crypto: api - Fix crypto_alloc_tfm/create_create_tfm return convention

This is based on a report and patch by Geert Uytterhoeven.

The functions crypto_alloc_tfm and create_create_tfm return a
pointer that needs to be adjusted by the caller when successful
and otherwise an error value.  This means that the caller has
to check for the error and only perform the adjustment if the
pointer returned is valid.

Since all callers want to make the adjustment and we know how
to adjust it ourselves, it's much easier to just return adjusted
pointer directly.

The only caveat is that we have to return a void * instead of
struct crypto_tfm *.  However, this isn't that bad because both
of these functions are for internal use only (by types code like
shash.c, not even algorithms code).

This patch also moves crypto_alloc_tfm into crypto/internal.h
(crypto_create_tfm is already there) to reflect this.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 7 insertions, 8 deletions

diff --git a/crypto/api.c b/crypto/api.c
index 56b6e0e..22385ca 100644
--- a/crypto/api.c
+++ b/crypto/api.c
@@ -453,8 +453,8 @@ err:
 }
 EXPORT_SYMBOL_GPL(crypto_alloc_base);
 
-struct crypto_tfm *crypto_create_tfm(struct crypto_alg *alg,
-				     const struct crypto_type *frontend)
+void *crypto_create_tfm(struct crypto_alg *alg,
+			const struct crypto_type *frontend)
 {
 	char *mem;
 	struct crypto_tfm *tfm = NULL;
@@ -488,9 +488,9 @@ out_free_tfm:
 		crypto_shoot_alg(alg);
 	kfree(mem);
 out_err:
-	tfm = ERR_PTR(err);
+	mem = ERR_PTR(err);
 out:
-	return tfm;
+	return mem;
 }
 EXPORT_SYMBOL_GPL(crypto_create_tfm);
 
@@ -514,12 +514,11 @@ EXPORT_SYMBOL_GPL(crypto_create_tfm);
  *
  *	In case of error the return value is an error pointer.
  */
-struct crypto_tfm *crypto_alloc_tfm(const char *alg_name,
-				    const struct crypto_type *frontend,
-				    u32 type, u32 mask)
+void *crypto_alloc_tfm(const char *alg_name,
+		       const struct crypto_type *frontend, u32 type, u32 mask)
 {
 	struct crypto_alg *(*lookup)(const char *name, u32 type, u32 mask);
-	struct crypto_tfm *tfm;
+	void *tfm;
 	int err;
 
 	type &= frontend->maskclear;