From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751786AbbDHGYk (ORCPT ); Wed, 8 Apr 2015 02:24:40 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55053 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751372AbbDHGYM (ORCPT ); Wed, 8 Apr 2015 02:24:12 -0400 From: Jarod Wilson To: linux-kernel@vger.kernel.org Cc: Jarod Wilson , Christoph Hellwig , Jens Axboe , Tejun Heo , Alexander Viro , Markus Pargmann , Stefan Weinhuber , Stefan Haberland , Sebastian Ott , Fabian Frederick , Ming Lei , David Herrmann , Mike Galbraith , Andrew Morton , Peter Zijlstra , nbd-general@lists.sourceforge.net, linux-s390@vger.kernel.org Subject: [PATCH 1/7] block: export blkdev_reread_part() and __blkdev_reread_part() Date: Wed, 8 Apr 2015 02:23:40 -0400 Message-Id: <1428474226-27386-2-git-send-email-jarod@redhat.com> In-Reply-To: <1428474226-27386-1-git-send-email-jarod@redhat.com> References: <1428218688-4092-1-git-send-email-ming.lei@canonical.com> <1428474226-27386-1-git-send-email-jarod@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch exports blkdev_reread_part() for block drivers, also introduce __blkdev_reread_part(), a lockless version. For some drivers, such as loop, a reread of partitions can be run from the release path, and bd_mutex may already be held prior to calling ioctl_by_bdev(bdev, BLKRRPART, 0), so introduce a lockless path for use in such cases. CC: Christoph Hellwig CC: Jens Axboe CC: Tejun Heo CC: Alexander Viro CC: Markus Pargmann CC: Stefan Weinhuber CC: Stefan Haberland CC: Sebastian Ott CC: Fabian Frederick CC: Ming Lei CC: David Herrmann CC: Mike Galbraith CC: Andrew Morton CC: Peter Zijlstra CC: nbd-general@lists.sourceforge.net CC: linux-s390@vger.kernel.org Signed-off-by: Jarod Wilson --- block/ioctl.c | 26 +++++++++++++++++++++++--- include/linux/fs.h | 3 +++ 2 files changed, 26 insertions(+), 3 deletions(-) diff --git a/block/ioctl.c b/block/ioctl.c index 7d8befd..64a4fcb 100644 --- a/block/ioctl.c +++ b/block/ioctl.c @@ -150,21 +150,41 @@ static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user } } -static int blkdev_reread_part(struct block_device *bdev) +/* + * This is an exported API for the block driver, and will not + * acquire bd_mutex, leaving it up to the caller to handle + * any necessary locking. + */ +int __blkdev_reread_part(struct block_device *bdev) { struct gendisk *disk = bdev->bd_disk; - int res; if (!disk_part_scan_enabled(disk) || bdev != bdev->bd_contains) return -EINVAL; if (!capable(CAP_SYS_ADMIN)) return -EACCES; + + return rescan_partitions(disk, bdev); +} +EXPORT_SYMBOL(__blkdev_reread_part); + +/* + * This is an exported API for the block driver, and will + * acquire bd_mutex. Make sure you aren't calling it with + * bd_mutex already held, or we'll return -EBUSY. + */ +int blkdev_reread_part(struct block_device *bdev) +{ + int res; + if (!mutex_trylock(&bdev->bd_mutex)) return -EBUSY; - res = rescan_partitions(disk, bdev); + res = __blkdev_reread_part(bdev); mutex_unlock(&bdev->bd_mutex); + return res; } +EXPORT_SYMBOL(blkdev_reread_part); static int blk_ioctl_discard(struct block_device *bdev, uint64_t start, uint64_t len, int secure) diff --git a/include/linux/fs.h b/include/linux/fs.h index f4131e8..11398e3 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2245,6 +2245,9 @@ extern struct block_device *blkdev_get_by_path(const char *path, fmode_t mode, extern struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder); extern void blkdev_put(struct block_device *bdev, fmode_t mode); +extern int __blkdev_reread_part(struct block_device *bdev); +extern int blkdev_reread_part(struct block_device *bdev); + #ifdef CONFIG_SYSFS extern int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk); extern void bd_unlink_disk_holder(struct block_device *bdev, -- 1.8.3.1