pipe_get_pages(): switch to append_pipe()

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@zeniv.linux.org.uk>

diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index c48c836..415d51b 100644 (file)
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1304,10 +1304,9 @@ 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, off, chunk;
        struct page **p;
-       ssize_t left;
+       size_t left;
 
        if (!sanity(i))
                return -EFAULT;
@@ -1319,38 +1318,16 @@ 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++, left -= chunk) {
+               struct page *page = append_pipe(i, left, &off);
                if (!page)
                        break;
+               chunk = min_t(size_t, left, PAGE_SIZE - off);
                get_page(*p++ = page);
-               left -= size;
        }
        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,