From d3e2439b0f339de319d27118f6de365753081179 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Wed, 6 Jul 2022 14:03:07 +0200 Subject: [PATCH] wifi: mac80211: fix link manipulation When we add non-deflink pointers, we need to remove the link[0] pointer to deflink in case link[0] is not valid afterwards. Also, we need to add that back when there are no more valid links. Reorg the code to fix that. Signed-off-by: Johannes Berg --- net/mac80211/iface.c | 44 ++++++++++++++++++++++++++------------------ 1 file changed, 26 insertions(+), 18 deletions(-) diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c index f4341f378d4e..7410370c291b 100644 --- a/net/mac80211/iface.c +++ b/net/mac80211/iface.c @@ -463,6 +463,10 @@ static int ieee80211_vif_update_links(struct ieee80211_sub_if_data *sdata, if (old_links == new_links) return 0; + /* if there were no old links, need to clear the pointers to deflink */ + if (!old_links) + rem |= BIT(0); + /* allocate new link structures first */ for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) { link = kzalloc(sizeof(*link), GFP_KERNEL); @@ -480,6 +484,22 @@ static int ieee80211_vif_update_links(struct ieee80211_sub_if_data *sdata, BUILD_BUG_ON(sizeof(old_data) != sizeof(sdata->link)); memcpy(old_data, sdata->link, sizeof(old_data)); + /* grab old links to free later */ + for_each_set_bit(link_id, &rem, IEEE80211_MLD_MAX_NUM_LINKS) { + RCU_INIT_POINTER(sdata->link[link_id], NULL); + RCU_INIT_POINTER(sdata->vif.link_conf[link_id], NULL); + + if (rcu_access_pointer(sdata->link[link_id]) == &sdata->deflink) + continue; + /* + * we must have allocated the data through this path so + * we know we can free both at the same time + */ + to_free[link_id] = container_of(rcu_access_pointer(sdata->link[link_id]), + typeof(*links[link_id]), + data); + } + /* link them into data structures */ for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) { WARN_ON(!use_deflink && @@ -490,10 +510,9 @@ static int ieee80211_vif_update_links(struct ieee80211_sub_if_data *sdata, ieee80211_link_setup(&link->data); } - for_each_set_bit(link_id, &rem, IEEE80211_MLD_MAX_NUM_LINKS) { - RCU_INIT_POINTER(sdata->link[link_id], NULL); - RCU_INIT_POINTER(sdata->vif.link_conf[link_id], NULL); - } + if (new_links == 0) + ieee80211_link_init(sdata, -1, &sdata->deflink, + &sdata->vif.bss_conf); sdata->vif.valid_links = new_links; @@ -506,25 +525,14 @@ static int ieee80211_vif_update_links(struct ieee80211_sub_if_data *sdata, memcpy(sdata->link, old_data, sizeof(old_data)); memcpy(sdata->vif.link_conf, old, sizeof(old)); sdata->vif.valid_links = old_links; - /* and free the newly allocated links */ - goto deinit; + /* and free (only) the newly allocated links */ + memset(to_free, 0, sizeof(links)); + goto free; } /* use deflink/bss_conf again if and only if there are no more links */ use_deflink = new_links == 0; - for_each_set_bit(link_id, &rem, IEEE80211_MLD_MAX_NUM_LINKS) { - if (rcu_access_pointer(sdata->link[link_id]) == &sdata->deflink) - continue; - /* - * we must have allocated the data through this path so - * we know we can free both at the same time - */ - to_free[link_id] = container_of(rcu_access_pointer(sdata->link[link_id]), - typeof(*links[link_id]), - data); - } - goto deinit; free: /* if we failed during allocation, only free all */ -- 2.25.1