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

[Christian Brauner]

Rely on the fd exit path machinery.

Signed-off-by: Christian Brauner (Amutable) <brau...@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