Re: [B.A.T.M.A.N.] [PATCH] batman-adv: generalise tt_local_reset_flags()

[Simon Wunderlich <simon.wunderlich@s2003.tu-chemnitz.de>]

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Hey Antonio,

I don't quite understand what this patch is good for - it generalises the function,
but does not use the function at another point. So what it is good for (next to
add more complexity to batman ;] ).

Furthermore it counts the changes and adds it to num_local_tt, is there a bug fix
hidden in this patch somewhere? :)

Cheers,
	Simon

On Sun, Oct 30, 2011 at 08:09:01PM +0100, Antonio Quartulli wrote:
> The tt_local_reset_flags() is actually used for one use case only. It is not
> generalised enough to be used indifferent situations. This patch make it general
> enough in order to let other code use it whenever a flag flip is requested over
> the whole hash table (passed as parameter).
> 
> Signed-off-by: Antonio Quartulli <ordex@autistici.org>
> ---
> 
> This patch depends on:
> 
> batman-adv: create a common substructure for tt_global/local_entry
> 
> 
>  translation-table.c |   31 ++++++++++++++++++++-----------
>  1 files changed, 20 insertions(+), 11 deletions(-)
> 
> diff --git a/translation-table.c b/translation-table.c
> index 76134bc..5b60aba 100644
> --- a/translation-table.c
> +++ b/translation-table.c
> @@ -1695,19 +1695,20 @@ void tt_free(struct bat_priv *bat_priv)
>  	kfree(bat_priv->tt_buff);
>  }
>  
> -/* This function will reset the specified flags from all the entries in
> - * the given hash table and will increment num_local_tt for each involved
> - * entry */
> -static void tt_local_reset_flags(struct bat_priv *bat_priv, uint16_t flags)
> +/* This function will flip to new_value (if not already) the specified flags for
> + * all the entries in the given hash table and returns the number of modified
> + * entries */
> +static uint16_t tt_flip_flags(struct hashtable_t *hash, uint16_t flags,
> +			     uint8_t new_value)
>  {
>  	uint32_t i;
> -	struct hashtable_t *hash = bat_priv->tt_local_hash;
> +	uint16_t changed_num = 0;
>  	struct hlist_head *head;
>  	struct hlist_node *node;
>  	struct tt_common_entry *tt_common_entry;
>  
>  	if (!hash)
> -		return;
> +		goto out;
>  
>  	for (i = 0; i < hash->size; i++) {
>  		head = &hash->table[i];
> @@ -1715,14 +1716,18 @@ static void tt_local_reset_flags(struct bat_priv *bat_priv, uint16_t flags)
>  		rcu_read_lock();
>  		hlist_for_each_entry_rcu(tt_common_entry, node,
>  					 head, hash_entry) {
> -			if (!(tt_common_entry->flags & flags))
> +			if ((tt_common_entry->flags & flags) != new_value)
>  				continue;
> -			tt_common_entry->flags &= ~flags;
> -			atomic_inc(&bat_priv->num_local_tt);
> +			/* depending on 'new_value', enable or disable the flags
> +			 * pointed by 'flags' */
> +			tt_common_entry->flags &=
> +				(~flags | (new_value ? flags : NO_FLAGS));
> +			changed_num++;
>  		}
>  		rcu_read_unlock();
>  	}
> -
> +out:
> +	return changed_num;
>  }
>  
>  /* Purge out all the tt local entries marked with TT_CLIENT_PENDING */
> @@ -1766,7 +1771,11 @@ static void tt_local_purge_pending_clients(struct bat_priv *bat_priv)
>  
>  void tt_commit_changes(struct bat_priv *bat_priv)
>  {
> -	tt_local_reset_flags(bat_priv, TT_CLIENT_NEW);
> +	uint16_t changed_num = tt_flip_flags(bat_priv->tt_local_hash,
> +					    TT_CLIENT_NEW, 0);
> +	/* all the reset entries have now to be effectively counted as local
> +	 * entries */
> +	atomic_add(changed_num, &bat_priv->num_local_tt);
>  	tt_local_purge_pending_clients(bat_priv);
>  
>  	/* Increment the TTVN only once per OGM interval */
> -- 
> 1.7.3.4
> 
> 

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