From patchwork Sun Aug 30 06:24:36 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 11744755 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A5D1D14E5 for ; Sun, 30 Aug 2020 06:27:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8D86B208DB for ; Sun, 30 Aug 2020 06:27:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="X5Hgm4D+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728757AbgH3G0d (ORCPT ); Sun, 30 Aug 2020 02:26:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58512 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726507AbgH3GZD (ORCPT ); Sun, 30 Aug 2020 02:25:03 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B312FC06123E; Sat, 29 Aug 2020 23:25:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; 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=zPuO1RiCFtAaXcTW9QuEi3RCIZQfS8nNc4ZkqYoXzUI=; b=X5Hgm4D+Dhmy+jYDDIulCsBSl+ j45NjJ5ULDX7vsTfe7RtBYeV2IZiyMkKxuLQTmhJC/2LLbK2NvJZl+xEoJ+JBXkDxL25dweEGuID9 tep2TDthrDzzmPck3gaVsqFYP6kfUEJPAn4H1xOfaZhT4Yuu9u3UATFU8PTtTUILopdPk9xKC9lGD Gg232TMu4V/ImaWH+0oBbgXI7PsbB02KySpCWxjJ3hjHt57r3B8uynbArc77OgkV54zBsC36Rxhtn 0UaH+f2fxbh4uiQWtpKC7CtVWR0NQjqF5JNoyzzyRrKNu0hkPD8SFoRUCztDeSHJ6TqeZLN0NO2O4 4H0qyt2w==; Received: from [2001:4bb8:18c:45ba:9892:9e86:5202:32f0] (helo=localhost) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kCGls-0002NW-Co; Sun, 30 Aug 2020 06:24:56 +0000 From: Christoph Hellwig To: Jens Axboe Cc: Greg Kroah-Hartman , "Rafael J. Wysocki" , Denis Efremov , "David S. Miller" , Song Liu , Al Viro , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org, linux-raid@vger.kernel.org, linux-scsi@vger.kernel.org, linux-m68k@lists.linux-m68k.org Subject: [PATCH 10/19] brd: use __register_blkdev to allocate devices on demand Date: Sun, 30 Aug 2020 08:24:36 +0200 Message-Id: <20200830062445.1199128-11-hch@lst.de> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200830062445.1199128-1-hch@lst.de> References: <20200830062445.1199128-1-hch@lst.de> MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Use the simpler mechanism attached to major_name to allocate a brd device when a currently unregistered minor is accessed. Signed-off-by: Christoph Hellwig --- drivers/block/brd.c | 39 +++++++++++---------------------------- 1 file changed, 11 insertions(+), 28 deletions(-) diff --git a/drivers/block/brd.c b/drivers/block/brd.c index 2723a70eb85593..c8ac36351115ef 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -427,14 +427,15 @@ static void brd_free(struct brd_device *brd) kfree(brd); } -static struct brd_device *brd_init_one(int i, bool *new) +static void brd_probe(dev_t dev) { struct brd_device *brd; + int i = MINOR(dev) / max_part; - *new = false; + mutex_lock(&brd_devices_mutex); list_for_each_entry(brd, &brd_devices, brd_list) { if (brd->brd_number == i) - goto out; + goto out_unlock; } brd = brd_alloc(i); @@ -443,9 +444,9 @@ static struct brd_device *brd_init_one(int i, bool *new) add_disk(brd->brd_disk); list_add_tail(&brd->brd_list, &brd_devices); } - *new = true; -out: - return brd; + +out_unlock: + mutex_unlock(&brd_devices_mutex); } static void brd_del_one(struct brd_device *brd) @@ -455,23 +456,6 @@ static void brd_del_one(struct brd_device *brd) brd_free(brd); } -static struct kobject *brd_probe(dev_t dev, int *part, void *data) -{ - struct brd_device *brd; - struct kobject *kobj; - bool new; - - mutex_lock(&brd_devices_mutex); - brd = brd_init_one(MINOR(dev) / max_part, &new); - kobj = brd ? get_disk_and_module(brd->brd_disk) : NULL; - mutex_unlock(&brd_devices_mutex); - - if (new) - *part = 0; - - return kobj; -} - static inline void brd_check_and_reset_par(void) { if (unlikely(!max_part)) @@ -511,11 +495,12 @@ static int __init brd_init(void) * dynamically. */ - if (register_blkdev(RAMDISK_MAJOR, "ramdisk")) + if (__register_blkdev(RAMDISK_MAJOR, "ramdisk", brd_probe)) return -EIO; brd_check_and_reset_par(); + mutex_lock(&brd_devices_mutex); for (i = 0; i < rd_nr; i++) { brd = brd_alloc(i); if (!brd) @@ -533,9 +518,7 @@ static int __init brd_init(void) brd->brd_disk->queue = brd->brd_queue; add_disk(brd->brd_disk); } - - blk_register_region(MKDEV(RAMDISK_MAJOR, 0), 1UL << MINORBITS, - THIS_MODULE, brd_probe, NULL, NULL); + mutex_unlock(&brd_devices_mutex); pr_info("brd: module loaded\n"); return 0; @@ -545,6 +528,7 @@ static int __init brd_init(void) list_del(&brd->brd_list); brd_free(brd); } + mutex_unlock(&brd_devices_mutex); unregister_blkdev(RAMDISK_MAJOR, "ramdisk"); pr_info("brd: module NOT loaded !!!\n"); @@ -558,7 +542,6 @@ static void __exit brd_exit(void) list_for_each_entry_safe(brd, next, &brd_devices, brd_list) brd_del_one(brd); - blk_unregister_region(MKDEV(RAMDISK_MAJOR, 0), 1UL << MINORBITS); unregister_blkdev(RAMDISK_MAJOR, "ramdisk"); pr_info("brd: module unloaded\n");