cred: remove old {override,revert}_creds() helpers

They are now unused.

Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Jeff Layton <[email protected]>
Reviewed-by: Jens Axboe <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>

Author: brauner

include/linux/cred.h

@@ -155,8 +155,6 @@ extern struct cred *prepare_creds(void);
 extern struct cred *prepare_exec_creds(void);
 extern int commit_creds(struct cred *);
 extern void abort_creds(struct cred *);
-extern const struct cred *override_creds(const struct cred *);
-extern void revert_creds(const struct cred *);
 extern struct cred *prepare_kernel_cred(struct task_struct *);
 extern int set_security_override(struct cred *, u32);
 extern int set_security_override_from_ctx(struct cred *, const char *);
@@ -172,11 +170,6 @@ static inline bool cap_ambient_invariant_ok(const struct cred *cred)
 					  cred->cap_inheritable));
 }
 
-/*
- * Override creds without bumping reference count. Caller must ensure
- * reference remains valid or has taken reference. Almost always not the
- * interface you want. Use override_creds()/revert_creds() instead.
- */
 static inline const struct cred *override_creds_light(const struct cred *override_cred)
 {
 	const struct cred *old = current->cred;

kernel/cred.c

@@ -476,56 +476,6 @@ void abort_creds(struct cred *new)
 }
 EXPORT_SYMBOL(abort_creds);
 
-/**
- * override_creds - Override the current process's subjective credentials
- * @new: The credentials to be assigned
- *
- * Install a set of temporary override subjective credentials on the current
- * process, returning the old set for later reversion.
- */
-const struct cred *override_creds(const struct cred *new)
-{
-	const struct cred *old;
-
-	kdebug("override_creds(%p{%ld})", new,
-	       atomic_long_read(&new->usage));
-
-	/*
-	 * NOTE! This uses 'get_new_cred()' rather than 'get_cred()'.
-	 *
-	 * That means that we do not clear the 'non_rcu' flag, since
-	 * we are only installing the cred into the thread-synchronous
-	 * '->cred' pointer, not the '->real_cred' pointer that is
-	 * visible to other threads under RCU.
-	 */
-	get_new_cred((struct cred *)new);
-	old = override_creds_light(new);
-
-	kdebug("override_creds() = %p{%ld}", old,
-	       atomic_long_read(&old->usage));
-	return old;
-}
-EXPORT_SYMBOL(override_creds);
-
-/**
- * revert_creds - Revert a temporary subjective credentials override
- * @old: The credentials to be restored
- *
- * Revert a temporary set of override subjective credentials to an old set,
- * discarding the override set.
- */
-void revert_creds(const struct cred *old)
-{
-	const struct cred *override = current->cred;
-
-	kdebug("revert_creds(%p{%ld})", old,
-	       atomic_long_read(&old->usage));
-
-	revert_creds_light(old);
-	put_cred(override);
-}
-EXPORT_SYMBOL(revert_creds);
-
 /**
  * cred_fscmp - Compare two credentials with respect to filesystem access.
  * @a: The first credential