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=-9.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 7252CC5B578 for ; Mon, 1 Jul 2019 06:20:54 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 2DD102146E for ; Mon, 1 Jul 2019 06:20:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="QJEmvFA0" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2DD102146E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 5377B8E0006; Mon, 1 Jul 2019 02:20:45 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 49C336B000C; Mon, 1 Jul 2019 02:20:45 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2C6B08E0006; Mon, 1 Jul 2019 02:20:45 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-pg1-f207.google.com (mail-pg1-f207.google.com [209.85.215.207]) by kanga.kvack.org (Postfix) with ESMTP id E059C6B0008 for ; Mon, 1 Jul 2019 02:20:44 -0400 (EDT) Received: by mail-pg1-f207.google.com with SMTP id c18so7034902pgk.2 for ; Sun, 30 Jun 2019 23:20:44 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:dkim-signature:from:to:cc:subject:date :message-id:in-reply-to:references:mime-version :content-transfer-encoding; bh=6YVs6Gmoqc0otAH1cnOxSKX8bCa6JUPIlHPM9q8lNZk=; b=Pgzbwg4VNS29xyaTNaYk+HBXTDBK941ckKGxCkazQe0EbIg5d5KZ5xXgjjTqbgiBr3 ddIZd5IpE4qy6IACL1Wc+Qct8ToV16TQqNeIk/ehNHaU3jQDOEC31bQA3RFkHpd1ms1U /VKGVoTn9Ine58hVu5BLRN1bDAtmlVG3pm+djleTtClLb7onEtZSF6lH1JRxgnRBCXNV mKu9TgFubSJ7RUwM20YgFj96E7/1rMpc54Z5UHB1S4ggGT+C71qOmuVl5GrRA/oLD3/m ui8QljTb8Fh3myIYK7TjSK7DVCybu9wAuY3EHBWhZ7VgxhVr0FP16m+wPWXacUPZxGky 0onQ== X-Gm-Message-State: APjAAAWes1A39pCfjiDKv0BEmr/+Qy54IA/h2QWuDWbn85asskPEiZWL O/4wKSiZWBdUbf0dQffw62F5blvtCLX6giCEpDOlTYX34hr3cGPXeclcDa4TAhSTj2xTacMYF11 LNvfuEUiuu11Q5O/VgrC1IuQP/dlaYH4fIdq6NpQ8OD54ogUqBvqvlyL+WT/7bGI= X-Received: by 2002:a17:902:aa95:: with SMTP id d21mr26074074plr.185.1561962044545; Sun, 30 Jun 2019 23:20:44 -0700 (PDT) X-Google-Smtp-Source: APXvYqw5HBiHlVt/4RSGDNRPsSgzowluDy6Hj/iOWIjDS9M0AfFyYyRulPQN/SjMDcRpOaX+BpoH X-Received: by 2002:a17:902:aa95:: with SMTP id d21mr26074020plr.185.1561962043763; Sun, 30 Jun 2019 23:20:43 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1561962043; cv=none; d=google.com; s=arc-20160816; b=vtDi/XkJgCoV90j4siUdREh4P9fu/dlu9cxgZnpM8ccQ7f583wKn08mDfR1SGPH3U5 7Q5m7yqpEBCySOq+sX4YC/OdKa/CXGD/HzG3agvEF5T8oZ3ecQCFgn3OQfosfFFt7fVN gW/ttBFT2ZxMIBEXP6REV7BZ0optw5/pRq2NsKZXK/EHgP2pKHsyFUZt1dK2dd76tl/I FDbGpFyqFYx8SBf8QlIeBTw2TCkAd808A9YENtGv9+pLZuU/zMHtTU1acHRit0S3AYOn 7iXsdhWnViEReXcEAtigcNdhTJ9hhjnUTjtrhOhbuFyeAjZ1m79MkUuMETaUhfkFcLe1 uJlA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:dkim-signature; bh=6YVs6Gmoqc0otAH1cnOxSKX8bCa6JUPIlHPM9q8lNZk=; b=H7tDB095tsrTwASclwFrZvLYc980wt2Wj0sVKyz1X/JtWebs4SjLtjK8zXwWM/jK8x hm+1j60mGw/MRisF64ibl9RgUmSppNPUwSKR10gwxjDHrBJwk0DNTeD/bTboWwWtdorr TKTSTILs9X5tYtQ8IAemj9KoKQdmN7bHu31y3xsjaX7tHyjiQ+6Ei9bdFyz9V+ENmO8A r8GdYCZttt7zq7Y9hGpEHMkRcUoyUUS3iXQ1BSFUkLdtVRwSR3PbiJiqpHWModyTRyrn mfgCj8zuxjRKTo+9mqI2Uf49pnHjywqZILhCPMqZ3nYwGotCHcaeKj7DTX96IIQN1Miv 9A+w== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20170209 header.b=QJEmvFA0; spf=pass (google.com: best guess record for domain of batv+bb02ddf78a79a38d855c+5790+infradead.org+hch@bombadil.srs.infradead.org designates 2607:7c80:54:e::133 as permitted sender) smtp.mailfrom=BATV+bb02ddf78a79a38d855c+5790+infradead.org+hch@bombadil.srs.infradead.org Received: from bombadil.infradead.org (bombadil.infradead.org. [2607:7c80:54:e::133]) by mx.google.com with ESMTPS id x24si9486043pjt.88.2019.06.30.23.20.43 for (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Sun, 30 Jun 2019 23:20:43 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of batv+bb02ddf78a79a38d855c+5790+infradead.org+hch@bombadil.srs.infradead.org designates 2607:7c80:54:e::133 as permitted sender) client-ip=2607:7c80:54:e::133; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20170209 header.b=QJEmvFA0; spf=pass (google.com: best guess record for domain of batv+bb02ddf78a79a38d855c+5790+infradead.org+hch@bombadil.srs.infradead.org designates 2607:7c80:54:e::133 as permitted sender) smtp.mailfrom=BATV+bb02ddf78a79a38d855c+5790+infradead.org+hch@bombadil.srs.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Transfer-Encoding: Content-Type:MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc: To:From:Sender:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=6YVs6Gmoqc0otAH1cnOxSKX8bCa6JUPIlHPM9q8lNZk=; b=QJEmvFA0ZXqEAKaJiHM/HXwFE BSDxo8D5Gtm1+W+1HqT50hAN9Vh8w++KZFTiCpoIRCsYVHvPKzZ98vwHICze2dMHHTu3MsptL1C6n O7g1pctaJ6PIxWWaR5gx83uyX1fdaWlJFe+20rb2/lZKp2kvGbX/hePtlJ+l1VRy9cv2q0Pl47sDG hujb0eQDbUAEB4ydfc/IjZP6MvWHN4HqpeTZB5VBq8IphPMfDVqZdFKemBiZSdAOokusox6fM/e83 lBP6J/AanqzUQcGlT6hto+xPFgmHndkzmYuFM2q3Nj++ZQg8nkmgRFK6bl0H0cuLbH771Sx7SdPMa obMHsTfmg==; Received: from [46.140.178.35] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.92 #3 (Red Hat Linux)) id 1hhpg8-0002w7-AT; Mon, 01 Jul 2019 06:20:40 +0000 From: Christoph Hellwig To: Dan Williams , =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= , Jason Gunthorpe , Ben Skeggs Cc: Ira Weiny , linux-mm@kvack.org, nouveau@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-nvdimm@lists.01.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, John Hubbard , Ralph Campbell , Philip Yang Subject: [PATCH 08/22] mm/hmm: Hold a mmgrab from hmm to mm Date: Mon, 1 Jul 2019 08:20:06 +0200 Message-Id: <20190701062020.19239-9-hch@lst.de> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190701062020.19239-1-hch@lst.de> References: <20190701062020.19239-1-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html 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: From: Jason Gunthorpe So long as a struct hmm pointer exists, so should the struct mm it is linked too. Hold the mmgrab() as soon as a hmm is created, and mmdrop() it once the hmm refcount goes to zero. Since mmdrop() (ie a 0 kref on struct mm) is now impossible with a !NULL mm->hmm delete the hmm_hmm_destroy(). Signed-off-by: Jason Gunthorpe Reviewed-by: Jérôme Glisse Reviewed-by: John Hubbard Reviewed-by: Ralph Campbell Reviewed-by: Ira Weiny Reviewed-by: Christoph Hellwig Tested-by: Philip Yang --- include/linux/hmm.h | 3 --- kernel/fork.c | 1 - mm/hmm.c | 22 ++++------------------ 3 files changed, 4 insertions(+), 22 deletions(-) diff --git a/include/linux/hmm.h b/include/linux/hmm.h index 1fba6979adf4..1d97b6d62c5b 100644 --- a/include/linux/hmm.h +++ b/include/linux/hmm.h @@ -577,14 +577,11 @@ static inline int hmm_vma_fault(struct hmm_mirror *mirror, } /* Below are for HMM internal use only! Not to be used by device driver! */ -void hmm_mm_destroy(struct mm_struct *mm); - static inline void hmm_mm_init(struct mm_struct *mm) { mm->hmm = NULL; } #else /* IS_ENABLED(CONFIG_HMM_MIRROR) */ -static inline void hmm_mm_destroy(struct mm_struct *mm) {} static inline void hmm_mm_init(struct mm_struct *mm) {} #endif /* IS_ENABLED(CONFIG_HMM_MIRROR) */ diff --git a/kernel/fork.c b/kernel/fork.c index 75675b9bf6df..c704c3cedee7 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -673,7 +673,6 @@ void __mmdrop(struct mm_struct *mm) WARN_ON_ONCE(mm == current->active_mm); mm_free_pgd(mm); destroy_context(mm); - hmm_mm_destroy(mm); mmu_notifier_mm_destroy(mm); check_mm(mm); put_user_ns(mm->user_ns); diff --git a/mm/hmm.c b/mm/hmm.c index 22a97ada108b..080b17a2e87e 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -20,6 +20,7 @@ #include #include #include +#include #include #include #include @@ -73,6 +74,7 @@ static struct hmm *hmm_get_or_create(struct mm_struct *mm) hmm->notifiers = 0; hmm->dead = false; hmm->mm = mm; + mmgrab(hmm->mm); spin_lock(&mm->page_table_lock); if (!mm->hmm) @@ -100,6 +102,7 @@ static struct hmm *hmm_get_or_create(struct mm_struct *mm) mm->hmm = NULL; spin_unlock(&mm->page_table_lock); error: + mmdrop(hmm->mm); kfree(hmm); return NULL; } @@ -121,6 +124,7 @@ static void hmm_free(struct kref *kref) mm->hmm = NULL; spin_unlock(&mm->page_table_lock); + mmdrop(hmm->mm); mmu_notifier_call_srcu(&hmm->rcu, hmm_free_rcu); } @@ -129,24 +133,6 @@ static inline void hmm_put(struct hmm *hmm) kref_put(&hmm->kref, hmm_free); } -void hmm_mm_destroy(struct mm_struct *mm) -{ - struct hmm *hmm; - - spin_lock(&mm->page_table_lock); - hmm = mm_get_hmm(mm); - mm->hmm = NULL; - if (hmm) { - hmm->mm = NULL; - hmm->dead = true; - spin_unlock(&mm->page_table_lock); - hmm_put(hmm); - return; - } - - spin_unlock(&mm->page_table_lock); -} - static void hmm_release(struct mmu_notifier *mn, struct mm_struct *mm) { struct hmm *hmm = container_of(mn, struct hmm, mmu_notifier); -- 2.20.1