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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 2F0DBC56201 for ; Mon, 9 Nov 2020 09:12:13 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5ED342076E for ; Mon, 9 Nov 2020 09:12:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5ED342076E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 70B5F6B0036; Mon, 9 Nov 2020 04:12:11 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 6BAB56B005D; Mon, 9 Nov 2020 04:12:11 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5AA416B0068; Mon, 9 Nov 2020 04:12:11 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0062.hostedemail.com [216.40.44.62]) by kanga.kvack.org (Postfix) with ESMTP id 286886B0036 for ; Mon, 9 Nov 2020 04:12:11 -0500 (EST) Received: from smtpin12.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id B5BC88120 for ; Mon, 9 Nov 2020 09:12:10 +0000 (UTC) X-FDA: 77464313220.12.rat28_4d08abf272eb Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin12.hostedemail.com (Postfix) with ESMTP id 9507518055196 for ; Mon, 9 Nov 2020 09:12:10 +0000 (UTC) X-HE-Tag: rat28_4d08abf272eb X-Filterd-Recvd-Size: 2002 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf36.hostedemail.com (Postfix) with ESMTP for ; Mon, 9 Nov 2020 09:12:09 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 52E0D6736F; Mon, 9 Nov 2020 10:12:06 +0100 (CET) Date: Mon, 9 Nov 2020 10:12:06 +0100 From: Christoph Hellwig To: Logan Gunthorpe Cc: linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, linux-pci@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux-foundation.org, Stephen Bates , Christoph Hellwig , Dan Williams , Jason Gunthorpe , Christian =?iso-8859-1?Q?K=F6nig?= , Ira Weiny , John Hubbard , Don Dutile , Matthew Wilcox , Daniel Vetter Subject: Re: [RFC PATCH 01/15] PCI/P2PDMA: Don't sleep in upstream_bridge_distance_warn() Message-ID: <20201109091206.GA28918@lst.de> References: <20201106170036.18713-1-logang@deltatee.com> <20201106170036.18713-2-logang@deltatee.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201106170036.18713-2-logang@deltatee.com> User-Agent: Mutt/1.5.17 (2007-11-01) 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 Fri, Nov 06, 2020 at 10:00:22AM -0700, Logan Gunthorpe wrote: > In order to call this function from a dma_map function, it must not sleep. > The only reason it does sleep so to allocate the seqbuf to print > which devices are within the ACS path. > > Switch the kmalloc call to use GFP_NOWAIT and simply not print that > message if the buffer fails to be allocated. Please pass in the actual gfp_t. Especially from an I/O path GFP_NOWAIT is not the right gfp_t anyway, you probably want GFP_ATOMIC there. But also for the path where we can sleep we should allow that.