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Mon, 15 Sep 2025 21:48:10 -0700 (PDT) Received: from pengdl-pc.mioffice.cn ([43.224.245.249]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-25ef09c77f8sm104600605ad.15.2025.09.15.21.48.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 15 Sep 2025 21:48:09 -0700 (PDT) From: pengdonglin To: tj@kernel.org, tony.luck@intel.com, jani.nikula@linux.intel.com, ap420073@gmail.com, jv@jvosburgh.net, freude@linux.ibm.com, bcrl@kvack.org, trondmy@kernel.org, longman@redhat.com, kees@kernel.org Cc: bigeasy@linutronix.de, hdanton@sina.com, paulmck@kernel.org, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev, linux-nfs@vger.kernel.org, linux-aio@kvack.org, linux-fsdevel@vger.kernel.org, linux-security-module@vger.kernel.org, netdev@vger.kernel.org, intel-gfx@lists.freedesktop.org, linux-wireless@vger.kernel.org, linux-acpi@vger.kernel.org, linux-s390@vger.kernel.org, cgroups@vger.kernel.org, pengdonglin Subject: [PATCH v3 00/14] Remove redundant rcu_read_lock/unlock() in spin_lock Date: Tue, 16 Sep 2025 12:47:21 +0800 Message-Id: <20250916044735.2316171-1-dolinux.peng@gmail.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-rt-devel@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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