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authorMikulas Patocka <mpatocka@redhat.com>2014-01-14 04:37:54 +0400
committerMike Snitzer <snitzer@redhat.com>2014-01-15 08:23:04 +0400
commit2995fa78e423d7193f3b57835f6c1c75006a0315 (patch)
tree9f107c0503a3c0ba58559a62847e9236f3fd1951 /drivers/md/dm-sysfs.c
parent55b082e614e219fb5199a6f93e648ed35d3c96d5 (diff)
downloadlinux-2995fa78e423d7193f3b57835f6c1c75006a0315.tar.xz
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 <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
Diffstat (limited to 'drivers/md/dm-sysfs.c')
-rw-r--r--drivers/md/dm-sysfs.c5
1 files changed, 0 insertions, 5 deletions
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