From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933421AbbA1EPL (ORCPT ); Tue, 27 Jan 2015 23:15:11 -0500 Received: from mail.kernel.org ([198.145.29.136]:37249 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760604AbbA1EPG (ORCPT ); Tue, 27 Jan 2015 23:15:06 -0500 From: lizf@kernel.org To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Keith Busch , Jens Axboe , Zefan Li Subject: [PATCH 3.4 20/91] block: Fix dev_t minor allocation lifetime Date: Wed, 28 Jan 2015 12:06:47 +0800 Message-Id: <1422418236-12852-40-git-send-email-lizf@kernel.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1422418050-12581-1-git-send-email-lizf@kernel.org> References: <1422418050-12581-1-git-send-email-lizf@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Keith Busch 3.4.105-rc1 review patch. If anyone has any objections, please let me know. ------------------ commit 2da78092dda13f1efd26edbbf99a567776913750 upstream. Releases the dev_t minor when all references are closed to prevent another device from acquiring the same major/minor. Since the partition's release may be invoked from call_rcu's soft-irq context, the ext_dev_idr's mutex had to be replaced with a spinlock so as not so sleep. Signed-off-by: Keith Busch Signed-off-by: Jens Axboe [lizf: Backported to 3.4: - adjust context - remove idr_preload() and idr_preload_end()] Signed-off-by: Zefan Li --- block/genhd.c | 18 +++++++++--------- block/partition-generic.c | 2 +- 2 files changed, 10 insertions(+), 10 deletions(-) diff --git a/block/genhd.c b/block/genhd.c index d815a0f..54867f4 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -27,10 +27,10 @@ struct kobject *block_depr; /* for extended dynamic devt allocation, currently only one major is used */ #define NR_EXT_DEVT (1 << MINORBITS) -/* For extended devt allocation. ext_devt_mutex prevents look up +/* For extended devt allocation. ext_devt_lock prevents look up * results from going away underneath its user. */ -static DEFINE_MUTEX(ext_devt_mutex); +static DEFINE_SPINLOCK(ext_devt_lock); static DEFINE_IDR(ext_devt_idr); static struct device_type disk_type; @@ -420,13 +420,13 @@ int blk_alloc_devt(struct hd_struct *part, dev_t *devt) do { if (!idr_pre_get(&ext_devt_idr, GFP_KERNEL)) return -ENOMEM; - mutex_lock(&ext_devt_mutex); + spin_lock(&ext_devt_lock); rc = idr_get_new(&ext_devt_idr, part, &idx); if (!rc && idx >= NR_EXT_DEVT) { idr_remove(&ext_devt_idr, idx); rc = -EBUSY; } - mutex_unlock(&ext_devt_mutex); + spin_unlock(&ext_devt_lock); } while (rc == -EAGAIN); if (rc) @@ -453,9 +453,9 @@ void blk_free_devt(dev_t devt) return; if (MAJOR(devt) == BLOCK_EXT_MAJOR) { - mutex_lock(&ext_devt_mutex); + spin_lock(&ext_devt_lock); idr_remove(&ext_devt_idr, blk_mangle_minor(MINOR(devt))); - mutex_unlock(&ext_devt_mutex); + spin_unlock(&ext_devt_lock); } } @@ -662,7 +662,6 @@ void del_gendisk(struct gendisk *disk) if (!sysfs_deprecated) sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk))); device_del(disk_to_dev(disk)); - blk_free_devt(disk_to_dev(disk)->devt); } EXPORT_SYMBOL(del_gendisk); @@ -687,13 +686,13 @@ struct gendisk *get_gendisk(dev_t devt, int *partno) } else { struct hd_struct *part; - mutex_lock(&ext_devt_mutex); + spin_lock(&ext_devt_lock); part = idr_find(&ext_devt_idr, blk_mangle_minor(MINOR(devt))); if (part && get_disk(part_to_disk(part))) { *partno = part->partno; disk = part_to_disk(part); } - mutex_unlock(&ext_devt_mutex); + spin_unlock(&ext_devt_lock); } return disk; @@ -1101,6 +1100,7 @@ static void disk_release(struct device *dev) { struct gendisk *disk = dev_to_disk(dev); + blk_free_devt(dev->devt); disk_release_events(disk); kfree(disk->random); disk_replace_part_tbl(disk, NULL); diff --git a/block/partition-generic.c b/block/partition-generic.c index 7b8b8d1..daafc85 100644 --- a/block/partition-generic.c +++ b/block/partition-generic.c @@ -211,6 +211,7 @@ static const struct attribute_group *part_attr_groups[] = { static void part_release(struct device *dev) { struct hd_struct *p = dev_to_part(dev); + blk_free_devt(dev->devt); free_part_stats(p); free_part_info(p); kfree(p); @@ -253,7 +254,6 @@ void delete_partition(struct gendisk *disk, int partno) rcu_assign_pointer(ptbl->last_lookup, NULL); kobject_put(part->holder_dir); device_del(part_to_dev(part)); - blk_free_devt(part_devt(part)); hd_struct_put(part); } -- 1.9.1