From patchwork Thu Oct 20 13:20:48 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu Kuai X-Patchwork-Id: 13013426 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 04AFAC4332F for ; Thu, 20 Oct 2022 12:59:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230188AbiJTM66 (ORCPT ); Thu, 20 Oct 2022 08:58:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52376 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229679AbiJTM64 (ORCPT ); Thu, 20 Oct 2022 08:58:56 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 253521CCCC2; Thu, 20 Oct 2022 05:58:53 -0700 (PDT) Received: from dggemv704-chm.china.huawei.com (unknown [172.30.72.53]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4MtSMl4CnJzHv5y; Thu, 20 Oct 2022 20:58:43 +0800 (CST) Received: from kwepemm600009.china.huawei.com (7.193.23.164) by dggemv704-chm.china.huawei.com (10.3.19.47) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Thu, 20 Oct 2022 20:58:49 +0800 Received: from huawei.com (10.175.127.227) by kwepemm600009.china.huawei.com (7.193.23.164) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Thu, 20 Oct 2022 20:58:48 +0800 From: Yu Kuai To: , , , , , , , CC: , , , Subject: [PATCH -nect RFC v2 1/2] block: add helpers for bd_holder_dir refcount management Date: Thu, 20 Oct 2022 21:20:48 +0800 Message-ID: <20221020132049.3947415-2-yukuai3@huawei.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20221020132049.3947415-1-yukuai3@huawei.com> References: <20221020132049.3947415-1-yukuai3@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.127.227] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To kwepemm600009.china.huawei.com (7.193.23.164) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Currently the lifecycle of bd_holder_dir is problematic, it can be freed in del_gendisk() while it can still be accessed before disk_release(). And there in no way to know if the kobject if freed by kobject_put() for now, thus add a new field in bloce_device to manage refcount of bd_holder_dir seperately. Prepare to fix the problem in following patch. Signed-off-by: Yu Kuai --- block/blk.h | 3 +++ block/genhd.c | 27 +++++++++++++++++++++++++++ include/linux/blk_types.h | 1 + 3 files changed, 31 insertions(+) diff --git a/block/blk.h b/block/blk.h index d6ea0d1a6db0..fef868b4169c 100644 --- a/block/blk.h +++ b/block/blk.h @@ -458,6 +458,9 @@ extern const struct address_space_operations def_blk_aops; int disk_register_independent_access_ranges(struct gendisk *disk); void disk_unregister_independent_access_ranges(struct gendisk *disk); +bool bd_try_get_holder_dir(struct block_device *bdev); +void bd_put_holder_dir(struct block_device *bdev); + #ifdef CONFIG_FAIL_MAKE_REQUEST bool should_fail_request(struct block_device *part, unsigned int bytes); #else /* CONFIG_FAIL_MAKE_REQUEST */ diff --git a/block/genhd.c b/block/genhd.c index 17b33c62423d..53f9c8b2690a 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -375,6 +375,33 @@ int disk_scan_partitions(struct gendisk *disk, fmode_t mode) return 0; } +bool bd_try_get_holder_dir(struct block_device *bdev) +{ + mutex_lock(&bdev->bd_disk->open_mutex); + if (!bdev->holder_dir_ref) { + mutex_unlock(&bdev->bd_disk->open_mutex); + return false; + } + + bdev->holder_dir_ref++; + mutex_unlock(&bdev->bd_disk->open_mutex); + return true; +} + +void bd_put_holder_dir(struct block_device *bdev) +{ + mutex_lock(&bdev->bd_disk->open_mutex); + if (WARN_ON(bdev->holder_dir_ref <= 0)) + goto out; + + if (!(--bdev->holder_dir_ref)) { + kobject_put(bdev->bd_holder_dir); + bdev->bd_holder_dir = NULL; + } +out: + mutex_unlock(&bdev->bd_disk->open_mutex); +} + /** * device_add_disk - add disk information to kernel list * @parent: parent device for the disk diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index e0b098089ef2..550c8e15af49 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -53,6 +53,7 @@ struct block_device { int bd_holders; bool bd_write_holder; struct kobject *bd_holder_dir; + int holder_dir_ref; u8 bd_partno; spinlock_t bd_size_lock; /* for bd_inode->i_size updates */ struct gendisk * bd_disk;