From patchwork Sat Apr 17 09:40:38 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miaohe Lin X-Patchwork-Id: 12209619 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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 26839C433ED for ; Sat, 17 Apr 2021 09:41:58 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id CDF7F611AC for ; Sat, 17 Apr 2021 09:41:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CDF7F611AC Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 297E46B0071; Sat, 17 Apr 2021 05:41:54 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2742B6B0073; Sat, 17 Apr 2021 05:41:54 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E817B6B0075; Sat, 17 Apr 2021 05:41:53 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0164.hostedemail.com [216.40.44.164]) by kanga.kvack.org (Postfix) with ESMTP id B083A6B0071 for ; Sat, 17 Apr 2021 05:41:53 -0400 (EDT) Received: from smtpin26.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 2D61D4DDB for ; Sat, 17 Apr 2021 09:41:53 +0000 (UTC) X-FDA: 78041367306.26.9F6C2EF Received: from szxga05-in.huawei.com (szxga05-in.huawei.com [45.249.212.191]) by imf02.hostedemail.com (Postfix) with ESMTP id 8F1F740002C8 for ; Sat, 17 Apr 2021 09:41:33 +0000 (UTC) Received: from DGGEMS410-HUB.china.huawei.com (unknown [172.30.72.58]) by szxga05-in.huawei.com (SkyGuard) with ESMTP id 4FMp2C0yb9zyPGg; Sat, 17 Apr 2021 17:39:31 +0800 (CST) Received: from huawei.com (10.175.104.175) by DGGEMS410-HUB.china.huawei.com (10.3.19.210) with Microsoft SMTP Server id 14.3.498.0; Sat, 17 Apr 2021 17:41:39 +0800 From: Miaohe Lin To: CC: , , , , , , , , , , , , , Subject: [PATCH v2 4/5] mm/swap: remove confusing checking for non_swap_entry() in swap_ra_info() Date: Sat, 17 Apr 2021 05:40:38 -0400 Message-ID: <20210417094039.51711-5-linmiaohe@huawei.com> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20210417094039.51711-1-linmiaohe@huawei.com> References: <20210417094039.51711-1-linmiaohe@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.104.175] X-CFilter-Loop: Reflected X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 8F1F740002C8 X-Stat-Signature: r9rjhubouq8a89o3efnu34hmch5rbcgq Received-SPF: none (huawei.com>: No applicable sender policy available) receiver=imf02; identity=mailfrom; envelope-from=""; helo=szxga05-in.huawei.com; client-ip=45.249.212.191 X-HE-DKIM-Result: none/none X-HE-Tag: 1618652493-126388 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: While we released the pte lock, somebody else might faulted in this pte. So we should check whether it's swap pte first to guard against such race or swp_type would be unexpected. But the swap_entry isn't used in this function and we will have enough checking when we really operate the PTE entries later. So checking for non_swap_entry() is not really needed here and should be removed to avoid confusion. Signed-off-by: Miaohe Lin --- mm/swap_state.c | 6 ------ 1 file changed, 6 deletions(-) diff --git a/mm/swap_state.c b/mm/swap_state.c index 272ea2108c9d..df5405384520 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c @@ -721,7 +721,6 @@ static void swap_ra_info(struct vm_fault *vmf, { struct vm_area_struct *vma = vmf->vma; unsigned long ra_val; - swp_entry_t entry; unsigned long faddr, pfn, fpfn; unsigned long start, end; pte_t *pte, *orig_pte; @@ -739,11 +738,6 @@ static void swap_ra_info(struct vm_fault *vmf, faddr = vmf->address; orig_pte = pte = pte_offset_map(vmf->pmd, faddr); - entry = pte_to_swp_entry(*pte); - if ((unlikely(non_swap_entry(entry)))) { - pte_unmap(orig_pte); - return; - } fpfn = PFN_DOWN(faddr); ra_val = GET_SWAP_RA_VAL(vma);