Commit 79fddc4e authored by Al Viro's avatar Al Viro

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: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 8924feff
......@@ -203,8 +203,6 @@ ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
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 @@ ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
}
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 @@ static long do_splice(struct file *in, loff_t __user *off_in,
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 @@ static long vmsplice_to_pipe(struct file *file, const struct iovec __user *uiov,
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 @@ static long vmsplice_to_pipe(struct file *file, const struct iovec __user *uiov,
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;
}
......
......@@ -72,6 +72,8 @@ extern ssize_t __splice_from_pipe(struct pipe_inode_info *,
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 *);
......
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