linux-kernel - Re: [PATCH 3/4] rhashtable: use bit_spin

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Mon, 8 Apr 2019 10:34:16 +0800
From:   Herbert Xu <herbert@...dor.apana.org.au>
To:     NeilBrown <neilb@...e.com>
Cc:     Thomas Graf <tgraf@...g.ch>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/4] rhashtable: use bit_spin_locks to protect hash
 bucket.

Hi Neil:

On Tue, Apr 02, 2019 at 10:07:45AM +1100, NeilBrown wrote:
>
> @@ -263,13 +311,13 @@ void rhashtable_free_and_destroy(struct rhashtable *ht,
>  				 void *arg);
>  void rhashtable_destroy(struct rhashtable *ht);
>  
> -struct rhash_head __rcu **rht_bucket_nested(const struct bucket_table *tbl,
> -					    unsigned int hash);
> -struct rhash_head __rcu **__rht_bucket_nested(const struct bucket_table *tbl,
> -					      unsigned int hash);
> -struct rhash_head __rcu **rht_bucket_nested_insert(struct rhashtable *ht,
> -						   struct bucket_table *tbl,
> +struct rhash_lock_head __rcu **rht_bucket_nested(const struct bucket_table *tbl,
> +						 unsigned int hash);

I don't think this opaque type should be marked as __rcu.  Because
you can't directly dereference it and once you put it through rht_ptr
then that's the pointer that should carry the __rcu marker.

If you add the __rcu here then you generate a lot of extra noise
in the code that isn't needed.

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