Re: [PATCH] cfg80211: Pass lockdep expression to RCU lists
From: Arend Van Spriel <arend.vanspriel@broadcom.com>
Date: 2020-02-19 21:33:34
Also in:
linux-kernel-mentees, linux-wireless, lkml
Possibly related (same subject, not in this thread)
- 2020-02-19 · Re: [PATCH] cfg80211: Pass lockdep expression to RCU lists · Arend Van Spriel <arend.vanspriel@broadcom.com>
- 2020-02-19 · Re: [PATCH] cfg80211: Pass lockdep expression to RCU lists · "Paul E. McKenney" <paulmck@kernel.org>
- 2020-02-19 · Re: [PATCH] cfg80211: Pass lockdep expression to RCU lists · Johannes Berg <johannes@sipsolutions.net>
- 2020-02-19 · [PATCH] cfg80211: Pass lockdep expression to RCU lists · Amol Grover <hidden>
On 2/19/2020 10:29 PM, Johannes Berg wrote:
On Wed, 2020-02-19 at 22:27 +0100, Arend Van Spriel wrote:quoted
On 2/19/2020 10:13 AM, Johannes Berg wrote:quoted
On Wed, 2020-02-19 at 14:41 +0530, Amol Grover wrote:quoted
- WARN_ON_ONCE(!rcu_read_lock_held() && !lockdep_rtnl_is_held()); - - list_for_each_entry_rcu(pos, &rdev->sched_scan_req_list, list) { + list_for_each_entry_rcu(pos, &rdev->sched_scan_req_list, list, + lockdep_rtnl_is_held()) {Huh, I didn't even know you _could_ do that :)Me neither ;-). Above you are removing the WARN_ON_ONCE() entirely. Would it not be good to keep the WARN_ON_ONCE() with only the !rcu_read_lock_held() check.Not needed, the macro expansion will already contain rcu_read_lock_any_held() just like in all the other cases where you pass a lockdep condition to RCU helpers.
Ah, yes. I see it in __list_check_rcu(). Thanks, Arend