From patchwork Fri Oct 9 07:59:22 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Daniel Vetter X-Patchwork-Id: 11825337 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 40BC9109B for ; Fri, 9 Oct 2020 08:02:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 18FFE21D6C for ; Fri, 9 Oct 2020 08:02:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="WPX0SQh+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732673AbgJIICM (ORCPT ); Fri, 9 Oct 2020 04:02:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49524 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732689AbgJIIAM (ORCPT ); Fri, 9 Oct 2020 04:00:12 -0400 Received: from mail-wm1-x342.google.com (mail-wm1-x342.google.com [IPv6:2a00:1450:4864:20::342]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AF8F3C0613A7 for ; Fri, 9 Oct 2020 01:00:00 -0700 (PDT) Received: by mail-wm1-x342.google.com with SMTP id 13so8866652wmf.0 for ; Fri, 09 Oct 2020 01:00:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=VGrUY4m6p5xG/5TwFTmhTR39yvHelSEgKxkZWp9gwIE=; b=WPX0SQh+d+jDaKjHU8oXPWwTFZ6I9d8chtJOOB3w8FfTWBwLtHGTAa8q7Z5CACAZY3 UkSQDp1/O2GnYgBbniIxNjhdXdLdXrAJABesUu7pGtQKY9YclRRFLDYKvNjJkG8Ypaxd nZyL986vmmMLudJmb5AlQdezveAb4RTPx7bHo= 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=VGrUY4m6p5xG/5TwFTmhTR39yvHelSEgKxkZWp9gwIE=; b=Oag3WWqd/WQ+WFCYiYtqF4cD9uELY4WAHlANNttLulBYPgNPntcv0K+NMrUXHvCfxN qHV0DXQ/iSbXqTcyRZOX5/y63J3J+Or2waI8C5OYosuMQJ/gpoBZHP/clNPWV+4IGict ug1r7a6w2PkYj6b1uctD+9C3KsS0k4/lbeOh30o1pRLhab8Vnp3yCZtTeoDtc6s0W2J6 B9tqXi7BHetNe1yvkvQvGXosGrBW2nSQALdoqYdz36KsJ1yMQn8A/pbecxkv3P870iG2 FK9j9sfY1xYxCk9AVwUK8Q0rBrbxl/RWoqNE7u3HaXltzGOBv+mG/OXan7RdJr/2vOrh 7wBw== X-Gm-Message-State: AOAM530vByTUWdYwlaUroVAdQQbOG8cdwVS16F5pBuwQcNrQInxHK6Y+ Ia0Ka5xPuzGeN/AzxDwGDULHjg== X-Google-Smtp-Source: ABdhPJza4YHBFB+hGZoQR0pL1SAV181vUPmZGDI7HJVs1HjO1uxQPcpRwnUTFuwYtwPHyDbyitWzBQ== X-Received: by 2002:a1c:e045:: with SMTP id x66mr12816887wmg.104.1602230399345; Fri, 09 Oct 2020 00:59:59 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id u17sm11634118wri.45.2020.10.09.00.59.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 09 Oct 2020 00:59:58 -0700 (PDT) From: Daniel Vetter To: DRI Development , LKML Cc: kvm@vger.kernel.org, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-media@vger.kernel.org, linux-s390@vger.kernel.org, Daniel Vetter , Daniel Vetter , Jason Gunthorpe , Pawel Osciak , Marek Szyprowski , Kyungmin Park , Tomasz Figa , Mauro Carvalho Chehab , Andrew Morton , John Hubbard , =?utf-8?b?SsOpcsO0bWUgR2xpc3Nl?= , Jan Kara , Dan Williams Subject: [PATCH v2 05/17] mm/frame-vector: Use FOLL_LONGTERM Date: Fri, 9 Oct 2020 09:59:22 +0200 Message-Id: <20201009075934.3509076-6-daniel.vetter@ffwll.ch> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201009075934.3509076-1-daniel.vetter@ffwll.ch> References: <20201009075934.3509076-1-daniel.vetter@ffwll.ch> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org This is used by media/videbuf2 for persistent dma mappings, not just for a single dma operation and then freed again, so needs FOLL_LONGTERM. Unfortunately current pup_locked doesn't support FOLL_LONGTERM due to locking issues. Rework the code to pull the pup path out from the mmap_sem critical section as suggested by Jason. By relying entirely on the vma checks in pin_user_pages and follow_pfn (for vm_flags and vma_is_fsdax) we can also streamline the code a lot. Signed-off-by: Daniel Vetter Cc: Jason Gunthorpe Cc: Pawel Osciak Cc: Marek Szyprowski Cc: Kyungmin Park Cc: Tomasz Figa Cc: Mauro Carvalho Chehab Cc: Andrew Morton Cc: John Hubbard Cc: Jérôme Glisse Cc: Jan Kara Cc: Dan Williams Cc: linux-mm@kvack.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-samsung-soc@vger.kernel.org Cc: linux-media@vger.kernel.org --- v2: Streamline the code and further simplify the loop checks (Jason) --- mm/frame_vector.c | 50 ++++++++++++++--------------------------------- 1 file changed, 15 insertions(+), 35 deletions(-) diff --git a/mm/frame_vector.c b/mm/frame_vector.c index 10f82d5643b6..d44779e56313 100644 --- a/mm/frame_vector.c +++ b/mm/frame_vector.c @@ -38,7 +38,6 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames, struct vm_area_struct *vma; int ret = 0; int err; - int locked; if (nr_frames == 0) return 0; @@ -48,40 +47,25 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames, start = untagged_addr(start); - mmap_read_lock(mm); - locked = 1; - vma = find_vma_intersection(mm, start, start + 1); - if (!vma) { - ret = -EFAULT; - goto out; - } - - /* - * While get_vaddr_frames() could be used for transient (kernel - * controlled lifetime) pinning of memory pages all current - * users establish long term (userspace controlled lifetime) - * page pinning. Treat get_vaddr_frames() like - * get_user_pages_longterm() and disallow it for filesystem-dax - * mappings. - */ - if (vma_is_fsdax(vma)) { - ret = -EOPNOTSUPP; - goto out; - } - - if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) { + ret = pin_user_pages_fast(start, nr_frames, + FOLL_FORCE | FOLL_WRITE | FOLL_LONGTERM, + (struct page **)(vec->ptrs)); + if (ret > 0) { vec->got_ref = true; vec->is_pfns = false; - ret = pin_user_pages_locked(start, nr_frames, - gup_flags, (struct page **)(vec->ptrs), &locked); - goto out; + goto out_unlocked; } + mmap_read_lock(mm); vec->got_ref = false; vec->is_pfns = true; do { unsigned long *nums = frame_vector_pfns(vec); + vma = find_vma_intersection(mm, start, start + 1); + if (!vma) + break; + while (ret < nr_frames && start + PAGE_SIZE <= vma->vm_end) { err = follow_pfn(vma, start, &nums[ret]); if (err) { @@ -92,17 +76,13 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames, start += PAGE_SIZE; ret++; } - /* - * We stop if we have enough pages or if VMA doesn't completely - * cover the tail page. - */ - if (ret >= nr_frames || start < vma->vm_end) + /* Bail out if VMA doesn't completely cover the tail page. */ + if (start < vma->vm_end) break; - vma = find_vma_intersection(mm, start, start + 1); - } while (vma && vma->vm_flags & (VM_IO | VM_PFNMAP)); + } while (ret < nr_frames); out: - if (locked) - mmap_read_unlock(mm); + mmap_read_unlock(mm); +out_unlocked: if (!ret) ret = -EFAULT; if (ret > 0)