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[209.85.167.52]) by smtp.gmail.com with ESMTPSA id m10sm1420773lfo.184.2020.09.19.12.13.17 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 19 Sep 2020 12:13:18 -0700 (PDT) Received: by mail-lf1-f52.google.com with SMTP id m5so9744068lfp.7 for ; Sat, 19 Sep 2020 12:13:17 -0700 (PDT) X-Received: by 2002:a19:8907:: with SMTP id l7mr12464193lfd.105.1600542797553; Sat, 19 Sep 2020 12:13:17 -0700 (PDT) MIME-Version: 1.0 References: <20200919091751.011116649@linutronix.de> <20200919173906.GQ32101@casper.infradead.org> In-Reply-To: <20200919173906.GQ32101@casper.infradead.org> From: Linus Torvalds Date: Sat, 19 Sep 2020 12:13:01 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [patch RFC 00/15] mm/highmem: Provide a preemptible variant of kmap_atomic & friends To: Matthew Wilcox Cc: Thomas Gleixner , LKML , linux-arch , Paul McKenney , "the arch/x86 maintainers" , Sebastian Andrzej Siewior , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , Will Deacon , Andrew Morton , Linux-MM , 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 , Ard Biesheuvel , Herbert Xu , Vineet Gupta , "open list:SYNOPSYS ARC ARCHITECTURE" , Arnd Bergmann , 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 Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Sep 19, 2020 at 10:39 AM Matthew Wilcox wrote: > > My concern with that is people might use kmap() and then pass the address > to a different task. So we need to audit the current users of kmap() > and convert any that do that into using vmap() instead. Ahh. Yes, I guess they might do that. It sounds strange, but not entirely crazy - I could imagine some "PIO thread" that does IO to a page that has been set up by somebody else using kmap(). Or similar. Linus From mboxrd@z Thu Jan 1 00:00:00 1970 From: Linus Torvalds Date: Sat, 19 Sep 2020 19:13:01 +0000 Subject: Re: [patch RFC 00/15] mm/highmem: Provide a preemptible variant of kmap_atomic & friends Message-Id: List-Id: References: <20200919091751.011116649@linutronix.de> <20200919173906.GQ32101@casper.infradead.org> In-Reply-To: <20200919173906.GQ32101@casper.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Matthew Wilcox Cc: Juri Lelli , Peter Zijlstra , Sebastian Andrzej Siewior , dri-devel , linux-mips@vger.kernel.org, Ben Segall , Max Filippov , Guo Ren , linux-sparc , Vincent Chen , Will Deacon , Ard Biesheuvel , linux-arch , Vincent Guittot , Herbert Xu , Michael Ellerman , the arch/x86 maintainers , Russell King , linux-csky@vger.kernel.org, David Airlie , Mel Gorman , "open list:SYNOPSYS ARC ARCHITECTURE" , linux-xtensa@linux-xtensa.org, Paul McKenney , intel-gfx , linuxppc-dev , Steven Rostedt , Rodrigo Vivi , Thomas Gleixner , Dietmar Eggemann , Linux ARM , Chris Zankel , Michal Simek , Thomas Bogendoerfer , Nick Hu , Linux-MM , Vineet Gupta , LKML , Arnd Bergmann , Paul Mackerras , Andrew Morton , Daniel Bristot de Oliveira , "David S. Miller" , Greentime Hu On Sat, Sep 19, 2020 at 10:39 AM Matthew Wilcox wrote: > > My concern with that is people might use kmap() and then pass the address > to a different task. So we need to audit the current users of kmap() > and convert any that do that into using vmap() instead. Ahh. Yes, I guess they might do that. It sounds strange, but not entirely crazy - I could imagine some "PIO thread" that does IO to a page that has been set up by somebody else using kmap(). Or similar. Linus 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=-3.9 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 