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authorAl Viro <viro@zeniv.linux.org.uk>2022-06-11 02:52:03 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2022-08-08 22:37:17 -0400
commite3b42964f84c028f352c11269661d47f6ca4ab2e (patch)
treea74959fdf8e98b0333abb88b223871ff3da4524a /lib/iov_iter.c
parent8fad7767edcfd3f93e0d9985cb2dc1db270b8719 (diff)
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: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'lib/iov_iter.c')
-rw-r--r--lib/iov_iter.c80
1 files changed, 25 insertions, 55 deletions
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index e22c272cb420..bf600b4fe980 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -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)
{
@@ -1359,23 +1319,33 @@ 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);
- return maxsize;
+ 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,
@@ -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