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[0/2] fix DT overlays when device links are released

Message ID 20240202-fix-device-links-overlays-v1-0-f9fd1404c8e2@analog.com
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Series fix DT overlays when device links are released | expand

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Nuno Sa via B4 Relay Feb. 2, 2024, 12:18 p.m. UTC 
Link to RFC:
 * https://lore.kernel.org/lkml/20240123-fix-device-links-overlays-v1-1-9e4f6acaab6c@analog.com/

Changes since RFC:
 * Use a dedicated workqueue to remove devlinks;
 * Flush the devlink workqueue before checking the of_node refcount
   value.

The following series is the result of the discussion I had with Rafael.
To sum up the fundamental issue, device links drop their refcounts
asynchronously and that means that the of_node refcount associated with
the device will also be dropped asynchronously. Now, in
__of_changeset_entry_destroy(), the assumption is that the node refcount
must be 1 and that cannot be guaranteed given the above.

I'm pasting again the link of the first time I exposed the issue where
one can see the resulps (big splat) of failing DT assumption:

https://lore.kernel.org/linux-devicetree/20230511151047.1779841-1-nuno.sa@analog.com/

---
Nuno Sa (2):
      driver: core: add dedicated workqueue for devlink removal
      of: dynamic: flush devlinks workqueue before destroying the changeset

 drivers/base/core.c    | 33 +++++++++++++++++++++++++++++----
 drivers/of/dynamic.c   |  8 ++++++++
 include/linux/fwnode.h |  1 +
 3 files changed, 38 insertions(+), 4 deletions(-)
---
base-commit: 6613476e225e090cc9aad49be7fa504e290dd33d
change-id: 20240123-fix-device-links-overlays-5422e033a09b
--

Thanks!
- Nuno Sá