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=-16.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 AEEC6C4360C for ; Tue, 27 Apr 2021 16:20:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7E7CD61151 for ; Tue, 27 Apr 2021 16:20:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237865AbhD0QV3 (ORCPT ); Tue, 27 Apr 2021 12:21:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50882 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237503AbhD0QTc (ORCPT ); Tue, 27 Apr 2021 12:19:32 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 22322C061574; Tue, 27 Apr 2021 09:18:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=o5zGnmhRQBVMOFTbkoOK4C6A9eTSah00I6u2NMKUqBo=; b=sYzCoxyyNGvmiZFWjQJwOl3HZu Qepx+XmERJTR4Mz+5wqIqxDrohcmc+XgyoJdo7dSDRPdawcyvrfeTIBic03RMWl4hDMdxn4P4gs+c OdodF3UMXb41RY8+PW8CK/AIHFo/lsDpKjk+Z4uKrb4KEgSAOHEhWrX5GZln5rTQVFSR8FmQCsBqj o+Z7noib3iflBRAZ8slLtgrATGX8E8sOx9COJsjlgsQMNOPCVUwaGJXWN+ED8SZoZib9VR58rXecX F5Q4Byt4Z45sfXIkHb/BhI+dZ3/7KBvCoGN7OJaXbUh6aM+lK7d6+IHzpFHHHG+id98/qwtanFRMP SeX7hJNg==; Received: from [2001:4bb8:18c:28b2:c772:7205:2aa4:840d] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.94 #2 (Red Hat Linux)) id 1lbQQ4-00Gr47-2P; Tue, 27 Apr 2021 16:18:40 +0000 From: Christoph Hellwig To: Jens Axboe Cc: Jeffle Xu , Ming Lei , Damien Le Moal , Keith Busch , Sagi Grimberg , "Wunderlich, Mark" , "Vasudevan, Anil" , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH 02/15] block: don't try to poll multi-bio I/Os in __blkdev_direct_IO Date: Tue, 27 Apr 2021 18:16:06 +0200 Message-Id: <20210427161619.1294399-3-hch@lst.de> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210427161619.1294399-1-hch@lst.de> References: <20210427161619.1294399-1-hch@lst.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org If an iocb is split into multiple bios we can't poll for both. So don't bother to even try to poll in that case. Signed-off-by: Christoph Hellwig --- fs/block_dev.c | 37 ++++++++++++++----------------------- 1 file changed, 14 insertions(+), 23 deletions(-) diff --git a/fs/block_dev.c b/fs/block_dev.c index a5244e08b6c8..df651f468e11 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -375,7 +375,7 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, struct blk_plug plug; struct blkdev_dio *dio; struct bio *bio; - bool is_poll = (iocb->ki_flags & IOCB_HIPRI) != 0; + bool is_poll = (iocb->ki_flags & IOCB_HIPRI), do_poll = false; bool is_read = (iov_iter_rw(iter) == READ), is_sync; loff_t pos = iocb->ki_pos; blk_qc_t qc = BLK_QC_T_NONE; @@ -437,22 +437,9 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, pos += bio->bi_iter.bi_size; nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS); - if (!nr_pages) { - bool polled = false; - - if (iocb->ki_flags & IOCB_HIPRI) { - bio_set_polled(bio, iocb); - polled = true; - } - - qc = submit_bio(bio); - - if (polled) - WRITE_ONCE(iocb->ki_cookie, qc); - break; - } - - if (!dio->multi_bio) { + if (dio->multi_bio) { + atomic_inc(&dio->ref); + } else if (nr_pages) { /* * AIO needs an extra reference to ensure the dio * structure which is embedded into the first bio @@ -462,11 +449,16 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, bio_get(bio); dio->multi_bio = true; atomic_set(&dio->ref, 2); - } else { - atomic_inc(&dio->ref); + } else if (is_poll) { + bio_set_polled(bio, iocb); + do_poll = true; + } + qc = submit_bio(bio); + if (!nr_pages) { + if (do_poll) + WRITE_ONCE(iocb->ki_cookie, qc); + break; } - - submit_bio(bio); bio = bio_alloc(GFP_KERNEL, nr_pages); } @@ -481,8 +473,7 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, if (!READ_ONCE(dio->waiter)) break; - if (!(iocb->ki_flags & IOCB_HIPRI) || - !blk_poll(bdev_get_queue(bdev), qc, true)) + if (!do_poll || !blk_poll(bdev_get_queue(bdev), qc, true)) blk_io_schedule(); } __set_current_state(TASK_RUNNING); -- 2.30.1