From patchwork Mon Nov 16 14:57:35 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 325838 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=-12.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 D4F42C64EBC for ; Mon, 16 Nov 2020 15:03:52 +0000 (UTC) Received: from vger.kernel.org (unknown [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 77A03206B7 for ; Mon, 16 Nov 2020 15:03:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="nsafq+rG" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 77A03206B7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=ceph-devel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730695AbgKPPC7 (ORCPT ); Mon, 16 Nov 2020 10:02:59 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49114 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730904AbgKPO7Y (ORCPT ); Mon, 16 Nov 2020 09:59:24 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 62196C0613CF; Mon, 16 Nov 2020 06:59:24 -0800 (PST) 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=PZFkyvf1145z+UDf1b5Hj+jOh1AFkHrQzn1ghiqKhDM=; b=nsafq+rGm1Rv8PLkOskpq2E1WT GblaGkEbRxaXt7tMa8lsB0T/f5O44rOftO550QMTTXAsaN06O33HbZWw8qR8BuIC5LY1K1bDXw7h0 fXI0JFhYf8Q4CM2W+FyYMvt6rxUABlRFuwShsT5ZmrGbHYU704qrV+elTl5Y7tXYggWdyVa22D/65 XFEMEvNDmXdMEgGAPYiI8eQrdp7u2i1IGbuQVMZNL0XJlhyMGFQuZahfLnp3Jg/O7cmqHPhKanuYM OxeKkCkWcJqNNHH4YMUIOwRSUBMRc+b1rwJCOum2gr3Iswu9BqnghgCeZoZpkFA0tR3BGhjo23NTg G+sn0B+g==; 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 1kefyK-0003zL-Gc; Mon, 16 Nov 2020 14:59:12 +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=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 44/78] loop: use __register_blkdev to allocate devices on demand Date: Mon, 16 Nov 2020 15:57:35 +0100 Message-Id: <20201116145809.410558-45-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 Precedence: bulk List-ID: X-Mailing-List: ceph-devel@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/loop.c | 30 ++++++++---------------------- 1 file changed, 8 insertions(+), 22 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 41caf799df721f..9a27d4f1c08aac 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -2231,24 +2231,18 @@ static int loop_lookup(struct loop_device **l, int i) return ret; } -static struct kobject *loop_probe(dev_t dev, int *part, void *data) +static void loop_probe(dev_t dev) { + int idx = MINOR(dev) >> part_shift; struct loop_device *lo; - struct kobject *kobj; - int err; + + if (max_loop && idx >= max_loop) + return; mutex_lock(&loop_ctl_mutex); - err = loop_lookup(&lo, MINOR(dev) >> part_shift); - if (err < 0) - err = loop_add(&lo, MINOR(dev) >> part_shift); - if (err < 0) - kobj = NULL; - else - kobj = get_disk_and_module(lo->lo_disk); + if (loop_lookup(&lo, idx) < 0) + loop_add(&lo, idx); mutex_unlock(&loop_ctl_mutex); - - *part = 0; - return kobj; } static long loop_control_ioctl(struct file *file, unsigned int cmd, @@ -2368,14 +2362,11 @@ static int __init loop_init(void) goto err_out; - if (register_blkdev(LOOP_MAJOR, "loop")) { + if (__register_blkdev(LOOP_MAJOR, "loop", loop_probe)) { err = -EIO; goto misc_out; } - blk_register_region(MKDEV(LOOP_MAJOR, 0), range, - THIS_MODULE, loop_probe, NULL, NULL); - /* pre-create number of devices given by config or max_loop */ mutex_lock(&loop_ctl_mutex); for (i = 0; i < nr; i++) @@ -2401,16 +2392,11 @@ static int loop_exit_cb(int id, void *ptr, void *data) static void __exit loop_exit(void) { - unsigned long range; - - range = max_loop ? max_loop << part_shift : 1UL << MINORBITS; - mutex_lock(&loop_ctl_mutex); idr_for_each(&loop_index_idr, &loop_exit_cb, NULL); idr_destroy(&loop_index_idr); - blk_unregister_region(MKDEV(LOOP_MAJOR, 0), range); unregister_blkdev(LOOP_MAJOR, "loop"); misc_deregister(&loop_misc);