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    Subject[PATCH v2 1/5] amba: Fix resource leak for drivers without .remove
    Date
    From: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

    Consider an amba driver with a .probe but without a .remove callback (e.g.
    pl061_gpio_driver). The function amba_probe() is called to bind a device
    and so dev_pm_domain_attach() and others are called. As there is no remove
    callback amba_remove() isn't called at unbind time however and so calling
    dev_pm_domain_detach() is missed and the pm domain keeps active.

    To fix this always use the core driver callbacks and handle missing amba
    callbacks there. For probe refuse registration as a driver without probe
    doesn't make sense.

    Fixes: 7cfe249475fd ("ARM: AMBA: Add pclk support to AMBA bus infrastructure")
    Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
    Reviewed-by: Arnd Bergmann <arnd@arndb.de>
    Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
    ---
    drivers/amba/bus.c | 20 ++++++++++++--------
    1 file changed, 12 insertions(+), 8 deletions(-)

    diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c
    index ecc304149067..b5f5ca4e3f34 100644
    --- a/drivers/amba/bus.c
    +++ b/drivers/amba/bus.c
    @@ -299,10 +299,11 @@ static int amba_remove(struct device *dev)
    {
    struct amba_device *pcdev = to_amba_device(dev);
    struct amba_driver *drv = to_amba_driver(dev->driver);
    - int ret;
    + int ret = 0;

    pm_runtime_get_sync(dev);
    - ret = drv->remove(pcdev);
    + if (drv->remove)
    + ret = drv->remove(pcdev);
    pm_runtime_put_noidle(dev);

    /* Undo the runtime PM settings in amba_probe() */
    @@ -319,7 +320,9 @@ static int amba_remove(struct device *dev)
    static void amba_shutdown(struct device *dev)
    {
    struct amba_driver *drv = to_amba_driver(dev->driver);
    - drv->shutdown(to_amba_device(dev));
    +
    + if (drv->shutdown)
    + drv->shutdown(to_amba_device(dev));
    }

    /**
    @@ -332,12 +335,13 @@ static void amba_shutdown(struct device *dev)
    */
    int amba_driver_register(struct amba_driver *drv)
    {
    - drv->drv.bus = &amba_bustype;
    + if (!drv->probe)
    + return -EINVAL;

    -#define SETFN(fn) if (drv->fn) drv->drv.fn = amba_##fn
    - SETFN(probe);
    - SETFN(remove);
    - SETFN(shutdown);
    + drv->drv.bus = &amba_bustype;
    + drv->drv.probe = amba_probe;
    + drv->drv.remove = amba_remove;
    + drv->drv.shutdown = amba_shutdown;

    return driver_register(&drv->drv);
    }
    --
    2.29.2
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