keys: Kill off request_key_async{,_with_auxdata}

    is a blob of length callout_len, if given (the length may be 0).

 *  A key can be requested asynchronously by calling one of::

	struct key *request_key_async(const struct key_type *type,

				      const char *description,

				      const void *callout_info,

				      size_t callout_len);

    or::

	struct key *request_key_async_with_auxdata(const struct key_type *type,

						   const char *description,

						   const char *callout_info,

					     	   size_t callout_len,

					     	   void *aux);

    which are asynchronous equivalents of request_key() and

    request_key_with_auxdata() respectively.

    These two functions return with the key potentially still under

    construction.  To wait for construction completion, the following should be

    called::

	int wait_for_key_construction(struct key *key, bool intr);

    The function will wait for the key to finish being constructed and then

    invokes key_validate() to return an appropriate value to indicate the state

    of the key (0 indicates the key is usable).

    If intr is true, then the wait can be interrupted by a signal, in which

    case error ERESTARTSYS will be returned.

 *  To search for a key under RCU conditions, call::

	struct key *request_key_rcu(const struct key_type *type,

					     size_t callout_len,

					     void *aux);

or::

	struct key *request_key_async(const struct key_type *type,

				      const char *description,

				      const char *callout_info,

				      size_t callout_len);

or::

	struct key *request_key_async_with_auxdata(const struct key_type *type,

						   const char *description,

						   const char *callout_info,

					     	   size_t callout_len,

						   void *aux);

or::

	struct key *request_key_rcu(const struct key_type *type,

destroyed.  The kernel interface returns a pointer directly to the key, and

it's up to the caller to destroy the key.

The request_key*_with_auxdata() calls are like the in-kernel request_key*()

calls, except that they permit auxiliary data to be passed to the upcaller (the

The request_key_with_auxdata() calls is like the in-kernel request_key() call,

except that they permit auxiliary data to be passed to the upcaller (the

default is NULL).  This is only useful for those key types that define their

own upcall mechanism rather than using /sbin/request-key.

The two async in-kernel calls may return keys that are still in the process of

being constructed.  The two non-async ones will wait for construction to

complete first.

The request_key_rcu() call is like the in-kernel request_key() call, except

that it doesn't check for keys that are under construction and doesn't attempt

to construct missing keys.

					    size_t callout_len,

					    void *aux);

extern struct key *request_key_async(struct key_type *type,

				     const char *description,

				     const void *callout_info,

				     size_t callout_len);

extern struct key *request_key_async_with_auxdata(struct key_type *type,

						  const char *description,

						  const void *callout_info,

						  size_t callout_len,

						  void *aux);

extern int wait_for_key_construction(struct key *key, bool intr);

extern int key_validate(const struct key *key);

}

EXPORT_SYMBOL(request_key_with_auxdata);

/*

 * request_key_async - Request a key (allow async construction)

 * @type: Type of key.

 * @description: The searchable description of the key.

 * @callout_info: The data to pass to the instantiation upcall (or NULL).

 * @callout_len: The length of callout_info.

 *

 * As for request_key_and_link() except that it does not add the returned key

 * to a keyring if found, new keys are always allocated in the user's quota and

 * no auxiliary data can be passed.

 *

 * The caller should call wait_for_key_construction() to wait for the

 * completion of the returned key if it is still undergoing construction.

 */

struct key *request_key_async(struct key_type *type,

			      const char *description,

			      const void *callout_info,

			      size_t callout_len)

{

	return request_key_and_link(type, description, callout_info,

				    callout_len, NULL, NULL,

				    KEY_ALLOC_IN_QUOTA);

}

EXPORT_SYMBOL(request_key_async);

/*

 * request a key with auxiliary data for the upcaller (allow async construction)

 * @type: Type of key.

 * @description: The searchable description of the key.

 * @callout_info: The data to pass to the instantiation upcall (or NULL).

 * @callout_len: The length of callout_info.

 * @aux: Auxiliary data for the upcall.

 *

 * As for request_key_and_link() except that it does not add the returned key

 * to a keyring if found and new keys are always allocated in the user's quota.

 *

 * The caller should call wait_for_key_construction() to wait for the

 * completion of the returned key if it is still undergoing construction.

 */

struct key *request_key_async_with_auxdata(struct key_type *type,

					   const char *description,

					   const void *callout_info,

					   size_t callout_len,

					   void *aux)

{

	return request_key_and_link(type, description, callout_info,

				    callout_len, aux, NULL, KEY_ALLOC_IN_QUOTA);

}

EXPORT_SYMBOL(request_key_async_with_auxdata);

/**

 * request_key_rcu - Request key from RCU-read-locked context

 * @type: The type of key we want.