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Baochen Qiang
53d7c99719
Current documentation on RCU in ath11k_mac_op_ipv6_changed() says:
/* Note: read_lock_bh() calls rcu_read_lock() */
read_lock_bh(&idev->lock);
This is wrong because without enabling CONFIG_PREEMPT_RT
rcu_read_lock() is not called by read_lock_bh(). The reason
why current code works even in a CONFIG_PREEMPT_RT=n kernel
is because atomic_notifier_call_chain() already does that for
us, see:
int atomic_notifier_call_chain()
{
...
rcu_read_lock();
ret = notifier_call_chain(&nh->head, val, v, -1, NULL);
rcu_read_unlock();
...
}
and backtrace:
ath11k_mac_op_ipv6_changed
ieee80211_ifa6_changed
notifier_call_chain
atomic_notifier_call_chain
So update the comment to make it correct.
This is found during code review, compile tested only.
Fixes: feafe59c89 ("wifi: ath11k: use RCU when accessing struct inet6_dev::ac_list")
Signed-off-by: Baochen Qiang <quic_bqiang@quicinc.com>
Acked-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://msgid.link/20240531022411.6543-1-quic_bqiang@quicinc.com
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.