sev-dev: use prepare credential guard

Use the prepare credential guard for allocating a new set of
credentials.

Link: https://patch.msgid.link/20251103-work-creds-guards-prepare_creds-v1-3-b447b82f2c9b@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index c5e22af04abb0e311661537a9d3e728780511137..be3e5454c28558890d00d59b68e2d5e0f301344d 100644 (file)
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -261,22 +261,22 @@ static struct file *open_file_as_root(const char *filename, int flags, umode_t m
 {
        struct path root __free(path_put) = {};
        struct file *fp;
-       struct cred *cred;
        const struct cred *old_cred;
 
        task_lock(&init_task);
        get_fs_root(init_task.fs, &root);
        task_unlock(&init_task);
 
-       cred = prepare_creds();
+       CLASS(prepare_creds, cred)();
        if (!cred)
                return ERR_PTR(-ENOMEM);
+
        cred->fsuid = GLOBAL_ROOT_UID;
        old_cred = override_creds(cred);
 
        fp = file_open_root(&root, filename, flags, mode);
 
-       put_cred(revert_creds(old_cred));
+       revert_creds(old_cred);
 
        return fp;
 }