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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 0155FC43461 for ; Tue, 15 Sep 2020 06:24:12 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 0D9382076C for ; Tue, 15 Sep 2020 06:24:10 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0D9382076C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=gondor.apana.org.au Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 2A9EF90000A; Tue, 15 Sep 2020 02:24:09 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 25B496B007D; Tue, 15 Sep 2020 02:24:09 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1233890000A; Tue, 15 Sep 2020 02:24:09 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0139.hostedemail.com [216.40.44.139]) by kanga.kvack.org (Postfix) with ESMTP id F009B6B0078 for ; Tue, 15 Sep 2020 02:24:08 -0400 (EDT) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id AA205181AEF15 for ; Tue, 15 Sep 2020 06:24:08 +0000 (UTC) X-FDA: 77264305776.17.frogs63_2a096e72710f Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin17.hostedemail.com (Postfix) with ESMTP id 73EB8180D0181 for ; Tue, 15 Sep 2020 06:24:08 +0000 (UTC) X-HE-Tag: frogs63_2a096e72710f X-Filterd-Recvd-Size: 4372 Received: from fornost.hmeau.com (helcar.hmeau.com [216.24.177.18]) by imf09.hostedemail.com (Postfix) with ESMTP for ; Tue, 15 Sep 2020 06:24:07 +0000 (UTC) Received: from gwarestrin.arnor.me.apana.org.au ([192.168.0.7]) by fornost.hmeau.com with smtp (Exim 4.92 #5 (Debian)) id 1kI4Mf-0007aN-HK; Tue, 15 Sep 2020 16:22:54 +1000 Received: by gwarestrin.arnor.me.apana.org.au (sSMTP sendmail emulation); Tue, 15 Sep 2020 16:22:53 +1000 Date: Tue, 15 Sep 2020 16:22:53 +1000 From: Herbert Xu To: Ard Biesheuvel Cc: Linus Torvalds , Thomas Gleixner , LKML , linux-arch , Sebastian Andrzej Siewior , Valentin Schneider , Richard Henderson , Ivan Kokshaysky , Matt Turner , alpha , Jeff Dike , Richard Weinberger , Anton Ivanov , linux-um , Brian Cain , linux-hexagon@vger.kernel.org, Geert Uytterhoeven , linux-m68k , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , Will Deacon , Andrew Morton , Linux-MM , Ingo Molnar , Russell King , Linux ARM , Chris Zankel , Max Filippov , linux-xtensa@linux-xtensa.org, Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , David Airlie , Daniel Vetter , intel-gfx , dri-devel , "Paul E. McKenney" , Josh Triplett , Mathieu Desnoyers , Lai Jiangshan , Shuah Khan , rcu@vger.kernel.org, "open list:KERNEL SELFTEST FRAMEWORK References: <20200914204209.256266093@linutronix.de> <871rj4owfn.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-Rspamd-Queue-Id: 73EB8180D0181 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 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 Tue, Sep 15, 2020 at 09:20:59AM +0300, Ard Biesheuvel wrote: > > The documentation of kmap_atomic() states the following: > > * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap > * gives a more generic (and caching) interface. But kmap_atomic can > * be used in IRQ contexts, so in some (very limited) cases we need > * it. > > so if this is no longer accurate, perhaps we should fix it? This hasn't been accurate for at least ten years :) > But another reason I tried to avoid kmap_atomic() is that it disables > preemption unconditionally, even on 64-bit architectures where HIGHMEM > is irrelevant. So using kmap_atomic() here means that the bulk of > WireGuard packet encryption runs with preemption disabled, essentially > for legacy reasons. Agreed. We should definitely fix that. Thanks, -- Email: Herbert Xu Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt