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pipe_get_pages(): switch to append_pipe()

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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>
This commit is contained in:
Al Viro 2022-06-14 16:38:53 -04:00
parent eba2d3d798
commit 746de1f86f
1 changed files with 6 additions and 29 deletions
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35
lib/iov_iter.c
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@ -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,