Commit e3b42964 authored by Al Viro's avatar Al Viro
Browse files

ITER_PIPE: fold push_pipe() into __pipe_get_pages() 



	Expand the only remaining call of push_pipe() (in
__pipe_get_pages()), combine it with the page-collecting loop there.

Note that the only reason it's not a loop doing append_pipe() is
that append_pipe() is advancing, while iov_iter_get_pages() is not.
As soon as it switches to saner semantics, this thing will switch
to using append_pipe().

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 8fad7767

lib/iov_iter.c

+25 −55
Original line number Diff line number Diff line
@@ -450,46 +450,6 @@ static inline void data_start(const struct iov_iter *i, 
	*offp = off;

}



static size_t push_pipe(struct iov_iter *i, size_t size,

			int *iter_headp, size_t *offp)

{

	struct pipe_inode_info *pipe = i->pipe;

	unsigned int iter_head;

	size_t off;

	ssize_t left;



	if (unlikely(size > i->count))

		size = i->count;

	if (unlikely(!size))

		return 0;



	left = size;

	data_start(i, &iter_head, &off);

	*iter_headp = iter_head;

	*offp = off;

	if (off) {

		struct pipe_buffer *buf = pipe_buf(pipe, iter_head);



		left -= PAGE_SIZE - off;

		if (left <= 0) {

			buf->len += size;

			return size;

		}

		buf->len = PAGE_SIZE;

	}

	while (!pipe_full(pipe->head, pipe->tail, pipe->max_usage)) {

		struct page *page = push_anon(pipe,

					      min_t(ssize_t, left, PAGE_SIZE));

		if (!page)

			break;



		left -= PAGE_SIZE;

		if (left <= 0)

			return size;

	}

	return size - left;

}



static size_t copy_pipe_to_iter(const void *addr, size_t bytes,

				struct iov_iter *i)

{
@@ -1359,24 +1319,34 @@ static inline ssize_t __pipe_get_pages(struct iov_iter *i, 
				size_t maxsize,

				struct page **pages,

				int iter_head,

				size_t *start)

				size_t off)

{

	struct pipe_inode_info *pipe = i->pipe;

	unsigned int p_mask = pipe->ring_size - 1;

	ssize_t n = push_pipe(i, maxsize, &iter_head, start);

	if (!n)

		return -EFAULT;

	ssize_t left = maxsize;



	maxsize = n;

	n += *start;

	while (n > 0) {

		get_page(*pages++ = pipe->bufs[iter_head & p_mask].page);

		iter_head++;

		n -= PAGE_SIZE;

	}

	if (off) {

		struct pipe_buffer *buf = pipe_buf(pipe, iter_head);



		get_page(*pages++ = buf->page);

		left -= PAGE_SIZE - off;

		if (left <= 0) {

			buf->len += maxsize;

			return maxsize;

		}

		buf->len = PAGE_SIZE;

	}

	while (!pipe_full(pipe->head, pipe->tail, pipe->max_usage)) {

		struct page *page = push_anon(pipe,

					      min_t(ssize_t, left, PAGE_SIZE));

		if (!page)

			break;

		get_page(*pages++ = page);

		left -= PAGE_SIZE;

		if (left <= 0)

			return maxsize;

	}

	return maxsize - left ? : -EFAULT;

}



static ssize_t pipe_get_pages(struct iov_iter *i,

		   struct page **pages, size_t maxsize, unsigned maxpages,
@@ -1393,7 +1363,7 @@ static ssize_t pipe_get_pages(struct iov_iter *i, 
	npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe);

	capacity = min(npages, maxpages) * PAGE_SIZE - *start;



	return __pipe_get_pages(i, min(maxsize, capacity), pages, iter_head, start);

	return __pipe_get_pages(i, min(maxsize, capacity), pages, iter_head, *start);

}



static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa,
@@ -1575,7 +1545,7 @@ static ssize_t pipe_get_pages_alloc(struct iov_iter *i, 
	p = get_pages_array(npages);

	if (!p)

		return -ENOMEM;

	n = __pipe_get_pages(i, maxsize, p, iter_head, start);

	n = __pipe_get_pages(i, maxsize, p, iter_head, *start);

	if (n > 0)

		*pages = p;

	else