = min_t(int, left, PAGE_SIZE - start);
> +
> + buf.page = pages[i];
> + buf.offset = start;
> + buf.len = size;
> + ret = add_to_pipe(pipe, &buf);
> + if (unlikely(ret < 0)) {
> + iov_iter_revert(from, left);
> + // this one got dropped by add_to_pipe()
> + while (++i < n)
> + put_page(pages[i]);
> + goto out;
> }
> - copied -= size;
> + total += ret;
> + left -= size;
> + start = 0;
> }
> }
> +out:
> return total ? total : ret;
> }
>
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
