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Wysocki" , Hanjun Guo , pengdonglin Subject: [PATCH v3 01/14] ACPI: APEI: Remove redundant rcu_read_lock/unlock() in spin_lock Date: Tue, 16 Sep 2025 12:47:22 +0800 Message-Id: <20250916044735.2316171-2-dolinux.peng@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20250916044735.2316171-1-dolinux.peng@gmail.com> References: <20250916044735.2316171-1-dolinux.peng@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Mailman-Approved-At: Tue, 16 Sep 2025 14:55:20 +0000 X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" From: pengdonglin 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. Cc: "Rafael J. Wysocki" Cc: Tony Luck Cc: Hanjun Guo Signed-off-by: pengdonglin Signed-off-by: pengdonglin --- drivers/acpi/apei/ghes.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c index a0d54993edb3..97ee19f2cae0 100644 --- a/drivers/acpi/apei/ghes.c +++ b/drivers/acpi/apei/ghes.c @@ -1207,12 +1207,10 @@ static int ghes_notify_hed(struct notifier_block *this, unsigned long event, int ret = NOTIFY_DONE; spin_lock_irqsave(&ghes_notify_lock_irq, flags); - rcu_read_lock(); list_for_each_entry_rcu(ghes, &ghes_hed, list) { if (!ghes_proc(ghes)) ret = NOTIFY_OK; } - rcu_read_unlock(); spin_unlock_irqrestore(&ghes_notify_lock_irq, flags); return ret; -- 2.34.1