netdev - Re: [PATCH wpan-next 5/5] mac802154: Avoid new associations while disassociating

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Date: Thu, 7 Dec 2023 21:49:46 +0100
From: Stefan Schmidt <stefan@...enfreihafen.org>
To: Miquel Raynal <miquel.raynal@...tlin.com>,
 Alexander Aring <alex.aring@...il.com>, linux-wpan@...r.kernel.org
Cc: David Girault <david.girault@...vo.com>,
 Romuald Despres <romuald.despres@...vo.com>,
 Frederic Blain <frederic.blain@...vo.com>,
 Nicolas Schodet <nico@...fr.eu.org>,
 Guilhem Imberton <guilhem.imberton@...vo.com>,
 Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
 "David S. Miller" <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>,
 Paolo Abeni <pabeni@...hat.com>, Eric Dumazet <edumazet@...gle.com>,
 netdev@...r.kernel.org
Subject: Re: [PATCH wpan-next 5/5] mac802154: Avoid new associations while
 disassociating

Hello.

On 28.11.23 12:16, Miquel Raynal wrote:
> While disassociating from a PAN ourselves, let's set the maximum number
> of associations temporarily to zero to be sure no new device tries to
> associate with us.
> 
> Signed-off-by: Miquel Raynal <miquel.raynal@...tlin.com>
> ---
>   include/net/cfg802154.h |  4 +++-
>   net/ieee802154/pan.c    |  8 +++++++-
>   net/mac802154/cfg.c     | 11 ++++++++---
>   3 files changed, 18 insertions(+), 5 deletions(-)
> 
> diff --git a/include/net/cfg802154.h b/include/net/cfg802154.h
> index a64bbcd71f10..cd95711b12b8 100644
> --- a/include/net/cfg802154.h
> +++ b/include/net/cfg802154.h
> @@ -589,8 +589,10 @@ cfg802154_device_is_child(struct wpan_dev *wpan_dev,
>    * cfg802154_set_max_associations - Limit the number of future associations
>    * @wpan_dev: the wpan device
>    * @max: the maximum number of devices we accept to associate
> + * @return: the old maximum value
>    */
> -void cfg802154_set_max_associations(struct wpan_dev *wpan_dev, unsigned int max);
> +unsigned int cfg802154_set_max_associations(struct wpan_dev *wpan_dev,
> +					    unsigned int max);
>   
>   /**
>    * cfg802154_get_free_short_addr - Get a free address among the known devices
> diff --git a/net/ieee802154/pan.c b/net/ieee802154/pan.c
> index fb5b0af2ef68..249df7364b3e 100644
> --- a/net/ieee802154/pan.c
> +++ b/net/ieee802154/pan.c
> @@ -94,10 +94,16 @@ __le16 cfg802154_get_free_short_addr(struct wpan_dev *wpan_dev)
>   }
>   EXPORT_SYMBOL_GPL(cfg802154_get_free_short_addr);
>   
> -void cfg802154_set_max_associations(struct wpan_dev *wpan_dev, unsigned int max)
> +unsigned int cfg802154_set_max_associations(struct wpan_dev *wpan_dev,
> +					    unsigned int max)
>   {
> +	unsigned int old_max;
> +
>   	lockdep_assert_held(&wpan_dev->association_lock);
>   
> +	old_max = wpan_dev->max_associations;
>   	wpan_dev->max_associations = max;
> +
> +	return old_max;
>   }
>   EXPORT_SYMBOL_GPL(cfg802154_set_max_associations);
> diff --git a/net/mac802154/cfg.c b/net/mac802154/cfg.c
> index 17e2032fac24..ef7f23af043f 100644
> --- a/net/mac802154/cfg.c
> +++ b/net/mac802154/cfg.c
> @@ -389,6 +389,7 @@ static int mac802154_disassociate_from_parent(struct wpan_phy *wpan_phy,
>   	struct ieee802154_local *local = wpan_phy_priv(wpan_phy);
>   	struct ieee802154_pan_device *child, *tmp;
>   	struct ieee802154_sub_if_data *sdata;
> +	unsigned int max_assoc;
>   	u64 eaddr;
>   	int ret;
>   
> @@ -397,6 +398,7 @@ static int mac802154_disassociate_from_parent(struct wpan_phy *wpan_phy,
>   	/* Start by disassociating all the children and preventing new ones to
>   	 * attempt associations.
>   	 */
> +	max_assoc = cfg802154_set_max_associations(wpan_dev, 0);
>   	list_for_each_entry_safe(child, tmp, &wpan_dev->children, node) {
>   		ret = mac802154_send_disassociation_notif(sdata, child,
>   							  IEEE802154_COORD_WISHES_DEVICE_TO_LEAVE);
> @@ -429,14 +431,17 @@ static int mac802154_disassociate_from_parent(struct wpan_phy *wpan_phy,
>   	if (local->hw.flags & IEEE802154_HW_AFILT) {
>   		ret = drv_set_pan_id(local, wpan_dev->pan_id);
>   		if (ret < 0)
> -			return ret;
> +			goto reset_mac_assoc;
>   
>   		ret = drv_set_short_addr(local, wpan_dev->short_addr);
>   		if (ret < 0)
> -			return ret;
> +			goto reset_mac_assoc;
>   	}
>   
> -	return 0;
> +reset_mac_assoc:
> +	cfg802154_set_max_associations(wpan_dev, max_assoc);
> +
> +	return ret;
>   }
>   
>   static int mac802154_disassociate_child(struct wpan_phy *wpan_phy,

Acked-by: Stefan Schmidt <stefan@...enfreihafen.org>

regards
Stefan Schmidt