7B599C43463 for ; Sat, 19 Sep 2020 19:19:21 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C980821741 for ; Sat, 19 Sep 2020 19:19:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="SNvzyY/D" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C980821741 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id F0E4F6B0037; Sat, 19 Sep 2020 15:19:19 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id EBE896B0055; Sat, 19 Sep 2020 15:19:19 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D8AB16B005A; Sat, 19 Sep 2020 15:19:19 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0043.hostedemail.com [216.40.44.43]) by kanga.kvack.org (Postfix) with ESMTP id C1E9F6B0037 for ; Sat, 19 Sep 2020 15:19:19 -0400 (EDT) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 8082B21E4 for ; Sat, 19 Sep 2020 19:19:19 +0000 (UTC) X-FDA: 77280774438.23.swim62_210d44827136 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin23.hostedemail.com (Postfix) with ESMTP id 5C7B837604 for ; Sat, 19 Sep 2020 19:19:19 +0000 (UTC) X-HE-Tag: swim62_210d44827136 X-Filterd-Recvd-Size: 5647 Received: from mail-lf1-f66.google.com (mail-lf1-f66.google.com [209.85.167.66]) by imf25.hostedemail.com (Postfix) with ESMTP for ; Sat, 19 Sep 2020 19:19:18 +0000 (UTC) Received: by mail-lf1-f66.google.com with SMTP id b12so9738276lfp.9 for ; Sat, 19 Sep 2020 12:19:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=10sVGN8u2TwfCpnAq/jp4iLrESxL2PzGGvVZbBHI37U=; b=SNvzyY/D28nrQ/9in1B6Dzi002SQEpeIWQ8e1hzmI9hVRDCDcHjzeJE8AlbYJKjj8B G7NnpY7h0luEeygyoDxqLDk2AWGbQCdyloo3Y9XIxWLvxZdXjZ/NeK2kaD/mL0YWoior T+0jhpZUK76WT2Sz7na41qAPiBNog2OUpnoIA= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=10sVGN8u2TwfCpnAq/jp4iLrESxL2PzGGvVZbBHI37U=; b=V2AtN239g6wBDIMK/A2Z7duwJRPzaCFrqHh7+NDspMfHC8EnpUTL46pxqB0vS2KKUM 6pyUyZDE5cM1mSCLSJVByCpoheKdtNjBFnpfKznXH4oZlUTSTBs/iq0d+BC5UFKtXC7s So2y+ZZP/TywnZhb5BUlS5zuM9cDqO9ZUtfyAnMbAzSGcoDBl8ZLQtbDgifYG4VMWXST mdC/zHCb8RcxeDT+NNJyJTNPzzPlQB687X3EV8nhWpoETDIcCj+IILuQ7+K1AbJHOsNa iNGF5iY9q4bIP05UXlxaipmH8fNu3J3IHsn+kQ/PQT6u5ptazVMM74YlRz6hYAaX2nIE BphA== X-Gm-Message-State: AOAM5316jNqctYRX9uLtxT/PXGj8W3GwOaoAvTqPCuePYpqakJC5JU4D IljS8Reg4weoAPzficB1ldPlbvtYPbtONg== X-Google-Smtp-Source: ABdhPJyu7HohBXC5fBOFMKXqnqERGmslJ0xFXgcDxGZlXEZOkfP3br9m9ElnslSmKMtSfOGgbU8maw== X-Received: by 2002:ac2:560f:: with SMTP id v15mr14531503lfd.550.1600543156841; Sat, 19 Sep 2020 12:19:16 -0700 (PDT) Received: from mail-lj1-f172.google.com (mail-lj1-f172.google.com. [209.85.208.172]) by smtp.gmail.com with ESMTPSA id t15sm1394987ljg.139.2020.09.19.12.19.16 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 19 Sep 2020 12:19:16 -0700 (PDT) Received: by mail-lj1-f172.google.com with SMTP id k25so7760378ljg.9 for ; Sat, 19 Sep 2020 12:19:16 -0700 (PDT) X-Received: by 2002:a19:8907:: with SMTP id l7mr12464193lfd.105.1600542797553; Sat, 19 Sep 2020 12:13:17 -0700 (PDT) MIME-Version: 1.0 References: <20200919091751.011116649@linutronix.de> <20200919173906.GQ32101@casper.infradead.org> In-Reply-To: <20200919173906.GQ32101@casper.infradead.org> From: Linus Torvalds Date: Sat, 19 Sep 2020 12:13:01 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [patch RFC 00/15] mm/highmem: Provide a preemptible variant of kmap_atomic & friends To: Matthew Wilcox Cc: Thomas Gleixner , LKML , linux-arch , Paul McKenney , "the arch/x86 maintainers" , Sebastian Andrzej Siewior , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , Will Deacon , Andrew Morton , Linux-MM , 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 , Ard Biesheuvel , Herbert Xu , Vineet Gupta , "open list:SYNOPSYS ARC ARCHITECTURE" , Arnd Bergmann , 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 Content-Type: text/plain; charset="UTF-8" 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, Sep 19, 2020 at 10:39 AM Matthew Wilcox wrote: > > My concern with that is people might use kmap() and then pass the address > to a different task. So we need to audit the current users of kmap() > and convert any that do that into using vmap() instead. Ahh. Yes, I guess they might do that. It sounds strange, but not entirely crazy - I could imagine some "PIO thread" that does IO to a page that has been set up by somebody else using kmap(). Or similar. 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[209.85.208.174]) by smtp.gmail.com with ESMTPSA id a192sm1396292lfd.51.2020.09.19.12.21.12 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 19 Sep 2020 12:21:12 -0700 (PDT) Received: by mail-lj1-f174.google.com with SMTP id k25so7802170ljk.0 for ; Sat, 19 Sep 2020 12:21:12 -0700 (PDT) X-Received: by 2002:a19:8907:: with SMTP id l7mr12464193lfd.105.1600542797553; Sat, 19 Sep 2020 12:13:17 -0700 (PDT) MIME-Version: 1.0 References: <20200919091751.011116649@linutronix.de> <20200919173906.GQ32101@casper.infradead.org> In-Reply-To: <20200919173906.GQ32101@casper.infradead.org> From: Linus Torvalds Date: Sat, 19 Sep 2020 12:13:01 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [patch RFC 00/15] mm/highmem: Provide a preemptible variant of kmap_atomic & friends To: Matthew Wilcox Content-Type: text/plain; charset="UTF-8" X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Juri Lelli , Peter Zijlstra , Sebastian Andrzej Siewior , Joonas Lahtinen , dri-devel , linux-mips@vger.kernel.org, Ben Segall , Max Filippov , Guo Ren , linux-sparc , Vincent Chen , Will Deacon , Ard Biesheuvel , linux-arch , Vincent Guittot , Herbert Xu , the arch/x86 maintainers , Russell King , linux-csky@vger.kernel.org, David Airlie , Mel Gorman , "open list:SYNOPSYS ARC ARCHITECTURE" , linux-xtensa@linux-xtensa.org, Paul McKenney , intel-gfx , linuxppc-dev , Steven Rostedt , Jani Nikula , Rodrigo Vivi , Thomas Gleixner , Dietmar Eggemann , Linux ARM , Chris Zankel , Michal Simek , Thomas Bogendoerfer , Nick Hu , Linux-MM , Vineet Gupta , LKML , Arnd Bergmann , Daniel Vetter , Paul Mackerras , Andrew Morton , Daniel Bristot de Oliveira , "David S. Miller" , Greentime Hu Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Sat, Sep 19, 2020 at 10:39 AM Matthew Wilcox wrote: > > My concern with that is people might use kmap() and then pass the address > to a different task. So we need to audit the current users of kmap() > and convert any that do that into using vmap() instead. Ahh. Yes, I guess they might do that. It sounds strange, but not entirely crazy - I could imagine some "PIO thread" that does IO to a page that has been set up by somebody else using kmap(). Or similar. Linus 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=-6.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 BDE4FC43464 for ; Sat, 19 Sep 2020 19:20:30 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 553692075E for ; Sat, 19 Sep 2020 19:20:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="h/OtbMih"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="SNvzyY/D" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 553692075E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-snps-arc-bounces+linux-snps-arc=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:To:Subject:Message-ID:Date:From:In-Reply-To: