diff options
Diffstat (limited to 'block/ioctl.c')
| -rw-r--r-- | block/ioctl.c | 37 |
1 files changed, 32 insertions, 5 deletions
diff --git a/block/ioctl.c b/block/ioctl.c index 7d8befde2aca..8061eba42887 100644 --- a/block/ioctl.c +++ b/block/ioctl.c @@ -150,21 +150,48 @@ 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. This API should be used in case that + * caller has held bd_mutex already. + */ +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; - if (!mutex_trylock(&bdev->bd_mutex)) - return -EBUSY; - res = rescan_partitions(disk, bdev); + + lockdep_assert_held(&bdev->bd_mutex); + + return rescan_partitions(disk, bdev); +} +EXPORT_SYMBOL(__blkdev_reread_part); + +/* + * This is an exported API for the block driver, and will + * try to acquire bd_mutex. If bd_mutex has been held already + * in current context, please call __blkdev_reread_part(). + * + * Make sure the held locks in current context aren't required + * in open()/close() handler and I/O path for avoiding ABBA deadlock: + * - bd_mutex is held before calling block driver's open/close + * handler + * - reading partition table may submit I/O to the block device + */ +int blkdev_reread_part(struct block_device *bdev) +{ + int res; + + mutex_lock(&bdev->bd_mutex); + 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) |