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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 B3EB2C282C4 for ; Sat, 9 Feb 2019 09:24:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 77B8420857 for ; Sat, 9 Feb 2019 09:24:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726836AbfBIJYL (ORCPT ); Sat, 9 Feb 2019 04:24:11 -0500 Received: from mx2.suse.de ([195.135.220.15]:52354 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726047AbfBIJYL (ORCPT ); Sat, 9 Feb 2019 04:24:11 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 77B3AACAE; Sat, 9 Feb 2019 09:24:10 +0000 (UTC) Subject: Re: [PATCH 03/19] block: add bio_set_polled() helper To: Jens Axboe , linux-aio@kvack.org, linux-block@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, jannh@google.com, viro@ZenIV.linux.org.uk References: <20190208173423.27014-1-axboe@kernel.dk> <20190208173423.27014-4-axboe@kernel.dk> From: Hannes Reinecke Message-ID: <331ba3f1-979f-01aa-74c1-fa5c53cb5a96@suse.de> Date: Sat, 9 Feb 2019 10:24:06 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.0 MIME-Version: 1.0 In-Reply-To: <20190208173423.27014-4-axboe@kernel.dk> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 2/8/19 6:34 PM, Jens Axboe wrote: > For the upcoming async polled IO, we can't sleep allocating requests. > If we do, then we introduce a deadlock where the submitter already > has async polled IO in-flight, but can't wait for them to complete > since polled requests must be active found and reaped. > > Utilize the helper in the blockdev DIRECT_IO code. > > Reviewed-by: Christoph Hellwig > Signed-off-by: Jens Axboe > --- > fs/block_dev.c | 4 ++-- > include/linux/bio.h | 14 ++++++++++++++ > 2 files changed, 16 insertions(+), 2 deletions(-) > Reviewed-by: Hannes Reinecke Cheers, Hannes