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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 8834DC43140 for ; Fri, 6 Sep 2019 08:50:52 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4210B20578 for ; Fri, 6 Sep 2019 08:50:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4210B20578 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id CA3F66B0003; Fri, 6 Sep 2019 04:50:51 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C540D6B0006; Fri, 6 Sep 2019 04:50:51 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B1C9E6B0007; Fri, 6 Sep 2019 04:50:51 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0131.hostedemail.com [216.40.44.131]) by kanga.kvack.org (Postfix) with ESMTP id 8871F6B0003 for ; Fri, 6 Sep 2019 04:50:51 -0400 (EDT) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with SMTP id 1E1D062DD for ; Fri, 6 Sep 2019 08:50:51 +0000 (UTC) X-FDA: 75903875502.17.week16_7baf8eb982823 X-HE-Tag: week16_7baf8eb982823 X-Filterd-Recvd-Size: 13724 Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by imf45.hostedemail.com (Postfix) with ESMTP for ; Fri, 6 Sep 2019 08:50:49 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 7801F301A3E3; Fri, 6 Sep 2019 08:50:48 +0000 (UTC) Received: from [10.36.117.162] (ovpn-117-162.ams2.redhat.com [10.36.117.162]) by smtp.corp.redhat.com (Postfix) with ESMTP id 38E31100194E; Fri, 6 Sep 2019 08:50:41 +0000 (UTC) Subject: Re: [PATCH v2 1/7] mm/gup: Rename "nonblocking" to "locked" where proper To: Peter Xu , linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Hugh Dickins , Maya Gokhale , Jerome Glisse , Pavel Emelyanov , Johannes Weiner , Martin Cracauer , Marty McFadden , Shaohua Li , Andrea Arcangeli , Mike Kravetz , Denis Plotnikov , Mike Rapoport , Linus Torvalds , Mel Gorman , "Kirill A . Shutemov" , "Dr . David Alan Gilbert" References: <20190905101534.9637-1-peterx@redhat.com> <20190905101534.9637-2-peterx@redhat.com> From: David Hildenbrand Openpgp: preference=signencrypt Autocrypt: addr=david@redhat.com; prefer-encrypt=mutual; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwX4EEwECACgFAljj9eoCGwMFCQlmAYAGCwkI BwMCBhUIAgkKCwQWAgMBAh4BAheAAAoJEE3eEPcA/4Na5IIP/3T/FIQMxIfNzZshIq687qgG 8UbspuE/YSUDdv7r5szYTK6KPTlqN8NAcSfheywbuYD9A4ZeSBWD3/NAVUdrCaRP2IvFyELj xoMvfJccbq45BxzgEspg/bVahNbyuBpLBVjVWwRtFCUEXkyazksSv8pdTMAs9IucChvFmmq3 jJ2vlaz9lYt/lxN246fIVceckPMiUveimngvXZw21VOAhfQ+/sofXF8JCFv2mFcBDoa7eYob s0FLpmqFaeNRHAlzMWgSsP80qx5nWWEvRLdKWi533N2vC/EyunN3HcBwVrXH4hxRBMco3jvM m8VKLKao9wKj82qSivUnkPIwsAGNPdFoPbgghCQiBjBe6A75Z2xHFrzo7t1jg7nQfIyNC7ez MZBJ59sqA9EDMEJPlLNIeJmqslXPjmMFnE7Mby/+335WJYDulsRybN+W5rLT5aMvhC6x6POK z55fMNKrMASCzBJum2Fwjf/VnuGRYkhKCqqZ8gJ3OvmR50tInDV2jZ1DQgc3i550T5JDpToh dPBxZocIhzg+MBSRDXcJmHOx/7nQm3iQ6iLuwmXsRC6f5FbFefk9EjuTKcLMvBsEx+2DEx0E UnmJ4hVg7u1PQ+2Oy+Lh/opK/BDiqlQ8Pz2jiXv5xkECvr/3Sv59hlOCZMOaiLTTjtOIU7Tq 7ut6OL64oAq+zsFNBFXLn5EBEADn1959INH2cwYJv0tsxf5MUCghCj/CA/lc/LMthqQ773ga uB9mN+F1rE9cyyXb6jyOGn+GUjMbnq1o121Vm0+neKHUCBtHyseBfDXHA6m4B3mUTWo13nid 0e4AM71r0DS8+KYh6zvweLX/LL5kQS9GQeT+QNroXcC1NzWbitts6TZ+IrPOwT1hfB4WNC+X 2n4AzDqp3+ILiVST2DT4VBc11Gz6jijpC/KI5Al8ZDhRwG47LUiuQmt3yqrmN63V9wzaPhC+ xbwIsNZlLUvuRnmBPkTJwwrFRZvwu5GPHNndBjVpAfaSTOfppyKBTccu2AXJXWAE1Xjh6GOC 8mlFjZwLxWFqdPHR1n2aPVgoiTLk34LR/bXO+e0GpzFXT7enwyvFFFyAS0Nk1q/7EChPcbRb hJqEBpRNZemxmg55zC3GLvgLKd5A09MOM2BrMea+l0FUR+PuTenh2YmnmLRTro6eZ/qYwWkC u8FFIw4pT0OUDMyLgi+GI1aMpVogTZJ70FgV0pUAlpmrzk/bLbRkF3TwgucpyPtcpmQtTkWS gDS50QG9DR/1As3LLLcNkwJBZzBG6PWbvcOyrwMQUF1nl4SSPV0LLH63+BrrHasfJzxKXzqg rW28CTAE2x8qi7e/6M/+XXhrsMYG+uaViM7n2je3qKe7ofum3s4vq7oFCPsOgwARAQABwsFl BBgBAgAPBQJVy5+RAhsMBQkJZgGAAAoJEE3eEPcA/4NagOsP/jPoIBb/iXVbM+fmSHOjEshl KMwEl/m5iLj3iHnHPVLBUWrXPdS7iQijJA/VLxjnFknhaS60hkUNWexDMxVVP/6lbOrs4bDZ NEWDMktAeqJaFtxackPszlcpRVkAs6Msn9tu8hlvB517pyUgvuD7ZS9gGOMmYwFQDyytpepo YApVV00P0u3AaE0Cj/o71STqGJKZxcVhPaZ+LR+UCBZOyKfEyq+ZN311VpOJZ1IvTExf+S/5 lqnciDtbO3I4Wq0ArLX1gs1q1XlXLaVaA3yVqeC8E7kOchDNinD3hJS4OX0e1gdsx/e6COvy qNg5aL5n0Kl4fcVqM0LdIhsubVs4eiNCa5XMSYpXmVi3HAuFyg9dN+x8thSwI836FoMASwOl C7tHsTjnSGufB+D7F7ZBT61BffNBBIm1KdMxcxqLUVXpBQHHlGkbwI+3Ye+nE6HmZH7IwLwV W+Ajl7oYF+jeKaH4DZFtgLYGLtZ1LDwKPjX7VAsa4Yx7S5+EBAaZGxK510MjIx6SGrZWBrrV TEvdV00F2MnQoeXKzD7O4WFbL55hhyGgfWTHwZ457iN9SgYi1JLPqWkZB0JRXIEtjd4JEQcx +8Umfre0Xt4713VxMygW0PnQt5aSQdMD58jHFxTk092mU+yIHj5LeYgvwSgZN4airXk5yRXl SE+xAvmumFBY Organization: Red Hat GmbH Message-ID: Date: Fri, 6 Sep 2019 10:50:40 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190905101534.9637-2-peterx@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.41]); Fri, 06 Sep 2019 08:50:48 +0000 (UTC) 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 05.09.19 12:15, Peter Xu wrote: > There's plenty of places around __get_user_pages() that has a parameter > "nonblocking" which does not really mean that "it won't block" (because > it can really block) but instead it shows whether the mmap_sem is > released by up_read() during the page fault handling mostly when > VM_FAULT_RETRY is returned. > > We have the correct naming in e.g. get_user_pages_locked() or > get_user_pages_remote() as "locked", however there're still many places > that are using the "nonblocking" as name. > > Renaming the places to "locked" where proper to better suite the > functionality of the variable. While at it, fixing up some of the > comments accordingly. > > Reviewed-by: Mike Rapoport > Reviewed-by: Jerome Glisse > Signed-off-by: Peter Xu > --- > mm/gup.c | 44 +++++++++++++++++++++----------------------- > mm/hugetlb.c | 8 ++++---- > 2 files changed, 25 insertions(+), 27 deletions(-) > > diff --git a/mm/gup.c b/mm/gup.c > index 98f13ab37bac..eddbb95dcb8f 100644 > --- a/mm/gup.c > +++ b/mm/gup.c > @@ -622,12 +622,12 @@ static int get_gate_page(struct mm_struct *mm, unsigned long address, > } > > /* > - * mmap_sem must be held on entry. If @nonblocking != NULL and > - * *@flags does not include FOLL_NOWAIT, the mmap_sem may be released. > - * If it is, *@nonblocking will be set to 0 and -EBUSY returned. > + * mmap_sem must be held on entry. If @locked != NULL and *@flags > + * does not include FOLL_NOWAIT, the mmap_sem may be released. If it > + * is, *@locked will be set to 0 and -EBUSY returned. > */ > static int faultin_page(struct task_struct *tsk, struct vm_area_struct *vma, > - unsigned long address, unsigned int *flags, int *nonblocking) > + unsigned long address, unsigned int *flags, int *locked) > { > unsigned int fault_flags = 0; > vm_fault_t ret; > @@ -639,7 +639,7 @@ static int faultin_page(struct task_struct *tsk, struct vm_area_struct *vma, > fault_flags |= FAULT_FLAG_WRITE; > if (*flags & FOLL_REMOTE) > fault_flags |= FAULT_FLAG_REMOTE; > - if (nonblocking) > + if (locked) > fault_flags |= FAULT_FLAG_ALLOW_RETRY; > if (*flags & FOLL_NOWAIT) > fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT; > @@ -665,8 +665,8 @@ static int faultin_page(struct task_struct *tsk, struct vm_area_struct *vma, > } > > if (ret & VM_FAULT_RETRY) { > - if (nonblocking && !(fault_flags & FAULT_FLAG_RETRY_NOWAIT)) > - *nonblocking = 0; > + if (locked && !(fault_flags & FAULT_FLAG_RETRY_NOWAIT)) > + *locked = 0; > return -EBUSY; > } > > @@ -743,7 +743,7 @@ static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags) > * only intends to ensure the pages are faulted in. > * @vmas: array of pointers to vmas corresponding to each page. > * Or NULL if the caller does not require them. > - * @nonblocking: whether waiting for disk IO or mmap_sem contention > + * @locked: whether we're still with the mmap_sem held > * > * Returns number of pages pinned. This may be fewer than the number > * requested. If nr_pages is 0 or negative, returns 0. If no pages > @@ -772,13 +772,11 @@ static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags) > * appropriate) must be called after the page is finished with, and > * before put_page is called. > * > - * If @nonblocking != NULL, __get_user_pages will not wait for disk IO > - * or mmap_sem contention, and if waiting is needed to pin all pages, > - * *@nonblocking will be set to 0. Further, if @gup_flags does not > - * include FOLL_NOWAIT, the mmap_sem will be released via up_read() in > - * this case. > + * If @locked != NULL, *@locked will be set to 0 when mmap_sem is > + * released by an up_read(). That can happen if @gup_flags does not > + * have FOLL_NOWAIT. > * > - * A caller using such a combination of @nonblocking and @gup_flags > + * A caller using such a combination of @locked and @gup_flags > * must therefore hold the mmap_sem for reading only, and recognize > * when it's been released. Otherwise, it must be held for either > * reading or writing and will not be released. > @@ -790,7 +788,7 @@ static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags) > static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, > unsigned long start, unsigned long nr_pages, > unsigned int gup_flags, struct page **pages, > - struct vm_area_struct **vmas, int *nonblocking) > + struct vm_area_struct **vmas, int *locked) > { > long ret = 0, i = 0; > struct vm_area_struct *vma = NULL; > @@ -834,7 +832,7 @@ static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, > if (is_vm_hugetlb_page(vma)) { > i = follow_hugetlb_page(mm, vma, pages, vmas, > &start, &nr_pages, i, > - gup_flags, nonblocking); > + gup_flags, locked); > continue; > } > } > @@ -852,7 +850,7 @@ static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, > page = follow_page_mask(vma, start, foll_flags, &ctx); > if (!page) { > ret = faultin_page(tsk, vma, start, &foll_flags, > - nonblocking); > + locked); > switch (ret) { > case 0: > goto retry; > @@ -1178,7 +1176,7 @@ EXPORT_SYMBOL(get_user_pages_remote); > * @vma: target vma > * @start: start address > * @end: end address > - * @nonblocking: > + * @locked: whether the mmap_sem is still held > * > * This takes care of mlocking the pages too if VM_LOCKED is set. > * > @@ -1186,14 +1184,14 @@ EXPORT_SYMBOL(get_user_pages_remote); > * > * vma->vm_mm->mmap_sem must be held. > * > - * If @nonblocking is NULL, it may be held for read or write and will > + * If @locked is NULL, it may be held for read or write and will > * be unperturbed. > * > - * If @nonblocking is non-NULL, it must held for read only and may be > - * released. If it's released, *@nonblocking will be set to 0. > + * If @locked is non-NULL, it must held for read only and may be > + * released. If it's released, *@locked will be set to 0. > */ > long populate_vma_page_range(struct vm_area_struct *vma, > - unsigned long start, unsigned long end, int *nonblocking) > + unsigned long start, unsigned long end, int *locked) > { > struct mm_struct *mm = vma->vm_mm; > unsigned long nr_pages = (end - start) / PAGE_SIZE; > @@ -1228,7 +1226,7 @@ long populate_vma_page_range(struct vm_area_struct *vma, > * not result in a stack expansion that recurses back here. > */ > return __get_user_pages(current, mm, start, nr_pages, gup_flags, > - NULL, NULL, nonblocking); > + NULL, NULL, locked); > } > > /* > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index ede7e7f5d1ab..5f816ee42206 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -4251,7 +4251,7 @@ int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm, > long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, > struct page **pages, struct vm_area_struct **vmas, > unsigned long *position, unsigned long *nr_pages, > - long i, unsigned int flags, int *nonblocking) > + long i, unsigned int flags, int *locked) > { > unsigned long pfn_offset; > unsigned long vaddr = *position; > @@ -4322,7 +4322,7 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, > spin_unlock(ptl); > if (flags & FOLL_WRITE) > fault_flags |= FAULT_FLAG_WRITE; > - if (nonblocking) > + if (locked) > fault_flags |= FAULT_FLAG_ALLOW_RETRY; > if (flags & FOLL_NOWAIT) > fault_flags |= FAULT_FLAG_ALLOW_RETRY | > @@ -4339,9 +4339,9 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, > break; > } > if (ret & VM_FAULT_RETRY) { > - if (nonblocking && > + if (locked && > !(fault_flags & FAULT_FLAG_RETRY_NOWAIT)) > - *nonblocking = 0; > + *locked = 0; > *nr_pages = 0; > /* > * VM_FAULT_RETRY must not return an > Reviewed-by: David Hildenbrand -- Thanks, David / dhildenb