From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt1-x830.google.com (mail-qt1-x830.google.com [IPv6:2607:f8b0:4864:20::830]) by sourceware.org (Postfix) with ESMTPS id 1E5ED3857C56 for ; Fri, 21 May 2021 19:02:54 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 1E5ED3857C56 Received: by mail-qt1-x830.google.com with SMTP id f8so16065095qth.6 for ; Fri, 21 May 2021 12:02:54 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=YpECcBny64HdJvwctfy467PBOxAHOtMZTHg2m+G4jkI=; b=LQqCJH/dQDWixHJgKlwdz0/Kwlh65Drrkud6+lQnL+VhEU8gAJ8guztv7anLUaZ1U6 azxLx0R2BFokFHXozuEAcLC9F7PH/T+mCXdskFhZTDor8hyKn8SiurCrPXZ8Xu0wvnOs g6M1JRiGXI+1W+GjVm7w27HmeRVoXMOIwlNauHJEF66F6vumL0PNBkDSaQTwXkFto6kh 1r7gHjlmjAEXzuyHIZDx0mwmqBzSvpEui+t2WQ7izhUfhUvrZhsse/6dyZ5ZgzxxFjLG RPwf8HXZTj6bHbCSIXp1GmC05GB+UmjAJu8w/qWShINdtAShEsIkjBrl1b8Lfq022tz9 pSJA== X-Gm-Message-State: AOAM531TvLTD6FwTiKxMj753kyjrntczaHMlmXdGYYGSKs+pGxIvIWj5 yzV5ROY/y+AoUCGlrOlV0gia0+0qDPeNvA== X-Google-Smtp-Source: ABdhPJxIE/wceB5h0+dAKi96HATcBATvpu05CQ7YYww02X3VRIs8Estpc7LKVvE3+RHzjH9U2Z91Hw== X-Received: by 2002:a05:622a:1756:: with SMTP id l22mr12763280qtk.367.1621623773449; Fri, 21 May 2021 12:02:53 -0700 (PDT) Received: from [192.168.1.4] ([177.194.37.86]) by smtp.gmail.com with ESMTPSA id r16sm4945533qtx.36.2021.05.21.12.02.52 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 21 May 2021 12:02:53 -0700 (PDT) Subject: Re: [PATCH v2 06/25] linux: Add fallback for 64-bit time_t SO_TIMESTAMP{NS} To: Florian Weimer Cc: Adhemerval Zanella via Libc-alpha References: <20210518205613.1487824-1-adhemerval.zanella@linaro.org> <20210518205613.1487824-7-adhemerval.zanella@linaro.org> <87v97dsxub.fsf@oldenburg.str.redhat.com> <4937dcf7-574a-097d-c809-5d95fdde1e24@linaro.org> <87zgwo53vh.fsf@oldenburg.str.redhat.com> From: Adhemerval Zanella Message-ID: Date: Fri, 21 May 2021 16:02:50 -0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: <87zgwo53vh.fsf@oldenburg.str.redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-6.7 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, NICE_REPLY_A, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 21 May 2021 19:02:55 -0000 On 21/05/2021 15:38, Florian Weimer wrote: > * Adhemerval Zanella: > >> On 20/05/2021 03:50, Florian Weimer wrote: >>> * Adhemerval Zanella via Libc-alpha: >>> >>>> Calls with __TIMESIZE=32 will see the converted 64-bit time control >>>> messages as spurious control message of unknown type. Calls with >>>> __TIMESIZE=64 running on pre-time64 kernels will see the original >>>> message as a spurious control ones of unknown typ while running on >>>> kernel with native 64-bit time support will only see the time64 version >>>> of the control message. >>> >>> Does the mirror what the kernel does? I have some concerns about >>> backwards compatibility here, but if the kernel does it as well, that is >>> likely a non-issue. >> >> The SO_TIMESTAMP{NS}_OLD to SO_TIMESTAMP{NS}_NEW for _TIME_BITS=64 is >> what this patch does to add some compatibility. From kernel code: >> net/socket.c > > Will anything new show up for _TIME_BITS=32 on legacy architectures? It will if a library setup a SO_TIMESTAMP{NS}_NEW (assuming running on newer kernels), since afaik the timestamp is set on socket buffer within kernel (so my understanding is in theory one can see multiple different timestamps formats on same socket).