From patchwork Thu Apr 26 10:34:21 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 10365489 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id F142A602DC for ; Thu, 26 Apr 2018 10:48:24 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id DB90827031 for ; Thu, 26 Apr 2018 10:48:24 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id CF4AC27FA5; Thu, 26 Apr 2018 10:48:24 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI autolearn=unavailable version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id E922128701 for ; Thu, 26 Apr 2018 10:48:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=ow/WQv2Xd/lX3COzfXpmkgs9t4WgDs0OF32dibpI7iM=; b=kzLEjYEDIodgvbRh14xrenOgJa 701uB45/2eiivTMduGc23qZxjQa8a2gJl52K1Tnsu5RsQn382BqzROl+cIzfotWP3jFMmwvMCNFhf X5HELPteHFuj3c0HsEtO5dVXRqvDSEwlVmdeUPupSzTAitgtQGSAMhB10o7db8mHnXiGjwU4lgT57 o9tyhk/Vtk3wqwIrv2lKjSC+WsIgKaPANC3EAQadPdL9aFh98miBQnGPBrzL9ZhPJXmcmztjVO5zq rCxrtfg4j4vYW4lDE7B5atX+jyizd1MLPaeZ3khE3BDlvumKGPbthAVubMuHq/qy3yNcuC8jVWRsx /wPFFe4Q==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1fBeRe-0003DL-2k; Thu, 26 Apr 2018 10:48:10 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1fBeET-00022M-0L for linux-arm-kernel@lists.infradead.org; Thu, 26 Apr 2018 10:34:39 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 56FF416EA; Thu, 26 Apr 2018 03:34:10 -0700 (PDT) Received: from edgewater-inn.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 26DDD3F5B7; Thu, 26 Apr 2018 03:34:10 -0700 (PDT) Received: by edgewater-inn.cambridge.arm.com (Postfix, from userid 1000) id 4F9DF1AE5152; Thu, 26 Apr 2018 11:34:29 +0100 (BST) From: Will Deacon To: linux-kernel@vger.kernel.org Subject: [PATCH v3 07/14] locking/qspinlock: Use atomic_cond_read_acquire Date: Thu, 26 Apr 2018 11:34:21 +0100 Message-Id: <1524738868-31318-8-git-send-email-will.deacon@arm.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1524738868-31318-1-git-send-email-will.deacon@arm.com> References: <1524738868-31318-1-git-send-email-will.deacon@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20180426_033433_143904_88BEF4E3 X-CRM114-Status: GOOD ( 12.05 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: peterz@infradead.org, boqun.feng@gmail.com, will.deacon@arm.com, longman@redhat.com, paulmck@linux.vnet.ibm.com, mingo@kernel.org, linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP Rather than dig into the counter field of the atomic_t inside the qspinlock structure so that we can call smp_cond_load_acquire, use atomic_cond_read_acquire instead, which operates on the atomic_t directly. Cc: Peter Zijlstra Cc: Ingo Molnar Signed-off-by: Will Deacon --- kernel/locking/qspinlock.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c index e42f50d69ed6..5e383cfe4cce 100644 --- a/kernel/locking/qspinlock.c +++ b/kernel/locking/qspinlock.c @@ -337,8 +337,8 @@ void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val) * barriers. */ if (val & _Q_LOCKED_MASK) { - smp_cond_load_acquire(&lock->val.counter, - !(VAL & _Q_LOCKED_MASK)); + atomic_cond_read_acquire(&lock->val, + !(VAL & _Q_LOCKED_MASK)); } /* @@ -441,8 +441,8 @@ void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val) * * The PV pv_wait_head_or_lock function, if active, will acquire * the lock and return a non-zero value. So we have to skip the - * smp_cond_load_acquire() call. As the next PV queue head hasn't been - * designated yet, there is no way for the locked value to become + * atomic_cond_read_acquire() call. As the next PV queue head hasn't + * been designated yet, there is no way for the locked value to become * _Q_SLOW_VAL. So both the set_locked() and the * atomic_cmpxchg_relaxed() calls will be safe. * @@ -452,7 +452,7 @@ void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val) if ((val = pv_wait_head_or_lock(lock, node))) goto locked; - val = smp_cond_load_acquire(&lock->val.counter, !(VAL & _Q_LOCKED_PENDING_MASK)); + val = atomic_cond_read_acquire(&lock->val, !(VAL & _Q_LOCKED_PENDING_MASK)); locked: /* @@ -469,7 +469,7 @@ void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val) /* In the PV case we might already have _Q_LOCKED_VAL set */ if ((val & _Q_TAIL_MASK) == tail) { /* - * The smp_cond_load_acquire() call above has provided the + * The atomic_cond_read_acquire() call above has provided the * necessary acquire semantics required for locking. */ old = atomic_cmpxchg_relaxed(&lock->val, val, _Q_LOCKED_VAL);