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    Subject[PATCH AUTOSEL 5.7 10/53] gpu: host1x: Detach driver on unregister
    Date
    From: Thierry Reding <treding@nvidia.com>

    [ Upstream commit d9a0a05bf8c76e6dc79230669a8b5d685b168c30 ]

    Currently when a host1x device driver is unregistered, it is not
    detached from the host1x controller, which means that the device
    will stay around and when the driver is registered again, it may
    bind to the old, stale device rather than the new one that was
    created from scratch upon driver registration. This in turn can
    cause various weird crashes within the driver core because it is
    confronted with a device that was already deleted.

    Fix this by detaching the driver from the host1x controller when
    it is unregistered. This ensures that the deleted device also is
    no longer present in the device list that drivers will bind to.

    Reported-by: Sowjanya Komatineni <skomatineni@nvidia.com>
    Signed-off-by: Thierry Reding <treding@nvidia.com>
    Tested-by: Sowjanya Komatineni <skomatineni@nvidia.com>
    Signed-off-by: Thierry Reding <treding@nvidia.com>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/gpu/host1x/bus.c | 9 +++++++++
    1 file changed, 9 insertions(+)

    diff --git a/drivers/gpu/host1x/bus.c b/drivers/gpu/host1x/bus.c
    index 6a995db51d6d8..e201f62d62c0c 100644
    --- a/drivers/gpu/host1x/bus.c
    +++ b/drivers/gpu/host1x/bus.c
    @@ -686,8 +686,17 @@ EXPORT_SYMBOL(host1x_driver_register_full);
    */
    void host1x_driver_unregister(struct host1x_driver *driver)
    {
    + struct host1x *host1x;
    +
    driver_unregister(&driver->driver);

    + mutex_lock(&devices_lock);
    +
    + list_for_each_entry(host1x, &devices, list)
    + host1x_detach_driver(host1x, driver);
    +
    + mutex_unlock(&devices_lock);
    +
    mutex_lock(&drivers_lock);
    list_del_init(&driver->list);
    mutex_unlock(&drivers_lock);
    --
    2.25.1
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