[PATCH v7 5/8] loop: be paranoid on exit and prevent new additions / removals

Luis Chamberlain
2020-06-19T20:47:53Z

Be pedantic on removal as well and hold the mutex.
This should prevent uses of addition while we exit.

Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
drivers/block/loop.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index c33bbbfd1bd9..d55e1b52f076 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -2402,6 +2402,8 @@ static void __exit loop_exit(void)

range = max_loop ? max_loop << part_shift : 1UL << MINORBITS;

+ mutex_lock(&loop_ctl_mutex);
+
idr_for_each(&loop_index_idr, &loop_exit_cb, NULL);
idr_destroy(&loop_index_idr);

@@ -2409,6 +2411,8 @@ static void __exit loop_exit(void)
unregister_blkdev(LOOP_MAJOR, "loop");

misc_deregister(&loop_misc);
+
+ mutex_unlock(&loop_ctl_mutex);
}

module_init(loop_init);
--
2.26.2