From mboxrd@z Thu Jan 1 00:00:00 1970 From: Clemens Fruhwirth Subject: Re: [PATCH] Forcing capacity sizes for block devices - (sorry, gmail ruined inlining with wordwrapping in the last mail) Date: Sun, 20 Dec 2009 14:19:08 +0100 Message-ID: <4B2E244C.8070705@endorphin.org> References: <2f83750a0912200405v77f39a7eifef024cc4cb10a20@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-fx0-f221.google.com ([209.85.220.221]:52679 "EHLO mail-fx0-f221.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754828AbZLTNTR (ORCPT ); Sun, 20 Dec 2009 08:19:17 -0500 Received: by fxm21 with SMTP id 21so4023386fxm.21 for ; Sun, 20 Dec 2009 05:19:15 -0800 (PST) In-Reply-To: <2f83750a0912200405v77f39a7eifef024cc4cb10a20@mail.gmail.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: linux-scsi@vger.kernel.org, grundler@google.com Make the size attribute of block devices writable via sysfs. This allows userspace to force device boundaries in cases where the device driver is unable to detect the correct size, as with spec-incompliant SD card readers. diff -uprN -X linux-2.6.32-vanilla/Documentation/dontdiff linux-2.6.32-vanilla/block/genhd.c linux-2.6.32-patched/block/genhd.c --- linux-2.6.32-vanilla/block/genhd.c 2009-12-03 04:51:21.000000000 +0100 +++ linux-2.6.32-patched/block/genhd.c 2009-12-15 14:38:24.962463446 +0100 @@ -865,7 +865,7 @@ static DEVICE_ATTR(range, S_IRUGO, disk_ static DEVICE_ATTR(ext_range, S_IRUGO, disk_ext_range_show, NULL); static DEVICE_ATTR(removable, S_IRUGO, disk_removable_show, NULL); static DEVICE_ATTR(ro, S_IRUGO, disk_ro_show, NULL); -static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL); +static DEVICE_ATTR(size, S_IRUGO | S_IWUSR, part_size_show, part_size_set); static DEVICE_ATTR(alignment_offset, S_IRUGO, disk_alignment_offset_show, NULL); static DEVICE_ATTR(capability, S_IRUGO, disk_capability_show, NULL); static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL); diff -uprN -X linux-2.6.32-vanilla/Documentation/dontdiff linux-2.6.32-vanilla/fs/partitions/check.c linux-2.6.32-patched/fs/partitions/check.c --- linux-2.6.32-vanilla/fs/partitions/check.c 2009-12-03 04:51:21.000000000 +0100 +++ linux-2.6.32-patched/fs/partitions/check.c 2009-12-19 10:38:58.745294907 +0100 @@ -219,6 +219,18 @@ ssize_t part_size_show(struct device *de return sprintf(buf, "%llu\n",(unsigned long long)p->nr_sects); } +ssize_t part_size_set(struct device *dev, + struct device_attribute *attr, char *buf, size_t len) +{ + struct hd_struct *p = dev_to_part(dev); + unsigned long long val; + if (strict_strtoull(buf, 0, &val)) + return -EINVAL; + + p->nr_sects = val; + return len; +} + ssize_t part_alignment_offset_show(struct device *dev, struct device_attribute *attr, char *buf) { diff -uprN -X linux-2.6.32-vanilla/Documentation/dontdiff linux-2.6.32-vanilla/include/linux/genhd.h linux-2.6.32-patched/include/linux/genhd.h --- linux-2.6.32-vanilla/include/linux/genhd.h 2009-12-03 04:51:21.000000000 +0100 +++ linux-2.6.32-patched/include/linux/genhd.h 2009-12-19 10:40:30.900871273 +0100 @@ -549,6 +549,9 @@ extern void blk_unregister_region(dev_t extern ssize_t part_size_show(struct device *dev, struct device_attribute *attr, char *buf); +extern ssize_t part_size_set(struct device *dev, + struct device_attribute *attr, char *buf, + size_t len); extern ssize_t part_stat_show(struct device *dev, struct device_attribute *attr, char *buf); extern ssize_t part_inflight_show(struct device *dev, Signed-off-by: Clemens Fruhwirth Reviewed-by: Grant Grundler