[PATCH RFC POC 37/50] tpm: vtpm_proxy: install the server descriptor 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>
---
 drivers/char/tpm/tpm_vtpm_proxy.c | 30 +++++++++---------------------
 1 file changed, 9 insertions(+), 21 deletions(-)

diff --git a/drivers/char/tpm/tpm_vtpm_proxy.c b/drivers/char/tpm/tpm_vtpm_proxy.c
index b81fd2a537df..8eb87044596a 100644
--- a/drivers/char/tpm/tpm_vtpm_proxy.c
+++ b/drivers/char/tpm/tpm_vtpm_proxy.c
@@ -531,8 +531,8 @@ static struct file *vtpm_proxy_create_device(
 				 struct vtpm_proxy_new_dev *vtpm_new_dev)
 {
 	struct proxy_dev *proxy_dev;
-	int rc, fd;
 	struct file *file;
+	int rc;
 
 	if (vtpm_new_dev->flags & ~VTPM_PROXY_FLAGS_ALL)
 		return ERR_PTR(-EOPNOTSUPP);
@@ -544,20 +544,15 @@ static struct file *vtpm_proxy_create_device(
 	proxy_dev->flags = vtpm_new_dev->flags;
 
 	/* setup an anonymous file for the server-side */
-	fd = get_unused_fd_flags(O_RDWR);
-	if (fd < 0) {
-		rc = fd;
+	FD_PREPARE(fdf, O_RDWR,
+		   anon_inode_getfile("[vtpms]", &vtpm_proxy_fops, proxy_dev,
+				      O_RDWR));
+	if (IS_ERR(fdf)) {
+		rc = PTR_ERR(fdf);
 		goto err_delete_proxy_dev;
 	}
+	file = fd_prepare_file(fdf);
 
-	file = anon_inode_getfile("[vtpms]", &vtpm_proxy_fops, proxy_dev,
-				  O_RDWR);
-	if (IS_ERR(file)) {
-		rc = PTR_ERR(file);
-		goto err_put_unused_fd;
-	}
-
-	/* from now on we can unwind with put_unused_fd() + fput() */
 	/* simulate an open() on the server side */
 	vtpm_proxy_fops_open(file);
 
@@ -566,16 +561,13 @@ static struct file *vtpm_proxy_create_device(
 
 	vtpm_proxy_work_start(proxy_dev);
 
-	vtpm_new_dev->fd = fd;
+	vtpm_new_dev->fd = fd_prepare_fd(fdf);
 	vtpm_new_dev->major = MAJOR(proxy_dev->chip->dev.devt);
 	vtpm_new_dev->minor = MINOR(proxy_dev->chip->dev.devt);
 	vtpm_new_dev->tpm_num = proxy_dev->chip->dev_num;
 
 	return file;
 
-err_put_unused_fd:
-	put_unused_fd(fd);
-
 err_delete_proxy_dev:
 	vtpm_proxy_delete_proxy_dev(proxy_dev);
 
@@ -640,13 +632,9 @@ static long vtpmx_ioc_new_dev(struct file *file, unsigned int ioctl,
 		return PTR_ERR(vtpm_file);
 
 	if (copy_to_user(vtpm_new_dev_p, &vtpm_new_dev,
-			 sizeof(vtpm_new_dev))) {
-		put_unused_fd(vtpm_new_dev.fd);
-		fput(vtpm_file);
+			 sizeof(vtpm_new_dev)))
 		return -EFAULT;
-	}
 
-	fd_install(vtpm_new_dev.fd, vtpm_file);
 	return 0;
 }
 

-- 
2.53.0