From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Paul E. McKenney" Subject: Re: [PATCH 01/18] drivers core: Add I/O ASID allocator Date: Tue, 9 Apr 2019 15:08:45 -0700 Message-ID: <20190409220845.GM14111@linux.ibm.com> References: <1554767973-30125-1-git-send-email-jacob.jun.pan@linux.intel.com> <1554767973-30125-2-git-send-email-jacob.jun.pan@linux.intel.com> <20190409100049.GC9224@smile.fi.intel.com> <20190409100436.GA28683@infradead.org> <20190409103030.GK9224@smile.fi.intel.com> <20190409145308.GZ14111@linux.ibm.com> <20190409152130.GS9224@smile.fi.intel.com> Reply-To: paulmck@linux.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20190409152130.GS9224@smile.fi.intel.com> Sender: linux-kernel-owner@vger.kernel.org To: Andriy Shevchenko Cc: Christoph Hellwig , Jacob Pan , iommu@lists.linux-foundation.org, LKML , Joerg Roedel , David Woodhouse , Alex Williamson , Jean-Philippe Brucker , Yi Liu , "Tian, Kevin" , Raj Ashok , Lu Baolu List-Id: iommu@lists.linux-foundation.org On Tue, Apr 09, 2019 at 06:21:30PM +0300, Andriy Shevchenko wrote: > On Tue, Apr 09, 2019 at 07:53:08AM -0700, Paul E. McKenney wrote: > > On Tue, Apr 09, 2019 at 01:30:30PM +0300, Andriy Shevchenko wrote: > > > On Tue, Apr 09, 2019 at 03:04:36AM -0700, Christoph Hellwig wrote: > > > > On Tue, Apr 09, 2019 at 01:00:49PM +0300, Andriy Shevchenko wrote: > > > > > I think it makes sense to add a helper macro to rcupdate.h > > > > > (and we have several cases in kernel that can utilize it) > > > > > > > > > > #define kfree_non_null_rcu(ptr, rcu_head) \ > > > > > do { \ > > > > > if (ptr) \ > > > > > kfree_rcu(ptr, rcu_head); \ > > > > > } while (0) > > > > > > > > > > as a more common pattern for resource deallocators. > > > > > > > > I think that should move straight into kfree_rcu. > > > > > > Possible. I didn't dare to offer this due to lack of knowledge how it's used in > > > other places. > > > > > > > In general > > > > we expect *free* to deal with NULL pointers transparently, so we > > > > should do so here as well. > > > > > > Exactly my point, thanks. > > > > As shown below? > > Looks pretty much good to me, thanks! > Reviewed-by: Andriy Shevchenko Applied, thank you! Thanx, Paul > > And now that you mention it, it is a bit surprising that no one has > > complained before. ;-) > > > > Thanx, Paul > > > > ------------------------------------------------------------------------ > > > > commit 23ad938244968e9d2a8001a1c52887c113b182f6 > > Author: Paul E. McKenney > > Date: Tue Apr 9 07:48:18 2019 -0700 > > > > rcu: Make kfree_rcu() ignore NULL pointers > > > > This commit makes the kfree_rcu() macro's semantics be consistent > > with the likes of kfree() by adding a check for NULL pointers, so > > that kfree_rcu(NULL, ...) is a no-op. > > > > Reported-by: Andriy Shevchenko > > Reported-by: Christoph Hellwig > > Signed-off-by: Paul E. McKenney > > > > diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h > > index 922bb6848813..c68649b9bcec 100644 > > --- a/include/linux/rcupdate.h > > +++ b/include/linux/rcupdate.h > > @@ -828,9 +828,13 @@ static inline notrace void rcu_read_unlock_sched_notrace(void) > > * The BUILD_BUG_ON check must not involve any function calls, hence the > > * checks are done in macros here. > > */ > > -#define kfree_rcu(ptr, rcu_head) \ > > - __kfree_rcu(&((ptr)->rcu_head), offsetof(typeof(*(ptr)), rcu_head)) > > - > > +#define kfree_rcu(ptr, rhf) \ > > +do { \ > > + typeof (ptr) ___p = (ptr); \ > > + \ > > + if (___p) \ > > + __kfree_rcu(&((___p)->rhf), offsetof(typeof(*(ptr)), rhf)); \ > > +} while (0) > > > > /* > > * Place this after a lock-acquisition primitive to guarantee that > > > > -- > With Best Regards, > Andy Shevchenko > > 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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT autolearn=unavailable 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 2562AC10F0E for ; Tue, 9 Apr 2019 23:17:27 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id EDAD620857 for ; Tue, 9 Apr 2019 23:17:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EDAD620857 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id B0814106B; Tue, 9 Apr 2019 23:17:26 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id C6E571054 for ; Tue, 9 Apr 2019 23:17:10 +0000 (UTC) X-Greylist: delayed 01:06:33 by SQLgrey-1.7.6 Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 4BC34CF for ; Tue, 9 Apr 2019 23:17:10 +0000 (UTC) Received: from pps.filterd (m0098420.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x39MAY48119166 for ; Tue, 9 Apr 2019 18:10:36 -0400 Received: from e11.ny.us.ibm.com (e11.ny.us.ibm.com [129.33.205.201]) by mx0b-001b2d01.pphosted.com with ESMTP id 2rs2hm35gt-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 09 Apr 2019 18:10:34 -0400 Received: from localhost by e11.ny.us.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) Tue, 9 Apr 2019 23:08:44 +0100 Received: from b01ledav003.gho.pok.ibm.com (b01ledav003.gho.pok.ibm.com [9.57.199.108]) by b01cxnp23032.