Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932692Ab1EXOgQ (ORCPT ); Tue, 24 May 2011 10:36:16 -0400 Received: from mail-pz0-f46.google.com ([209.85.210.46]:38592 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932601Ab1EXOgN (ORCPT ); Tue, 24 May 2011 10:36:13 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=from:to:cc:subject:date:message-id:x-mailer:in-reply-to:references; b=PDb1u0+XtbrCKefmBx1o6taEyESyzpzUDnZ7Z54q3OC11KrcTpiRp652cjrJTKuHCC 59Kx4D7fSqWKAH2RBrrEyQy97l2TUwkW6tErbrI13cvHR1wZlhcwtnkhRUSepKQHo4ay nCmaZcrdDc8dujkg+owwZsBcgKXqxgsmwLFS4= From: Namhyung Kim To: Jens Axboe Cc: linux-kernel@vger.kernel.org, Laurent Vivier Subject: [PATCH 2/2] loop: handle on-demand devices correctly Date: Tue, 24 May 2011 23:36:01 +0900 Message-Id: <1306247761-2246-2-git-send-email-namhyung@gmail.com> X-Mailer: git-send-email 1.7.5.2 In-Reply-To: <1306247761-2246-1-git-send-email-namhyung@gmail.com> References: <1306247761-2246-1-git-send-email-namhyung@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3511 Lines: 90 When finding or allocating a loop device, loop_probe() did not take partition numbers into account so that it can result to a different device. Consider following example: $ sudo modprobe loop max_part=15 $ ls -l /dev/loop* brw-rw---- 1 root disk 7, 0 2011-05-24 22:16 /dev/loop0 brw-rw---- 1 root disk 7, 16 2011-05-24 22:16 /dev/loop1 brw-rw---- 1 root disk 7, 32 2011-05-24 22:16 /dev/loop2 brw-rw---- 1 root disk 7, 48 2011-05-24 22:16 /dev/loop3 brw-rw---- 1 root disk 7, 64 2011-05-24 22:16 /dev/loop4 brw-rw---- 1 root disk 7, 80 2011-05-24 22:16 /dev/loop5 brw-rw---- 1 root disk 7, 96 2011-05-24 22:16 /dev/loop6 brw-rw---- 1 root disk 7, 112 2011-05-24 22:16 /dev/loop7 $ sudo mknod /dev/loop8 b 7 128 $ sudo losetup /dev/loop8 ~/temp/disk-with-3-parts.img $ sudo losetup -a /dev/loop128: [0805]:278201 (/home/namhyung/temp/disk-with-3-parts.img) $ ls -l /dev/loop* brw-rw---- 1 root disk 7, 0 2011-05-24 22:16 /dev/loop0 brw-rw---- 1 root disk 7, 16 2011-05-24 22:16 /dev/loop1 brw-rw---- 1 root disk 7, 2048 2011-05-24 22:18 /dev/loop128 brw-rw---- 1 root disk 7, 2049 2011-05-24 22:18 /dev/loop128p1 brw-rw---- 1 root disk 7, 2050 2011-05-24 22:18 /dev/loop128p2 brw-rw---- 1 root disk 7, 2051 2011-05-24 22:18 /dev/loop128p3 brw-rw---- 1 root disk 7, 32 2011-05-24 22:16 /dev/loop2 brw-rw---- 1 root disk 7, 48 2011-05-24 22:16 /dev/loop3 brw-rw---- 1 root disk 7, 64 2011-05-24 22:16 /dev/loop4 brw-rw---- 1 root disk 7, 80 2011-05-24 22:16 /dev/loop5 brw-rw---- 1 root disk 7, 96 2011-05-24 22:16 /dev/loop6 brw-rw---- 1 root disk 7, 112 2011-05-24 22:16 /dev/loop7 brw-r--r-- 1 root root 7, 128 2011-05-24 22:17 /dev/loop8 After this patch, /dev/loop8 - instead of /dev/loop128 - was accessed correctly. In addition, 'range' passed to blk_register_region() should include all range of dev_t that LOOP_MAJOR can address. It does not need to be limited by partition numbers unless 'max_loop' param was specified. Signed-off-by: Namhyung Kim Cc: Laurent Vivier --- drivers/block/loop.c | 8 ++++---- 1 files changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index cbf7052d1dd5..c59a672a3de0 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -1658,7 +1658,7 @@ static struct kobject *loop_probe(dev_t dev, int *part, void *data) struct kobject *kobj; mutex_lock(&loop_devices_mutex); - lo = loop_init_one(dev & MINORMASK); + lo = loop_init_one(MINOR(dev) >> part_shift); kobj = lo ? get_disk(lo->lo_disk) : ERR_PTR(-ENOMEM); mutex_unlock(&loop_devices_mutex); @@ -1699,10 +1699,10 @@ static int __init loop_init(void) if (max_loop) { nr = max_loop; - range = max_loop; + range = max_loop << part_shift; } else { nr = 8; - range = 1UL << (MINORBITS - part_shift); + range = 1UL << MINORBITS; } if (register_blkdev(LOOP_MAJOR, "loop")) @@ -1741,7 +1741,7 @@ static void __exit loop_exit(void) unsigned long range; struct loop_device *lo, *next; - range = max_loop ? max_loop : 1UL << (MINORBITS - part_shift); + range = max_loop ? max_loop << part_shift : 1UL << MINORBITS; list_for_each_entry_safe(lo, next, &loop_devices, lo_list) loop_del_one(lo); -- 1.7.5.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/