Revert "crypto: api - Add crypto_tfm_get"

This reverts commit e470d423b0 which is
commit ae131f4970 upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: I5292b6943ca50ef57b754862ddd33f7a782310c9
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

crypto/api.c

@@ -408,7 +408,6 @@ struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type,
 		goto out_err;
 
 	tfm->__crt_alg = alg;
-	refcount_set(&tfm->refcnt, 1);
 
 	err = crypto_init_ops(tfm, type, mask);
 	if (err)
@@ -508,7 +507,6 @@ void *crypto_create_tfm_node(struct crypto_alg *alg,
 	tfm = (struct crypto_tfm *)(mem + tfmsize);
 	tfm->__crt_alg = alg;
 	tfm->node = node;
-	refcount_set(&tfm->refcnt, 1);
 
 	err = frontend->init_tfm(tfm);
 	if (err)
@@ -621,8 +619,6 @@ void crypto_destroy_tfm(void *mem, struct crypto_tfm *tfm)
 	if (IS_ERR_OR_NULL(mem))
 		return;
 
-	if (!refcount_dec_and_test(&tfm->refcnt))
-		return;
 	alg = tfm->__crt_alg;
 
 	if (!tfm->exit && alg->cra_exit)

crypto/internal.h

@@ -10,7 +10,6 @@
 
 #include <crypto/algapi.h>
 #include <linux/completion.h>
-#include <linux/err.h>
 #include <linux/jump_label.h>
 #include <linux/list.h>
 #include <linux/module.h>
@@ -185,10 +184,5 @@ static inline int crypto_is_test_larval(struct crypto_larval *larval)
 	return larval->alg.cra_driver_name[0];
 }
 
-static inline struct crypto_tfm *crypto_tfm_get(struct crypto_tfm *tfm)
-{
-	return refcount_inc_not_zero(&tfm->refcnt) ? tfm : ERR_PTR(-EOVERFLOW);
-}
-
 #endif	/* _CRYPTO_INTERNAL_H */
 

include/linux/crypto.h

@@ -642,7 +642,6 @@ int crypto_has_alg(const char *name, u32 type, u32 mask);
  */
 
 struct crypto_tfm {
-	refcount_t refcnt;
 
 	u32 crt_flags;