[PATCH v5 7/7] loop: be paranoid on exit and prevent new additions / removals

From: Luis Chamberlain
Date: Fri May 15 2020 - 23:20:29 EST


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@xxxxxxxxxx>
Signed-off-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
---
drivers/block/loop.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 14372df0f354..54fbcbd930de 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -2333,6 +2333,8 @@ 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);

@@ -2340,6 +2342,8 @@ 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