From patchwork Thu Oct 29 14:58:32 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 1390220 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=linux-ide-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; secure) header.d=infradead.org header.i=@infradead.org header.a=rsa-sha256 header.s=casper.20170209 header.b=HrC9j+ri; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4CMTtY6jtpz9sSC for ; Fri, 30 Oct 2020 02:31:17 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728351AbgJ2PbA (ORCPT ); Thu, 29 Oct 2020 11:31:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46540 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728249AbgJ2Pa7 (ORCPT ); Thu, 29 Oct 2020 11:30:59 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 687AFC0613D3; Thu, 29 Oct 2020 08:21:07 -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=gVY2C3Yr3hbZHWXTJ3PuAFR8cZ/e33HSpQGIidM7NRQ=; b=HrC9j+riyfO1S9gr/g++5iI0N3 74NLSLyzTtNUKZ9XF3rwp2K1v/s+fjg2qcSYjf8QOmUICfgBrPeOSA1jbxUxF7r9HJB4hbyRx7eHk FojcS1VgBVwdrVokJXM0BtgkFwqQskJ3K8Dx40UqDdugqgQFIJHy1X4dw53zzQAjv29HotPTRtdHB 3MOvjgI/R4rDuc4u757UYn1+KcRPt8DRgowi8eh9QpLFKw9ZJA3a4+GIU3UDH6ViAVvzgnqkn6GmD fohXz6rwzElTUCRi/NGIC3TGBpsu/Az9PdclZijenq0WSNuZgbFUF38rLy8pFKTK4Ov2TQ1iwWu7X 6bFOAwYg==; Received: from 089144193201.atnat0002.highway.a1.net ([89.144.193.201] helo=localhost) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kY9jQ-0006nN-Gz; Thu, 29 Oct 2020 15:20:55 +0000 From: Christoph Hellwig To: Jens Axboe Cc: Greg Kroah-Hartman , "Rafael J. Wysocki" , Denis Efremov , "David S. Miller" , Song Liu , Al Viro , Finn Thain , Michael Schmitz , 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, Hannes Reinecke Subject: [PATCH 09/18] brd: use __register_blkdev to allocate devices on demand Date: Thu, 29 Oct 2020 15:58:32 +0100 Message-Id: <20201029145841.144173-10-hch@lst.de> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201029145841.144173-1-hch@lst.de> References: <20201029145841.144173-1-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 Precedence: bulk List-ID: X-Mailing-List: linux-ide@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 Reviewed-by: Hannes Reinecke --- 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 cc49a921339f77..c43a6ab4b1f39f 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -426,14 +426,15 @@ 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); @@ -442,9 +443,9 @@ 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) @@ -454,23 +455,6 @@ 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)) @@ -510,11 +494,12 @@ 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) @@ -532,9 +517,7 @@ 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; @@ -544,6 +527,7 @@ 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"); @@ -557,7 +541,6 @@ 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");