[PATCH 2/3] splice: remove the old default splice_read/splice_write implementations

[Christoph Hellwig <hch@xxxxxx>]

Everything sensible now either has explicit splice_read/write methods or
implements ->read_iter/->write_iter.  Remove the old default
implementations and just return -EINVAL in that case.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
 fs/splice.c | 112 ++----------------------------------------------------------
 1 file changed, 2 insertions(+), 110 deletions(-)

diff --git a/fs/splice.c b/fs/splice.c
index ecf8d6edbb30..1117db47376b 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -347,22 +347,6 @@ const struct pipe_buf_operations nosteal_pipe_buf_ops = {
 };
 EXPORT_SYMBOL(nosteal_pipe_buf_ops);
 
-static ssize_t kernel_readv(struct file *file, const struct kvec *vec,
-			    unsigned long vlen, loff_t offset)
-{
-	mm_segment_t old_fs;
-	loff_t pos = offset;
-	ssize_t res;
-
-	old_fs = get_fs();
-	set_fs(get_ds());
-	/* The cast to a user pointer is valid due to the set_fs() */
-	res = vfs_readv(file, (const struct iovec __user *)vec, vlen, &pos, 0);
-	set_fs(old_fs);
-
-	return res;
-}
-
 ssize_t kernel_write(struct file *file, const char *buf, size_t count,
 			    loff_t pos)
 {
@@ -379,71 +363,6 @@ ssize_t kernel_write(struct file *file, const char *buf, size_t count,
 }
 EXPORT_SYMBOL(kernel_write);
 
-static ssize_t default_file_splice_read(struct file *in, loff_t *ppos,
-				 struct pipe_inode_info *pipe, size_t len,
-				 unsigned int flags)
-{
-	struct kvec *vec, __vec[PIPE_DEF_BUFFERS];
-	struct iov_iter to;
-	struct page **pages;
-	unsigned int nr_pages;
-	size_t offset, base, copied = 0;
-	ssize_t res;
-	int i;
-
-	if (pipe->nrbufs == pipe->buffers)
-		return -EAGAIN;
-
-	/*
-	 * Try to keep page boundaries matching to source pagecache ones -
-	 * it probably won't be much help, but...
-	 */
-	offset = *ppos & ~PAGE_MASK;
-
-	iov_iter_pipe(&to, ITER_PIPE | READ, pipe, len + offset);
-
-	res = iov_iter_get_pages_alloc(&to, &pages, len + offset, &base);
-	if (res <= 0)
-		return -ENOMEM;
-
-	nr_pages = DIV_ROUND_UP(res + base, PAGE_SIZE);
-
-	vec = __vec;
-	if (nr_pages > PIPE_DEF_BUFFERS) {
-		vec = kmalloc(nr_pages * sizeof(struct kvec), GFP_KERNEL);
-		if (unlikely(!vec)) {
-			res = -ENOMEM;
-			goto out;
-		}
-	}
-
-	pipe->bufs[to.idx].offset = offset;
-	pipe->bufs[to.idx].len -= offset;
-
-	for (i = 0; i < nr_pages; i++) {
-		size_t this_len = min_t(size_t, len, PAGE_SIZE - offset);
-		vec[i].iov_base = page_address(pages[i]) + offset;
-		vec[i].iov_len = this_len;
-		len -= this_len;
-		offset = 0;
-	}
-
-	res = kernel_readv(in, vec, nr_pages, *ppos);
-	if (res > 0) {
-		copied = res;
-		*ppos += res;
-	}
-
-	if (vec != __vec)
-		kfree(vec);
-out:
-	for (i = 0; i < nr_pages; i++)
-		put_page(pages[i]);
-	kvfree(pages);
-	iov_iter_advance(&to, copied);	/* truncates and discards */
-	return res;
-}
-
 /*
  * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos'
  * using sendpage(). Return the number of bytes sent.
@@ -801,33 +720,6 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
 
 EXPORT_SYMBOL(iter_file_splice_write);
 
-static int write_pipe_buf(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
-			  struct splice_desc *sd)
-{
-	int ret;
-	void *data;
-	loff_t tmp = sd->pos;
-
-	data = kmap(buf->page);
-	ret = __kernel_write(sd->u.file, data + buf->offset, sd->len, &tmp);
-	kunmap(buf->page);
-
-	return ret;
-}
-
-static ssize_t default_file_splice_write(struct pipe_inode_info *pipe,
-					 struct file *out, loff_t *ppos,
-					 size_t len, unsigned int flags)
-{
-	ssize_t ret;
-
-	ret = splice_from_pipe(pipe, out, ppos, len, flags, write_pipe_buf);
-	if (ret > 0)
-		*ppos += ret;
-
-	return ret;
-}
-
 /**
  * generic_splice_sendpage - splice data from a pipe to a socket
  * @pipe:	pipe to splice from
@@ -863,7 +755,7 @@ static long do_splice_from(struct pipe_inode_info *pipe, struct file *out,
 	else if (out->f_op->write_iter)
 		splice_write = iter_file_splice_write;
 	else
-		splice_write = default_file_splice_write;
+		return -EINVAL;
 
 	return splice_write(pipe, out, ppos, len, flags);
 }
@@ -894,7 +786,7 @@ static long do_splice_to(struct file *in, loff_t *ppos,
 	else if (in->f_op->read_iter)
 		splice_read = iter_file_splice_read;
 	else
-		splice_read = default_file_splice_read;
+		return -EINVAL;
 
 	return splice_read(in, ppos, pipe, len, flags);
 }
-- 
2.11.0