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=-14.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 589CAC2D0A3 for ; Fri, 6 Nov 2020 23:28:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F29CB20867 for ; Fri, 6 Nov 2020 23:28:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="BecthK+s"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="0OIGaGyV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728753AbgKFX1S (ORCPT ); Fri, 6 Nov 2020 18:27:18 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:38388 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728097AbgKFX1P (ORCPT ); Fri, 6 Nov 2020 18:27:15 -0500 Date: Fri, 06 Nov 2020 23:27:11 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1604705232; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=B5IyjPhQQdFFMRsjwnh1tjtHqPuzPCk+VjEqADgUMF0=; b=BecthK+s024vaS00aOnhB1FyiifNIOVJ8/M3RT7B89KTOu5fFkJUriye40VePFxGLsVZi9 n2DdfD87nC/eskX7DQHX5lDlWwLLWjr7Q9KBkx/P2UXUBe+h6PSq6Hzj+X0/4FbjXyzY9r SeI9130KAxAR5Nf0biVt9QZSFr8aXquUaQTTlFHDGQzNF+yXjMEGSZAIMihNKuDW0dUC3F USGSCwL9mJC9+rXSVTmhti8YzhxZd8pkOGwVO/X+qE6xrOJjW67ybvMWU5rXsOqZeCwEXY eSVR21FJDNtS650KHumw8ZU5Frw0c4nJaWKgcjiEj038sugKNYNbG3Kj4tHIXA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1604705232; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=B5IyjPhQQdFFMRsjwnh1tjtHqPuzPCk+VjEqADgUMF0=; b=0OIGaGyVozckob2JwjNMiEUmYjPYSAIzjHahrEpyJj4yxdqVnq7TqQFLM7CPd1BNTY7QJV DDAGAk8JhKCXWgCg== From: "tip-bot2 for Thomas Gleixner" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: core/mm] Documentation/io-mapping: Remove outdated blurb Cc: Thomas Gleixner , Christoph Hellwig , Andrew Morton , x86 , LKML In-Reply-To: <20201103095858.734064977@linutronix.de> References: <20201103095858.734064977@linutronix.de> MIME-Version: 1.0 Message-ID: <160470523160.397.1285623680777934426.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the core/mm branch of tip: Commit-ID: 9bf6f7bab3bad4b30f108fca25aa5297dff0973f Gitweb: https://git.kernel.org/tip/9bf6f7bab3bad4b30f108fca25aa5297dff0973f Author: Thomas Gleixner AuthorDate: Tue, 03 Nov 2020 10:27:33 +01:00 Committer: Thomas Gleixner CommitterDate: Fri, 06 Nov 2020 23:14:58 +01:00 Documentation/io-mapping: Remove outdated blurb The implementation details in the documentation are outdated and not really helpful. Remove them. Signed-off-by: Thomas Gleixner Cc: Christoph Hellwig Cc: Andrew Morton Link: https://lore.kernel.org/r/20201103095858.734064977@linutronix.de --- Documentation/driver-api/io-mapping.rst | 22 ---------------------- 1 file changed, 22 deletions(-) diff --git a/Documentation/driver-api/io-mapping.rst b/Documentation/driver-api/io-mapping.rst index a966239..e33b882 100644 --- a/Documentation/driver-api/io-mapping.rst +++ b/Documentation/driver-api/io-mapping.rst @@ -73,25 +73,3 @@ for pages mapped with io_mapping_map_wc. At driver close time, the io_mapping object must be freed:: void io_mapping_free(struct io_mapping *mapping) - -Current Implementation -====================== - -The initial implementation of these functions uses existing mapping -mechanisms and so provides only an abstraction layer and no new -functionality. - -On 64-bit processors, io_mapping_create_wc calls ioremap_wc for the whole -range, creating a permanent kernel-visible mapping to the resource. The -map_atomic and map functions add the requested offset to the base of the -virtual address returned by ioremap_wc. - -On 32-bit processors with HIGHMEM defined, io_mapping_map_atomic_wc uses -kmap_atomic_pfn to map the specified page in an atomic fashion; -kmap_atomic_pfn isn't really supposed to be used with device pages, but it -provides an efficient mapping for this usage. - -On 32-bit processors without HIGHMEM defined, io_mapping_map_atomic_wc and -io_mapping_map_wc both use ioremap_wc, a terribly inefficient function which -performs an IPI to inform all processors about the new mapping. This results -in a significant performance penalty.