[PATCH 6.18.y 4/6] fuse-uring: refactor setting up copy state for payload copying

[Sasha Levin <sashal@kernel.org>]

From: Joanne Koong <joannelkoong@gmail.com>

[ Upstream commit c0f9203732fc70de8d20697270bfe405481eac14 ]

Add a new helper function setup_fuse_copy_state() to contain the logic
for setting up the copy state for payload copying.

Reviewed-by: Bernd Schubert <bschubert@ddn.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Baokun Li <libaokun@linux.alibaba.com>
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Stable-dep-of: fd10f40af314 ("fuse: copy request headers via a stack buffer for io-uring")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/fuse/dev_uring.c | 38 ++++++++++++++++++++++++--------------
 1 file changed, 24 insertions(+), 14 deletions(-)

diff --git a/fs/fuse/dev_uring.c b/fs/fuse/dev_uring.c
index f3c8f0d8117e1..52e7580ec88fd 100644
--- a/fs/fuse/dev_uring.c
+++ b/fs/fuse/dev_uring.c
@@ -643,6 +643,27 @@ static int copy_header_from_ring(struct fuse_ring_ent *ent,
 	return 0;
 }
 
+static int setup_fuse_copy_state(struct fuse_copy_state *cs,
+				 struct fuse_ring *ring, struct fuse_req *req,
+				 struct fuse_ring_ent *ent, int dir,
+				 struct iov_iter *iter)
+{
+	int err;
+
+	err = import_ubuf(dir, ent->payload, ring->max_payload_sz, iter);
+	if (err) {
+		pr_info_ratelimited("fuse: Import of user buffer failed\n");
+		return err;
+	}
+
+	fuse_copy_init(cs, dir == ITER_DEST, iter);
+
+	cs->is_uring = true;
+	cs->req = req;
+
+	return 0;
+}
+
 static int fuse_uring_copy_from_ring(struct fuse_ring *ring,
 				     struct fuse_req *req,
 				     struct fuse_ring_ent *ent)
@@ -658,15 +679,10 @@ static int fuse_uring_copy_from_ring(struct fuse_ring *ring,
 	if (err)
 		return err;
 
-	err = import_ubuf(ITER_SOURCE, ent->payload, ring->max_payload_sz,
-			  &iter);
+	err = setup_fuse_copy_state(&cs, ring, req, ent, ITER_SOURCE, &iter);
 	if (err)
 		return err;
 
-	fuse_copy_init(&cs, false, &iter);
-	cs.is_uring = true;
-	cs.req = req;
-
 	err = fuse_copy_out_args(&cs, args, ring_in_out.payload_sz);
 	fuse_copy_finish(&cs);
 	return err;
@@ -689,15 +705,9 @@ static int fuse_uring_args_to_ring(struct fuse_ring *ring, struct fuse_req *req,
 		.commit_id = req->in.h.unique,
 	};
 
-	err = import_ubuf(ITER_DEST, ent->payload, ring->max_payload_sz, &iter);
-	if (err) {
-		pr_info_ratelimited("fuse: Import of user buffer failed\n");
+	err = setup_fuse_copy_state(&cs, ring, req, ent, ITER_DEST, &iter);
+	if (err)
 		return err;
-	}
-
-	fuse_copy_init(&cs, true, &iter);
-	cs.is_uring = true;
-	cs.req = req;
 
 	if (num_args > 0) {
 		/*
-- 
2.53.0