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authorChristoph Hellwig <hch@lst.de>2021-05-14 15:18:41 +0200
committerJens Axboe <axboe@kernel.dk>2021-05-20 07:59:35 -0600
commit6c60ff048ca1e0739f39aa25996543c6e662a46c (patch)
tree2cbd9f0a9f9c0e49600c999500d7c388e6c8ec4e /block/genhd.c
parent9a66e6bd7e9ba51d83854aaf7670014e9538e462 (diff)
block: prevent block device lookups at the beginning of del_gendisk
As an artifact of how gendisk lookup used to work in earlier kernels, GENHD_FL_UP is only cleared very late in del_gendisk, and a global lock is used to prevent opens from succeeding while del_gendisk is tearing down the gendisk. Switch to clearing the flag early and under bd_mutex so that callers can use bd_mutex to stabilize the flag, which removes the need for the global mutex. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20210514131842.1600568-2-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/genhd.c')
-rw-r--r--block/genhd.c11
1 files changed, 1 insertions, 10 deletions
diff --git a/block/genhd.c b/block/genhd.c
index 39ca97b0edc6..9f8cb7beaad1 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -29,8 +29,6 @@
static struct kobject *block_depr;
-DECLARE_RWSEM(bdev_lookup_sem);
-
/* for extended dynamic devt allocation, currently only one major is used */
#define NR_EXT_DEVT (1 << MINORBITS)
static DEFINE_IDA(ext_devt_ida);
@@ -609,13 +607,8 @@ void del_gendisk(struct gendisk *disk)
blk_integrity_del(disk);
disk_del_events(disk);
- /*
- * Block lookups of the disk until all bdevs are unhashed and the
- * disk is marked as dead (GENHD_FL_UP cleared).
- */
- down_write(&bdev_lookup_sem);
-
mutex_lock(&disk->part0->bd_mutex);
+ disk->flags &= ~GENHD_FL_UP;
blk_drop_partitions(disk);
mutex_unlock(&disk->part0->bd_mutex);
@@ -629,8 +622,6 @@ void del_gendisk(struct gendisk *disk)
remove_inode_hash(disk->part0->bd_inode);
set_capacity(disk, 0);
- disk->flags &= ~GENHD_FL_UP;
- up_write(&bdev_lookup_sem);
if (!(disk->flags & GENHD_FL_HIDDEN)) {
sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi");