[PATCH RFC POC 32/50] liveupdate: install the session descriptors when the ioctl returns

[Christian Brauner <brauner@kernel.org>]

Rely on the fd exit path machinery.

Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
---
 kernel/liveupdate/luo_core.c    | 48 ++++++++++++-----------------------------
 kernel/liveupdate/luo_session.c | 24 ++++++---------------
 2 files changed, 21 insertions(+), 51 deletions(-)

diff --git a/kernel/liveupdate/luo_core.c b/kernel/liveupdate/luo_core.c
index 1b2bda22902d..3899bbf30b53 100644
--- a/kernel/liveupdate/luo_core.c
+++ b/kernel/liveupdate/luo_core.c
@@ -270,61 +270,41 @@ struct luo_device_state {
 static int luo_ioctl_create_session(struct luo_ucmd *ucmd)
 {
 	struct liveupdate_ioctl_create_session *argp = ucmd->cmd;
+	const struct fd_slot *fd;
 	struct file *file;
 	int err;
 
-	argp->fd = get_unused_fd_flags(O_CLOEXEC);
-	if (argp->fd < 0)
-		return argp->fd;
+	fd = fd_prepare(O_CLOEXEC);
+	if (IS_ERR(fd))
+		return PTR_ERR(fd);
 
 	err = luo_session_create(argp->name, &file);
 	if (err)
-		goto err_put_fd;
-
-	err = luo_ucmd_respond(ucmd, sizeof(*argp));
-	if (err)
-		goto err_put_file;
-
-	fd_install(argp->fd, file);
-
-	return 0;
+		return err;
 
-err_put_file:
-	fput(file);
-err_put_fd:
-	put_unused_fd(argp->fd);
+	argp->fd = fd_stage(fd, file);
 
-	return err;
+	return luo_ucmd_respond(ucmd, sizeof(*argp));
 }
 
 static int luo_ioctl_retrieve_session(struct luo_ucmd *ucmd)
 {
 	struct liveupdate_ioctl_retrieve_session *argp = ucmd->cmd;
+	const struct fd_slot *fd;
 	struct file *file;
 	int err;
 
-	argp->fd = get_unused_fd_flags(O_CLOEXEC);
-	if (argp->fd < 0)
-		return argp->fd;
+	fd = fd_prepare(O_CLOEXEC);
+	if (IS_ERR(fd))
+		return PTR_ERR(fd);
 
 	err = luo_session_retrieve(argp->name, &file);
 	if (err < 0)
-		goto err_put_fd;
-
-	err = luo_ucmd_respond(ucmd, sizeof(*argp));
-	if (err)
-		goto err_put_file;
-
-	fd_install(argp->fd, file);
-
-	return 0;
+		return err;
 
-err_put_file:
-	fput(file);
-err_put_fd:
-	put_unused_fd(argp->fd);
+	argp->fd = fd_stage(fd, file);
 
-	return err;
+	return luo_ucmd_respond(ucmd, sizeof(*argp));
 }
 
 static int luo_open(struct inode *inodep, struct file *filep)
diff --git a/kernel/liveupdate/luo_session.c b/kernel/liveupdate/luo_session.c
index f48e9a4185f9..7de35bad1ede 100644
--- a/kernel/liveupdate/luo_session.c
+++ b/kernel/liveupdate/luo_session.c
@@ -282,33 +282,23 @@ static int luo_session_retrieve_fd(struct luo_session *session,
 				   struct luo_ucmd *ucmd)
 {
 	struct liveupdate_session_retrieve_fd *argp = ucmd->cmd;
+	const struct fd_slot *fd;
 	struct file *file;
 	int err;
 
-	argp->fd = get_unused_fd_flags(O_CLOEXEC);
-	if (argp->fd < 0)
-		return argp->fd;
+	fd = fd_prepare(O_CLOEXEC);
+	if (IS_ERR(fd))
+		return PTR_ERR(fd);
 
 	mutex_lock(&session->mutex);
 	err = luo_retrieve_file(&session->file_set, argp->token, &file);
 	mutex_unlock(&session->mutex);
 	if (err < 0)
-		goto err_put_fd;
-
-	err = luo_ucmd_respond(ucmd, sizeof(*argp));
-	if (err)
-		goto err_put_file;
-
-	fd_install(argp->fd, file);
-
-	return 0;
+		return err;
 
-err_put_file:
-	fput(file);
-err_put_fd:
-	put_unused_fd(argp->fd);
+	argp->fd = fd_stage(fd, file);
 
-	return err;
+	return luo_ucmd_respond(ucmd, sizeof(*argp));
 }
 
 static int luo_session_finish(struct luo_session *session,

-- 
2.53.0