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    SubjectRe: [PATCH v3] crypto: remove instance when test failed
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    Am Donnerstag, 9. April 2015, 17:40:35 schrieb Herbert Xu:

    Hi Herbert,

    >On Thu, Apr 09, 2015 at 11:22:19AM +0200, Stephan Mueller wrote:
    >> I tested it and this approach does not work.
    >>
    >> If I see that right, the reason for that is the following: The suggestion
    >> is
    >> to grab the ref count at the start of the function followed by a
    >> __crypto_register_alg. __crypto_register_alg however sets the refcount to 1
    >> unconditionally. That means that the final put of the alg will most likely
    >> set the refcount to 0 that causes an issue with all other operations (at
    >> least I cannot allocate HMAC or CMAC any more -- the ones I currently
    >> test).
    >>
    >> So, the grabing of the alg must happen after the invocation of
    >> __crypto_register_alg.
    >
    >Well let's move it then.

    Perfect. This now works with the changed patch too. I will resend my patch as
    v4 -- note that this new patch depends on your patch here as otherwise
    instances do not work at all. :-)
    >
    >---8<---
    >crypto: api - Move alg ref count init to crypto_check_alg
    >
    >We currently initialise the crypto_alg ref count in the function
    >__crypto_register_alg. As one of the callers of that function
    >crypto_register_instance needs to obtain a ref count before it
    >calls __crypto_register_alg, we need to move the initialisation
    >out of there.
    >
    >Since both callers of __crypto_register_alg call crypto_check_alg,
    >this is the logical place to perform the initialisation.
    >
    >Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

    Acked-by: Stephan Mueller <smueller@chronox.de>
    >
    >diff --git a/crypto/algapi.c b/crypto/algapi.c
    >index f1d0307..1462c68 100644
    >--- a/crypto/algapi.c
    >+++ b/crypto/algapi.c
    >@@ -64,6 +64,8 @@ static int crypto_check_alg(struct crypto_alg *alg)
    > if (alg->cra_priority < 0)
    > return -EINVAL;
    >
    >+ atomic_set(&alg->cra_refcnt, 1);
    >+
    > return crypto_set_driver_name(alg);
    > }
    >
    >@@ -187,7 +189,6 @@ static struct crypto_larval *__crypto_register_alg(struct
    >crypto_alg *alg)
    >
    > ret = -EEXIST;
    >
    >- atomic_set(&alg->cra_refcnt, 1);
    > list_for_each_entry(q, &crypto_alg_list, cra_list) {
    > if (q == alg)
    > goto err;


    Ciao
    Stephan


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