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authorMing Lei <ming.lei@redhat.com>2020-09-01 18:07:38 +0800
committerJens Axboe <axboe@kernel.dk>2020-09-01 08:34:08 -0600
commitcafe01ef8fcb248583038e1be071383530fe355a (patch)
treeaf141eea39609d18694bc3a9f8531ce53c8c3254 /block
parentde1b0ee490eafdf65fac9eef9925391a8369f2dc (diff)
block: release disk reference in hd_struct_free_work
Commit e8c7d14ac6c3 ("block: revert back to synchronous request_queue removal") stops to release request queue from wq context because that commit supposed all blk_put_queue() is called in context which is allowed to sleep. However, this assumption isn't true because we release disk's reference in partition's percpu_ref's ->release() which doesn't allow to sleep, because the ->release() is run via call_rcu(). Fixes this issue by moving put disk reference into hd_struct_free_work() Fixes: e8c7d14ac6c3 ("block: revert back to synchronous request_queue removal") Reported-by: Ilya Dryomov <idryomov@gmail.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Tested-by: Ilya Dryomov <idryomov@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r--block/partitions/core.c10
1 files changed, 9 insertions, 1 deletions
diff --git a/block/partitions/core.c b/block/partitions/core.c
index e62a98a8eeb7..5a18c8edabbc 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -278,6 +278,15 @@ static void hd_struct_free_work(struct work_struct *work)
{
struct hd_struct *part =
container_of(to_rcu_work(work), struct hd_struct, rcu_work);
+ struct gendisk *disk = part_to_disk(part);
+
+ /*
+ * Release the disk reference acquired in delete_partition here.
+ * We can't release it in hd_struct_free because the final put_device
+ * needs process context and thus can't be run directly from a
+ * percpu_ref ->release handler.
+ */
+ put_device(disk_to_dev(disk));
part->start_sect = 0;
part->nr_sects = 0;
@@ -293,7 +302,6 @@ static void hd_struct_free(struct percpu_ref *ref)
rcu_dereference_protected(disk->part_tbl, 1);
rcu_assign_pointer(ptbl->last_lookup, NULL);
- put_device(disk_to_dev(disk));
INIT_RCU_WORK(&part->rcu_work, hd_struct_free_work);
queue_rcu_work(system_wq, &part->rcu_work);