Merge branch 'work.splice_read' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull VFS splice updates from Al Viro:
 "There's a bunch of branches this cycle, both mine and from other folks
  and I'd rather send pull requests separately.

  This one is the conversion of ->splice_read() to ITER_PIPE iov_iter
  (and introduction of such). Gets rid of a lot of code in fs/splice.c
  and elsewhere; there will be followups, but these are for the next
  cycle...  Some pipe/splice-related cleanups from Miklos in the same
  branch as well"

* 'work.splice_read' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  pipe: fix comment in pipe_buf_operations
  pipe: add pipe_buf_steal() helper
  pipe: add pipe_buf_confirm() helper
  pipe: add pipe_buf_release() helper
  pipe: add pipe_buf_get() helper
  relay: simplify relay_file_read()
  switch default_file_splice_read() to use of pipe-backed iov_iter
  switch generic_file_splice_read() to use of ->read_iter()
  new iov_iter flavour: pipe-backed
  fuse_dev_splice_read(): switch to add_to_pipe()
  skb_splice_bits(): get rid of callback
  new helper: add_to_pipe()
  splice: lift pipe_lock out of splice_to_pipe()
  splice: switch get_iovec_page_array() to iov_iter
  splice_to_pipe(): don't open-code wakeup_pipe_readers()
  consistent treatment of EFAULT on O_DIRECT read/write

1 files changed, 16 insertions, 47 deletions

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index c41bde26c338..70ea57c7b6bb 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -728,7 +728,7 @@ static int fuse_copy_fill(struct fuse_copy_state *cs)
 		struct pipe_buffer *buf = cs->pipebufs;
 
 		if (!cs->write) {
-			err = buf->ops->confirm(cs->pipe, buf);
+			err = pipe_buf_confirm(cs->pipe, buf);
 			if (err)
 				return err;
 
@@ -827,7 +827,7 @@ static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
 
 	fuse_copy_finish(cs);
 
-	err = buf->ops->confirm(cs->pipe, buf);
+	err = pipe_buf_confirm(cs->pipe, buf);
 	if (err)
 		return err;
 
@@ -840,7 +840,7 @@ static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
 	if (cs->len != PAGE_SIZE)
 		goto out_fallback;
 
-	if (buf->ops->steal(cs->pipe, buf) != 0)
+	if (pipe_buf_steal(cs->pipe, buf) != 0)
 		goto out_fallback;
 
 	newpage = buf->page;
@@ -1341,9 +1341,8 @@ static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
 				    struct pipe_inode_info *pipe,
 				    size_t len, unsigned int flags)
 {
-	int ret;
+	int total, ret;
 	int page_nr = 0;
-	int do_wakeup = 0;
 	struct pipe_buffer *bufs;
 	struct fuse_copy_state cs;
 	struct fuse_dev *fud = fuse_get_dev(in);
@@ -1362,52 +1361,23 @@ static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
 	if (ret < 0)
 		goto out;
 
-	ret = 0;
-	pipe_lock(pipe);
-
-	if (!pipe->readers) {
-		send_sig(SIGPIPE, current, 0);
-		if (!ret)
-			ret = -EPIPE;
-		goto out_unlock;
-	}
-
 	if (pipe->nrbufs + cs.nr_segs > pipe->buffers) {
 		ret = -EIO;
-		goto out_unlock;
+		goto out;
 	}
 
-	while (page_nr < cs.nr_segs) {
-		int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
-		struct pipe_buffer *buf = pipe->bufs + newbuf;
-
-		buf->page = bufs[page_nr].page;
-		buf->offset = bufs[page_nr].offset;
-		buf->len = bufs[page_nr].len;
+	for (ret = total = 0; page_nr < cs.nr_segs; total += ret) {
 		/*
 		 * Need to be careful about this.  Having buf->ops in module
 		 * code can Oops if the buffer persists after module unload.
 		 */
-		buf->ops = &nosteal_pipe_buf_ops;
-
-		pipe->nrbufs++;
-		page_nr++;
-		ret += buf->len;
-
-		if (pipe->files)
-			do_wakeup = 1;
-	}
-
-out_unlock:
-	pipe_unlock(pipe);
-
-	if (do_wakeup) {
-		smp_mb();
-		if (waitqueue_active(&pipe->wait))
-			wake_up_interruptible(&pipe->wait);
-		kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
+		bufs[page_nr].ops = &nosteal_pipe_buf_ops;
+		ret = add_to_pipe(pipe, &bufs[page_nr++]);
+		if (unlikely(ret < 0))
+			break;
 	}
-
+	if (total)
+		ret = total;
 out:
 	for (; page_nr < cs.nr_segs; page_nr++)
 		put_page(bufs[page_nr].page);
@@ -1992,7 +1962,7 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
 			pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
 			pipe->nrbufs--;
 		} else {
-			ibuf->ops->get(pipe, ibuf);
+			pipe_buf_get(pipe, ibuf);
 			*obuf = *ibuf;
 			obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
 			obuf->len = rem;
@@ -2014,10 +1984,9 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
 
 	ret = fuse_dev_do_write(fud, &cs, len);
 
-	for (idx = 0; idx < nbuf; idx++) {
-		struct pipe_buffer *buf = &bufs[idx];
-		buf->ops->release(pipe, buf);
-	}
+	for (idx = 0; idx < nbuf; idx++)
+		pipe_buf_release(pipe, &bufs[idx]);
+
 out:
 	kfree(bufs);
 	return ret;