From mboxrd@z Thu Jan 1 00:00:00 1970 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 775D8C43334 for ; Mon, 13 Jun 2022 14:52:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1386293AbiFMOwT (ORCPT ); Mon, 13 Jun 2022 10:52:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44140 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1386301AbiFMOtQ (ORCPT ); Mon, 13 Jun 2022 10:49:16 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B4F0EC2EC4; Mon, 13 Jun 2022 04:53:26 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id D30B0B80EDD; Mon, 13 Jun 2022 11:53:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 356A1C341C0; Mon, 13 Jun 2022 11:53:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1655121187; bh=ggenJEKAVXkVp+EDsAyPGRdkEc/hNaddQxwC6i2POkg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PtoqtozIXmNcuKiGqFdI2AXBxrpgTrT7okdXiAUU4ttfIaQ03KFxiXidjRNkQK+de cg7iPm3HaFeqbatsEjcyAcJTrzWSCoFkLQH1bCf+TUeksBHBseSMfl1h95UUuDlyjt 6z9m1ZMYBtTlKDFAgxYINLW1kto0cuZqEtYUGyDE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ming Lei , Christoph Hellwig , Jens Axboe Subject: [PATCH 5.17 296/298] block, loop: support partitions without scanning Date: Mon, 13 Jun 2022 12:13:10 +0200 Message-Id: <20220613094934.054060026@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220613094924.913340374@linuxfoundation.org> References: <20220613094924.913340374@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Christoph Hellwig commit b9684a71fca793213378dd410cd11675d973eaa1 upstream. Historically we did distinguish between a flag that surpressed partition scanning, and a combinations of the minors variable and another flag if any partitions were supported. This was generally confusing and doesn't make much sense, but some corner case uses of the loop driver actually do want to support manually added partitions on a device that does not actively scan for partitions. To make things worsee the loop driver also wants to dynamically toggle the scanning for partitions on a live gendisk, which makes the disk->flags updates non-atomic. Introduce a new GD_SUPPRESS_PART_SCAN bit in disk->state that disables just scanning for partitions, and toggle that instead of GENHD_FL_NO_PART in the loop driver. Fixes: 1ebe2e5f9d68 ("block: remove GENHD_FL_EXT_DEVT") Reported-by: Ming Lei Signed-off-by: Christoph Hellwig Reviewed-by: Ming Lei Link: https://lore.kernel.org/r/20220527055806.1972352-1-hch@lst.de Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- block/genhd.c | 2 ++ drivers/block/loop.c | 8 ++++---- include/linux/genhd.h | 1 + 3 files changed, 7 insertions(+), 4 deletions(-) --- a/block/genhd.c +++ b/block/genhd.c @@ -380,6 +380,8 @@ int disk_scan_partitions(struct gendisk if (disk->flags & (GENHD_FL_NO_PART | GENHD_FL_HIDDEN)) return -EINVAL; + if (test_bit(GD_SUPPRESS_PART_SCAN, &disk->state)) + return -EINVAL; if (disk->open_partitions) return -EBUSY; --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -1067,7 +1067,7 @@ static int loop_configure(struct loop_de lo->lo_flags |= LO_FLAGS_PARTSCAN; partscan = lo->lo_flags & LO_FLAGS_PARTSCAN; if (partscan) - lo->lo_disk->flags &= ~GENHD_FL_NO_PART; + clear_bit(GD_SUPPRESS_PART_SCAN, &lo->lo_disk->state); loop_global_unlock(lo, is_loop); if (partscan) @@ -1186,7 +1186,7 @@ static void __loop_clr_fd(struct loop_de */ lo->lo_flags = 0; if (!part_shift) - lo->lo_disk->flags |= GENHD_FL_NO_PART; + set_bit(GD_SUPPRESS_PART_SCAN, &lo->lo_disk->state); mutex_lock(&lo->lo_mutex); lo->lo_state = Lo_unbound; mutex_unlock(&lo->lo_mutex); @@ -1296,7 +1296,7 @@ out_unfreeze: if (!err && (lo->lo_flags & LO_FLAGS_PARTSCAN) && !(prev_lo_flags & LO_FLAGS_PARTSCAN)) { - lo->lo_disk->flags &= ~GENHD_FL_NO_PART; + clear_bit(GD_SUPPRESS_PART_SCAN, &lo->lo_disk->state); partscan = true; } out_unlock: @@ -2028,7 +2028,7 @@ static int loop_add(int i) * userspace tools. Parameters like this in general should be avoided. */ if (!part_shift) - disk->flags |= GENHD_FL_NO_PART; + set_bit(GD_SUPPRESS_PART_SCAN, &disk->state); atomic_set(&lo->lo_refcnt, 0); mutex_init(&lo->lo_mutex); lo->lo_number = i; --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -110,6 +110,7 @@ struct gendisk { #define GD_READ_ONLY 1 #define GD_DEAD 2 #define GD_NATIVE_CAPACITY 3 +#define GD_SUPPRESS_PART_SCAN 5 struct mutex open_mutex; /* open/close mutex */ unsigned open_partitions; /* number of open partitions */