linux-kernel - Re: [PATCH v2 13/62] firewire: convert to idr

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Date:	Mon, 4 Feb 2013 19:16:41 +0100
From:	Stefan Richter <stefanr@...6.in-berlin.de>
To:	Tejun Heo <tj@...nel.org>
Cc:	akpm@...ux-foundation.org, linux-kernel@...r.kernel.org,
	rusty@...tcorp.com.au, bfields@...ldses.org,
	skinsbursky@...allels.com, ebiederm@...ssion.com,
	jmorris@...ei.org, axboe@...nel.dk,
	linux1394-devel@...ts.sourceforge.net
Subject: Re: [PATCH v2 13/62] firewire: convert to idr_alloc()

On Feb 04 Tejun Heo wrote:
> Convert to the much saner new idr interface.
> 
> Only compile tested.
> 
> v2: Stefan pointed out that add_client_resource() may be called from
>     non-process context.  Preload iff @gfp_mask contains __GFP_WAIT.
>     Also updated to include minor upper limit check.
> 
> Signed-off-by: Tejun Heo <tj@...nel.org>
> Cc: Stefan Richter <stefanr@...6.in-berlin.de>
> Cc: linux1394-devel@...ts.sourceforge.net

Acked-by: Stefan Richter <stefanr@...6.in-berlin.de>
> ---
>  drivers/firewire/core-cdev.c   |   19 ++++++++++---------
>  drivers/firewire/core-device.c |    8 +-------
>  2 files changed, 11 insertions(+), 16 deletions(-)
> 
> --- a/drivers/firewire/core-cdev.c
> +++ b/drivers/firewire/core-cdev.c
> @@ -487,27 +487,28 @@ static int ioctl_get_info(struct client
>  static int add_client_resource(struct client *client,
>  			       struct client_resource *resource, gfp_t gfp_mask)
>  {
> +	bool preload = gfp_mask & __GFP_WAIT;
>  	unsigned long flags;
>  	int ret;
>  
> - retry:
> -	if (idr_pre_get(&client->resource_idr, gfp_mask) == 0)
> -		return -ENOMEM;
> -
> +	if (preload)
> +		idr_preload(gfp_mask);
>  	spin_lock_irqsave(&client->lock, flags);
> +
>  	if (client->in_shutdown)
>  		ret = -ECANCELED;
>  	else
> -		ret = idr_get_new(&client->resource_idr, resource,
> -				  &resource->handle);
> +		ret = idr_alloc(&client->resource_idr, resource, 0, 0,
> +				GFP_NOWAIT);
>  	if (ret >= 0) {
> +		resource->handle = ret;
>  		client_get(client);
>  		schedule_if_iso_resource(resource);
>  	}
> -	spin_unlock_irqrestore(&client->lock, flags);
>  
> -	if (ret == -EAGAIN)
> -		goto retry;
> +	spin_unlock_irqrestore(&client->lock, flags);
> +	if (preload)
> +		idr_preload_end();
>  
>  	return ret < 0 ? ret : 0;
>  }
> --- a/drivers/firewire/core-device.c
> +++ b/drivers/firewire/core-device.c
> @@ -1017,13 +1017,7 @@ static void fw_device_init(struct work_s
>  
>  	fw_device_get(device);
>  	down_write(&fw_device_rwsem);
> -	ret = idr_pre_get(&fw_device_idr, GFP_KERNEL) ?
> -	      idr_get_new(&fw_device_idr, device, &minor) :
> -	      -ENOMEM;
> -	if (minor >= 1 << MINORBITS) {
> -		idr_remove(&fw_device_idr, minor);
> -		minor = -ENOSPC;
> -	}
> +	ret = idr_alloc(&fw_device_idr, device, 0, 1 << MINORBITS, GFP_KERNEL);
>  	up_write(&fw_device_rwsem);
>  
>  	if (ret < 0)



-- 
Stefan Richter
-=====-===-= --=- --=--
http://arcgraph.de/sr/
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