From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 79690331225 for ; Fri, 19 Dec 2025 12:06:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766145982; cv=none; b=MvypkQoS/Q00qTXnmHF5+GDltuLZrC/gntLaR7c5TJAlGiDJaUPtkBv7zaOCxaESC/MKWJvGHcb5ETxRLXvnS8FdwdqGlQj/plS4yhznCOSN3cZQj/qz6HUO2UTcJE4q8SG3lKnoQNB94G59wx9oSCcAYZrDHIjVcfNGY1Fseuo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766145982; c=relaxed/simple; bh=ICSw1Gb+bvlIImpGJ6ZaLP+dJBt9YGwUwZB2tO44IAk=; h=From:In-Reply-To:References:To:Cc:Subject:MIME-Version: Content-Type:Date:Message-ID; b=XO11PE5+Nr3hH1W3iPWvLCRlEmWLPpLZFEitHkFLJBqT0s2JsKjophf7u0YppbTK3V1qRjarAZEfp9WZ3AGrAJIm6IopCpP1V3zh9qA0ExHJ5zZjz2EIhktUWJmkZ8y5KnmLlZLf3N0Rku3reJxwZP8E6Kh46n4bY6ydAnJb2AU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=LxhO3EBc; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="LxhO3EBc" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1766145978; 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=Ar0CUvCqBxXAgp51z8oF+97RLBA8Nure7aZEO7TfKZ8=; b=LxhO3EBcO5xkmt6VLyAfl8avzMXF+OBBTPesCqV8hkFGpJCbvsAbppUIO0EEqJGErljn4p +38sWAD8xvYp/vNH0G4BoFnv6Yj86uWsm6G/nOChvdowlMSyj+l08KXzyDNgE+1SqcjQSI TCFBoKs3zp+BXLnhPogODzPhrQw+gLY= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-281-YpIytl2-OUupyr-e949haA-1; Fri, 19 Dec 2025 07:06:15 -0500 X-MC-Unique: YpIytl2-OUupyr-e949haA-1 X-Mimecast-MFC-AGG-ID: YpIytl2-OUupyr-e949haA_1766145973 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id CACAD1956046; Fri, 19 Dec 2025 12:06:12 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.42.28.5]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 325EA194C65A; Fri, 19 Dec 2025 12:06:10 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <2332946.iZASKD2KPV@weasel> References: <2332946.iZASKD2KPV@weasel> <20251210-virtio_trans_iter-v1-1-92eee6d8b6db@codewreck.org> To: Christian Schoenebeck Cc: dhowells@redhat.com, Eric Van Hensbergen , Latchesar Ionkov , asmadeus@codewreck.org, Chris Arges , v9fs@lists.linux.dev, linux-kernel@vger.kernel.org, Matthew Wilcox , linux-fsdevel@vger.kernel.org Subject: Re: [PATCH] 9p/virtio: restrict page pinning to user_backed_iter() iovec Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <815150.1766145968.1@warthog.procyon.org.uk> Date: Fri, 19 Dec 2025 12:06:08 +0000 Message-ID: <815151.1766145968@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Christian Schoenebeck wrote: > > - if (!iov_iter_is_kvec(data)) { > > + if (user_backed_iter(data)) { That looks wrong. If the I/O is coming through netfslib, you should never see ITER_UBUF or ITER_IOVEC in the filesystem. David