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Subject[PATCH 2/4] amba: Fix resource leak for drivers without .remove
Date
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")
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 8658e0533b67..8c4a42df47c6 100644
--- a/drivers/amba/bus.c
+++ b/drivers/amba/bus.c
@@ -300,10 +300,11 @@ 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() */
@@ -320,7 +321,9 @@ 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));
}

/**
@@ -333,12 +336,13 @@ 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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