sev-dev: use override credential guards

Use override credential guards for scoped credential override with
automatic restoration on scope exit.

Link: https://patch.msgid.link/20251103-work-creds-guards-prepare_creds-v1-4-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 be3e5454c28558890d00d59b68e2d5e0f301344d..b28a6f50daaaa0fb1ccff7520b5af69c31a0c862 100644 (file)
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -260,8 +260,6 @@ static int sev_cmd_buffer_len(int cmd)
 static struct file *open_file_as_root(const char *filename, int flags, umode_t mode)
 {
        struct path root __free(path_put) = {};
-       struct file *fp;
-       const struct cred *old_cred;
 
        task_lock(&init_task);
        get_fs_root(init_task.fs, &root);
@@ -272,13 +270,9 @@ static struct file *open_file_as_root(const char *filename, int flags, umode_t m
                return ERR_PTR(-ENOMEM);
 
        cred->fsuid = GLOBAL_ROOT_UID;
-       old_cred = override_creds(cred);
-
-       fp = file_open_root(&root, filename, flags, mode);
-
-       revert_creds(old_cred);
 
-       return fp;
+       scoped_with_creds(cred)
+               return file_open_root(&root, filename, flags, mode);
 }
 
 static int sev_read_init_ex_file(void)