Re: [PATCH 76/77] sctp: convert to idr_alloc()

[Neil Horman]

On Wed, Feb 06, 2013 at 11:40:48AM -0800, Tejun Heo wrote:
> Convert to the much saner new idr interface.
> 
> Only compile tested.
> 
> v2: Don't preload if @gfp doesn't contain __GFP_WAIT as the function
>     may be being called from non-process ocntext.  Also, add a comment
>     explaining @idr_low never becomes zero.
> 
> Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
> Acked-by: Neil Horman <nhorman@xxxxxxxxxxxxx>
> Cc: Vlad Yasevich <vyasevich@xxxxxxxxx>
> Cc: Sridhar Samudrala <sri@xxxxxxxxxx>
> Cc: linux-sctp@xxxxxxxxxxxxxxx
> ---
>  net/sctp/associola.c | 31 +++++++++++++++----------------
>  1 file changed, 15 insertions(+), 16 deletions(-)
> 
> diff --git a/net/sctp/associola.c b/net/sctp/associola.c
> index b45ed1f..0c9a791 100644
> --- a/net/sctp/associola.c
> +++ b/net/sctp/associola.c
> @@ -1592,32 +1592,31 @@ int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
>  /* Set an association id for a given association */
>  int sctp_assoc_set_id(struct sctp_association *asoc, gfp_t gfp)
>  {
> -	int assoc_id;
> -	int error = 0;
> +	bool preload = gfp & __GFP_WAIT;
> +	int ret;
>  
>  	/* If the id is already assigned, keep it. */
>  	if (asoc->assoc_id)
> -		return error;
> -retry:
> -	if (unlikely(!idr_pre_get(&sctp_assocs_id, gfp)))
> -		return -ENOMEM;
> +		return 0;
>  
> +	if (preload)
> +		idr_preload(gfp);
>  	spin_lock_bh(&sctp_assocs_id_lock);
> -	error = idr_get_new_above(&sctp_assocs_id, (void *)asoc,
> -				    idr_low, &assoc_id);
> -	if (!error) {
> -		idr_low = assoc_id + 1;
> +	/* 0 is not a valid id, idr_low is always >= 1 */
> +	ret = idr_alloc(&sctp_assocs_id, asoc, idr_low, 0, GFP_NOWAIT);
> +	if (ret >= 0) {
> +		idr_low = ret + 1;
>  		if (idr_low == INT_MAX)
>  			idr_low = 1;
>  	}
>  	spin_unlock_bh(&sctp_assocs_id_lock);
> -	if (error == -EAGAIN)
> -		goto retry;
> -	else if (error)
> -		return error;
> +	if (preload)
> +		idr_preload_end();
> +	if (ret < 0)
> +		return ret;
>  
> -	asoc->assoc_id = (sctp_assoc_t) assoc_id;
> -	return error;
> +	asoc->assoc_id = (sctp_assoc_t)ret;
> +	return 0;
>  }
>  
>  /* Free the ASCONF queue */
> -- 
> 1.8.1
> 
> --
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> 
Acked-by: Neil Horman <nhorman@xxxxxxxxxxxxx>

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