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Message-Id: <200805201209.00546.IvDoorn@gmail.com>
Date: Tue, 20 May 2008 12:09:00 +0200
From: Ivo van Doorn <ivdoorn@...il.com>
To: Henrique de Moraes Holschuh <hmh@....eng.br>
Cc: linux-kernel@...r.kernel.org, Thomas Renninger <trenn@...e.de>
Subject: Re: [PATCH 11/15] rfkill: add notifier chains support
On Sunday 18 May 2008, Henrique de Moraes Holschuh wrote:
> Add a notifier chain for use by the rfkill class. This notifier chain
> signals the following events (more to be added when needed):
>
> 1. rfkill: rfkill device state has changed
>
> A pointer to the rfkill struct will be passed as a parameter.
>
> The notifier message types have been added to include/linux/rfkill.h
> instead of to include/linux/notifier.h in order to avoid the madness of
> modifying a header used globally (and that triggers an almost full tree
> rebuild every time it is touched) with information that is of interest only
> to code that includes the rfkill.h header.
>
> Signed-off-by: Henrique de Moraes Holschuh <hmh@....eng.br>
Besides the spelling comments from Thomas, patch is fine with me.
Acked-by: Ivo van Doorn <IvDoorn@...il.com>
> Cc: Ivo van Doorn <IvDoorn@...il.com>
> ---
> include/linux/rfkill.h | 7 +++++
> net/rfkill/rfkill.c | 70 +++++++++++++++++++++++++++++++++++++++++++++--
> 2 files changed, 74 insertions(+), 3 deletions(-)
>
> diff --git a/include/linux/rfkill.h b/include/linux/rfkill.h
> index c0cab7d..98667be 100644
> --- a/include/linux/rfkill.h
> +++ b/include/linux/rfkill.h
> @@ -117,4 +117,11 @@ static inline char *rfkill_get_led_name(struct rfkill *rfkill)
> #endif
> }
>
> +/* rfkill notification chain */
> +#define RFKILL_STATE_CHANGED 0x0001 /* state of a normal rfkill
> + switch has changed */
> +
> +int register_rfkill_notifier(struct notifier_block *nb);
> +int unregister_rfkill_notifier(struct notifier_block *nb);
> +
> #endif /* RFKILL_H */
> diff --git a/net/rfkill/rfkill.c b/net/rfkill/rfkill.c
> index f11220b..251defe 100644
> --- a/net/rfkill/rfkill.c
> +++ b/net/rfkill/rfkill.c
> @@ -46,6 +46,49 @@ MODULE_PARM_DESC(default_state,
>
> static enum rfkill_state rfkill_states[RFKILL_TYPE_MAX];
>
> +static BLOCKING_NOTIFIER_HEAD(rfkill_notifier_list);
> +
> +
> +/**
> + * register_rfkill_notifier - Add notifier to rfkill notifier chain
> + * @nb: pointer to the new entry to add to the chain
> + *
> + * See blocking_notifier_chain_register() for return value and further
> + * observations.
> + *
> + * Adds a notifier to the rfkill notifier chain. The chain will be
> + * called with a pointer to the relevant rfkill structure as a parameter,
> + * refer to include/linux/rfkill.h for the possible events.
> + *
> + * Notifiers added to this chain are to always return NOTIFY_DONE. This
> + * chain is a blocking notifier chain: notifiers can sleep.
> + *
> + * Calls to this chain may have been done through a workqueue. One must
> + * one must assume unordered assynchronous behaviour, there is no way to
> + * know if actions related to the event that generated the notification
> + * have been carried out already.
> + */
> +int register_rfkill_notifier(struct notifier_block *nb)
> +{
> + return blocking_notifier_chain_register(&rfkill_notifier_list, nb);
> +}
> +EXPORT_SYMBOL_GPL(register_rfkill_notifier);
> +
> +/**
> + * unregister_rfkill_notifier - remove notifier from rfkill notifier chain
> + * @nb: pointer to the entry to remove from the chain
> + *
> + * See blocking_notifier_chain_unregister() for return value and further
> + * observations.
> + *
> + * Removes a notifier from the rfkill notifier chain.
> + */
> +int unregister_rfkill_notifier(struct notifier_block *nb)
> +{
> + return blocking_notifier_chain_unregister(&rfkill_notifier_list, nb);
> +}
> +EXPORT_SYMBOL_GPL(unregister_rfkill_notifier);
> +
>
> static void rfkill_led_trigger(struct rfkill *rfkill,
> enum rfkill_state state)
> @@ -62,14 +105,25 @@ static void rfkill_led_trigger(struct rfkill *rfkill,
> #endif /* CONFIG_RFKILL_LEDS */
> }
>
> +static void notify_rfkill_state_change(struct rfkill *rfkill)
> +{
> + blocking_notifier_call_chain(&rfkill_notifier_list,
> + RFKILL_STATE_CHANGED,
> + rfkill);
> +}
> +
> static void update_rfkill_state(struct rfkill *rfkill)
> {
> - enum rfkill_state newstate;
> + enum rfkill_state newstate, oldstate;
>
> if (rfkill->get_state) {
> mutex_lock(&rfkill->mutex);
> - if (!rfkill->get_state(rfkill->data, &newstate))
> + if (!rfkill->get_state(rfkill->data, &newstate)) {
> + oldstate = rfkill->state;
> rfkill->state = newstate;
> + if (oldstate != newstate)
> + notify_rfkill_state_change(rfkill);
> + }
> mutex_unlock(&rfkill->mutex);
> }
> }
> @@ -93,8 +147,10 @@ static int rfkill_toggle_radio(struct rfkill *rfkill,
> rfkill->state = state;
> }
>
> - if (force || rfkill->state != oldstate)
> + if (force || rfkill->state != oldstate) {
> rfkill_led_trigger(rfkill, rfkill->state);
> + notify_rfkill_state_change(rfkill);
> + }
>
> return retval;
> }
> @@ -139,8 +195,16 @@ EXPORT_SYMBOL(rfkill_switch_all);
> */
> int rfkill_force_state(struct rfkill *rfkill, enum rfkill_state state)
> {
> + enum rfkill_state oldstate;
> +
> mutex_lock(&rfkill->mutex);
> +
> + oldstate = rfkill->state;
> rfkill->state = state;
> +
> + if (state != oldstate)
> + notify_rfkill_state_change(rfkill);
> +
> mutex_unlock(&rfkill->mutex);
>
> return 0;
--
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