[PATCH] splice: direct call for default_file_splice*()

From: Pavel Begunkov
Date: Mon Jan 20 2020 - 15:51:08 EST


Indirect calls could be very expensive nowadays, so try to use direct calls
whenever possible.

Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
---
fs/splice.c | 17 ++++-------------
1 file changed, 4 insertions(+), 13 deletions(-)

diff --git a/fs/splice.c b/fs/splice.c
index 6a6f30432688..91448d855ff0 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -852,15 +852,10 @@ EXPORT_SYMBOL(generic_splice_sendpage);
static long do_splice_from(struct pipe_inode_info *pipe, struct file *out,
loff_t *ppos, size_t len, unsigned int flags)
{
- ssize_t (*splice_write)(struct pipe_inode_info *, struct file *,
- loff_t *, size_t, unsigned int);
-
if (out->f_op->splice_write)
- splice_write = out->f_op->splice_write;
+ return out->f_op->splice_write(pipe, out, ppos, len, flags);
else
- splice_write = default_file_splice_write;
-
- return splice_write(pipe, out, ppos, len, flags);
+ return default_file_splice_write(pipe, out, ppos, len, flags);
}

/*
@@ -870,8 +865,6 @@ static long do_splice_to(struct file *in, loff_t *ppos,
struct pipe_inode_info *pipe, size_t len,
unsigned int flags)
{
- ssize_t (*splice_read)(struct file *, loff_t *,
- struct pipe_inode_info *, size_t, unsigned int);
int ret;

if (unlikely(!(in->f_mode & FMODE_READ)))
@@ -885,11 +878,9 @@ static long do_splice_to(struct file *in, loff_t *ppos,
len = MAX_RW_COUNT;

if (in->f_op->splice_read)
- splice_read = in->f_op->splice_read;
+ return in->f_op->splice_read(in, ppos, pipe, len, flags);
else
- splice_read = default_file_splice_read;
-
- return splice_read(in, ppos, pipe, len, flags);
+ return default_file_splice_read(in, ppos, pipe, len, flags);
}

/**
--
2.24.0