Re: [PATCH v3 3/5] i3c: master: add i3c_for_each_dev helper

[Greg KH <gregkh@linuxfoundation.org>]

On Wed, Feb 19, 2020 at 01:20:41AM +0100, Vitor Soares wrote:
> Introduce i3c_for_each_dev(), an i3c device iterator for use by i3cdev.
> 
> Signed-off-by: Vitor Soares <vitor.soares@synopsys.com>
> ---
>  drivers/i3c/internals.h |  1 +
>  drivers/i3c/master.c    | 12 ++++++++++++
>  2 files changed, 13 insertions(+)
> 
> diff --git a/drivers/i3c/internals.h b/drivers/i3c/internals.h
> index bc062e8..a6deedf 100644
> --- a/drivers/i3c/internals.h
> +++ b/drivers/i3c/internals.h
> @@ -24,4 +24,5 @@ int i3c_dev_enable_ibi_locked(struct i3c_dev_desc *dev);
>  int i3c_dev_request_ibi_locked(struct i3c_dev_desc *dev,
>  			       const struct i3c_ibi_setup *req);
>  void i3c_dev_free_ibi_locked(struct i3c_dev_desc *dev);
> +int i3c_for_each_dev(void *data, int (*fn)(struct device *, void *));
>  #endif /* I3C_INTERNAL_H */
> diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
> index 21c4372..8e22da2 100644
> --- a/drivers/i3c/master.c
> +++ b/drivers/i3c/master.c
> @@ -2640,6 +2640,18 @@ void i3c_dev_free_ibi_locked(struct i3c_dev_desc *dev)
>  	dev->ibi = NULL;
>  }
>  
> +int i3c_for_each_dev(void *data, int (*fn)(struct device *, void *))
> +{
> +	int res;
> +
> +	mutex_lock(&i3c_core_lock);
> +	res = bus_for_each_dev(&i3c_bus_type, NULL, data, fn);
> +	mutex_unlock(&i3c_core_lock);

Ick, why the lock?  Are you _sure_ you need that?  The core should
handle any list locking issues here, right?

I don't see bus-specific-locks around other subsystem functions that do
this (like usb_for_each_dev).

thanks,

greg k-h

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