Re: crypto: hang in crypto_larval_lookup

On Sat, Feb 25, 2017 at 04:20:22PM -0300, Marcelo Cerri wrote:

Yeah, I agree. This should work as long as the module aliases are
correct, which is enough.

Other templates will not trigger the same error since they don't have to
try more than one underlying algorithm. But I think this is still
desirable for the remaining templates to avoid a long chain of unused
fallbacks as in the example I gave in my previous email.

Probably a helper function to return the correct mask might be useful
for readability and to avoid duplicate code.

You're right.  Here is a patch to add a helper for this.
Thanks!

---8<---
Subject: crypto: api - Add crypto_requires_off helper

This patch adds crypto_requires_off which is an extension of
crypto_requires_sync for similar bits such as NEED_FALLBACK.

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

diff --git a/include/crypto/algapi.h b/include/crypto/algapi.h
index ebe4ded..436c4c2 100644
--- a/include/crypto/algapi.h
+++ b/include/crypto/algapi.h

@@ -360,13 +360,18 @@ static inline struct crypto_alg *crypto_get_attr_alg(struct rtattr **tb,
 	return crypto_attr_alg(tb[1], type, mask);
 }
 
+static inline int crypto_requires_off(u32 type, u32 mask, u32 off)
+{
+	return (type ^ off) & mask & off;
+}
+
 /*
  * Returns CRYPTO_ALG_ASYNC if type/mask requires the use of sync algorithms.
  * Otherwise returns zero.
  */
 static inline int crypto_requires_sync(u32 type, u32 mask)
 {
-	return (type ^ CRYPTO_ALG_ASYNC) & mask & CRYPTO_ALG_ASYNC;
+	return crypto_requires_off(type, mask, CRYPTO_ALG_ASYNC);
 }
 
 noinline unsigned long __crypto_memneq(const void *a, const void *b, size_t size);

-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt