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| author | Mikulas Patocka <mpatocka@redhat.com> | 2014-01-13 19:37:54 -0500 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2014-01-14 23:23:04 -0500 |
| commit | 2995fa78e423d7193f3b57835f6c1c75006a0315 (patch) | |
| tree | 9f107c0503a3c0ba58559a62847e9236f3fd1951 /drivers/md/dm-sysfs.c | |
| parent | 55b082e614e219fb5199a6f93e648ed35d3c96d5 (diff) | |
| download | lwn-2995fa78e423d7193f3b57835f6c1c75006a0315.tar.gz lwn-2995fa78e423d7193f3b57835f6c1c75006a0315.zip | |
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.c | 5 |
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 |