References:MIME-Version:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=YL7nbrYqH8ZqpL3eE6A64UXeq0x/QW1RJ5GjZjwb5hQ=; b=h/OtbMih2hFkXG43+18/FKbR+ 8GtCHWkbzEJu1bV9MtIAlvZA5NCWY7BBnPF/6EAOgpvxrxcIqVX2DgT+4ZulhP7fwxM2WYAW7VOqW uTnRxFVpBN7fiRk3eLinZRDd96L+9+ZCSx7vKckXiKGbP3ELXU7HcefAUpNWLi5bXRIc2gk8kJr0+ zVK8YilGKfms5Yo2c3NKFQF6tLumuvcJuH8cjW5YUd9SdyIFvRubDHwtQ8WBaih0L9asjJk2zc2vf VSDbvIgG8MtWtvoUifjs+22LqaVoQoGqSsH3hZf6xqM2l88a+sxPW1QpLb7VZzbFRh+cYhq8VWThH 5XGnpp5Eg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kJiPN-0002b2-E5; Sat, 19 Sep 2020 19:20:29 +0000 Received: from mail-ed1-x541.google.com ([2a00:1450:4864:20::541]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kJiPL-0002aZ-JP for linux-snps-arc@lists.infradead.org; Sat, 19 Sep 2020 19:20:28 +0000 Received: by mail-ed1-x541.google.com with SMTP id ay8so9149901edb.8 for ; Sat, 19 Sep 2020 12:20:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=10sVGN8u2TwfCpnAq/jp4iLrESxL2PzGGvVZbBHI37U=; b=SNvzyY/D28nrQ/9in1B6Dzi002SQEpeIWQ8e1hzmI9hVRDCDcHjzeJE8AlbYJKjj8B G7NnpY7h0luEeygyoDxqLDk2AWGbQCdyloo3Y9XIxWLvxZdXjZ/NeK2kaD/mL0YWoior T+0jhpZUK76WT2Sz7na41qAPiBNog2OUpnoIA= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=10sVGN8u2TwfCpnAq/jp4iLrESxL2PzGGvVZbBHI37U=; b=qwbmn0LyCJG1BRjNT6H2E/m87BdX0nyX+3v2UTLrI4PojP2dF4UJ06NdBYXQJrgGrl 5zSUV+9cpfDNYsUQ8ClJ/LBqcvdbX56BARlSFGgawhB4XxcDTsKwT8Py1rEIBvjJ1tXU mUWaTjoPytQZJI0HatWSAB/A7PgNIiQzpIr8qAIUQzjk9VxillmigeDuheIEdedj8779 F1j1xmcvKz18rWEV4pBJX8JHbZbwbxCkWh3CkdtI4h6Q8P26w2SJm1SyE3Xq+O/RrDfD /G4JDopk6ihelq77sWE2awkfePxhq4xqb2dnebCK54LS2tP86jkHq1pxMrhuo+rYjT2U 3nJg== X-Gm-Message-State: AOAM531VbNOwn6PA3zCwRAWs3v1xIcKFlnGwRdS/GV2a4SBUI4EawQXy Wmv9VJjQ0O9WCzKoMbO8fpeETSk3SB1K+Q== X-Google-Smtp-Source: ABdhPJyQ/5M2N6PLGTkKkjJGc7QlxeqssiFgrsFlTsbLHUtyg7Pyu2+74qq4cFbHKoMEWs47BkCJPQ== X-Received: by 2002:aa7:d88a:: with SMTP id u10mr45216868edq.217.1600543226265; Sat, 19 Sep 2020 12:20:26 -0700 (PDT) Received: from mail-ed1-f53.google.com (mail-ed1-f53.google.com. [209.85.208.53]) by smtp.gmail.com with ESMTPSA id x6sm4965558ejf.59.2020.09.19.12.20.25 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 19 Sep 2020 12:20:26 -0700 (PDT) Received: by mail-ed1-f53.google.com with SMTP id l17so9113383edq.12 for ; Sat, 19 Sep 2020 12:20:25 -0700 (PDT) X-Received: by 2002:a19:8907:: with SMTP id l7mr12464193lfd.105.1600542797553; Sat, 19 Sep 2020 12:13:17 -0700 (PDT) MIME-Version: 1.0 References: <20200919091751.011116649@linutronix.de> <20200919173906.GQ32101@casper.infradead.org> In-Reply-To: <20200919173906.GQ32101@casper.infradead.org> From: Linus Torvalds Date: Sat, 19 Sep 2020 12:13:01 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [patch RFC 00/15] mm/highmem: Provide a preemptible variant of kmap_atomic & friends To: Matthew Wilcox X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200919_152027_652258_BABA84D9 X-CRM114-Status: GOOD ( 16.41 ) X-BeenThere: linux-snps-arc@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on Synopsys ARC Processors List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Juri Lelli , Peter Zijlstra , Benjamin Herrenschmidt , Sebastian Andrzej Siewior , Joonas Lahtinen , dri-devel , linux-mips@vger.kernel.org, Ben Segall , Max Filippov , Guo Ren , linux-sparc , Vincent Chen , Will Deacon , Ard Biesheuvel , linux-arch , Vincent Guittot , Herbert Xu , Michael Ellerman , the arch/x86 maintainers , Russell King , linux-csky@vger.kernel.org, David Airlie , Mel Gorman , "open list:SYNOPSYS ARC