netdev - [PATCH v3 00/14] Remove redundant rcu_read_lock/unlock() in spin

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Message-Id: <20250916044735.2316171-1-dolinux.peng@gmail.com>
Date: Tue, 16 Sep 2025 12:47:21 +0800
From: pengdonglin <dolinux.peng@...il.com>
To: tj@...nel.org,
	tony.luck@...el.com,
	jani.nikula@...ux.intel.com,
	ap420073@...il.com,
	jv@...sburgh.net,
	freude@...ux.ibm.com,
	bcrl@...ck.org,
	trondmy@...nel.org,
	longman@...hat.com,
	kees@...nel.org
Cc: bigeasy@...utronix.de,
	hdanton@...a.com,
	paulmck@...nel.org,
	linux-kernel@...r.kernel.org,
	linux-rt-devel@...ts.linux.dev,
	linux-nfs@...r.kernel.org,
	linux-aio@...ck.org,
	linux-fsdevel@...r.kernel.org,
	linux-security-module@...r.kernel.org,
	netdev@...r.kernel.org,
	intel-gfx@...ts.freedesktop.org,
	linux-wireless@...r.kernel.org,
	linux-acpi@...r.kernel.org,
	linux-s390@...r.kernel.org,
	cgroups@...r.kernel.org,
	pengdonglin <dolinux.peng@...il.com>
Subject: [PATCH v3 00/14] Remove redundant rcu_read_lock/unlock() in spin_lock

Since commit a8bb74acd8efe ("rcu: Consolidate RCU-sched update-side function definitions")
there is no difference between rcu_read_lock(), rcu_read_lock_bh() and
rcu_read_lock_sched() in terms of RCU read section and the relevant grace
period. That means that spin_lock(), which implies rcu_read_lock_sched(),
also implies rcu_read_lock().

There is no need no explicitly start a RCU read section if one has already
been started implicitly by spin_lock().

Simplify the code and remove the inner rcu_read_lock() invocation.

[1] https://elixir.bootlin.com/linux/v6.17-rc5/source/Documentation/RCU/rcu_dereference.rst#L407
[2] https://lore.kernel.org/lkml/20180829222021.GA29944@linux.vnet.ibm.com/
[3] https://lwn.net/Articles/777036/
[4] https://lore.kernel.org/lkml/6435833a-bdcb-4114-b29d-28b7f436d47d@paulmck-laptop/

pengdonglin (14):
  ACPI: APEI: Remove redundant rcu_read_lock/unlock() in spin_lock
  drm/i915/gt: Remove redundant rcu_read_lock/unlock() in spin_lock
  fs: aio: Remove redundant rcu_read_lock/unlock() in spin_lock
  nfs: Remove redundant rcu_read_lock/unlock() in spin_lock
  s390/pkey: Remove redundant rcu_read_lock/unlock() in spin_lock
  ipc: Remove redundant rcu_read_lock/unlock() in spin_lock
  yama: Remove redundant rcu_read_lock/unlock() in spin_lock
  cgroup: Remove redundant rcu_read_lock/unlock() in spin_lock
  cgroup/cpuset: Remove redundant rcu_read_lock/unlock() in spin_lock
  wifi: mac80211: Remove redundant rcu_read_lock/unlock() in spin_lock
  net: ncsi: Remove redundant rcu_read_lock/unlock() in spin_lock
  net: amt: Remove redundant rcu_read_lock/unlock() in spin_lock
  net: bonding: Remove redundant rcu_read_lock/unlock() in spin_lock
  wifi: ath9k: Remove redundant rcu_read_lock/unlock() in spin_lock

 drivers/acpi/apei/ghes.c                        |  2 --
 drivers/gpu/drm/i915/gt/intel_ring_submission.c |  2 --
 drivers/net/amt.c                               |  8 --------
 drivers/net/bonding/bond_3ad.c                  |  2 --
 drivers/net/wireless/ath/ath9k/xmit.c           |  2 --
 drivers/s390/crypto/pkey_base.c                 |  3 ---
 fs/aio.c                                        |  6 ++----
 fs/nfs/callback_proc.c                          |  2 --
 fs/nfs/nfs4state.c                              |  2 --
 fs/nfs/pnfs.c                                   | 12 +-----------
 fs/nfs/pnfs_dev.c                               |  4 ----
 ipc/msg.c                                       |  1 -
 ipc/sem.c                                       |  1 -
 ipc/shm.c                                       |  1 -
 ipc/util.c                                      |  2 --
 kernel/cgroup/cgroup.c                          |  2 --
 kernel/cgroup/cpuset.c                          |  6 ------
 kernel/cgroup/debug.c                           |  4 ----
 net/mac80211/cfg.c                              |  2 --
 net/mac80211/debugfs.c                          |  2 --
 net/mac80211/debugfs_netdev.c                   |  2 --
 net/mac80211/debugfs_sta.c                      |  2 --
 net/mac80211/sta_info.c                         |  2 --
 net/ncsi/ncsi-manage.c                          |  2 --
 security/yama/yama_lsm.c                        |  4 ----
 25 files changed, 3 insertions(+), 75 deletions(-)

-- 
2.34.1