Messages in this thread | | | From | Martin Blumenstingl <> | Date | Sun, 25 Jul 2021 23:36:13 +0200 | Subject | Re: [PATCH RFC v1 5/7] rtw88: Configure the registers from rtw_bf_assoc() outside the RCU lock |
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Hi Ping-Ke,
On Mon, Jul 19, 2021 at 7:47 AM Pkshih <pkshih@realtek.com> wrote: [...] > The rcu_read_lock() in this function is used to access ieee80211_find_sta() and protect 'sta'. > A simple way is to shrink the critical section, like: > > rcu_read_lock(); > > sta = ieee80211_find_sta(vif, bssid); > if (!sta) { > rtw_warn(rtwdev, "failed to find station entry for bss %pM\n", > bssid); > rcu_read_unlock(); > } > > vht_cap = &sta->vht_cap; > > rcu_read_unlock(); I agree that reducing the amount of code under the lock will help my use-case as well in your code-example I am wondering if we should change struct ieee80211_sta_vht_cap *vht_cap; vht_cap = &sta->vht_cap; to struct ieee80211_sta_vht_cap vht_cap; vht_cap = sta->vht_cap;
My thinking is that ieee80211_sta may be freed in parallel to this code running. If that cannot happen then your code will be fine.
So I am hoping that you can also share your thoughts on this one.
Thank you and best regards, Martin
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