From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Mon, 13 Aug 2018 09:38:53 +0200 (CEST) Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:52910 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S23992869AbeHMHiupBEvX (ORCPT ); Mon, 13 Aug 2018 09:38:50 +0200 Received: from pps.filterd (m0098393.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w7D7YRNq055870 for ; Mon, 13 Aug 2018 03:38:48 -0400 Received: from e06smtp07.uk.ibm.com (e06smtp07.uk.ibm.com [195.75.94.103]) by mx0a-001b2d01.pphosted.com with ESMTP id 2ku1ebr859-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 13 Aug 2018 03:38:48 -0400 Received: from localhost by e06smtp07.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Mon, 13 Aug 2018 08:38:39 +0100 Received: from d06av24.portsmouth.uk.ibm.com (d06av24.portsmouth.uk.ibm.com [9.149.105.60]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w7D7ccNd36438066 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 13 Aug 2018 07:38:38 GMT Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id AF03A42045; Mon, 13 Aug 2018 10:38:44 +0100 (BST) Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A8DCD4203F; Mon, 13 Aug 2018 10:38:41 +0100 (BST) Received: from [9.124.35.193] (unknown [9.124.35.193]) by d06av24.portsmouth.uk.ibm.com (Postfix) with ESMTP; Mon, 13 Aug 2018 10:38:41 +0100 (BST) Subject: Re: [PATCH v8 3/6] Uprobes: Support SDT markers having reference count (semaphore) To: Song Liu Cc: srikar@linux.vnet.ibm.com, Oleg Nesterov , Steven Rostedt , mhiramat@kernel.org, Peter Zijlstra , mingo@redhat.com, acme@kernel.org, alexander.shishkin@linux.intel.com, jolsa@redhat.com, namhyung@kernel.org, open list , ananth@linux.vnet.ibm.com, Alexis Berlemont , naveen.n.rao@linux.vnet.ibm.com, linux-arm-kernel@lists.infradead.org, linux-mips@linux-mips.org, linux@armlinux.org.uk, ralf@linux-mips.org, paul.burton@mips.com, Ravi Bangoria References: <20180809041856.1547-1-ravi.bangoria@linux.ibm.com> <20180809041856.1547-4-ravi.bangoria@linux.ibm.com> <95a1221e-aecc-42be-5239-a2c2429be176@linux.ibm.com> From: Ravi Bangoria Date: Mon, 13 Aug 2018 13:08:34 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <95a1221e-aecc-42be-5239-a2c2429be176@linux.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 18081307-0028-0000-0000-000002E9ED79 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18081307-0029-0000-0000-000023A3075B Message-Id: <5b693a28-5a0b-1adc-a805-b66dfbe7bdd7@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-08-13_02:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1807170000 definitions=main-1808130085 Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 65553 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: ravi.bangoria@linux.ibm.com Precedence: bulk List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: linux-mips X-List-ID: linux-mips List-subscribe: List-owner: List-post: List-archive: X-list: linux-mips Hi Song, On 08/13/2018 11:17 AM, Ravi Bangoria wrote: >>> + >>> +static void delayed_uprobe_remove(struct uprobe *uprobe, struct mm_struct *mm) >>> +{ >>> + struct list_head *pos, *q; >>> + struct delayed_uprobe *du; >>> + >>> + if (!uprobe && !mm) >>> + return; >> And do we really need this check? > > > Yes. delayed_uprobe_remove(uprobe=NULL, mm=NULL) is an invalid case. If I remove > this check, code below (or more accurately code suggested by Oleg) will remove > all entries from delayed_uprobe_list. So I will keep this check but put a comment > above function. > Sorry, my bad. Please ignore above comment. Even though, it saves us to unnecessary loop over entire delayed_uprobe_list when both uprobe and mm are NULL, that case is not possible with current code. Also, I'm not dereferencing any of them. So, IMHO it's fine to remove this check. Thanks, Ravi