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=-3.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 81679C388F9 for ; Fri, 30 Oct 2020 23:53:08 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C0A0C2071E for ; Fri, 30 Oct 2020 23:53:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="zRWoFFCv"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="KMZe+VR6" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C0A0C2071E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linutronix.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 20AF86B0036; Fri, 30 Oct 2020 19:53:07 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 1BC526B005C; Fri, 30 Oct 2020 19:53:07 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 081F36B005D; Fri, 30 Oct 2020 19:53:06 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0198.hostedemail.com [216.40.44.198]) by kanga.kvack.org (Postfix) with ESMTP id C71666B0036 for ; Fri, 30 Oct 2020 19:53:06 -0400 (EDT) Received: from smtpin10.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 6C9E61F1B for ; Fri, 30 Oct 2020 23:53:06 +0000 (UTC) X-FDA: 77430245172.10.cork05_1604e662729a Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin10.hostedemail.com (Postfix) with ESMTP id 5971216A4A9 for ; Fri, 30 Oct 2020 23:53:06 +0000 (UTC) X-HE-Tag: cork05_1604e662729a X-Filterd-Recvd-Size: 5039 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by imf46.hostedemail.com (Postfix) with ESMTP for ; Fri, 30 Oct 2020 23:53:05 +0000 (UTC) From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1604101982; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=fz1Lo4xloh2gm7jGRA98jpsF7G0W8WZ1zm340/bMNFg=; b=zRWoFFCvgFXvkgiRgd2PrNXxw0olM8jN9MbSlnu8Yx/bkkIwLGoWTGgE5i+fkO7y7sfeaU x3+aPSzi0iAtwo1vhwTgPleVK5/xOYWH8N2RRruBT8TdPfY1yZYoa6ljibdSog6RQ3gP6b u9DvoOLBFkfo24RQ7jamXSeMyTSj793ZoUFCoaa1YGqH033ahp/DnCR4xlXAoXzFSpH1x6 yOJ/OV0er2B/4NNw+gN17a5j9W4zYUWj6YivuiRxMsRVquNHl+BF1GTYOstjhD+cwgQEKq s06u8I7IY1uEbPndJCEK7r6MHG28vjegHSi8SyClVAIgl5+Ri/+FYGlgYb5bjQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1604101982; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=fz1Lo4xloh2gm7jGRA98jpsF7G0W8WZ1zm340/bMNFg=; b=KMZe+VR6xvtTrU+cGlKn5VqvqFkwQoQ6BREOoFpj295prEyjjry9cru4z4uwe8nMiBCbyb 2nsiSuFASxudGAAw== To: Linus Torvalds Cc: LKML , linux-arch , Peter Zijlstra , Paul McKenney , David Airlie , Daniel Vetter , Ard Biesheuvel , Herbert Xu , Christoph Hellwig , Sebastian Andrzej Siewior , Ingo Molnar , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , Andrew Morton , Linux-MM , the arch/x86 maintainers , Vineet Gupta , "open list\:SYNOPSYS ARC ARCHITECTURE" , Russell King , Arnd Bergmann , Linux ARM , Guo Ren , linux-csky@vger.kernel.org, Michal Simek , Thomas Bogendoerfer , linux-mips@vger.kernel.org, Nick Hu , Greentime Hu , Vincent Chen , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , linuxppc-dev , "David S. Miller" , linux-sparc , Chris Zankel , Max Filippov , linux-xtensa@linux-xtensa.org, Matthew Wilcox Subject: Re: [patch V2 00/18] mm/highmem: Preemptible variant of kmap_atomic & friends In-Reply-To: <87pn4zl2ia.fsf@nanos.tec.linutronix.de> References: <20201029221806.189523375@linutronix.de> <87pn50ob0s.fsf@nanos.tec.linutronix.de> <87blgknjcw.fsf@nanos.tec.linutronix.de> <87sg9vl59i.fsf@nanos.tec.linutronix.de> <87pn4zl2ia.fsf@nanos.tec.linutronix.de> Date: Sat, 31 Oct 2020 00:53:02 +0100 Message-ID: <87mu03l19d.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain 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: On Sat, Oct 31 2020 at 00:26, Thomas Gleixner wrote: > On Fri, Oct 30 2020 at 15:46, Linus Torvalds wrote: >> On Fri, Oct 30, 2020 at 3:26 PM Thomas Gleixner wrote: >> To me, your patch series has two big advantages: >> >> - more common code >> >> - kmap_local() becomes more of a no-op >> >> and the last thing we want is to expand on kmap. > > Happy to go with that. > > While trying to document the mess, I just stumbled over the abuse of > kmap_atomic_prot() in > > drivers/gpu/drm/ttm/ttm_bo_util.c: dst = kmap_atomic_prot(d, prot); > drivers/gpu/drm/ttm/ttm_bo_util.c: src = kmap_atomic_prot(s, prot); > drivers/gpu/drm/vmwgfx/vmwgfx_blit.c: kmap_atomic_prot(d->dst_pages[dst_page], > drivers/gpu/drm/vmwgfx/vmwgfx_blit.c: kmap_atomic_prot(d->src_pages[src_page], > > For !HIGHMEM kmap_atomic_prot() just ignores the 'prot' argument and > returns the page address. > > Moar patches to be written ... Sigh! Or not. This is actually correct by some definition of correct. For the non highmem case pgprot is set via the set_memory_*() functions and this just handles the highmem case. Comments are overrrated...