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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 36C8AC77B75 for ; Wed, 17 May 2023 10:40:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=sDKQFiju/xdsgZArl4vb+4pByI2FA3cuK3X7LHeu2HE=; b=Ki9/avoVEUAsBP huUwkaAaJBWXJuSbwcmVtlBfl1VYPMmQsszAEVvUznRIFwBkZaJj8OWRbPo9rckdYhfhp4o5x6ZD/ zfDOBg9xHhA26SkJQpuhOwMJHhrDthBe0MOHHIWU8Y/iDvGCR3e0M/8LDGFzYTfquMW/Aykx10TfI RrEy3G8RyCJT0Q+TFwMuJM0pF2AOrBkkgPP7MiORVnjuflAf/xnyvNAwSayoB2Tukwb2GzXWx7rYY drAX5bLu1CQCET5tw42JrrsU8S7bV3cfggQx5JkXtNaJji3p4lfI4/MgaR3VI3Ari/09MnHk+Gkcl NVJkt9IepwhnVj8t7IHQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1pzEaD-009SFC-01; Wed, 17 May 2023 10:40:37 +0000 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1pzEaA-009SEM-1I; Wed, 17 May 2023 10:40:35 +0000 Received: from pps.filterd (m0353723.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 34HAWh8p030125; Wed, 17 May 2023 10:39:33 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=date : from : to : cc : subject : message-id : in-reply-to : references : mime-version : content-type : content-transfer-encoding; s=pp1; bh=6o4UB5d8iRIZZq7T331T96/YmtIoyPZJVO895cK7BU4=; b=Qlb1r1C79y4iKHdQAqanT8rbJmqF8hpDVpHADvfmHgcOzINGCqecTLs6lklqCmaeUKZi LNo2SCVe642Qo5fhaxr/ou+1QQFdZf6fudSYdsYn1zj0/qda6lUKaL4wNzWc8ZwCpOGB u1jr8Jeldv7dhRYFAZce4H8UEXUhr2sOKWsFIUzuyQCAdsrgpetZ/OvfYv7ko7U4WoTl WIlXuWOUiMllj0buN4FxHg1xFrqq9szJZkHJpe+PgAPCqpQU+mAWYxRNQNulh9twB9sp 7Sk1CAWsYA8brwf7ADoH4AMfmPk6bkEJB+etoy2gytNtvsvI4B1v7NCryfl9JlR+J5XJ Lg== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3qmvpm9ncq-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 17 May 2023 10:39:33 +0000 Received: from m0353723.ppops.net (m0353723.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 34HAWq5Q030869; Wed, 17 May 2023 10:37:18 GMT Received: from ppma06ams.nl.ibm.com (66.31.33a9.ip4.static.sl-reverse.com [169.51.49.102]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3qmvpm9fk6-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 17 May 2023 10:37:18 +0000 Received: from pps.filterd (ppma06ams.nl.ibm.com [127.0.0.1]) by ppma06ams.nl.ibm.com (8.17.1.19/8.17.1.19) with ESMTP id 34H5hGdl019589; Wed, 17 May 2023 10:35:52 GMT Received: from smtprelay07.fra02v.mail.ibm.com ([9.218.2.229]) by ppma06ams.nl.ibm.com (PPS) with ESMTPS id 3qj1tdt3s3-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 17 May 2023 10:35:52 +0000 Received: from smtpav04.fra02v.mail.ibm.com (smtpav04.fra02v.mail.ibm.com [10.20.54.103]) by smtprelay07.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 34HAZmug51773938 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 17 May 2023 10:35:48 GMT Received: from smtpav04.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B38752004B; Wed, 17 May 2023 10:35:48 +0000 (GMT) Received: from smtpav04.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C636820043; Wed, 17 May 2023 10:35:47 +0000 (GMT) Received: from p-imbrenda (unknown [9.152.224.66]) by smtpav04.fra02v.mail.ibm.com (Postfix) with ESMTP; Wed, 17 May 2023 10:35:47 +0000 (GMT) Date: Wed, 17 May 2023 12:35:46 +0200 From: Claudio Imbrenda To: Hugh Dickins Cc: Andrew Morton , Mike Kravetz , Mike Rapoport , "Kirill A. Shutemov" , Matthew Wilcox , David Hildenbrand , Suren Baghdasaryan , Qi Zheng , Russell King , Catalin Marinas , Will Deacon , Geert