From patchwork Mon Nov 16 14:57:34 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 11909449 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 836DA138B for ; Mon, 16 Nov 2020 15:10:36 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 4285122240 for ; Mon, 16 Nov 2020 15:10:36 +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="q2Eui2HS" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4285122240 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.28081.56773 (Exim 4.92) (envelope-from ) id 1keg8X-00014O-VE; Mon, 16 Nov 2020 15:09:45 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 28081.56773; Mon, 16 Nov 2020 15:09:45 +0000 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1keg8X-00013i-8y; Mon, 16 Nov 2020 15:09:45 +0000 Received: by outflank-mailman (input) for mailman id 28081; Mon, 16 Nov 2020 15:09:42 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1keg1D-0006ni-69 for xen-devel@lists.xenproject.org; Mon, 16 Nov 2020 15:02:11 +0000 Received: from casper.infradead.org (unknown [2001:8b0:10b:1236::1]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id bec5bb8c-775a-4edf-b6a1-f9d2b128e1dd; Mon, 16 Nov 2020 14:59:24 +0000 (UTC) Received: from [2001:4bb8:180:6600:255b:7def:a93:4a09] (helo=localhost) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kefyI-0003z4-LX; Mon, 16 Nov 2020 14:59:11 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1keg1D-0006ni-69 for xen-devel@lists.xenproject.org; Mon, 16 Nov 2020 15:02:11 +0000 X-Inumbo-ID: bec5bb8c-775a-4edf-b6a1-f9d2b128e1dd Received: from casper.infradead.org (unknown [2001:8b0:10b:1236::1]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id bec5bb8c-775a-4edf-b6a1-f9d2b128e1dd; Mon, 16 Nov 2020 14:59:24 +0000 (UTC) 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=PqvTdxKlXNZLdjBDggPe+0dpl8BdkJnU5rWC71hrHK0=; b=q2Eui2HSznBIPI9cSjfWRkLiXv D7M1u2p1A7Bgss7fi8geS+IcBDfPIY7tG3iQsIcsu2pwlnpb6JkzHA9nQPyjhsgzFFr2f5V8gWY0R q0oyrC2H/s5XJqKuazQLgZxzSZuDhrLGiXIEEMHlBXx+6keZzYVXDEBv//T2nzeg8fA0yrA8TgRwk r0eZqTmdEAWKh5MSx2GpdmmFWrOrgA8uPwc9e459z4ahoYIjDlMtNVnWGRW3SsebzThr08Euwj40u FCjdDtLrrY8SFXrtoGuiZV87z8jk53zRslZsCywZYFngjpUQ7WpAm4CkVJQjfGDPL7bghqM+ajoud OS2SyUsg==; Received: from [2001:4bb8:180:6600:255b:7def:a93:4a09] (helo=localhost) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kefyI-0003z4-LX; Mon, 16 Nov 2020 14:59:11 +0000 From: Christoph Hellwig To: Jens Axboe Cc: Justin Sanders , Josef Bacik , Ilya Dryomov , Jack Wang , "Michael S. Tsirkin" , Jason Wang , Paolo Bonzini , Stefan Hajnoczi , Konrad Rzeszutek Wilk , =?utf-8?q?Roger_Pau_Monn?= =?utf-8?q?=C3=A9?= , Minchan Kim , Mike Snitzer , Song Liu , "Martin K. Petersen" , dm-devel@redhat.com, linux-block@vger.kernel.org, drbd-dev@lists.linbit.com, nbd@other.debian.org, ceph-devel@vger.kernel.org, xen-devel@lists.xenproject.org, linux-raid@vger.kernel.org, linux-nvme@lists.infradead.org, linux-scsi@vger.kernel.org, linux-fsdevel@vger.kernel.org, Hannes Reinecke Subject: [PATCH 43/78] brd: use __register_blkdev to allocate devices on demand Date: Mon, 16 Nov 2020 15:57:34 +0100 Message-Id: <20201116145809.410558-44-hch@lst.de> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201116145809.410558-1-hch@lst.de> References: <20201116145809.410558-1-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 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");