crypto: algapi - make unregistration functions return void

Some of the algorithm unregistration functions return -ENOENT when asked
to unregister a non-registered algorithm, while others always return 0
or always return void.  But no users check the return value, except for
two of the bulk unregistration functions which print a message on error
but still always return 0 to their caller, and crypto_del_alg() which
calls crypto_unregister_instance() which always returns 0.

Since unregistering a non-registered algorithm is always a kernel bug
but there isn't anything callers should do to handle this situation at
runtime, let's simplify things by making all the unregistration
functions return void, and moving the error message into
crypto_unregister_alg() and upgrading it to a WARN().

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 12 insertions, 22 deletions

diff --git a/Documentation/crypto/devel-algos.rst b/Documentation/crypto/devel-algos.rst
index fb6b7979a1de..f225a953ab4b 100644
--- a/Documentation/crypto/devel-algos.rst
+++ b/Documentation/crypto/devel-algos.rst
@@ -31,28 +31,18 @@ The counterparts to those functions are listed below.
 
 ::
 
-       int crypto_unregister_alg(struct crypto_alg *alg);
-       int crypto_unregister_algs(struct crypto_alg *algs, int count);
+       void crypto_unregister_alg(struct crypto_alg *alg);
+       void crypto_unregister_algs(struct crypto_alg *algs, int count);
 
 
-Notice that both registration and unregistration functions do return a
-value, so make sure to handle errors. A return code of zero implies
-success. Any return code < 0 implies an error.
+The registration functions return 0 on success, or a negative errno
+value on failure.  crypto_register_algs() succeeds only if it
+successfully registered all the given algorithms; if it fails partway
+through, then any changes are rolled back.
 
-The bulk registration/unregistration functions register/unregister each
-transformation in the given array of length count. They handle errors as
-follows:
-
--  crypto_register_algs() succeeds if and only if it successfully
-   registers all the given transformations. If an error occurs partway
-   through, then it rolls back successful registrations before returning
-   the error code. Note that if a driver needs to handle registration
-   errors for individual transformations, then it will need to use the
-   non-bulk function crypto_register_alg() instead.
-
--  crypto_unregister_algs() tries to unregister all the given
-   transformations, continuing on error. It logs errors and always
-   returns zero.
+The unregistration functions always succeed, so they don't have a
+return value.  Don't try to unregister algorithms that aren't
+currently registered.
 
 Single-Block Symmetric Ciphers [CIPHER]
 ---------------------------------------
@@ -169,10 +159,10 @@ are as follows:
 
 ::
 
-       int crypto_unregister_ahash(struct ahash_alg *alg);
+       void crypto_unregister_ahash(struct ahash_alg *alg);
 
-       int crypto_unregister_shash(struct shash_alg *alg);
-       int crypto_unregister_shashes(struct shash_alg *algs, int count);
+       void crypto_unregister_shash(struct shash_alg *alg);
+       void crypto_unregister_shashes(struct shash_alg *algs, int count);
 
 
 Cipher Definition With struct shash_alg and ahash_alg