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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , b.a.t.m.a.n@lists.open-mesh.org, Sven Eckelmann , stable@kernel.org, Nora Schiffer , Simon Wunderlich Subject: [PATCH net 01/15] batman-adv: gw: don't deselect gateway with active hardif Date: Fri, 19 Jun 2026 09:00:31 +0200 Message-ID: <20260619070045.438101-2-sw@simonwunderlich.de> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260619070045.438101-1-sw@simonwunderlich.de> References: <20260619070045.438101-1-sw@simonwunderlich.de> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Sven Eckelmann The batadv_hardif_cnt() was previously checking if there is an batadv_hard_iface->mesh_iface which is has the same mesh_iface. And since batadv_hardif_disable_interface() was resetting the batadv_hard_iface->mesh_iface after this check, it had to verify whether *1* interface was still part of the mesh_iface before it started the gateway deselection. But after batadv_hardif_cnt() is now checking the lower interfaces of mesh_iface and batadv_hardif_disable_interface() already removed the interface via netdev_upper_dev_unlink() earlier in this function, the check must now make sure that *0* interfaces can be found by batadv_hardif_cnt() before selected gateway must be deselected. Otherwise the deselection would already happen one batadv_hard_iface too early. Because a 0 hardif count from batadv_hardif_cnt() is equal to an empty list, it is possible to replace the counting with a simple list_empty(). Cc: stable@kernel.org Fixes: 7dc284702bcd ("batman-adv: store hard_iface as iflink private data") Reviewed-by: Nora Schiffer Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich --- net/batman-adv/hard-interface.c | 28 ++-------------------------- 1 file changed, 2 insertions(+), 26 deletions(-) diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c index 60cee2c2f2f41..03d01c20a9548 100644 --- a/net/batman-adv/hard-interface.c +++ b/net/batman-adv/hard-interface.c @@ -814,30 +814,6 @@ int batadv_hardif_enable_interface(struct batadv_hard_iface *hard_iface, return ret; } -/** - * batadv_hardif_cnt() - get number of interfaces enslaved to mesh interface - * @mesh_iface: mesh interface to check - * - * This function is only using RCU for locking - the result can therefore be - * off when another function is modifying the list at the same time. The - * caller can use the rtnl_lock to make sure that the count is accurate. - * - * Return: number of connected/enslaved hard interfaces - */ -static size_t batadv_hardif_cnt(struct net_device *mesh_iface) -{ - struct batadv_hard_iface *hard_iface; - struct list_head *iter; - size_t count = 0; - - rcu_read_lock(); - netdev_for_each_lower_private_rcu(mesh_iface, hard_iface, iter) - count++; - rcu_read_unlock(); - - return count; -} - /** * batadv_hardif_disable_interface() - Remove hard interface from mesh interface * @hard_iface: hard interface to be removed @@ -878,8 +854,8 @@ void batadv_hardif_disable_interface(struct batadv_hard_iface *hard_iface) netdev_upper_dev_unlink(hard_iface->net_dev, hard_iface->mesh_iface); batadv_hardif_recalc_extra_skbroom(hard_iface->mesh_iface); - /* nobody uses this interface anymore */ - if (batadv_hardif_cnt(hard_iface->mesh_iface) <= 1) + /* nobody uses this mesh interface anymore */ + if (list_empty(&hard_iface->mesh_iface->adj_list.lower)) batadv_gw_check_client_stop(bat_priv); hard_iface->mesh_iface = NULL; -- 2.47.3