ARCHITECTURE" , linux-xtensa@linux-xtensa.org, Paul McKenney , intel-gfx , linuxppc-dev , Steven Rostedt , Jani Nikula , Rodrigo Vivi , Thomas Gleixner , Dietmar Eggemann , Linux ARM , Chris Zankel , Michal Simek , Thomas Bogendoerfer , Nick Hu , Linux-MM , Vineet Gupta , LKML , Arnd Bergmann , Daniel Vetter , Paul Mackerras , Andrew Morton , Daniel Bristot de Oliveira , "David S. Miller" , Greentime Hu Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-snps-arc" Errors-To: linux-snps-arc-bounces+linux-snps-arc=archiver.kernel.org@lists.infradead.org On Sat, Sep 19, 2020 at 10:39 AM Matthew Wilcox wrote: > > My concern with that is people might use kmap() and then pass the address > to a different task. So we need to audit the current users of kmap() > and convert any that do that into using vmap() instead. Ahh. Yes, I guess they might do that. It sounds strange, but not entirely crazy - I could imagine some "PIO thread" that does IO to a page that has been set up by somebody else using kmap(). Or similar. Linus _______________________________________________ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc 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=-6.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 7110AC43464 for ; Sat, 19 Sep 2020 19:21:11 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 15EA121707 for ; Sat, 19 Sep 2020 19:21:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="NMB0pNZj"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="SNvzyY/D" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 15EA121707 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:To:Subject:Message-ID:Date:From:In-Reply-To: References:MIME-Version:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=LufrEiR2csfxer3mkxOak+LBj3Gn/mvIx0DdFjbfZHk=; b=NMB0pNZjHSjexLHYXbXpYuwXa 8TrxROZMEfTXyr6i6GkySEoGTgPEYS4YC/eqZSAmup7H3BMFg8pvspmHaNIleru47bpQrQ0st4ldv icxKAtlCQtDmdomMkmsQl6OZmT1jg2q/l8Y5sfyQcouu4u/FUx2p00zE76WvG3Jl19Sjm6dyiNFYF wR14TW+W1AjSnh3ull/oWia+a0tH28ntnsD83nF6BZQlPSL4E/Bn81a4AVa51p0D5306zdHQmzf1n xwt/IoFxctqpNP0o7UixXKvW78OGBDrW3kmy+ARUTfenKk+dV/GdxNsWOGqdNzPdc5VYJhqqV56W+ XZw4MQyhA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kJiOY-0002VY-ED; Sat, 19 Sep 2020 19:19:38 +0000 Received: from mail-ej1-x644.google.com ([2a00:1450:4864:20::644]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kJiOV-0002V8-79 for linux-arm-kernel@lists.infradead.org; Sat, 19 Sep 2020 19:19:36 +0000 Received: by mail-ej1-x644.google.com with SMTP id gr14so12539293ejb.1 for ; Sat, 19 Sep 2020 12:19:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=10sVGN8u2TwfCpnAq/jp4iLrESxL2PzGGvVZbBHI37U=; b=SNvzyY/D28nrQ/9in1B6Dzi002SQEpeIWQ8e1hzmI9hVRDCDcHjzeJE8AlbYJKjj8B G7NnpY7h0luEeygyoDxqLDk2AWGbQCdyloo3Y9XIxWLvxZdXjZ/NeK2kaD/mL0YWoior T+0jhpZUK76WT2Sz7na41qAPiBNog2OUpnoIA= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=10sVGN8u2TwfCpnAq/jp4iLrESxL2PzGGvVZbBHI37U=; b=ebAWTGPgFGko14EtodcJPuE0OKfBy/9DP4Q/QfkfYI3lrAdm9Vk7AkOi/h3fcGsS/b 3bvOh/BvpnlM5JyNGioQqO4Wgsp0eVg+NJrDXn5ysXixSRmR2YYGWUSynLDXduuOleH+ 5my7+Yrv7snIuqm/Kcz+C+k0S1Om/OvB/NlpHrK3nxYoKmJwro1Bg9tltFBaINjdYuHs EzeA0WiPyGXPy67FnZvXZ8CnJGnkBGQUFqvMPS4aSWCz7V1HaYPTaS9xALPyl8hDCLTX X+LGI51Hx0Ys3CzpkYMcwumlsZXyZ1WShRx93qCZ+s+YfhPcnLPX+2hywyMSFZ7iXnyW WWyg== X-Gm-Message-State: AOAM531PS8UUW+Q1gaRjU5ILWWe18osE6hp2Qfj87akoVJZtIxVf7q0G yhWGlbOA7tdGxbw59OrqFuddLtt7hUDqgw== X-Google-Smtp-Source: ABdhPJxa0/o2O1Os362xLRRqq1gRgpeGrppcLFm8LqVNZJsNPEWdZLZxITcsj7vX2beBw6la1FQh+Q== X-Received: by 2002:a17:906:cf9b:: with SMTP id um27mr42444708ejb.66.1600543173822; Sat, 