Re: [PATCH 3/6] staging: vme: keep track of registered buses

[Martyn Welch]

On 10/08/11 10:33, Manohar Vanga wrote:
> This patch adds a list which keeps track of all registered VME
> buses. This is required for adding refcounting later to bridge
> modules, something that is not currently implemented.
> 
> This is based on the changes introduced by Emilio G. Cota in the
> patch:
> 
>     https://lkml.org/lkml/2010/10/25/486
> 
> Signed-off-by: Manohar Vanga <manohar.vanga@xxxxxxx>

Looks OK:

Acked-by: Martyn Welch <martyn.welch@xxxxxx>

> ---
>  drivers/staging/vme/vme.c        |   46 ++++++++++++++++++++-----------------
>  drivers/staging/vme/vme_bridge.h |    1 +
>  2 files changed, 26 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/staging/vme/vme.c b/drivers/staging/vme/vme.c
> index 15a6161..f811d07 100644
> --- a/drivers/staging/vme/vme.c
> +++ b/drivers/staging/vme/vme.c
> @@ -34,9 +34,10 @@
>  #include "vme.h"
>  #include "vme_bridge.h"
>  
> -/* Bitmask and mutex to keep track of bridge numbers */
> +/* Bitmask and list of registered buses both protected by common mutex */
>  static unsigned int vme_bus_numbers;
> -static DEFINE_MUTEX(vme_bus_num_mtx);
> +static LIST_HEAD(vme_bus_list);
> +static DEFINE_MUTEX(vme_buses_lock);
>  
>  static void __exit vme_exit(void);
>  static int __init vme_init(void);
> @@ -1309,11 +1310,12 @@ EXPORT_SYMBOL(vme_slot_get);
>  
>  /* - Bridge Registration --------------------------------------------------- */
>  
> -/* call with vme_bus_num_mtx held */
> -static int __vme_alloc_bus_num(int bus_num)
> +/* call with vme_buses_lock held */
> +static int __vme_add_bus(struct vme_bridge *bridge)
>  {
>  	int num;
>  	int i;
> +	int bus_num = bridge->num;
>  
>  	if (bus_num == -1) {
>  		/* try to find a free bus number */
> @@ -1335,25 +1337,29 @@ static int __vme_alloc_bus_num(int bus_num)
>  		}
>  		num = bus_num;
>  	}
> +	bridge->num = num;
> +	list_add_tail(&bridge->bus_list, &vme_bus_list);
>  	vme_bus_numbers |= 1 << num;
> -	return num;
> +	return 0;
>  }
>  
> -static int vme_alloc_bus_num(int bus_num)
> +static int vme_add_bus(struct vme_bridge *bridge)
>  {
> -	int num;
> +	int ret;
>  
> -	mutex_lock(&vme_bus_num_mtx);
> -	num = __vme_alloc_bus_num(bus_num);
> -	mutex_unlock(&vme_bus_num_mtx);
> -	return num;
> +	mutex_lock(&vme_buses_lock);
> +	ret = __vme_add_bus(bridge);
> +	mutex_unlock(&vme_buses_lock);
> +
> +	return ret;
>  }
>  
> -static void vme_free_bus_num(int bus)
> +static void vme_remove_bus(struct vme_bridge *bridge)
>  {
> -	mutex_lock(&vme_bus_num_mtx);
> -	vme_bus_numbers &= ~(0x1 << bus);
> -	mutex_unlock(&vme_bus_num_mtx);
> +	mutex_lock(&vme_buses_lock);
> +	vme_bus_numbers &= ~(1 << bridge->num);
> +	list_del(&bridge->bus_list);
> +	mutex_unlock(&vme_buses_lock);
>  }
>  
>  int vme_register_bridge(struct vme_bridge *bridge)
> @@ -1362,12 +1368,10 @@ int vme_register_bridge(struct vme_bridge *bridge)
>  	int retval;
>  	int i;
>  
> -	retval = vme_alloc_bus_num(bridge->num);
> -	if (retval < 0)
> +	retval = vme_add_bus(bridge);
> +	if (retval)
>  		return retval;
>  
> -	bridge->num = retval;
> -
>  	/* This creates 32 vme "slot" devices. This equates to a slot for each
>  	 * ID available in a system conforming to the ANSI/VITA 1-1994
>  	 * specification.
> @@ -1398,7 +1402,7 @@ err_reg:
>  		dev = &bridge->dev[i];
>  		device_unregister(dev);
>  	}
> -	vme_free_bus_num(bridge->num);
> +	vme_remove_bus(bridge);
>  	return retval;
>  }
>  EXPORT_SYMBOL(vme_register_bridge);
> @@ -1413,7 +1417,7 @@ void vme_unregister_bridge(struct vme_bridge *bridge)
>  		dev = &bridge->dev[i];
>  		device_unregister(dev);
>  	}
> -	vme_free_bus_num(bridge->num);
> +	vme_remove_bus(bridge);
>  }
>  EXPORT_SYMBOL(vme_unregister_bridge);
>  
> diff --git a/drivers/staging/vme/vme_bridge.h b/drivers/staging/vme/vme_bridge.h
> index a9084f0..8959670 100644
> --- a/drivers/staging/vme/vme_bridge.h
> +++ b/drivers/staging/vme/vme_bridge.h
> @@ -112,6 +112,7 @@ struct vme_bridge {
>  	/* Bridge Info - XXX Move to private structure? */
>  	struct device *parent;	/* Parent device (eg. pdev->dev for PCI) */
>  	void *driver_priv;	/* Private pointer for the bridge driver */
> +	struct list_head bus_list; /* list of VME buses */
>  
>  	struct device dev[VME_SLOTS_MAX];	/* Device registered with
>  						 * device model on VME bus


-- 
Martyn Welch (Principal Software Engineer) | Registered in England and
GE Intelligent Platforms                   | Wales (3828642) at 100
T +44(0)127322748                          | Barbirolli Square, Manchester,
E martyn.welch@xxxxxx                      | M2 3AB  VAT:GB 927559189
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