[PATCH v4 06/19] ublk: split out ublk_user_copy() helper

[Caleb Sander Mateos <csander@purestorage.com>]

ublk_ch_read_iter() and ublk_ch_write_iter() are nearly identical except
for the iter direction. Split out a helper function ublk_user_copy() to
reduce the code duplication as these functions are about to get larger.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
---
 drivers/block/ublk_drv.c | 26 ++++++++++----------------
 1 file changed, 10 insertions(+), 16 deletions(-)

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index 22e82bbf50ce..225372cca404 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -2700,42 +2700,36 @@ static struct request *ublk_check_and_get_req(struct kiocb *iocb,
 fail:
 	ublk_put_req_ref(*io, req);
 	return ERR_PTR(-EACCES);
 }
 
-static ssize_t ublk_ch_read_iter(struct kiocb *iocb, struct iov_iter *to)
+static ssize_t
+ublk_user_copy(struct kiocb *iocb, struct iov_iter *iter, int dir)
 {
 	struct request *req;
 	struct ublk_io *io;
 	size_t buf_off;
 	size_t ret;
 
-	req = ublk_check_and_get_req(iocb, to, &buf_off, ITER_DEST, &io);
+	req = ublk_check_and_get_req(iocb, iter, &buf_off, dir, &io);
 	if (IS_ERR(req))
 		return PTR_ERR(req);
 
-	ret = ublk_copy_user_pages(req, buf_off, to, ITER_DEST);
+	ret = ublk_copy_user_pages(req, buf_off, iter, dir);
 	ublk_put_req_ref(io, req);
 
 	return ret;
 }
 
-static ssize_t ublk_ch_write_iter(struct kiocb *iocb, struct iov_iter *from)
+static ssize_t ublk_ch_read_iter(struct kiocb *iocb, struct iov_iter *to)
 {
-	struct request *req;
-	struct ublk_io *io;
-	size_t buf_off;
-	size_t ret;
-
-	req = ublk_check_and_get_req(iocb, from, &buf_off, ITER_SOURCE, &io);
-	if (IS_ERR(req))
-		return PTR_ERR(req);
-
-	ret = ublk_copy_user_pages(req, buf_off, from, ITER_SOURCE);
-	ublk_put_req_ref(io, req);
+	return ublk_user_copy(iocb, to, ITER_DEST);
+}
 
-	return ret;
+static ssize_t ublk_ch_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+	return ublk_user_copy(iocb, from, ITER_SOURCE);
 }
 
 static const struct file_operations ublk_ch_fops = {
 	.owner = THIS_MODULE,
 	.open = ublk_ch_open,
-- 
2.45.2