19 Sep 2020 12:19:33 -0700 (PDT) Received: from mail-ed1-f52.google.com (mail-ed1-f52.google.com. [209.85.208.52]) by smtp.gmail.com with ESMTPSA id w10sm5123394ejv.44.2020.09.19.12.19.33 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 19 Sep 2020 12:19:33 -0700 (PDT) Received: by mail-ed1-f52.google.com with SMTP id i1so9233867edv.2 for ; Sat, 19 Sep 2020 12:19:33 -0700 (PDT) X-Received: by 2002:a19:8907:: with SMTP id l7mr12464193lfd.105.1600542797553; Sat, 19 Sep 2020 12:13:17 -0700 (PDT) MIME-Version: 1.0 References: <20200919091751.011116649@linutronix.de> <20200919173906.GQ32101@casper.infradead.org> In-Reply-To: <20200919173906.GQ32101@casper.infradead.org> From: Linus Torvalds Date: Sat, 19 Sep 2020 12:13:01 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [patch RFC 00/15] mm/highmem: Provide a preemptible variant of kmap_atomic & friends To: Matthew Wilcox X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200919_151935_325295_D8B918C6 X-CRM114-Status: GOOD ( 17.94 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Juri Lelli , Peter Zijlstra , Benjamin Herrenschmidt , Sebastian Andrzej Siewior , Joonas Lahtinen , dri-devel , linux-mips@vger.kernel.org, Ben Segall , Max Filippov , Guo Ren , linux-sparc , Vincent Chen , Will Deacon , Ard Biesheuvel , linux-arch , Vincent Guittot , Herbert Xu , Michael Ellerman , the arch/x86 maintainers , Russell King , linux-csky@vger.kernel.org, David Airlie , Mel Gorman , "open list:SYNOPSYS ARC ARCHITECTURE" , linux-xtensa@linux-xtensa.org, Paul McKenney , intel-gfx , linuxppc-dev , Steven Rostedt , Jani Nikula , Rodrigo Vivi , Thomas Gleixner , Dietmar Eggemann , Linux ARM , Chris Zankel , Michal Simek , Thomas Bogendoerfer , Nick Hu , Linux-MM , Vineet Gupta , LKML , Arnd Bergmann , Daniel Vetter , Paul Mackerras , Andrew Morton , Daniel Bristot de Oliveira , "David S. Miller" , Greentime Hu Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Sat, Sep 19, 2020 at 10:39 AM Matthew Wilcox wrote: > > My concern with that is people might use kmap() and then pass the address > to a different task. So we need to audit the current users of kmap() > and convert any that do that into using vmap() instead. Ahh. Yes, I guess they might do that. It sounds strange, but not entirely crazy - I could imagine some "PIO thread" that does IO to a page that has been set up by somebody else using kmap(). Or similar. Linus _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel 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=-3.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 50EF9C43463 for ; Sat, 19 Sep 2020 19:21:11 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C78E42075E for ; Sat, 19 Sep 2020 19:21:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="SNvzyY/D" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C78E42075E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 0566489FAD; Sat, 19 Sep 2020 19:21:09 +0000 (UTC) Received: from mail-ed1-x543.google.com (mail-ed1-x543.google.com [IPv6:2a00:1450:4864:20::543]) by gabe.freedesktop.org (Postfix) with ESMTPS id B7BCC6E497 for ; Sat, 19 Sep 2020 19:19:57 +0000 (UTC) Received: by mail-ed1-x543.google.com with SMTP id w1so9202096edr.3 for ; Sat, 19 Sep 2020 12:19:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=10sVGN8u2TwfCpnAq/jp4iLrESxL2PzGGvVZbBHI37U=; b=SNvzyY/D28nrQ/9in1B6Dzi002SQEpeIWQ8e1hzmI9hVRDCDcHjzeJE8AlbYJKjj8B G7NnpY7h0luEeygyoDxqLDk2AWGbQCdyloo3Y9XIxWLvxZdXjZ/NeK2kaD/mL0YWoior