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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3E2EBECDFD0 for ; Fri, 14 Sep 2018 14:44:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DEB142083A for ; Fri, 14 Sep 2018 14:44:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DEB142083A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728429AbeINT7D (ORCPT ); Fri, 14 Sep 2018 15:59:03 -0400 Received: from mx2.suse.de ([195.135.220.15]:50146 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727864AbeINT7C (ORCPT ); Fri, 14 Sep 2018 15:59:02 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id EB982ACA8; Fri, 14 Sep 2018 14:44:09 +0000 (UTC) Subject: Re: [Xen-devel] [PATCH 5/6] xenbus: process be_watch events in xenwatch multithreading To: Dongli Zhang , xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org Cc: wei.liu2@citrix.com, konrad.wilk@oracle.com, srinivas.eeda@oracle.com, paul.durrant@citrix.com, boris.ostrovsky@oracle.com, roger.pau@citrix.com References: <1536910456-13337-1-git-send-email-dongli.zhang@oracle.com> <1536910456-13337-6-git-send-email-dongli.zhang@oracle.com> <8d6457cf-a105-3d88-bd38-d46b24f70501@suse.com> <8f4c7508-1e8f-9d7e-1327-f537917845f4@oracle.com> <0753b7b8-31a6-22f5-479a-2760fea0149c@oracle.com> From: Juergen Gross Openpgp: preference=signencrypt Autocrypt: addr=jgross@suse.com; prefer-encrypt=mutual; keydata= xsBNBFOMcBYBCACgGjqjoGvbEouQZw/ToiBg9W98AlM2QHV+iNHsEs7kxWhKMjrioyspZKOB ycWxw3ie3j9uvg9EOB3aN4xiTv4qbnGiTr3oJhkB1gsb6ToJQZ8uxGq2kaV2KL9650I1SJve dYm8Of8Zd621lSmoKOwlNClALZNew72NjJLEzTalU1OdT7/i1TXkH09XSSI8mEQ/ouNcMvIJ NwQpd369y9bfIhWUiVXEK7MlRgUG6MvIj6Y3Am/BBLUVbDa4+gmzDC9ezlZkTZG2t14zWPvx XP3FAp2pkW0xqG7/377qptDmrk42GlSKN4z76ELnLxussxc7I2hx18NUcbP8+uty4bMxABEB AAHNHkp1ZXJnZW4gR3Jvc3MgPGpncm9zc0BzdXNlLmRlPsLAeQQTAQIAIwUCU4xw6wIbAwcL CQgHAwIBBhUIAgkKCwQWAgMBAh4BAheAAAoJELDendYovxMvi4UH/Ri+OXlObzqMANruTd4N zmVBAZgx1VW6jLc8JZjQuJPSsd/a+bNr3BZeLV6lu4Pf1Yl2Log129EX1KWYiFFvPbIiq5M5 kOXTO8Eas4CaScCvAZ9jCMQCgK3pFqYgirwTgfwnPtxFxO/F3ZcS8jovza5khkSKL9JGq8Nk czDTruQ/oy0WUHdUr9uwEfiD9yPFOGqp4S6cISuzBMvaAiC5YGdUGXuPZKXLpnGSjkZswUzY d9BVSitRL5ldsQCg6GhDoEAeIhUC4SQnT9SOWkoDOSFRXZ+7+WIBGLiWMd+yKDdRG5RyP/8f 3tgGiB6cyuYfPDRGsELGjUaTUq3H2xZgIPfOwE0EU4xwFgEIAMsx+gDjgzAY4H1hPVXgoLK8 B93sTQFN9oC6tsb46VpxyLPfJ3T1A6Z6MVkLoCejKTJ3K9MUsBZhxIJ0hIyvzwI6aYJsnOew cCiCN7FeKJ/oA1RSUemPGUcIJwQuZlTOiY0OcQ5PFkV5YxMUX1F/aTYXROXgTmSaw0aC1Jpo w7Ss1mg4SIP/tR88/d1+HwkJDVW1RSxC1PWzGizwRv8eauImGdpNnseneO2BNWRXTJumAWDD pYxpGSsGHXuZXTPZqOOZpsHtInFyi5KRHSFyk2Xigzvh3b9WqhbgHHHE4PUVw0I5sIQt8hJq 5nH5dPqz4ITtCL9zjiJsExHuHKN3NZsAEQEAAcLAXwQYAQIACQUCU4xwFgIbDAAKCRCw3p3W KL8TL0P4B/9YWver5uD/y/m0KScK2f3Z3mXJhME23vGBbMNlfwbr+meDMrJZ950CuWWnQ+d+ Ahe0w1X7e3wuLVODzjcReQ/v7b4JD3wwHxe+88tgB9byc0NXzlPJWBaWV01yB2/uefVKryAf AHYEd0gCRhx7eESgNBe3+YqWAQawunMlycsqKa09dBDL1PFRosF708ic9346GLHRc6Vj5SRA UTHnQqLetIOXZm3a2eQ1gpQK9MmruO86Vo93p39bS1mqnLLspVrL4rhoyhsOyh0Hd28QCzpJ wKeHTd0MAWAirmewHXWPco8p1Wg+V+5xfZzuQY0f4tQxvOpXpt4gQ1817GQ5/Ed/wsDtBBgB CAAgFiEEhRJncuj2BJSl0Jf3sN6d1ii/Ey8FAlrd8NACGwIAgQkQsN6d1ii/Ey92IAQZFggA HRYhBFMtsHpB9jjzHji4HoBcYbtP2GO+BQJa3fDQAAoJEIBcYbtP2GO+TYsA/30H/0V6cr/W V+J/FCayg6uNtm3MJLo4rE+o4sdpjjsGAQCooqffpgA+luTT13YZNV62hAnCLKXH9n3+ZAgJ RtAyDWk1B/0SMDVs1wxufMkKC3Q/1D3BYIvBlrTVKdBYXPxngcRoqV2J77lscEvkLNUGsu/z W2pf7+P3mWWlrPMJdlbax00vevyBeqtqNKjHstHatgMZ2W0CFC4hJ3YEetuRBURYPiGzuJXU pAd7a7BdsqWC4o+GTm5tnGrCyD+4gfDSpkOT53S/GNO07YkPkm/8J4OBoFfgSaCnQ1izwgJQ jIpcG2fPCI2/hxf2oqXPYbKr1v4Z1wthmoyUgGN0LPTIm+B5vdY82wI5qe9uN6UOGyTH2B3p hRQUWqCwu2sqkI3LLbTdrnyDZaixT2T0f4tyF5Lfs+Ha8xVMhIyzNb1byDI5FKCb Message-ID: <62194cbd-be25-fc2e-f115-5111888d7bc6@suse.com> Date: Fri, 14 Sep 2018 16:44:09 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <0753b7b8-31a6-22f5-479a-2760fea0149c@oracle.com> Content-Type: text/plain; charset=utf-8 Content-Language: de-DE Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 14/09/18 16:29, Dongli Zhang wrote: > Hi Juergen, > > On 09/14/2018 10:26 PM, Juergen Gross wrote: >> On 14/09/18 16:18, Dongli Zhang wrote: >>> Hi Juergen, >>> >>> On 09/14/2018 05:12 PM, Juergen Gross wrote: >>>> On 14/09/18 09:34, Dongli Zhang wrote: >>>>> This is the 5th patch of a (6-patch) patch set. >>>>> >>>>> With this patch, watch event in relative path pattern >>>>> 'backend//i/...' can be processed in per-domU xenwatch >>>> >>>> superfluous "i" ----------^ >>>> >>>>> thread. >>>>> >>>>> Signed-off-by: Dongli Zhang >>>>> --- >>>>> drivers/xen/xenbus/xenbus_probe.c | 2 +- >>>>> drivers/xen/xenbus/xenbus_probe_backend.c | 32 +++++++++++++++++++++++++++++++ >>>>> include/xen/xenbus.h | 2 ++ >>>>> 3 files changed, 35 insertions(+), 1 deletion(-) >>>>> >>>>> diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c >>>>> index ba0644c..aa1b15a 100644 >>>>> --- a/drivers/xen/xenbus/xenbus_probe.c >>>>> +++ b/drivers/xen/xenbus/xenbus_probe.c >>>>> @@ -552,7 +552,7 @@ int xenbus_probe_devices(struct xen_bus_type *bus) >>>>> } >>>>> EXPORT_SYMBOL_GPL(xenbus_probe_devices); >>>>> >>>>> -static unsigned int char_count(const char *str, char c) >>>>> +unsigned int char_count(const char *str, char c) >>>> >>>> Please change the name of the function when making it globally >>>> visible, e.g. by prefixing "xenbus_". >>>> >>>> Generally I think you don't need to use it below. >>>> >>>>> { >>>>> unsigned int i, ret = 0; >>>>> >>>>> diff --git a/drivers/xen/xenbus/xenbus_probe_backend.c b/drivers/xen/xenbus/xenbus_probe_backend.c >>>>> index b0bed4f..50df86a 100644 >>>>> --- a/drivers/xen/xenbus/xenbus_probe_backend.c >>>>> +++ b/drivers/xen/xenbus/xenbus_probe_backend.c >>>>> @@ -211,9 +211,41 @@ static void backend_changed(struct xenbus_watch *watch, >>>>> xenbus_dev_changed(path, &xenbus_backend); >>>>> } >>>>> >>>>> +static domid_t path_to_domid(const char *path) >>>>> +{ >>>>> + const char *p = path; >>>>> + domid_t domid = 0; >>>>> + >>>>> + while (*p) { >>>>> + if (*p < '0' || *p > '9') >>>>> + break; >>>>> + domid = (domid << 3) + (domid << 1) + (*p - '0'); >>>> >>>> reinventing atoi()? >>>> >>>> Please don't do that. kstrtou16() seems to be a perfect fit. >>> >>> I did use kstrtou*() in the early prototype and realized kstrtou16() returns 0 >>> if the input string contains non-numerical characters. >>> >>> E.g., the example of input can be "1/0/state", where 1 is fotherend_id >>> (frontend_id) and 0 is handle. >>> >>> When "1/0/state" is used at input, kstrtou16() returns 0 (returned integer) and >>> -22 (error). >> >> Aah, okay. Then simple_strtoul()? > > I did consider simple_strtoul() initially. Unfortunately, it is obsolete (below > line 81). AFAIR, the patch would not be able to pass the check_patch script when > this function is used. Better use that than open coding a new instance of it. Another variant would be to use sscanf() or similar. Then you could even drop using strchr() by adding that in the format string: return (sscanf(path, "%*u/%u/", &domid) == 1) ? domid : DOMID_SELF; Juergen