Revert "crypto: shash - avoid comparing pointers to exported functions under CFI"

This reverts commit 22ca9f4a because CFI
no longer breaks cross-module function address equality, so
crypto_shash_alg_has_setkey() can now be an inline function like before.

This commit should not be backported to kernels that don't have the new
CFI implementation.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/shash.c

@@ -20,24 +20,12 @@
 
 static const struct crypto_type crypto_shash_type;
 
-static int shash_no_setkey(struct crypto_shash *tfm, const u8 *key,
-			   unsigned int keylen)
+int shash_no_setkey(struct crypto_shash *tfm, const u8 *key,
+		    unsigned int keylen)
 {
 	return -ENOSYS;
 }
-
-/*
- * Check whether an shash algorithm has a setkey function.
- *
- * For CFI compatibility, this must not be an inline function.  This is because
- * when CFI is enabled, modules won't get the same address for shash_no_setkey
- * (if it were exported, which inlining would require) as the core kernel will.
- */
-bool crypto_shash_alg_has_setkey(struct shash_alg *alg)
-{
-	return alg->setkey != shash_no_setkey;
-}
-EXPORT_SYMBOL_GPL(crypto_shash_alg_has_setkey);
+EXPORT_SYMBOL_GPL(shash_no_setkey);
 
 static int shash_setkey_unaligned(struct crypto_shash *tfm, const u8 *key,
 				  unsigned int keylen)

include/crypto/internal/hash.h

@@ -75,7 +75,13 @@ void crypto_unregister_ahashes(struct ahash_alg *algs, int count);
 int ahash_register_instance(struct crypto_template *tmpl,
 			    struct ahash_instance *inst);
 
-bool crypto_shash_alg_has_setkey(struct shash_alg *alg);
+int shash_no_setkey(struct crypto_shash *tfm, const u8 *key,
+		    unsigned int keylen);
+
+static inline bool crypto_shash_alg_has_setkey(struct shash_alg *alg)
+{
+	return alg->setkey != shash_no_setkey;
+}
 
 static inline bool crypto_shash_alg_needs_key(struct shash_alg *alg)
 {