From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: <3chas3@gmail.com> Received: from mail-qt0-f193.google.com (mail-qt0-f193.google.com [209.85.216.193]) by dpdk.org (Postfix) with ESMTP id 2CC531E34 for <dev@dpdk.org>; Mon, 18 Sep 2017 21:47:52 +0200 (CEST) Received: by mail-qt0-f193.google.com with SMTP id l25so1041030qtf.2 for <dev@dpdk.org>; Mon, 18 Sep 2017 12:47:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=qA6z9j21LCpUyZmXZgRIs9UJe8guP/NJ9ns/fASUElU=; b=YspAzb4qOR09iktR0PozVCVO8Xy9z9YRQTF/wkRBqsiu79g9UxPHkEJJPtj03LWXBq TVs3LEKDTKm0ZCU2ljvHdx51aaHrNMpZTuZ6zA3m+AgPzxeSyF3dDphQYNga8z0MKbDl YIroPOGQZ/3w1oUM5Mx5vJBFrHqz418iSqgRabTVnkoNbnP6IoFr9NOnqD8G3kagsimN epD1l1ULyeN7wNn9O+O56jkrkaPW4IYMo+Rv7ufTRiFV7MAJCC9j818WNSh8MKxSrKOD 4LUXVx+cb0RGkl/mSSwky8Hdj9rBooZ1IMktL95ZQHbP8/SG931OqcE4yfjeTQBavm+Y UKeA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=qA6z9j21LCpUyZmXZgRIs9UJe8guP/NJ9ns/fASUElU=; b=lKeTy2ebuVchxAIQt0BYXnrDra0oxeuvdhMf/k+DOIpEHWsL06su03Z0xGt053bVsR xSjTbT0Caz+JkaF4Tc426RnmqD7lrg0V+hElcVNjZQ9gr7xfJGi8eToWkm6YZ+1euWFc xogcCsjpV5E7AstWxzIWXNqjqb2gOkKPOU3qYxcO+Z6ULMW6IO0jDI3sRnLMPI1q5Poh BlPnrE0bu/ERfnoxUuDj7Rdi1PTg0Zc44ejYaclZ2DeiXv1+O6dG0C0WhvMnRuNnyaE9 vMdi18LkcaSTLYh6cb9rwa1ZeNXamvET5sFEThT4pu18h6/Meutho/qgZe10tMDOzAuA NdJg== X-Gm-Message-State: AHPjjUhouiSZxEcLeVwnMhE6rEbX/hGXMW4Ij3jgNxtKAfSBIn2fUHDL TQ5ydCiraV7tfv5z X-Google-Smtp-Source: AOwi7QDPlQ6gVU8ichyTRymab26b+6+O8s1p/kq7P2WLUHOUem2qPX3XnE0lul51Vy3UZ52vPfWzeQ== X-Received: by 10.200.40.146 with SMTP id i18mr39128575qti.94.1505764071431; Mon, 18 Sep 2017 12:47:51 -0700 (PDT) Received: from monolith.home (pool-96-255-82-208.washdc.fios.verizon.net. [96.255.82.208]) by smtp.gmail.com with ESMTPSA id w46sm5655310qta.84.2017.09.18.12.47.50 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 18 Sep 2017 12:47:50 -0700 (PDT) From: Chas Williams <3chas3@gmail.com> To: dev@dpdk.org Cc: bruce.richardson@intel.com, pablo.de.lara.guarch@intel.com, Chas Williams <chas3@att.com> Date: Mon, 18 Sep 2017 15:47:40 -0400 Message-Id: <20170918194740.23057-1-3chas3@gmail.com> X-Mailer: git-send-email 2.9.5 Subject: [dpdk-dev] [PATCH] hash: document rte_jhash() boundary behavior X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions <dev.dpdk.org> List-Unsubscribe: <http://dpdk.org/ml/options/dev>, <mailto:dev-request@dpdk.org?subject=unsubscribe> List-Archive: <http://dpdk.org/ml/archives/dev/> List-Post: <mailto:dev@dpdk.org> List-Help: <mailto:dev-request@dpdk.org?subject=help> List-Subscribe: <http://dpdk.org/ml/listinfo/dev>, <mailto:dev-request@dpdk.org?subject=subscribe> X-List-Received-Date: Mon, 18 Sep 2017 19:47:52 -0000 From: Chas Williams <chas3@att.com> Due to the uint32_t accesses in the hash computation, keys that aren't aligned to a uint32_t boundary or multiples of uint32_t in length, may see accesses beyond the end of the key. This may cross a page boundary. Signed-off-by: Chas Williams <chas3@att.com> --- lib/librte_hash/rte_jhash.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/lib/librte_hash/rte_jhash.h b/lib/librte_hash/rte_jhash.h index 207478c..3eca138 100644 --- a/lib/librte_hash/rte_jhash.h +++ b/lib/librte_hash/rte_jhash.h @@ -290,7 +290,10 @@ rte_jhash_32b_2hashes(const uint32_t *k, uint32_t length, uint32_t *pc, uint32_t /** * The most generic version, hashes an arbitrary sequence * of bytes. No alignment or length assumptions are made about - * the input key. + * the input key. For keys not aligned to four byte boundaries + * or a multiple of four bytes in length, the memory region + * just after may be read (but not used in the computation). + * This may cross a page boundary. * * @param key * Key to calculate hash of. -- 2.9.5