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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 89B7BC3601E for ; Thu, 10 Apr 2025 07:28:51 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id BB4572800AE; Thu, 10 Apr 2025 03:28:49 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B62202800AB; Thu, 10 Apr 2025 03:28:49 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A76FA2800AE; Thu, 10 Apr 2025 03:28:49 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 89C7B2800AB for ; Thu, 10 Apr 2025 03:28:49 -0400 (EDT) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 04530B9370 for ; Thu, 10 Apr 2025 07:28:49 +0000 (UTC) X-FDA: 83317307220.06.A595AD4 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf06.hostedemail.com (Postfix) with ESMTP id CB69C18000B for ; Thu, 10 Apr 2025 07:28:47 +0000 (UTC) Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b=3T5OHHOO; spf=none (imf06.hostedemail.com: domain of BATV+8af77f6ab8959e5caacb+7900+infradead.org+hch@bombadil.srs.infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=BATV+8af77f6ab8959e5caacb+7900+infradead.org+hch@bombadil.srs.infradead.org; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1744270128; h=from:from:sender: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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=5tt9Vmj5QLstTl76VcOwF5BGity5lMjGCb09kYesARo=; b=xaPf3Mv7Zhiih6nBI5p/a16RtRLUuwmFI/Exj/x5coERBo0VNCWPfZNYuG9D6tdJerFV2n fpfLVvCcCNRNpugDYpHwC9lUVK6hG3DohPLXNWhnxAqihr08kIy5pCVjwY51AjM7Ya+QjH 7effh4yGVAsfKpnZhaLmLodMLaoyXVg= ARC-Authentication-Results: i=1; imf06.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b=3T5OHHOO; spf=none (imf06.hostedemail.com: domain of BATV+8af77f6ab8959e5caacb+7900+infradead.org+hch@bombadil.srs.infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=BATV+8af77f6ab8959e5caacb+7900+infradead.org+hch@bombadil.srs.infradead.org; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1744270128; a=rsa-sha256; cv=none; b=m/MLlV/nitFunRDgloScsPNyZ9/Ps1GSnKBZHUMbNJyn1iVxyGeL0B0UOHLcsFtAGIGo+H XH1zUlWYyC606X7yGm9hPo5pORpI8WENyguL1YXK2wvxyFZnCxjDTeCqYiFCO/EOYOAGlw 77Hv2arHjKP8XPs6YXj64SLx9821vqU= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=5tt9Vmj5QLstTl76VcOwF5BGity5lMjGCb09kYesARo=; b=3T5OHHOOK9cc9iZBZ8i+YC++qO mKr6F6kzGiruNP4epYruf2pI5VVqgZBRiPxn2HjMz8kCqy0VQIFQgJDAC9XI9cKi+DMpCiw08BsT1 I8L1fs/0GnC0tzcvSHFq8hHgOaR5Cbo1Y7vy3Ra+y61sDpyM1N50f+S+OIRNyCaMEKbTdJLg4Ou2Q jM9yIbBYxduo5KDNexctT9STlcNQ8KpkzYk2hPbtySn2npJaIo5/NitTTUTTLlxyLJsaO1rPihaxr snlqoObUDKYhQMNSKp+Js2XtVy/ZSqDSyIg2VI4N8Uf68UVdUzR4ZWvE+NkMGd7KUxoQscpQEhOaO TyEV6UmA==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1u2mL3-00000009YVs-3fr3; Thu, 10 Apr 2025 07:28:42 +0000 Date: Thu, 10 Apr 2025 00:28:41 -0700 From: Christoph Hellwig To: John Hubbard Cc: David Hildenbrand , David Howells , "Kirill A. Shutemov" , willy@infradead.org, linux-mm@kvack.org, Jens Axboe , linux-block@vger.kernel.org Subject: Re: Does GUP page unpinning have to be done in the pinning context? Message-ID: References: <939183.1743762009@warthog.procyon.org.uk> <67d4486b-658e-4f3f-9a67-8785616e6905@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: CB69C18000B X-Stat-Signature: n5gu1kacb491d3cbqqjkfou9aqkfbbct X-HE-Tag: 1744270127-353669 X-HE-Meta: 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 zepOctPx 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000010, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Apr 09, 2025 at 07:56:07PM -0700, John Hubbard wrote: > This topic always worries me, because the original problem with > dirty pages is still unfixed: setting pages dirty upon unpinning > is both widely done (last time I checked), and yet broken, because > it doesn't do a mkdirty() call to set up writeback buffers. > > The solution always seemed to point toward "get a file lease on that > range, before pinning", but it's a contentious design area to say > the least. For the bio based direct I/O implementations we do set the pages dirty before starting I/O using bio_set_pages_dirty, which uses folio_mark_dirty and thus calls into the file systems using ->dirty_folio. But we also do a second pass on I/O completion before the buffers are unpinned. Which I think now that we pin the folios is superfluous.