1 files changed, 34 insertions, 42 deletions

diff --git a/fs/splice.c b/fs/splice.c
index 7a423ef8f854..4247933f9eaa 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -299,7 +299,7 @@ ssize_t direct_splice_read(struct file *in, loff_t *ppos,
 	struct kiocb kiocb;
 	struct page **pages;
 	ssize_t ret;
-	size_t used, npages, chunk, remain, reclaim;
+	size_t used, npages, chunk, remain, keep = 0;
 	int i;
 
 	/* Work out how much data we can actually add into the pipe */
@@ -313,7 +313,7 @@ ssize_t direct_splice_read(struct file *in, loff_t *ppos,
 	if (!bv)
 		return -ENOMEM;
 
-	pages = (void *)(bv + npages);
+	pages = (struct page **)(bv + npages);
 	npages = alloc_pages_bulk_array(GFP_USER, npages, pages);
 	if (!npages) {
 		kfree(bv);
@@ -336,11 +336,8 @@ ssize_t direct_splice_read(struct file *in, loff_t *ppos,
 	kiocb.ki_pos = *ppos;
 	ret = call_read_iter(in, &kiocb, &to);
 
-	reclaim = npages * PAGE_SIZE;
-	remain = 0;
 	if (ret > 0) {
-		reclaim -= ret;
-		remain = ret;
+		keep = DIV_ROUND_UP(ret, PAGE_SIZE);
 		*ppos = kiocb.ki_pos;
 		file_accessed(in);
 	} else if (ret < 0) {
@@ -353,14 +350,12 @@ ssize_t direct_splice_read(struct file *in, loff_t *ppos,
 	}
 
 	/* Free any pages that didn't get touched at all. */
-	reclaim /= PAGE_SIZE;
-	if (reclaim) {
-		npages -= reclaim;
-		release_pages(pages + npages, reclaim);
-	}
+	if (keep < npages)
+		release_pages(pages + keep, npages - keep);
 
 	/* Push the remaining pages into the pipe. */
-	for (i = 0; i < npages; i++) {
+	remain = ret;
+	for (i = 0; i < keep; i++) {
 		struct pipe_buffer *buf = pipe_head_buf(pipe);
 
 		chunk = min_t(size_t, remain, PAGE_SIZE);
@@ -396,29 +391,13 @@ ssize_t generic_file_splice_read(struct file *in, loff_t *ppos,
 				 struct pipe_inode_info *pipe, size_t len,
 				 unsigned int flags)
 {
-	struct iov_iter to;
-	struct kiocb kiocb;
-	int ret;
-
-	iov_iter_pipe(&to, ITER_DEST, pipe, len);
-	init_sync_kiocb(&kiocb, in);
-	kiocb.ki_pos = *ppos;
-	ret = call_read_iter(in, &kiocb, &to);
-	if (ret > 0) {
-		*ppos = kiocb.ki_pos;
-		file_accessed(in);
-	} else if (ret < 0) {
-		/* free what was emitted */
-		pipe_discard_from(pipe, to.start_head);
-		/*
-		 * callers of ->splice_read() expect -EAGAIN on
-		 * "can't put anything in there", rather than -EFAULT.
-		 */
-		if (ret == -EFAULT)
-			ret = -EAGAIN;
-	}
-
-	return ret;
+	if (unlikely(*ppos >= file_inode(in)->i_sb->s_maxbytes))
+		return 0;
+	if (unlikely(!len))
+		return 0;
+	if (in->f_flags & O_DIRECT)
+		return direct_splice_read(in, ppos, pipe, len, flags);
+	return filemap_splice_read(in, ppos, pipe, len, flags);
 }
 EXPORT_SYMBOL(generic_file_splice_read);
 
@@ -860,12 +839,24 @@ static long do_splice_from(struct pipe_inode_info *pipe, struct file *out,
 	return out->f_op->splice_write(pipe, out, ppos, len, flags);
 }
 
-/*
- * Attempt to initiate a splice from a file to a pipe.
+/**
+ * vfs_splice_read - Read data from a file and splice it into a pipe
+ * @in:		File to splice from
+ * @ppos:	Input file offset
+ * @pipe:	Pipe to splice to
+ * @len:	Number of bytes to splice
+ * @flags:	Splice modifier flags (SPLICE_F_*)
+ *
+ * Splice the requested amount of data from the input file to the pipe.  This
+ * is synchronous as the caller must hold the pipe lock across the entire
+ * operation.
+ *
+ * If successful, it returns the amount of data spliced, 0 if it hit the EOF or
+ * a hole and a negative error code otherwise.
  */
-static long do_splice_to(struct file *in, loff_t *ppos,
-			 struct pipe_inode_info *pipe, size_t len,
-			 unsigned int flags)
+long vfs_splice_read(struct file *in, loff_t *ppos,
+		     struct pipe_inode_info *pipe, size_t len,
+		     unsigned int flags)
 {
 	unsigned int p_space;
 	int ret;
@@ -888,6 +879,7 @@ static long do_splice_to(struct file *in, loff_t *ppos,
 		return warn_unsupported(in, "read");
 	return in->f_op->splice_read(in, ppos, pipe, len, flags);
 }
+EXPORT_SYMBOL_GPL(vfs_splice_read);
 
 /**
  * splice_direct_to_actor - splices data directly between two non-pipes
@@ -957,7 +949,7 @@ ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd,
 		size_t read_len;
 		loff_t pos = sd->pos, prev_pos = pos;
 
-		ret = do_splice_to(in, &pos, pipe, len, flags);
+		ret = vfs_splice_read(in, &pos, pipe, len, flags);
 		if (unlikely(ret <= 0))
 			goto out_release;
 
@@ -1105,7 +1097,7 @@ long splice_file_to_pipe(struct file *in,
 	pipe_lock(opipe);
 	ret = wait_for_space(opipe, flags);
 	if (!ret)
-		ret = do_splice_to(in, offset, opipe, len, flags);
+		ret = vfs_splice_read(in, offset, opipe, len, flags);
 	pipe_unlock(opipe);
 	if (ret > 0)
 		wakeup_pipe_readers(opipe);