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Wed, 25 Sep 2019 17:45:04 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x8PHhpFw088961; Wed, 25 Sep 2019 17:45:04 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserp3030.oracle.com with ESMTP id 2v82tkctk3-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 25 Sep 2019 17:45:04 +0000 Received: from abhmp0014.oracle.com (abhmp0014.oracle.com [141.146.116.20]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x8PHj021007588; Wed, 25 Sep 2019 17:45:00 GMT Received: from [192.168.1.222] (/71.63.128.209) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 25 Sep 2019 10:44:59 -0700 Subject: Re: [PATCH 1/2] userfaultfd: remove one unnecessary warn_on in __mcopy_atomic_hugetlb To: Wei Yang , akpm@linux-foundation.org, aarcange@redhat.com, hughd@google.com Cc: linux-mm@kvack.org References: <20190925121833.2766-1-richardw.yang@linux.intel.com> From: Mike Kravetz Message-ID: <3f69dc19-eb3b-ed46-62bc-c5e6e89ab6eb@oracle.com> Date: Wed, 25 Sep 2019 10:44:58 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <20190925121833.2766-1-richardw.yang@linux.intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9390 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1908290000 definitions=main-1909250155 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9390 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1908290000 definitions=main-1909250155 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 9/25/19 5:18 AM, Wei Yang wrote: > The warning here is to make sure address(dst_addr) and length(len - > copied) are huge page size aligned. > > While this is ensured by: > > dst_start and len is huge page size aligned > dst_addr equals to dst_start and increase huge page size each time > copied increase huge page size each time Can we also remove the following for the same reasons? diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index 640ff2bd9a69..f82d5ec698d8 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -262,7 +262,6 @@ static __always_inline ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm, pte_t dst_pteval; BUG_ON(dst_addr >= dst_start + len); - VM_BUG_ON(dst_addr & ~huge_page_mask(h)); /* * Serialize via hugetlb_fault_mutex -- Mike Kravetz > > This means this warning will never be triggered. > > Signed-off-by: Wei Yang > --- > mm/userfaultfd.c | 4 ---- > 1 file changed, 4 deletions(-) > > diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c > index c7ae74ce5ff3..7895c715000e 100644 > --- a/mm/userfaultfd.c > +++ b/mm/userfaultfd.c > @@ -243,10 +243,6 @@ static __always_inline ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm, > vm_shared = dst_vma->vm_flags & VM_SHARED; > } > > - if (WARN_ON(dst_addr & (vma_hpagesize - 1) || > - (len - copied) & (vma_hpagesize - 1))) > - goto out_unlock; > - > /* > * If not shared, ensure the dst_vma has a anon_vma. > */ >