On Mon, Mar 25, 2024 at 11:44:01AM -0500, Rob Herring wrote:
> On Mon, Mar 25, 2024 at 04:21:25PM +0100, Herve Codina wrote:
> > The commit 80dd33cf72d1 ("drivers: base: Fix device link removal")
> > introduces a workqueue to release the consumer and supplier devices used
> > in the devlink.
> > In the job queued, devices are release and in turn, when all the
> > references to these devices are dropped, the release function of the
> > device itself is called.
> >
> > Nothing is present to provide some synchronisation with this workqueue
> > in order to ensure that all ongoing releasing operations are done and
> > so, some other operations can be started safely.
> >
> > For instance, in the following sequence:
> > 1) of_platform_depopulate()
> > 2) of_overlay_remove()
> >
> > During the step 1, devices are released and related devlinks are removed
> > (jobs pushed in the workqueue).
> > During the step 2, OF nodes are destroyed but, without any
> > synchronisation with devlink removal jobs, of_overlay_remove() can raise
> > warnings related to missing of_node_put():
> > ERROR: memory leak, expected refcount 1 instead of 2
> >
> > Indeed, the missing of_node_put() call is going to be done, too late,
> > from the workqueue job execution.
> >
> > Introduce device_link_wait_removal() to offer a way to synchronize
> > operations waiting for the end of devlink removals (i.e. end of
> > workqueue jobs).
> > Also, as a flushing operation is done on the workqueue, the workqueue
> > used is moved from a system-wide workqueue to a local one.
> >
> > Cc: stable@xxxxxxxxxxxxxxx
> > Signed-off-by: Herve Codina <herve.codina@xxxxxxxxxxx>
> > Tested-by: Luca Ceresoli <luca.ceresoli@xxxxxxxxxxx>
> > Reviewed-by: Nuno Sa <nuno.sa@xxxxxxxxxx>
> > Reviewed-by: Saravana Kannan <saravanak@xxxxxxxxxx>
> > ---
> > drivers/base/core.c | 26 +++++++++++++++++++++++---
> > include/linux/device.h | 1 +
> > 2 files changed, 24 insertions(+), 3 deletions(-)
>
> Greg, can you ack and I'll take this series.
Looks semi-sane:
Acked-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
