netdev - Re: [PATCH] eHEA: Don't do memory allocation under lock if not necessary

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Message-Id: <200903111037.42736.ossthema@de.ibm.com>
Date:	Wed, 11 Mar 2009 10:37:42 +0100
From:	"Jan-Bernd Themann" <ossthema@...ibm.com>
To:	David Howells <dhowells@...hat.com>
Cc:	raisch@...ibm.com, themann@...ibm.com, tklein@...ibm.com,
	linuxppc-dev@...abs.org, netdev@...r.kernel.org
Subject: Re: [PATCH] eHEA: Don't do memory allocation under lock if not necessary

Hi David,

thanks for your patch. Coincidentally we have been working on a patch that 
does some locking rework and also touches this particular lock. 
So your patch finnally won't be required anymore. Thanks anyway for trying
to improve the eHEA driver!

I'm going to post our patch later today. 

Regards,
Jan-Bernd

On Wednesday 11 March 2009 09:44:57 David Howells wrote:
> In ehea_probe_adapter() the initial memory allocation and initialisation does
> not need to be done with the ehea_fw_handles.lock semaphore held.  Doing so
> extends the amount of time the lock is held unnecessarily.
> 
> Signed-off-by: David Howells <dhowells@...hat.com>
> ---
> 
>  drivers/net/ehea/ehea_main.c |   13 ++++++-------
>  1 files changed, 6 insertions(+), 7 deletions(-)
> 
> 
> diff --git a/drivers/net/ehea/ehea_main.c b/drivers/net/ehea/ehea_main.c
> index dfe9226..34480ae 100644
> --- a/drivers/net/ehea/ehea_main.c
> +++ b/drivers/net/ehea/ehea_main.c
> @@ -3370,18 +3370,19 @@ static int __devinit ehea_probe_adapter(struct of_device *dev,
>  		ehea_error("Invalid ibmebus device probed");
>  		return -EINVAL;
>  	}
> -	mutex_lock(&ehea_fw_handles.lock);
> 
>  	adapter = kzalloc(sizeof(*adapter), GFP_KERNEL);
>  	if (!adapter) {
> -		ret = -ENOMEM;
>  		dev_err(&dev->dev, "no mem for ehea_adapter\n");
> -		goto out;
> +		return -ENOMEM;
>  	}
> 
> -	list_add(&adapter->list, &adapter_list);
> -
>  	adapter->ofdev = dev;
> +	adapter->pd = EHEA_PD_ID;
> +
> +	mutex_lock(&ehea_fw_handles.lock);
> +
> +	list_add(&adapter->list, &adapter_list);
> 
>  	adapter_handle = of_get_property(dev->node, "ibm,hea-handle",
>  					 NULL);
> @@ -3395,8 +3396,6 @@ static int __devinit ehea_probe_adapter(struct of_device *dev,
>  		goto out_free_ad;
>  	}
> 
> -	adapter->pd = EHEA_PD_ID;
> -
>  	dev->dev.driver_data = adapter;
> 
> 
> 
> --
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