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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 27A77C433F5 for ; Thu, 10 Feb 2022 19:17:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343868AbiBJTRb (ORCPT ); Thu, 10 Feb 2022 14:17:31 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:51962 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343850AbiBJTR3 (ORCPT ); Thu, 10 Feb 2022 14:17:29 -0500 Received: from mail-pl1-x631.google.com (mail-pl1-x631.google.com [IPv6:2607:f8b0:4864:20::631]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3E682101C for ; Thu, 10 Feb 2022 11:17:30 -0800 (PST) Received: by mail-pl1-x631.google.com with SMTP id x4so2698298plb.4 for ; Thu, 10 Feb 2022 11:17:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:date:from:to:cc:subject:message-id:mime-version :content-disposition; bh=VFvt2qkldnELMoC2bjs+OiTFLeMglGyEe/KOlRSrFPg=; b=Mt+K4f4Z5tTvcvLCiB7B1+ELRU1eV8ITrrGZIjrOIuaHkLs9oAE2PvsxEdY/HiZOdn rPkQYqw52SdvrFY7RF6M+QPzZzdkwrr7tyecxQDCZAjUX3fQFIDcNWYuKCXMTvtK4pJ0 hbS3xwEIEaR13b1DQ2jk4a6roKxL88umON9aLTQULqq6sG1zM8hu/BCbDBWttAsX0oB7 OEQK7mw0Pry/3NRpBakM8GG3on4ec1U3rpDcsudsZQz2JrXUyK0Eus9lV6st1CZDzv9R xz4nGiG5vAy8IeMkMyxd+9xe4kg/D86EtsbOsLiWF1jDVczztwOkcEznvGhjkH/oyqm4 tgyw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :mime-version:content-disposition; bh=VFvt2qkldnELMoC2bjs+OiTFLeMglGyEe/KOlRSrFPg=; b=m/2bF15i6mtpcwGiIhaVSUv29Qi5aASKbJcwMkLlXDmFhoGA7Si2OeB5a8naZDhCBJ 3Ec4ZPWzX7tb4hcNHX67nZ8IXD4NB6q84eGaD9VMYlpthWf1IJ1c/wWwrJgI6YKEAw4S 5E/Zu57uAEPX0bh7G2M6HCZyx7tNDOQasXK4gKyMaSGCsZZ4qT4QUchsA/tkBwqONF5X Wbf2Nk9fyY8dG1RTuXl5NqChFWXChfoIT3gWgLMmy1HCKZpQQPklHgBSOeQ7SvwGeBju DwSVf+CyxNIPPEod7QekUf3dsuoYhLh+GEJIqpTMFICzrgyEtzBWovR65cTMwIawFm5b NTsQ== X-Gm-Message-State: AOAM531UTGMzGkZWfHEB0hCPCfe1LnyYXt+Xd4hYXeYjol60WOG4qLS7 lyVUBWiBOgbq3ujtL40AHiw= X-Google-Smtp-Source: ABdhPJxudCrdOavU2G4udreBtQwdp50xSkFsvlI1XpG+5jHk3B1Xc+OUuY+Q761FtI4njg9rfpvB5A== X-Received: by 2002:a17:90b:2251:: with SMTP id hk17mr4345884pjb.210.1644520649489; Thu, 10 Feb 2022 11:17:29 -0800 (PST) Received: from google.com ([2620:15c:211:201:4c8c:3496:9911:5b66]) by smtp.gmail.com with ESMTPSA id t9sm2891556pjg.44.2022.02.10.11.17.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 10 Feb 2022 11:17:28 -0800 (PST) Sender: Minchan Kim Date: Thu, 10 Feb 2022 11:17:27 -0800 From: Minchan Kim To: John Hubbard Cc: linux-mm , LKML Subject: pin_user_pages supports NULL pages arguments? Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * pin_user_pages() - pin user pages in memory for use by other devices < snip > * @pages: array that receives pointers to the pages pinned. * Should be at least nr_pages long. Or NULL, if caller * only intends to ensure the pages are faulted in. pin_user_pages(,, pages = NULL, ); gup_flags |= FOLL_PIN __get_user_pages_locked __get_user_pages .. VM_BUG_ON(!!pages != !!(gup_flags & (FOLL_GET | FOLL_PIN)));