Commit 2c855de9 authored by Al Viro's avatar Al Viro
Browse files

ITER_PIPE: clean pipe_advance() up 



instead of setting ->iov_offset for new position and calling
pipe_truncate() to adjust ->len of the last buffer and discard
everything after it, adjust ->len at the same time we set ->iov_offset
and use pipe_discard_from() to deal with buffers past that.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent ca591967

lib/iov_iter.c

+17 −17
Original line number Diff line number Diff line
@@ -845,27 +845,27 @@ static inline void pipe_truncate(struct iov_iter *i) 
static void pipe_advance(struct iov_iter *i, size_t size)

{

	struct pipe_inode_info *pipe = i->pipe;

	if (size) {

		struct pipe_buffer *buf;

		unsigned int p_mask = pipe->ring_size - 1;

		unsigned int i_head = i->head;

		size_t off = i->iov_offset, left = size;

	unsigned int off = i->iov_offset;



		if (off) /* make it relative to the beginning of buffer */

			left += off - pipe->bufs[i_head & p_mask].offset;

	if (!off && !size) {

		pipe_discard_from(pipe, i->start_head); // discard everything

		return;

	}

	i->count -= size;

	while (1) {

			buf = &pipe->bufs[i_head & p_mask];

			if (left <= buf->len)

		struct pipe_buffer *buf = pipe_buf(pipe, i->head);

		if (off) /* make it relative to the beginning of buffer */

			size += off - buf->offset;

		if (size <= buf->len) {

			buf->len = size;

			i->iov_offset = buf->offset + size;

			break;

			left -= buf->len;

			i_head++;

		}

		i->head = i_head;

		i->iov_offset = buf->offset + left;

		size -= buf->len;

		i->head++;

		off = 0;

	}

	i->count -= size;

	/* ... and discard everything past that point */

	pipe_truncate(i);

	pipe_discard_from(pipe, i->head + 1); // discard everything past this one

}



static void iov_iter_bvec_advance(struct iov_iter *i, size_t size)