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x39M8hqT30015542 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 9 Apr 2019 22:08:43 GMT Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id D03E2B20AC; Tue, 9 Apr 2019 22:08:43 +0000 (GMT) Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A184DB20AE; Tue, 9 Apr 2019 22:08:43 +0000 (GMT) Received: from paulmck-ThinkPad-W541 (unknown [9.70.82.188]) by b01ledav003.gho.pok.ibm.com (Postfix) with ESMTP; Tue, 9 Apr 2019 22:08:43 +0000 (GMT) Received: by paulmck-ThinkPad-W541 (Postfix, from userid 1000) id 27A9916C1140; Tue, 9 Apr 2019 15:08:45 -0700 (PDT) Date: Tue, 9 Apr 2019 15:08:45 -0700 From: "Paul E. McKenney" To: Andriy Shevchenko Subject: Re: [PATCH 01/18] drivers core: Add I/O ASID allocator References: <1554767973-30125-1-git-send-email-jacob.jun.pan@linux.intel.com> <1554767973-30125-2-git-send-email-jacob.jun.pan@linux.intel.com> <20190409100049.GC9224@smile.fi.intel.com> <20190409100436.GA28683@infradead.org> <20190409103030.GK9224@smile.fi.intel.com> <20190409145308.GZ14111@linux.ibm.com> <20190409152130.GS9224@smile.fi.intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190409152130.GS9224@smile.fi.intel.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 x-cbid: 19040922-2213-0000-0000-000003741565 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00010898; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000284; SDB=6.01186769; UDB=6.00621583; IPR=6.00967529; MB=3.00026368; MTD=3.00000008; XFM=3.00000015; UTC=2019-04-09 22:08:48 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19040922-2214-0000-0000-00005DF6D20C Message-Id: <20190409220845.GM14111@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-04-09_12:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=2 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=8.0.1-1810050000 definitions=main-1904090140 Cc: "Tian, Kevin" , Alex Williamson , Raj Ashok , Jean-Philippe Brucker , LKML , iommu@lists.linux-foundation.org, David Woodhouse X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: paulmck@linux.ibm.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org Message-ID: <20190409220845.kwdsHQ-slIpP5URT3dLLcbwOkPzM_aXvYfUVgsEbkU0@z> On Tue, Apr 09, 2019 at 06:21:30PM +0300, Andriy Shevchenko wrote: > On Tue, Apr 09, 2019 at 07:53:08AM -0700, Paul E. McKenney wrote: > > On Tue, Apr 09, 2019 at 01:30:30PM +0300, Andriy Shevchenko wrote: > > > On Tue, Apr 09, 2019 at 03:04:36AM -0700, Christoph Hellwig wrote: > > > > On Tue, Apr 09, 2019 at 01:00:49PM +0300, Andriy Shevchenko wrote: > > > > > I think it makes sense to add a helper macro to rcupdate.h > > > > > (and we have several cases in kernel that can utilize it) > > > > > > > > > > #define kfree_non_null_rcu(ptr, rcu_head) \ > > > > > do { \ > > > > > if (ptr) \ > > > > > kfree_rcu(ptr, rcu_head); \ > > > > > } while (0) > > > > > > > > > > as a more common pattern for resource deallocators. > > > > > > > > I think that should move straight into kfree_rcu. > > > > > > Possible. I didn't dare to offer this due to lack of knowledge how it's used in > > > other places. > > > > > > > In general > > > > we expect *free* to deal with NULL pointers transparently, so we > > > > should do so here as well. > > > > > > Exactly my point, thanks. > > > > As shown below? > > Looks pretty much good to me, thanks! > Reviewed-by: Andriy Shevchenko Applied, thank you! Thanx, Paul > > And now that you mention it, it is a bit surprising that no one has > > complained before. ;-) > > > > Thanx, Paul > > > > ------------------------------------------------------------------------ > > > > commit 23ad938244968e9d2a8001a1c52887c113b182f6 > > Author: Paul E. McKenney > > Date: Tue Apr 9 07:48:18 2019 -0700 > > > > rcu: Make kfree_rcu() ignore NULL pointers > > > > This commit makes the kfree_rcu() macro's semantics be consistent > > with the likes of kfree() by adding a check for NULL pointers, so > > that kfree_rcu(NULL, ...) is a no-op. > > > > Reported-by: Andriy Shevchenko > > Reported-by: Christoph Hellwig > > Signed-off-by: Paul E. McKenney > > > > diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h > > index 922bb6848813..c68649b9bcec 100644 > > --- a/include/linux/rcupdate.h > > +++ b/include/linux/rcupdate.h > > @@ -828,9 +828,13 @@ static inline notrace void rcu_read_unlock_sched_notrace(void) > > * The BUILD_BUG_ON check must not involve any function calls, hence the > > * checks are done in macros here. > > */ > > -#define kfree_rcu(ptr, rcu_head) \ > > - __kfree_rcu(&((ptr)->rcu_head), offsetof(typeof(*(ptr)), rcu_head)) > > - > > +#define kfree_rcu(ptr, rhf) \ > > +do { \ > > + typeof (ptr) ___p = (ptr); \ > > + \ > > + if (___p) \ > > + __kfree_rcu(&((___p)->rhf), offsetof(typeof(*(ptr)), rhf)); \ > > +} while (0) > > > > /* > > * Place this after a lock-acquisition primitive to guarantee that > > > > -- > With Best Regards, > Andy Shevchenko > > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu