From patchwork Tue Jun 15 13:24:39 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 12321351 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=-16.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 61C43C48BE8 for ; Tue, 15 Jun 2021 13:26:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 49BDA6147D for ; Tue, 15 Jun 2021 13:26:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230387AbhFON2I (ORCPT ); Tue, 15 Jun 2021 09:28:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53536 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229947AbhFON2H (ORCPT ); Tue, 15 Jun 2021 09:28:07 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C2E11C061574; Tue, 15 Jun 2021 06:26:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=1X21SF/7fmwg2FrGG5ahYeKQk8ivw4suEk6vCt/uQZM=; b=Yvjhr/bJmyJ/QCD+GCduqR8jqD RfTnBcPS7gxLwW7kxITRtCz0LU2jOF9jpt0JwCS1WO3/TpTYsfE0R4dPtZGTRx/ju2FqDrozih8Jk aiZGKwiuEcyhdyeL+PmvjvkV5PFLRvauaMoSuuu9uM+vJl3qs/9CTh7sD2QjB2KjfOb65mtU2myUn qkfsk6YjZlAK3U/zrVA/R5JbS2FbFJIRHZFLKMBJGzz6h8RCblaDBYsnT/foXESa+zQPlmJelf4oX Vi9UPEtaewyVKmdkil7ItuM/Sw7khkyPbd4o6gm/aAiy9bj/1GtYW24JZAJ9XsVUcVZw0mxAa3egy OVadjXDg==; Received: from [2001:4bb8:19b:fdce:9045:1e63:20f0:ca9] (helo=localhost) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1lt942-006nuT-C1; Tue, 15 Jun 2021 13:25:13 +0000 From: Christoph Hellwig To: Jens Axboe , Thomas Gleixner Cc: Thomas Bogendoerfer , Geoff Levand , Ilya Dryomov , Dongsheng Yang , Mike Snitzer , "James E.J. Bottomley" , Ira Weiny , dm-devel@redhat.com, linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, ceph-devel@vger.kernel.org, linux-arch@vger.kernel.org Subject: [PATCH 01/18] mm: add a kunmap_local_dirty helper Date: Tue, 15 Jun 2021 15:24:39 +0200 Message-Id: <20210615132456.753241-2-hch@lst.de> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210615132456.753241-1-hch@lst.de> References: <20210615132456.753241-1-hch@lst.de> MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Add a helper that calls flush_kernel_dcache_page before unmapping the local mapping. flush_kernel_dcache_page is required for all pages potentially mapped into userspace that were written to using kmap*, so having a helper that does the right thing can be very convenient. Signed-off-by: Christoph Hellwig --- include/linux/highmem-internal.h | 7 +++++++ include/linux/highmem.h | 4 ++++ 2 files changed, 11 insertions(+) diff --git a/include/linux/highmem-internal.h b/include/linux/highmem-internal.h index 7902c7d8b55f..bd37706db147 100644 --- a/include/linux/highmem-internal.h +++ b/include/linux/highmem-internal.h @@ -224,4 +224,11 @@ do { \ __kunmap_local(__addr); \ } while (0) +#define kunmap_local_dirty(__page, __addr) \ +do { \ + if (!PageSlab(__page)) \ + flush_kernel_dcache_page(__page); \ + kunmap_local(__addr); \ +} while (0) + #endif diff --git a/include/linux/highmem.h b/include/linux/highmem.h index 832b49b50c7b..65f548db4f2d 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -93,6 +93,10 @@ static inline void kmap_flush_unused(void); * On HIGHMEM enabled systems mapping a highmem page has the side effect of * disabling migration in order to keep the virtual address stable across * preemption. No caller of kmap_local_page() can rely on this side effect. + * + * If data is written to the returned kernel mapping, the callers needs to + * unmap the mapping using kunmap_local_dirty(), else kunmap_local() should + * be used. */ static inline void *kmap_local_page(struct page *page);