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,USER_AGENT_GIT autolearn=unavailable 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 F27A6C43600 for ; Wed, 12 May 2021 06:19:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D473B6191D for ; Wed, 12 May 2021 06:19:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230139AbhELGUT (ORCPT ); Wed, 12 May 2021 02:20:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36268 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229803AbhELGUS (ORCPT ); Wed, 12 May 2021 02:20:18 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AC340C061574; Tue, 11 May 2021 23:19:10 -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=6saAPsU6kJh2c9PPvGH8Mdntk/kERHTUb6DGNS1VeY0=; b=cMVDvHhi8JTmt30+GKLoPy56eI XEKOdQWniksyLZzUZp3OIds1mubW1LMKv0XGiTYJ7QUaC8bB8Upz0kdk6d6mrvoe5t0YItYDAtxG1 MVR4zoY/ROrHLX8y9ykvMijS46BLsjbRsBitFfUX8AYjr8FsIVKL5UhzgfVa/vUnqiZq3U7xAvERh JYbNttsbdTCUowa1JEP8vm44/9EwwZ0iduB4daLXUqvCRpG8aYMBOUGs6iM64q44GD+j3Hm5m4bfC rKDC5UDq3zh842V3YaT9Ehl4vPS9QpslOZQVGXhHwusgS+jPfdyKT12T8vhq4iX98CFtiaqjAEExM GlLBacLQ==; Received: from [2001:4bb8:198:fbc8:1036:7ab9:f97a:adbc] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.94 #2 (Red Hat Linux)) id 1lgiCz-00A8rW-12; Wed, 12 May 2021 06:19:01 +0000 From: Christoph Hellwig To: Jens Axboe , Song Liu Cc: Konrad Rzeszutek Wilk , =?UTF-8?q?Roger=20Pau=20Monn=C3=A9?= , Minchan Kim , Nitin Gupta , Stefan Haberland , Jan Hoeppner , linux-block@vger.kernel.org, linux-raid@vger.kernel.org, linux-s390@vger.kernel.org, linux-scsi@vger.kernel.org Subject: [PATCH 1/8] block: split __blkdev_get Date: Wed, 12 May 2021 08:18:49 +0200 Message-Id: <20210512061856.47075-2-hch@lst.de> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210512061856.47075-1-hch@lst.de> References: <20210512061856.47075-1-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 Split __blkdev_get into one helper for the whole device, and one for opening partitions. This removes the (bounded) recursion when opening a partition. Signed-off-by: Christoph Hellwig --- fs/block_dev.c | 115 +++++++++++++++++++++++-------------------------- 1 file changed, 55 insertions(+), 60 deletions(-) diff --git a/fs/block_dev.c b/fs/block_dev.c index b8abccd03e5d..d053510d2f6a 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1287,76 +1287,68 @@ int bdev_disk_changed(struct block_device *bdev, bool invalidate) */ EXPORT_SYMBOL_GPL(bdev_disk_changed); -/* - * bd_mutex locking: - * - * mutex_lock(part->bd_mutex) - * mutex_lock_nested(whole->bd_mutex, 1) - */ -static int __blkdev_get(struct block_device *bdev, fmode_t mode) +static int blkdev_get_whole(struct block_device *bdev, fmode_t mode) { struct gendisk *disk = bdev->bd_disk; int ret = 0; - if (!bdev->bd_openers) { - if (!bdev_is_partition(bdev)) { - ret = 0; - if (disk->fops->open) - ret = disk->fops->open(bdev, mode); - - if (!ret) - set_init_blocksize(bdev); - - /* - * If the device is invalidated, rescan partition - * if open succeeded or failed with -ENOMEDIUM. - * The latter is necessary to prevent ghost - * partitions on a removed medium. - */ - if (test_bit(GD_NEED_PART_SCAN, &disk->state) && - (!ret || ret == -ENOMEDIUM)) - bdev_disk_changed(bdev, ret == -ENOMEDIUM); - - if (ret) - return ret; - } else { - struct block_device *whole = bdgrab(disk->part0); - - mutex_lock_nested(&whole->bd_mutex, 1); - ret = __blkdev_get(whole, mode); - if (ret) { - mutex_unlock(&whole->bd_mutex); - bdput(whole); - return ret; - } - whole->bd_part_count++; - mutex_unlock(&whole->bd_mutex); - - if (!(disk->flags & GENHD_FL_UP) || - !bdev_nr_sectors(bdev)) { - __blkdev_put(whole, mode, 1); - bdput(whole); - return -ENXIO; - } - set_init_blocksize(bdev); + if (disk->fops->open) { + ret = disk->fops->open(bdev, mode); + if (ret) { + /* avoid ghost partitions on a removed medium */ + if (ret == -ENOMEDIUM && + test_bit(GD_NEED_PART_SCAN, &disk->state)) + bdev_disk_changed(bdev, true); + return ret; } + } + if (!bdev->bd_openers) { + set_init_blocksize(bdev); if (bdev->bd_bdi == &noop_backing_dev_info) bdev->bd_bdi = bdi_get(disk->queue->backing_dev_info); - } else { - if (!bdev_is_partition(bdev)) { - if (bdev->bd_disk->fops->open) - ret = bdev->bd_disk->fops->open(bdev, mode); - /* the same as first opener case, read comment there */ - if (test_bit(GD_NEED_PART_SCAN, &disk->state) && - (!ret || ret == -ENOMEDIUM)) - bdev_disk_changed(bdev, ret == -ENOMEDIUM); - if (ret) - return ret; - } } + if (test_bit(GD_NEED_PART_SCAN, &disk->state)) + bdev_disk_changed(bdev, false); bdev->bd_openers++; + return 0;; +} + +static int blkdev_get_part(struct block_device *part, fmode_t mode) +{ + struct gendisk *disk = part->bd_disk; + struct block_device *whole; + int ret; + + if (part->bd_openers) + goto done; + + whole = bdgrab(disk->part0); + mutex_lock_nested(&whole->bd_mutex, 1); + ret = blkdev_get_whole(whole, mode); + if (ret) { + mutex_unlock(&whole->bd_mutex); + goto out_put_whole; + } + whole->bd_part_count++; + mutex_unlock(&whole->bd_mutex); + + ret = -ENXIO; + if (!(disk->flags & GENHD_FL_UP) || !bdev_nr_sectors(part)) + goto out_blkdev_put; + + set_init_blocksize(part); + if (part->bd_bdi == &noop_backing_dev_info) + part->bd_bdi = bdi_get(disk->queue->backing_dev_info); +done: + part->bd_openers++; return 0; + +out_blkdev_put: + __blkdev_put(whole, mode, 1); +out_put_whole: + bdput(whole); + return ret; } struct block_device *blkdev_get_no_open(dev_t dev) @@ -1450,7 +1442,10 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder) disk_block_events(disk); mutex_lock(&bdev->bd_mutex); - ret =__blkdev_get(bdev, mode); + if (bdev_is_partition(bdev)) + ret = blkdev_get_part(bdev, mode); + else + ret = blkdev_get_whole(bdev, mode); if (ret) goto abort_claiming; if (mode & FMODE_EXCL) { -- 2.30.2