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[209.85.220.73]) by mx.google.com with SMTPS id r127sor5786237vke.51.2019.07.15.17.05.25 for (Google Transport Security); Mon, 15 Jul 2019 17:05:25 -0700 (PDT) Received-SPF: pass (google.com: domain of 3xrqtxqokcji309dkxgd9e2aa270.ya8749gj-886hwy6.ad2@flex--henryburns.bounces.google.com designates 209.85.220.73 as permitted sender) client-ip=209.85.220.73; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b="r/N2p4ZH"; spf=pass (google.com: domain of 3xrqtxqokcji309dkxgd9e2aa270.ya8749gj-886hwy6.ad2@flex--henryburns.bounces.google.com designates 209.85.220.73 as permitted sender) smtp.mailfrom=3xRQtXQoKCJI309DKxGD9E2AA270.yA8749GJ-886Hwy6.AD2@flex--henryburns.bounces.google.com; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=bM16Cxlynj/iYFnBhEVrgD674cLfvqLU43B4Z5mZd8I=; b=r/N2p4ZHJhSkKWCbefj7oLG94wDUQjVPvpVsO2bZgKuDB6odzuwkhgqvbFRar5HUSM F0Uee5JIrhmDjcjHNCYqP0u8lHTYYSn3P5mPCGUqXgaEfFm0vlsGVxLj41XRkh4JassI T55j3gjAdlSg1uZ8LLEGxKrPlRyotdJfmag6H/o9kkWnFeHryKqaCuOkKEDMzD7SCS18 64inrAv4F0E2JBmU86ETFJNPwo7XAlMBkS+jTgXic46jJcC/gfZFvRu2rZuCrPBU/+DD UWyMrmLLTGyjqm4yYyaofcm9Nw3LgJzqsQ+8xMf57fKGz/XDrayl8zrfMiG8bQejHqWU TV2A== X-Google-Smtp-Source: APXvYqyKghXqh+hUwmcq39WhjGsA7PEfDV7IUtnSHADGYoM5Fvn2cKgA8Y0Zc4zvh5r1tKWM+7vjLynajC+dIAJ5 X-Received: by 2002:a1f:dec7:: with SMTP id v190mr11423849vkg.39.1563235525244; Mon, 15 Jul 2019 17:05:25 -0700 (PDT) Date: Mon, 15 Jul 2019 17:05:20 -0700 Message-Id: <20190716000520.230595-1-henryburns@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.22.0.510.g264f2c817a-goog Subject: [PATCH v2] mm/z3fold.c: Reinitialize zhdr structs after migration From: Henry Burns To: Vitaly Vul Cc: Andrew Morton , Shakeel Butt , Jonathan Adams , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Henry Burns 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: X-Virus-Scanned: ClamAV using ClamSMTP z3fold_page_migration() calls memcpy(new_zhdr, zhdr, PAGE_SIZE). However, zhdr contains fields that can't be directly coppied over (ex: list_head, a circular linked list). We only need to initialize the linked lists in new_zhdr, as z3fold_isolate_page() already ensures that these lists are empty Additionally it is possible that zhdr->work has been placed in a workqueue. In this case we shouldn't migrate the page, as zhdr->work references zhdr as opposed to new_zhdr. Fixes: bba4c5f96ce4 ("mm/z3fold.c: support page migration") Signed-off-by: Henry Burns Reviewed-by: Shakeel Butt --- Changelog since v1: - Made comments explicityly refer to new_zhdr->buddy. mm/z3fold.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/mm/z3fold.c b/mm/z3fold.c index 42ef9955117c..f4b2283b19a3 100644 --- a/mm/z3fold.c +++ b/mm/z3fold.c @@ -1352,12 +1352,22 @@ static int z3fold_page_migrate(struct address_space *mapping, struct page *newpa z3fold_page_unlock(zhdr); return -EBUSY; } + if (work_pending(&zhdr->work)) { + z3fold_page_unlock(zhdr); + return -EAGAIN; + } new_zhdr = page_address(newpage); memcpy(new_zhdr, zhdr, PAGE_SIZE); newpage->private = page->private; page->private = 0; z3fold_page_unlock(zhdr); spin_lock_init(&new_zhdr->page_lock); + INIT_WORK(&new_zhdr->work, compact_page_work); + /* + * z3fold_page_isolate() ensures that new_zhdr->buddy is empty, + * so we only have to reinitialize it. + */ + INIT_LIST_HEAD(&new_zhdr->buddy); new_mapping = page_mapping(page); __ClearPageMovable(page); ClearPagePrivate(page);