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 2D686C3DA7D for ; Tue, 3 Jan 2023 17:45:38 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4CF538E0002; Tue, 3 Jan 2023 12:45:37 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 47F808E0001; Tue, 3 Jan 2023 12:45:37 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 346F38E0002; Tue, 3 Jan 2023 12:45:37 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 260B28E0001 for ; Tue, 3 Jan 2023 12:45:37 -0500 (EST) Received: from smtpin05.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 9EDB2A0AE1 for ; Tue, 3 Jan 2023 17:45:36 +0000 (UTC) X-FDA: 80314215072.05.F232172 Received: from mail-wr1-f50.google.com (mail-wr1-f50.google.com [209.85.221.50]) by imf09.hostedemail.com (Postfix) with ESMTP id EF9D2140010 for ; Tue, 3 Jan 2023 17:45:33 +0000 (UTC) Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=LHcGugh+; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf09.hostedemail.com: domain of lstoakes@gmail.com designates 209.85.221.50 as permitted sender) smtp.mailfrom=lstoakes@gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1672767934; 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=aWorniJ/fZrmchxeIYy/25/fnoIcc5YDmNnsRFvI5QM=; b=rTyAlnduvEC9c92T3myaIFKuCiAguZbEllVhiRRmaVHpwA3rcPPoum39h4QcQjL23G1pST xmL2hl8bwQOq3kAXQFMzRcTp2r5b9vRUQYuNeG/yca4n/HoeKG4wINC39IFN+cdTDVZa/B MCVLXx4wsmDvwwovksEmbwj5EE+vFJU= ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=LHcGugh+; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf09.hostedemail.com: domain of lstoakes@gmail.com designates 209.85.221.50 as permitted sender) smtp.mailfrom=lstoakes@gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1672767934; a=rsa-sha256; cv=none; b=PEBH/yGhcFZQold/iO48esvZOoCFUuTyFO7RBzgO92HWgqq5TU5/CxrXFV0K/kV154fs24 vGcRFu2XzAVkJiOLmpHy5f4BeOb2hiU7vP/DFxxzdDQna45xt6efzZJvDp9cH8wGq1Et98 d6osMU9X206sVD+pUJwjeq0AC1Ez7vc= Received: by mail-wr1-f50.google.com with SMTP id t15so21507451wro.9 for ; Tue, 03 Jan 2023 09:45:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=aWorniJ/fZrmchxeIYy/25/fnoIcc5YDmNnsRFvI5QM=; b=LHcGugh+WoE09WADK0yp4IoxnsyN8yUNqKwVPNs0pu1/7XejqLIdmtYwr+M+ivIr5s Om3LNIfuztLskZ1z8PT63KrLH0mL8GDL0V7T/clHfMyia1bbEteMt3oZ7JsUEAxmn6uy 2MDgesfs32DecMoaYghrAgOJYuL/L3VRv/mNAnylWkTRc/1Uw7zuWyW5ZPMHMnLSg79E 2cJ8amob8/W+9VlbALa6aYR1KDwn68ua/dwYmv1GQthawrHHq6ZZ5xuh+pJkm8yK/2ob JS6+UFd6wH/PDTo2f8+2rVQLaAXUAfGDlj8iHlddCGVUxwAxheR9MKUESs9JZvz/uMcK 8uHg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=aWorniJ/fZrmchxeIYy/25/fnoIcc5YDmNnsRFvI5QM=; b=uaGuO0sXT+g4OS2qnl+yBf9M5VcL4BRbCf0W4kaxInSn8+SWMydL3JxcwCWo2mx9zQ vP25B+2CaOr3EQUn6PAugYREPZTXb8wNiYTomNKwaZ7KNtsLfjmJ9//SFuGtyqTrN5Ok dC1gJTzt8fzLfEfO/taOaJjUIfIJZiCydQNo/XXuA5czDOHgeCpRwDPs+jnyeD1zFqok KC2JZ7YoBrfQhXdmypa+0aqIz2Gb0Bn6Cu+Yt9n4EkrF/3NyqDYXp0mdvqoabxwy399u og8kmqdPpA+UMC44kSuIqs/J7XsNkI71LYM4kC7xmtS1F1kxzWFTOoHWUg5l8mo3L80r 9HkA== X-Gm-Message-State: AFqh2kqER9nIp8Cp11UJboYi9OBgOIyRDQaH5V4CgVTVpZkAAhAisp5a 685y7ZlmwVd000Hoznb2xfk= X-Google-Smtp-Source: AMrXdXtZWSWW7441X12DeFasW4zh4Bz8D/keQ2oYwHzLvN5LeahZoA2hyRcksMRnDG3jjIPp4Vk0VQ== X-Received: by 2002:a5d:4e83:0:b0:29f:b589:157c with SMTP id e3-20020a5d4e83000000b0029fb589157cmr1734093wru.5.1672767932309; Tue, 03 Jan 2023 09:45:32 -0800 (PST) Received: from localhost (host81-157-153-247.range81-157.btcentralplus.com. [81.157.153.247]) by smtp.gmail.com with ESMTPSA id f13-20020a5d4dcd000000b0023659925b2asm31767946wru.51.2023.01.03.09.45.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 03 Jan 2023 09:45:31 -0800 (PST) Date: Tue, 3 Jan 2023 17:45:30 +0000 From: Lorenzo Stoakes To: Fenghua Yu Cc: Vinod Koul , Dave Jiang , dmaengine@vger.kernel.org, Tony Zhu , Andrew Morton , linux-mm@kvack.org, Christoph Hellwig Subject: Re: [PATCH 09/17] mm: export access_remote_vm() symbol Message-ID: References: <20230103163505.1569356-1-fenghua.yu@intel.com> <20230103163505.1569356-10-fenghua.yu@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230103163505.1569356-10-fenghua.yu@intel.com> X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: EF9D2140010 X-Stat-Signature: cpg5tikcjqy49h3ht84webm9adi3bh36 X-HE-Tag: 1672767933-291828 X-HE-Meta: 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 79NVlig/ 3xxqXLzaoSUs6GeESvYBna/rw9KMhCWC67HA/X/UO7Bv30FEJw8TQHfcKaJgDXZCFkctSOSNDHiPjTs7TGHoYYLs1t2ouPB+W6l+e7XIfF6EeFFehEYK57VYnBdxc6KbbIQ9A 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, Jan 03, 2023 at 08:34:57AM -0800, Fenghua Yu wrote: > From: Dave Jiang > > Export access_remote_vm() symbol for driver usage. The idxd driver would > like to use it to write the user's completion record that the hardware > device is not able to write to due to user page fault. > > Tested-by: Tony Zhu > Signed-off-by: Dave Jiang > Co-developed-by: Fenghua Yu > Signed-off-by: Fenghua Yu > Cc: Andrew Morton > Cc: linux-mm@kvack.org > --- > mm/memory.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/mm/memory.c b/mm/memory.c > index aad226daf41b..caae4deff987 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -5579,6 +5579,7 @@ int access_remote_vm(struct mm_struct *mm, unsigned long addr, > { > return __access_remote_vm(mm, addr, buf, len, gup_flags); > } > +EXPORT_SYMBOL_GPL(access_remote_vm); > > /* > * Access another process' address space. > -- > 2.32.0 > Can you explain what use case you have for exporting this? Currently this is only used by procfs. Additionally, it relies on a reference count being held on the mm which seems a little risky exposing to a driver. Is there a reason you can't use access_process_vm() which is exported and additionally handles the refrencing?