Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752050Ab1E0E5r (ORCPT ); Fri, 27 May 2011 00:57:47 -0400 Received: from mail-pz0-f46.google.com ([209.85.210.46]:37266 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750869Ab1E0E5q (ORCPT ); Fri, 27 May 2011 00:57:46 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=subject:from:to:cc:in-reply-to:references:content-type:date :message-id:mime-version:x-mailer:content-transfer-encoding; b=r9q06Y/XQ3tw5HVdYiIaw8Tw3A5KHDzv8T74udbNZBdU32zpDdyPQfyvsCOMbwJFsC kI5yc0e7f2yyNTJYN7rsP11XE8xmlMLnIa4jUD/1dHJKg6VaGpKOoWzt0JqFFTT9CJW3 Ge2w4bP7QFi9us2OipOEg0opbiFv5oTSaSrno= Subject: Re: [PATCH] loop: export module parameters From: Namhyung Kim To: Jens Axboe Cc: linux-kernel@vger.kernel.org, Laurent Vivier In-Reply-To: <1306302242-7019-1-git-send-email-namhyung@gmail.com> References: <1306302242-7019-1-git-send-email-namhyung@gmail.com> Content-Type: text/plain; charset="UTF-8" Date: Fri, 27 May 2011 13:57:38 +0900 Message-ID: <1306472258.2544.6.camel@leonhard> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2537 Lines: 75 2011-05-25 (수), 14:44 +0900, Namhyung Kim: > Export 'max_loop' and 'max_part' parameters to sysfs so user can know > that how many devices are allowed and how many partitions are supported. > > If 'max_loop' is 0, there is no restriction on the number of loop devices. > User can create/use the devices as many as minor numbers available. If > 'max_part' is 0, it means simply the device doesn't support partitioning. > > Also note that 'max_part' can be adjusted to power of 2 minus 1 form if > needed. User should check this value after the module loading if he/she > want to use that number correctly (i.e. fdisk, mknod, etc.). > > Signed-off-by: Namhyung Kim > Cc: Laurent Vivier > --- > drivers/block/loop.c | 17 ++++++++++++++--- > 1 files changed, 14 insertions(+), 3 deletions(-) > > diff --git a/drivers/block/loop.c b/drivers/block/loop.c > index c59a672a3de0..76c8da78212b 100644 > --- a/drivers/block/loop.c > +++ b/drivers/block/loop.c > @@ -1540,9 +1540,9 @@ static const struct block_device_operations lo_fops = { > * And now the modules code and kernel interface. > */ > static int max_loop; > -module_param(max_loop, int, 0); > +module_param(max_loop, int, S_IRUGO); > MODULE_PARM_DESC(max_loop, "Maximum number of loop devices"); > -module_param(max_part, int, 0); > +module_param(max_part, int, S_IRUGO); > MODULE_PARM_DESC(max_part, "Maximum number of partitions per loop device"); > MODULE_LICENSE("GPL"); > MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR); > @@ -1688,9 +1688,20 @@ static int __init loop_init(void) > */ > > part_shift = 0; > - if (max_part > 0) > + if (max_part > 0) { > part_shift = fls(max_part); > > + /* > + * Adjust max_part according to part_shift as it is exported > + * to user space so that user can decide correct minor number > + * if [s]he want to create more devices. > + * > + * Note that -1 is required because partition 0 is reserved > + * for the whole disk. > + */ > + max_part = (1UL << part_shift) - 1; > + } > + > if ((1UL << part_shift) > DISK_MAX_PARTS) > return -EINVAL; > Hi Jens, Could you please consider applying this in your tree too? It's exactly the same thing what I did for brd series. Thanks. -- Regards, Namhyung Kim -- 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/