From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AD637C433F5 for ; Sat, 30 Apr 2022 15:38:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1383010AbiD3Pli (ORCPT ); Sat, 30 Apr 2022 11:41:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44104 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352787AbiD3PlT (ORCPT ); Sat, 30 Apr 2022 11:41:19 -0400 Received: from mail-pj1-x1034.google.com (mail-pj1-x1034.google.com [IPv6:2607:f8b0:4864:20::1034]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 060B7A0BDD for ; Sat, 30 Apr 2022 08:37:57 -0700 (PDT) Received: by mail-pj1-x1034.google.com with SMTP id iq2-20020a17090afb4200b001d93cf33ae9so12887002pjb.5 for ; Sat, 30 Apr 2022 08:37:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rivosinc-com.20210112.gappssmtp.com; s=20210112; h=subject:date:message-id:in-reply-to:references:mime-version :content-transfer-encoding:cc:from:to; bh=GsO1g7Ro+rsf0io9vopg1aQfP2P2g91oLlrkEyQDXiM=; b=kF7TN9WBue7gogtLcWCSwM/BfmlmiiSeL5p6P+r9TFf7mJTPo7V03Vb2pERNLvb7OE aRiiolMYojHxd4x5cQCGpG9H2wT2LX9AGbU77WuAKd7VD9xTc7yVRQuxr9CmreoFTg1r PvNjg/njaujbrqAe+WzlaHXAa3YGjcCyPClqxCArzRUK1f4wnu8wIGOKQzuuPux3fanL dNudXAVOCI0w1bdRz0Bat3QH8ewK8iAbnP04kEkDwytD4R2TvR69JqSwtluXppkeLWp+ iJKg4ylgLJ4xSXkYkJB/5TkTjMKtqArr+XkBvDHr/ZIlgr8RD4A5+MLPtRKEzg0pyefW MJ6Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding:cc:from:to; bh=GsO1g7Ro+rsf0io9vopg1aQfP2P2g91oLlrkEyQDXiM=; b=nwmY3ooSq8xeijmIn/x6QsrDY7AUUAxw8PSWAEMmyMDwHwuUDA1auH6vHMKL415h5d 5S2GqWPlu7kF2E5Oga1Iee6madyZjTx5dFU/AQY3SvMuM/rdi3h0LRF/zxEDi0VqVIWE 8mK157qyylkwAicXsS/Bch7aY3sxME3flmuP3eGnZwDfK661nwnoJUqR4r5n6qUMvNyt z6bJXpjngn/h2uhEVib5uIfSOUWp0H11/DBECMJke2MqQm9i93Ngw0O8McZb+hH7k8OK Be6/CxEYxZ87kTzqLjB4wpvo/OwxKjouwiNaDuTxKEXut2a1Bu/Z23fsIdh8KXQWEO40 crZA== X-Gm-Message-State: AOAM533ReaQh1p56bxlin9heo+kNS50j9xP1+ADBaLIfvmq2MDZzWNAc NOf0who8usPyMKbmvJXjMEBiXw== X-Google-Smtp-Source: ABdhPJzNtj8d/a+lfHQeb2reqO0YCZeJo7LPF+70BVvrDTXjKfwmfYC5tWlm1kzXph5Ui9RlcPxgHQ== X-Received: by 2002:a17:902:8d8e:b0:159:4f6:c4aa with SMTP id v14-20020a1709028d8e00b0015904f6c4aamr4142558plo.115.1651333076544; Sat, 30 Apr 2022 08:37:56 -0700 (PDT) Received: from localhost (76-210-143-223.lightspeed.sntcca.sbcglobal.net. [76.210.143.223]) by smtp.gmail.com with ESMTPSA id m2-20020a17090a2c0200b001d7761ee6fcsm12923373pjd.3.2022.04.30.08.37.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 30 Apr 2022 08:37:56 -0700 (PDT) Subject: [PATCH v4 3/7] asm-generic: qrwlock: Document the spinlock fairness requirements Date: Sat, 30 Apr 2022 08:36:22 -0700 Message-Id: <20220430153626.30660-4-palmer@rivosinc.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220430153626.30660-1-palmer@rivosinc.com> References: <20220430153626.30660-1-palmer@rivosinc.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Cc: guoren@kernel.org, peterz@infradead.org, mingo@redhat.com, Will Deacon , longman@redhat.com, boqun.feng@gmail.com, jonas@southpole.se, stefan.kristiansson@saunalahti.fi, shorne@gmail.com, Paul Walmsley , Palmer Dabbelt , aou@eecs.berkeley.edu, Arnd Bergmann , Greg KH , sudipm.mukherjee@gmail.com, macro@orcam.me.uk, jszhang@kernel.org, linux-csky@vger.kernel.org, linux-kernel@vger.kernel.org, openrisc@lists.librecores.org, linux-riscv@lists.infradead.org, linux-arch@vger.kernel.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Palmer Dabbelt From: Palmer Dabbelt To: Arnd Bergmann Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org From: Palmer Dabbelt I could only find the fairness requirements documented as the C code, this calls them out in a comment just to be a bit more explicit. Signed-off-by: Palmer Dabbelt --- include/asm-generic/qrwlock.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/include/asm-generic/qrwlock.h b/include/asm-generic/qrwlock.h index 7ae0ece07b4e..24ae09c1db9f 100644 --- a/include/asm-generic/qrwlock.h +++ b/include/asm-generic/qrwlock.h @@ -2,6 +2,10 @@ /* * Queue read/write lock * + * These use generic atomic and locking routines, but depend on a fair spinlock + * implementation in order to be fair themselves. The implementation in + * asm-generic/spinlock.h meets these requirements. + * * (C) Copyright 2013-2014 Hewlett-Packard Development Company, L.P. * * Authors: Waiman Long -- 2.34.1