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| author | Mikulas Patocka <mpatocka@redhat.com> | 2014-01-13 19:37:54 -0500 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2014-04-02 00:58:43 +0100 |
| commit | 43057146932997ca54a2326cfd6abe9fe1ec5a9f (patch) | |
| tree | bfa876f0e2a6e1c327e42952dd3a51daea3299bd /drivers/md/Kconfig | |
| parent | b7785833fe6d2c3027d3e385d72bd31775031d2b (diff) | |
| download | kernel_samsung_smdk4412-43057146932997ca54a2326cfd6abe9fe1ec5a9f.zip kernel_samsung_smdk4412-43057146932997ca54a2326cfd6abe9fe1ec5a9f.tar.gz kernel_samsung_smdk4412-43057146932997ca54a2326cfd6abe9fe1ec5a9f.tar.bz2 | |
dm sysfs: fix a module unload race
commit 2995fa78e423d7193f3b57835f6c1c75006a0315 upstream.
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>
[bwh: Backported to 3.2:
- Adjust context
- Remove paranoid check of container_of() result in dm_get_from_kobject(),
which would now be incorrect
- Include <linux/export.h> in dm-builtin.c, included indirectly upstream]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'drivers/md/Kconfig')
| -rw-r--r-- | drivers/md/Kconfig | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig index faa4741..e10b6bb 100644 --- a/drivers/md/Kconfig +++ b/drivers/md/Kconfig @@ -185,8 +185,12 @@ config MD_FAULTY In unsure, say N. +config BLK_DEV_DM_BUILTIN + boolean + config BLK_DEV_DM tristate "Device mapper support" + select BLK_DEV_DM_BUILTIN ---help--- Device-mapper is a low level volume manager. It works by allowing people to specify mappings for ranges of logical sectors. Various |