Uytterhoeven , Greg Ungerer , Michal Simek , Thomas Bogendoerfer , Helge Deller , John David Anglin , "Aneesh Kumar K.V" , Michael Ellerman , Alexandre Ghiti , Palmer Dabbelt , Heiko Carstens , Christian Borntraeger , John Paul Adrian Glaubitz , "David S. Miller" , Chris Zankel , Max Filippov , x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 15/23] s390: allow pte_offset_map_lock() to fail Message-ID: <20230517123546.672fb9b0@p-imbrenda> In-Reply-To: <94aec8fe-383f-892-dcbf-d4c14e460a7@google.com> References: <77a5d8c-406b-7068-4f17-23b7ac53bc83@google.com> <94aec8fe-383f-892-dcbf-d4c14e460a7@google.com> Organization: IBM X-Mailer: Claws Mail 4.1.1 (GTK 3.24.37; x86_64-redhat-linux-gnu) MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: 8y_E68kURQ0ih8Y_-pXj5N6bPDOiuEZv X-Proofpoint-ORIG-GUID: ot2a0roI6HKgv_SkGdPLAhcx7gRQDDOX X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.254,Aquarius:18.0.957,Hydra:6.0.573,FMLib:17.11.170.22 definitions=2023-05-17_02,2023-05-16_01,2023-02-09_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 bulkscore=0 clxscore=1011 mlxscore=0 phishscore=0 spamscore=0 mlxlogscore=972 malwarescore=0 lowpriorityscore=0 impostorscore=0 priorityscore=1501 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2304280000 definitions=main-2305170081 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230517_034034_559535_7CD49BC2 X-CRM114-Status: GOOD ( 23.08 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, 9 May 2023 22:01:16 -0700 (PDT) Hugh Dickins wrote: > In rare transient cases, not yet made possible, pte_offset_map() and > pte_offset_map_lock() may not find a page table: handle appropriately. > > Signed-off-by: Hugh Dickins > --- > arch/s390/kernel/uv.c | 2 ++ > arch/s390/mm/gmap.c | 2 ++ > arch/s390/mm/pgtable.c | 12 +++++++++--- > 3 files changed, 13 insertions(+), 3 deletions(-) > > diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c > index cb2ee06df286..3c62d1b218b1 100644 > --- a/arch/s390/kernel/uv.c > +++ b/arch/s390/kernel/uv.c > @@ -294,6 +294,8 @@ int gmap_make_secure(struct gmap *gmap, unsigned long gaddr, void *uvcb) > > rc = -ENXIO; > ptep = get_locked_pte(gmap->mm, uaddr, &ptelock); > + if (!ptep) > + goto out; > if (pte_present(*ptep) && !(pte_val(*ptep) & _PAGE_INVALID) && pte_write(*ptep)) { > page = pte_page(*ptep); > rc = -EAGAIN; > diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c > index dc90d1eb0d55..d198fc9475a2 100644 > --- a/arch/s390/mm/gmap.c > +++ b/arch/s390/mm/gmap.c > @@ -2549,6 +2549,8 @@ static int __zap_zero_pages(pmd_t *pmd, unsigned long start, > spinlock_t *ptl; > > ptep = pte_offset_map_lock(walk->mm, pmd, addr, &ptl); > + if (!ptep) > + break; so if pte_offset_map_lock fails, we abort and skip both the failed entry and the rest of the entries? can pte_offset_map_lock be retried immediately if it fails? (consider that we currently don't allow THP with KVM guests) Would something like this: do { ptep = pte_offset_map_lock(...); mb(); /* maybe? */ } while (!ptep); make sense? otherwise maybe it's better to return an error and retry the whole walk_page_range() in s390_enable_sie() ? it's a slow path anyway. > if (is_zero_pfn(pte_pfn(*ptep))) > ptep_xchg_direct(walk->mm, addr, ptep, __pte(_PAGE_INVALID)); > pte_unmap_unlock(ptep, ptl); [...] _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel