From patchwork Wed Sep 11 07:10:01 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Xu X-Patchwork-Id: 11140465 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0C65C1395 for ; Wed, 11 Sep 2019 07:10:33 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C9D0A222BF for ; Wed, 11 Sep 2019 07:10:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C9D0A222BF 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 DF72C6B0007; Wed, 11 Sep 2019 03:10:31 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id DCEC26B0008; Wed, 11 Sep 2019 03:10:31 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CE4096B000A; Wed, 11 Sep 2019 03:10:31 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0069.hostedemail.com [216.40.44.69]) by kanga.kvack.org (Postfix) with ESMTP id AB2E36B0007 for ; Wed, 11 Sep 2019 03:10:31 -0400 (EDT) Received: from smtpin10.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with SMTP id 4AB69180AD80C for ; Wed, 11 Sep 2019 07:10:31 +0000 (UTC) X-FDA: 75921766662.10.sack91_78dae4b163419 X-Spam-Summary: 1,0,0,,d41d8cd98f00b204,peterx@redhat.com,::linux-kernel@vger.kernel.org:david@redhat.com:hughd@google.com:gokhale2@llnl.gov:jglisse@redhat.com:xemul@virtuozzo.com:hannes@cmpxchg.org:peterx@redhat.com:cracauer@cons.org:mcfadden8@llnl.gov:shli@fb.com:aarcange@redhat.com:mike.kravetz@oracle.com:dplotnikov@virtuozzo.com:rppt@linux.vnet.ibm.com:torvalds@linux-foundation.org:mgorman@suse.de:kirill@shutemov.name:dgilbert@redhat.com,RULES_HIT:30003:30029:30034:30054:30070:30090,0,RBL:209.132.183.28:@redhat.com:.lbl8.mailshell.net-62.18.0.0 64.10.201.10,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:ft,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:32,LUA_SUMMARY:none X-HE-Tag: sack91_78dae4b163419 X-Filterd-Recvd-Size: 11206 Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by imf50.hostedemail.com (Postfix) with ESMTP for ; Wed, 11 Sep 2019 07:10:30 +0000 (UTC) Received: from mail-pf1-f198.google.com (mail-pf1-f198.google.com [209.85.210.198]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 51F964E93D for ; Wed, 11 Sep 2019 07:10:29 +0000 (UTC) Received: by mail-pf1-f198.google.com with SMTP id w16so15021508pfj.9 for ; Wed, 11 Sep 2019 00:10:29 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=8UHD8q1/U4+zJWZ0Rga+lE/MalvoU0sZjG3OOCHgurM=; b=ngSUy1rbE2g5TzxgqL//0rf6xc1M9pyHAvvGsrwP/AeWAYa+8L/tHHw9F7y9oeBdfA BQkeBGo3cvyIC163Gt3L4WQb4DfLovuaiNl6vuCSSvN7KpomPNXvL0SfKeRGatUaOdtK w49M0w+4UapmS/u3tGRwdh26NBiPn7pR1fQDggi5FF5U13mkT0SUba/SbPxMqYtYsR+G ufbHrXxPWwQOnYzfrweG6BnEksadfZk4Y044aml6IweBrjHjYUwb9kLMmQDFx4JMtjpS MsDPC3jPGaHqQepBA9ROACSR5S+SYPE3L2JI7KXtQOwzOELEC9bYoiMTJsbf/CN02Tsp iM5A== X-Gm-Message-State: APjAAAVGu9OMMPgKFyxOh+NsfS6dq2coUTFEk56SntJWa8C5i9zWjedX 8yNu+KvJmjjrnmmuOV6Z/toJCmkGrpnTsnsUaOi/YlT1QfrMcrpuVRqwgdDFXCRN1s2xxAGQqDK kEslH1aK+kSU= X-Received: by 2002:a63:36c4:: with SMTP id d187mr5220191pga.262.1568185828290; Wed, 11 Sep 2019 00:10:28 -0700 (PDT) X-Google-Smtp-Source: APXvYqygqDcGnNZXvjBdxKGSiB6776Xw6PNFyorhND4rsWkFNwzyhaKjXod9pwhAnCIYE0MjnqA0Fg== X-Received: by 2002:a63:36c4:: with SMTP id d187mr5220154pga.262.1568185827979; Wed, 11 Sep 2019 00:10:27 -0700 (PDT) Received: from xz-x1.redhat.com ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id j10sm1573091pjn.3.2019.09.11.00.10.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 11 Sep 2019 00:10:27 -0700 (PDT) From: Peter Xu To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: David Hildenbrand , Hugh Dickins , Maya Gokhale , Jerome Glisse , Pavel Emelyanov , Johannes Weiner , peterx@redhat.com, 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" Subject: [PATCH v3 1/7] mm/gup: Rename "nonblocking" to "locked" where proper Date: Wed, 11 Sep 2019 15:10:01 +0800 Message-Id: <20190911071007.20077-2-peterx@redhat.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190911071007.20077-1-peterx@redhat.com> References: <20190911071007.20077-1-peterx@redhat.com> MIME-Version: 1.0 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: 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 Reviewed-by: David Hildenbrand 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