From 2995fa78e423d7193f3b57835f6c1c75006a0315 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Mon, 13 Jan 2014 19:37:54 -0500 Subject: dm sysfs: fix a module unload race This reverts commit be35f48610 ("dm: wait until embedded kobject is released before destroying a device") and provides an improved fix. The kobject release code that calls the completion must be placed in a non-module file, otherwise there is a module unload race (if the process calling dm_kobject_release is preempted and the DM module unloaded after the completion is triggered, but before dm_kobject_release returns). To fix this race, this patch moves the completion code to dm-builtin.c which is always compiled directly into the kernel if BLK_DEV_DM is selected. The patch introduces a new dm_kobject_holder structure, its purpose is to keep the completion and kobject in one place, so that it can be accessed from non-module code without the need to export the layout of struct mapped_device to that code. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer Cc: stable@vger.kernel.org --- drivers/md/dm-sysfs.c | 5 ----- 1 file changed, 5 deletions(-) (limited to 'drivers/md/dm-sysfs.c') diff --git a/drivers/md/dm-sysfs.c b/drivers/md/dm-sysfs.c index e0cc5d6a9e46..c62c5ab6aed5 100644 --- a/drivers/md/dm-sysfs.c +++ b/drivers/md/dm-sysfs.c @@ -79,11 +79,6 @@ static const struct sysfs_ops dm_sysfs_ops = { .show = dm_attr_show, }; -static void dm_kobject_release(struct kobject *kobj) -{ - complete(dm_get_completion_from_kobject(kobj)); -} - /* * dm kobject is embedded in mapped_device structure * no need to define release function here -- cgit v1.2.3