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[82.69.66.36]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-485885bbb51sm27883762f8f.30.2026.09.07.01.41.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 07 Sep 2026 01:41:56 -0700 (PDT) From: David Laight To: Waiman Long , Peter Zijlstra , Ingo Molnar , Will Deacon , Boqun Feng , linux-kernel@vger.kernel.org, Linus Torvalds , Yafang Shao , Steven Rostedt Cc: David Laight Subject: [PATCH v4 next 8/9] locking/osq: inline encode_cpu() and rename decode_cpu() Date: Mon, 7 Sep 2026 09:41:32 +0100 Message-Id: <20260907084133.3696-9-david.laight.linux@gmail.com> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20260907084133.3696-1-david.laight.linux@gmail.com> References: <20260907084133.3696-1-david.laight.linux@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Having a function to add the 1 offset to the cpu number doesn't make the code any easier to read. Just use smp_processor_id() + 1. Rename decode_cpu() to cpu_spin_node() to match what it does. No functional change. Signed-off-by: David Laight --- kernel/locking/osq_lock.c | 23 +++++++---------------- 1 file changed, 7 insertions(+), 16 deletions(-) diff --git a/kernel/locking/osq_lock.c b/kernel/locking/osq_lock.c index 144eb446c867..8dfd729d1a81 100644 --- a/kernel/locking/osq_lock.c +++ b/kernel/locking/osq_lock.c @@ -40,19 +40,10 @@ struct optimistic_spin_node { static DEFINE_PER_CPU(struct optimistic_spin_node, osq_node); -/* - * We use the value 0 to represent "no CPU", thus the encoded value - * will be the CPU number incremented by 1. - */ -static inline unsigned int encode_cpu(unsigned int cpu_nr) -{ - return cpu_nr + 1; -} - static inline struct optimistic_spin_node * -decode_cpu(unsigned int encoded_cpu_val) +cpu_spin_node(unsigned int offset_cpu_num) { - return per_cpu_ptr(&osq_node, encoded_cpu_val - 1); + return per_cpu_ptr(&osq_node, offset_cpu_num - 1); } /* @@ -74,7 +65,7 @@ decode_cpu(unsigned int encoded_cpu_val) static inline unsigned int osq_unlink_from_next(struct optimistic_spin_queue *lock, unsigned int prev) { - unsigned int curr = encode_cpu(smp_processor_id()); + unsigned int curr = smp_processor_id() + 1; struct optimistic_spin_node *node; unsigned int next; @@ -118,7 +109,7 @@ osq_unlink_from_next(struct optimistic_spin_queue *lock, unsigned int prev) * When called while unqueueing in osq_lock() this completes the * backwards link, the forwards link is done by the caller. */ - WRITE_ONCE(decode_cpu(next)->prev, prev); + WRITE_ONCE(cpu_spin_node(next)->prev, prev); return next; } @@ -126,7 +117,7 @@ osq_unlink_from_next(struct optimistic_spin_queue *lock, unsigned int prev) bool osq_lock(struct optimistic_spin_queue *lock) { struct optimistic_spin_node *node, *prev_ptr; - unsigned int curr = encode_cpu(smp_processor_id()); + unsigned int curr = smp_processor_id() + 1; unsigned int next, prev; /* @@ -140,7 +131,7 @@ bool osq_lock(struct optimistic_spin_queue *lock) return true; node = this_cpu_ptr(&osq_node); - prev_ptr = decode_cpu(prev); + prev_ptr = cpu_spin_node(prev); node->prev = prev; /* @@ -189,7 +180,7 @@ bool osq_lock(struct optimistic_spin_queue *lock) /* Lock acquired */ return true; - prev_ptr = decode_cpu(prev); + prev_ptr = cpu_spin_node(prev); if (data_race(prev_ptr->next) == curr && cmpxchg(&prev_ptr->next, curr, 0) == curr) -- 2.39.5