From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f50.google.com (mail-wm0-f50.google.com [74.125.82.50]) by dpdk.org (Postfix) with ESMTP id 4EC5C6968 for ; Tue, 17 May 2016 15:40:09 +0200 (CEST) Received: by mail-wm0-f50.google.com with SMTP id v200so21026623wmv.1 for ; Tue, 17 May 2016 06:40:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=6wind-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:user-agent:in-reply-to :references:mime-version:content-transfer-encoding; bh=sBlZXvgFnKWT7Eb+7AntF5FoLSog0KmuyTQ+Wkvly+g=; b=VLWwon3Ki2UKST/8D5k5gOheWQlFwe9Y8w6AgOMAhqxnv5YLSvZ5oNhjQDRLxMJzVW NrO0Ad7XYSkuIPyq2SIPwXM/z+A703jQ7UzN55CaAmwkYerEzLAnE9l+b70LcFSelM7c ipMRf1KER6Cik/IcCraBJcwaEO5WKXFSc9ehYAGzdyWDYPDrto9fNkvVoWqnVyf9+HE7 Nzh1HmdHSSwRJL+YQb/GhfqMO/nZwYRHxWWN/5ikRARtVBvQ0zhjCnWS5FSSPWU4mTuc gFYRIU453MiTXrQgWihF5CbsvJeOXkYdorXtgl8RlEacMDvTsw/N26JMYUTXDveqnGRU xxOQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:user-agent :in-reply-to:references:mime-version:content-transfer-encoding; bh=sBlZXvgFnKWT7Eb+7AntF5FoLSog0KmuyTQ+Wkvly+g=; b=fEPezG72wgSr/tnEAQ2jCZhG7n8Wzchp7NBBG+/nTRgmaRWoLyd48Rvk1L+Jwi5Cjv U8+BFzQkiI9d+jrUvctWC+/9LtoBs/fCaKLnIwts+maGJPeOKKD0VLggYc3EDxHJbYt4 Flu8rcdqUinoS7dW59FJ5ObfJ8JKgYsTA4aXka36m4ZCEM7g874bUtxTjEAge8Oyemnk HMFlLw196DHaS56MH2nXQAvkWwFvl8QtX/erLjoZgv0EnIoJr6NSJGtmOByTZ4loCw3L 057eL+Nr8FHMP/FKDAE+GqA7HI+nWzLEmh4AFe9SLliegaB54axDF1v6DBdcn7mRFYtT 7nOw== X-Gm-Message-State: AOPr4FWNLl97etMR002b6kGy9S4pjM94eQ3veq/TWKg+6wdYGjF8yK7EIP6NG0Kl7nIRKa6W X-Received: by 10.194.16.233 with SMTP id j9mr1558353wjd.51.1463492408975; Tue, 17 May 2016 06:40:08 -0700 (PDT) Received: from xps13.localnet (guy78-3-82-239-227-177.fbx.proxad.net. [82.239.227.177]) by smtp.gmail.com with ESMTPSA id m20sm3638955wma.23.2016.05.17.06.40.07 (version=TLSv1/SSLv3 cipher=OTHER); Tue, 17 May 2016 06:40:07 -0700 (PDT) From: Thomas Monjalon To: "Ananyev, Konstantin" Cc: dev@dpdk.org, Hiroyuki Mikita , olivier.matz@6wind.com Date: Tue, 17 May 2016 15:39:55 +0200 Message-ID: <1709340.0fJkCxgyM5@xps13> User-Agent: KMail/4.14.10 (Linux/4.1.6-1-ARCH; KDE/4.14.11; x86_64; ; ) In-Reply-To: <2601191342CEEE43887BDE71AB97725836B518A4@irsmsx105.ger.corp.intel.com> References: <1463327436-6863-1-git-send-email-h.mikita89@gmail.com> <2164081.rUYNJaTDcf@xps13> <2601191342CEEE43887BDE71AB97725836B518A4@irsmsx105.ger.corp.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Subject: Re: [dpdk-dev] [PATCH v2] mbuf: decrease refcnt when detaching X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 17 May 2016 13:40:09 -0000 2016-05-17 12:59, Ananyev, Konstantin: > > > The rte_pktmbuf_detach() function should decrease refcnt on a direct > > > buffer. > > > > As you have noticed, "whenever the indirect buffer is detached, > > the reference counter on the direct buffer is decremented." > > So the current behaviour of rte_pktmbuf_detach() is buggy. > > Why not fix it without renaming? > > If you consider this behavioral bug is part of the API, we > > can fix it in a new function unattach and deprecate detach. > > But Konstantin, why do you want to keep a restore function? > > What is the need? > > I think it might be a useful functionality in some situations: > some users can attach/detach to external memory buffers (no mbufs) > and similar functionality is required. Attach to external memory buffer (raw buffer) is not currently supported. > Let say right now examples/vhost/main.c has its own pktmbuf_detach_zcp() You should look at the commit http://dpdk.org/commit/68363d85 "examples/vhost: remove the non-working zero copy code" > which is doing pretty much the same - restore original values, after detaching > mbuf from external (virtio) memory buffer. > Would be good if we'll use a standard API function here. You are welcome to implement mbuf attach to raw buffer. But it is not a requirement for this fix.