T+0jhpZUK76WT2Sz7na41qAPiBNog2OUpnoIA= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=10sVGN8u2TwfCpnAq/jp4iLrESxL2PzGGvVZbBHI37U=; b=DiWacpqOLl+ntMlPP1+EN8P1DyneoPNiR5U+sZPjVTYlBxvgV5JFBKcrW0NbplC8/x X7YI/RknLtSfph5T7Y8N0bihp+5m2r2/br7vLi24Lg/jE/ZKCrFtyZ7EH+fO60QKc3Y0 xRg5iOrGxPvijfI/lRkXekIj6F53+Nak8LPzwyQfcFQdL1JONDOe6e8/rtEL6djy2z/t Mgz0R5E0GzQLTUV6NwBEktiqLNsBQdDNToUrrTGFxg9w3AftNFD1HE5pY/4PE2S4j8Of MnGPzjB1kGQXH+AshNYE5e2qsQyLAEB7n1AvOCinh/mahRBuQDFmkPviphNWpPcxkJHW Tggw== X-Gm-Message-State: AOAM53145LHStwdWRrgoFNaQ9HTi82uLFqRyOZx1IbzejyO+5GW8IiXW k2x6/VWMBY7sO2zB+FyPZvCPOqPNs8cNUQ== X-Google-Smtp-Source: ABdhPJwh1cggiU3buvhecGfg6fTR1avn4YBf8KKtjRIepoVgC5Ja45xbzhi5oOBFO70nhS1O1aTUjQ== X-Received: by 2002:aa7:d981:: with SMTP id u1mr43873444eds.250.1600543196135; Sat, 19 Sep 2020 12:19:56 -0700 (PDT) Received: from mail-wr1-f44.google.com (mail-wr1-f44.google.com. [209.85.221.44]) by smtp.gmail.com with ESMTPSA id p17sm4907352ejw.125.2020.09.19.12.19.55 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 19 Sep 2020 12:19:55 -0700 (PDT) Received: by mail-wr1-f44.google.com with SMTP id c18so8826241wrm.9 for ; Sat, 19 Sep 2020 12:19:55 -0700 (PDT) X-Received: by 2002:a19:8907:: with SMTP id l7mr12464193lfd.105.1600542797553; Sat, 19 Sep 2020 12:13:17 -0700 (PDT) MIME-Version: 1.0 References: <20200919091751.011116649@linutronix.de> <20200919173906.GQ32101@casper.infradead.org> In-Reply-To: <20200919173906.GQ32101@casper.infradead.org> From: Linus Torvalds Date: Sat, 19 Sep 2020 12:13:01 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [patch RFC 00/15] mm/highmem: Provide a preemptible variant of kmap_atomic & friends To: Matthew Wilcox X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Juri Lelli , Peter Zijlstra , Sebastian Andrzej Siewior , dri-devel , linux-mips@vger.kernel.org, Ben Segall , Max Filippov , Guo Ren , linux-sparc , Vincent Chen , Will Deacon , Ard Biesheuvel , linux-arch , Vincent Guittot , Herbert Xu , Michael Ellerman , the arch/x86 maintainers , Russell King , linux-csky@vger.kernel.org, David Airlie , Mel Gorman , "open list:SYNOPSYS ARC ARCHITECTURE" , linux-xtensa@linux-xtensa.org, Paul McKenney , intel-gfx , linuxppc-dev , Steven Rostedt , Rodrigo Vivi , Thomas Gleixner , Dietmar Eggemann , Linux ARM , Chris Zankel , Michal Simek , Thomas Bogendoerfer , Nick Hu , Linux-MM , Vineet Gupta , LKML , Arnd Bergmann , Paul Mackerras , Andrew Morton , Daniel Bristot de Oliveira , "David S. Miller" , Greentime Hu Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Sat, Sep 19, 2020 at 10:39 AM Matthew Wilcox wrote: > > My concern with that is people might use kmap() and then pass the address > to a different task. So we need to audit the current users of kmap() > and convert any that do that into using vmap() instead. Ahh. Yes, I guess they might do that. It sounds strange, but not entirely crazy - I could imagine some "PIO thread" that does IO to a page that has been set up by somebody else using kmap(). Or similar. Linus _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel 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=-3.