new helper: add_to_pipe()
single-buffer analogue of splice_to_pipe(); vmsplice_to_pipe() switched
to that, leaving splice_to_pipe() only for ->splice_read() instances
(and that only until they are converted as well).
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/splice.c b/fs/splice.c
index 2ca7e69..e13d935 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -203,8 +203,6 @@
buf->len = spd->partial[page_nr].len;
buf->private = spd->partial[page_nr].private;
buf->ops = spd->ops;
- if (spd->flags & SPLICE_F_GIFT)
- buf->flags |= PIPE_BUF_FLAG_GIFT;
pipe->nrbufs++;
page_nr++;
@@ -225,6 +223,27 @@
}
EXPORT_SYMBOL_GPL(splice_to_pipe);
+ssize_t add_to_pipe(struct pipe_inode_info *pipe, struct pipe_buffer *buf)
+{
+ int ret;
+
+ if (unlikely(!pipe->readers)) {
+ send_sig(SIGPIPE, current, 0);
+ ret = -EPIPE;
+ } else if (pipe->nrbufs == pipe->buffers) {
+ ret = -EAGAIN;
+ } else {
+ int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
+ pipe->bufs[newbuf] = *buf;
+ pipe->nrbufs++;
+ return buf->len;
+ }
+ buf->ops->release(pipe, buf);
+ buf->ops = NULL;
+ return ret;
+}
+EXPORT_SYMBOL(add_to_pipe);
+
void spd_release_page(struct splice_pipe_desc *spd, unsigned int i)
{
put_page(spd->pages[i]);
@@ -1415,32 +1434,50 @@
return -EINVAL;
}
-static int get_iovec_page_array(struct iov_iter *from,
- struct page **pages,
- struct partial_page *partial,
- unsigned int pipe_buffers)
+static int iter_to_pipe(struct iov_iter *from,
+ struct pipe_inode_info *pipe,
+ unsigned flags)
{
- int buffers = 0;
- while (iov_iter_count(from)) {
+ struct pipe_buffer buf = {
+ .ops = &user_page_pipe_buf_ops,
+ .flags = flags
+ };
+ size_t total = 0;
+ int ret = 0;
+ bool failed = false;
+
+ while (iov_iter_count(from) && !failed) {
+ struct page *pages[16];
ssize_t copied;
size_t start;
+ int n;
- copied = iov_iter_get_pages(from, pages + buffers, ~0UL,
- pipe_buffers - buffers, &start);
- if (copied <= 0)
- return buffers ? buffers : copied;
+ copied = iov_iter_get_pages(from, pages, ~0UL, 16, &start);
+ if (copied <= 0) {
+ ret = copied;
+ break;
+ }
- iov_iter_advance(from, copied);
- while (copied) {
+ for (n = 0; copied; n++, start = 0) {
int size = min_t(int, copied, PAGE_SIZE - start);
- partial[buffers].offset = start;
- partial[buffers].len = size;
+ if (!failed) {
+ buf.page = pages[n];
+ buf.offset = start;
+ buf.len = size;
+ ret = add_to_pipe(pipe, &buf);
+ if (unlikely(ret < 0)) {
+ failed = true;
+ } else {
+ iov_iter_advance(from, ret);
+ total += ret;
+ }
+ } else {
+ put_page(pages[n]);
+ }
copied -= size;
- start = 0;
- buffers++;
}
}
- return buffers;
+ return total ? total : ret;
}
static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
@@ -1501,17 +1538,11 @@
struct iovec iovstack[UIO_FASTIOV];
struct iovec *iov = iovstack;
struct iov_iter from;
- struct page *pages[PIPE_DEF_BUFFERS];
- struct partial_page partial[PIPE_DEF_BUFFERS];
- struct splice_pipe_desc spd = {
- .pages = pages,
- .partial = partial,
- .nr_pages_max = PIPE_DEF_BUFFERS,
- .flags = flags,
- .ops = &user_page_pipe_buf_ops,
- .spd_release = spd_release_page,
- };
long ret;
+ unsigned buf_flag = 0;
+
+ if (flags & SPLICE_F_GIFT)
+ buf_flag = PIPE_BUF_FLAG_GIFT;
pipe = get_pipe_info(file);
if (!pipe)
@@ -1522,26 +1553,13 @@
if (ret < 0)
return ret;
- if (splice_grow_spd(pipe, &spd)) {
- kfree(iov);
- return -ENOMEM;
- }
-
pipe_lock(pipe);
ret = wait_for_space(pipe, flags);
- if (!ret) {
- spd.nr_pages = get_iovec_page_array(&from, spd.pages,
- spd.partial,
- spd.nr_pages_max);
- if (spd.nr_pages <= 0)
- ret = spd.nr_pages;
- else
- ret = splice_to_pipe(pipe, &spd);
- }
+ if (!ret)
+ ret = iter_to_pipe(&from, pipe, buf_flag);
pipe_unlock(pipe);
if (ret > 0)
wakeup_pipe_readers(pipe);
- splice_shrink_spd(&spd);
kfree(iov);
return ret;
}
diff --git a/include/linux/splice.h b/include/linux/splice.h
index da2751d..58b300f 100644
--- a/include/linux/splice.h
+++ b/include/linux/splice.h
@@ -72,6 +72,8 @@
struct splice_desc *, splice_actor *);
extern ssize_t splice_to_pipe(struct pipe_inode_info *,
struct splice_pipe_desc *);
+extern ssize_t add_to_pipe(struct pipe_inode_info *,
+ struct pipe_buffer *);
extern ssize_t splice_direct_to_actor(struct file *, struct splice_desc *,
splice_direct_actor *);