Re: [PATCH] crypto: only wait for completion once

[Sebastian Andrzej Siewior <bigeasy@linutronix.de>]

On 2019-12-31 12:00:51 [+0200], John Mathew wrote:
> Proposed fix for the swake_up_all_locked warnings issue discussed in
> Link: https://lore.kernel.org/linux-rt-users/20191218165334.k4suur4gzlu62ibs@linutronix.de/T/#t
> Currently multiple wait for completions are scheduled for the same algo.
> Only one completes and the rest are returned with ENOENT. This patch
> checks for the name of the algorithm going to be waited up on, and if
> the algorithm is already being waited for completion return EAGAIN ,
> without accumulating completions and returning ENOENT.

Have you tested this patch and if so how?

> Signed-off-by: John Mathew <john.mathew@unikie.com>
> ---
>  crypto/api.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/crypto/api.c b/crypto/api.c
> index d8ba54142620..1c6004e7ab6c 100644
> --- a/crypto/api.c
> +++ b/crypto/api.c
> @@ -234,8 +234,12 @@ static struct crypto_alg *crypto_larval_lookup(const char *name, u32 type,
>  		alg = crypto_alg_lookup(name, type, mask);
>  	}
>  
> -	if (!IS_ERR_OR_NULL(alg) && crypto_is_larval(alg))
> -		alg = crypto_larval_wait(alg);
> +	if (!IS_ERR_OR_NULL(alg) && crypto_is_larval(alg))	{
> +		if (!strcmp(alg->cra_name, name))
> +			alg = ERR_PTR(-EAGAIN);
> +		else
> +			alg = crypto_larval_wait(alg);
> +	}
>  	else if (!alg)
>  		alg = crypto_larval_add(name, type, mask);
>  
Sebastian