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 F41B8C43463 for ; Sat, 19 Sep 2020 19:13:24 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A52F02158C for ; Sat, 19 Sep 2020 19:13:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="SNvzyY/D" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A52F02158C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id D42F96E04A; Sat, 19 Sep 2020 19:13:23 +0000 (UTC) Received: from mail-ej1-x641.google.com (mail-ej1-x641.google.com [IPv6:2a00:1450:4864:20::641]) by gabe.freedesktop.org (Postfix) with ESMTPS id 192EA6E04A for ; Sat, 19 Sep 2020 19:13:22 +0000 (UTC) Received: by mail-ej1-x641.google.com with SMTP id gx22so3419807ejb.5 for ; Sat, 19 Sep 2020 12:13:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=10sVGN8u2TwfCpnAq/jp4iLrESxL2PzGGvVZbBHI37U=; b=SNvzyY/D28nrQ/9in1B6Dzi002SQEpeIWQ8e1hzmI9hVRDCDcHjzeJE8AlbYJKjj8B G7NnpY7h0luEeygyoDxqLDk2AWGbQCdyloo3Y9XIxWLvxZdXjZ/NeK2kaD/mL0YWoior T+0jhpZUK76WT2Sz7na41qAPiBNog2OUpnoIA= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=10sVGN8u2TwfCpnAq/jp4iLrESxL2PzGGvVZbBHI37U=; b=Tj8ZOlCgGB3Kt8TbKTOt2rh6wwBmljTMQ1KQ+6kmhO3PUSorEuQnfPRxAe8NRhHQZa HZJqb1aErQJ9ok3GoH+pToC3fD/+aiQRjQWKADgye2vaPiZ8zPwM/sWpb/QsiusYgCAb SjMmVSA/VSNc5THvJOoV+Ct8dwqjBK6p0TUtW2v7CwyRguXGRoS0MO2U+Y84UN6lk3+H 3ZAY3qaMNIrk0CxKQ5+cOpbhr6vx6emvwI9sdV+1ZmrOBmdV7dROnq8ACe3OdEGWZ0vo UtYXNeaPSHu0RK3Hth0LnBlABwbfrlLaP3ZuxtCJtA79zSoChI6T+hb9g7nRxcefvQIf Ge9A== X-Gm-Message-State: AOAM532Uu9gH4tvJUR6KWCSbhB/HJ3tZFYXrbjjAf/p5Nc+lC+XDJO5y NU3waf3ON38bIALOyRROaFDPBcH20dGoUg== X-Google-Smtp-Source: ABdhPJy9m/ABd1NrV+op2OlgtJpCFBVT6XpeKULPj8CHw7n62Jx//0cPPz00DHNpmQJ2MSj6W8O8rw== X-Received: by 2002:a17:906:c1d2:: with SMTP id bw18mr43276023ejb.240.1600542800220; Sat, 19 Sep 2020 12:13:20 -0700 (PDT) Received: from mail-ej1-f54.google.com (mail-ej1-f54.google.com. [209.85.218.54]) by smtp.gmail.com with ESMTPSA id ef3sm4999519ejb.114.2020.09.19.12.13.18 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 19 Sep 2020 12:13:18 -0700 (PDT) Received: by mail-ej1-f54.google.com with SMTP id o8so12434909ejb.10 for ; Sat, 19 Sep 2020 12:13:18 -0700 (PDT) X-Received: by 2002:a19:8907:: with SMTP id l7mr12464193lfd.105.1600542797553; Sat, 19 Sep 2020 12:13:17 -0700 (PDT) MIME-Version: 1.0 References: <20200919091751.011116649@linutronix.de> <20200919173906.GQ32101@casper.infradead.org> In-Reply-To: <20200919173906.GQ32101@casper.infradead.org> From: Linus Torvalds Date: Sat, 19 Sep 2020 12:13:01 -0700 X-Gmail-Original-Message-ID: Message-ID: To: Matthew Wilcox Subject: Re: [Intel-gfx] [patch RFC 00/15] mm/highmem: Provide a preemptible variant of kmap_atomic & friends X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Juri Lelli , Peter Zijlstra , Benjamin Herrenschmidt , Sebastian Andrzej Siewior , dri-devel , linux-mips@vger.kernel.org, Ben Segall , Max Filippov , Guo Ren , linux-sparc , Vincent Chen , Will Deacon , Ard Biesheuvel , linux-arch , Herbert Xu , Michael Ellerman , the arch/x86 maintainers , Russell King , linux-csky@vger.kernel.org, David Airlie , Mel Gorman , "open list:SYNOPSYS ARC ARCHITECTURE" , linux-xtensa@linux-xtensa.org, Paul McKenney , intel-gfx , linuxppc-dev , Steven Rostedt , Thomas Gleixner , Dietmar Eggemann , Linux ARM , Chris Zankel , Michal Simek , Thomas Bogendoerfer , Nick Hu , Linux-MM , Vineet Gupta , LKML , Arnd Bergmann , Paul Mackerras , Andrew Morton , Daniel Bristot de Oliveira , "David S. Miller" , Greentime Hu Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Sat, Sep 19, 2020 at 10:39 AM Matthew Wilcox wrote: > > My concern with that is people might use kmap() and then pass the address > to a different task. So we need to audit the current users of kmap() > and convert any that do that into using vmap() instead. Ahh. Yes, I guess they might do that. It sounds strange, but not entirely crazy - I could imagine some "PIO thread" that does IO to a page that has been set up by somebody else using kmap(). Or similar. Linus _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx