[RFC -next 02/10] splice: Add helper that passes through splice_desc

[Joe Damato <jdamato@fastly.com>]

Add do_splice_from_sd which takes splice_desc as an argument. This
helper is just a wrapper around splice_write but will be extended. Use
the helper from existing splice code.

Signed-off-by: Joe Damato <jdamato@fastly.com>
---
 fs/splice.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/fs/splice.c b/fs/splice.c
index 2898fa1e9e63..9575074a1296 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -941,6 +941,15 @@ static ssize_t do_splice_from(struct pipe_inode_info *pipe, struct file *out,
 	return out->f_op->splice_write(pipe, out, ppos, len, flags);
 }
 
+static ssize_t do_splice_from_sd(struct pipe_inode_info *pipe, struct file *out,
+				 struct splice_desc *sd)
+{
+	if (unlikely(!out->f_op->splice_write))
+		return warn_unsupported(out, "write");
+	return out->f_op->splice_write(pipe, out, sd->opos, sd->total_len,
+				       sd->flags);
+}
+
 /*
  * Indicate to the caller that there was a premature EOF when reading from the
  * source and the caller didn't indicate they would be sending more data after
@@ -1161,7 +1170,7 @@ static int direct_splice_actor(struct pipe_inode_info *pipe,
 	long ret;
 
 	file_start_write(file);
-	ret = do_splice_from(pipe, file, sd->opos, sd->total_len, sd->flags);
+	ret = do_splice_from_sd(pipe, file, sd);
 	file_end_write(file);
 	return ret;
 }
@@ -1171,7 +1180,7 @@ static int splice_file_range_actor(struct pipe_inode_info *pipe,
 {
 	struct file *file = sd->u.file;
 
-	return do_splice_from(pipe, file, sd->opos, sd->total_len, sd->flags);
+	return do_splice_from_sd(pipe, file, sd);
 }
 
 static void direct_file_splice_eof(struct splice_desc *sd)
-- 
2.43.0