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authorPaul Bolle <pebolle@tiscali.nl>2016-02-18 21:29:08 +0100
committerDavid S. Miller <davem@davemloft.net>2016-02-19 21:52:41 +0100
commit8d2c3ab4445640957d136caa3629857d63544a2a (patch)
treee72809a721c5fb5ba5e0e90ee0a9d54175aeec1e
parentMerge tag 'wireless-drivers-for-davem-2016-02-18' of git://git.kernel.org/pub... (diff)
downloadlinux-8d2c3ab4445640957d136caa3629857d63544a2a.tar.xz
linux-8d2c3ab4445640957d136caa3629857d63544a2a.zip
ser_gigaset: use container_of() instead of detour
The purpose of gigaset_device_release() is to kfree() the struct ser_cardstate that contains our struct device. This is done via a bit of a detour. First we make our struct device's driver_data point to the container of our struct ser_cardstate (which is a struct cardstate). In gigaset_device_release() we then retrieve that driver_data again. And after that we finally kfree() the struct ser_cardstate that was saved in the struct cardstate. All of this can be achieved much easier by using container_of() to get from our struct device to its container, struct ser_cardstate. Do so. Note that at the time the detour was implemented commit b8b2c7d845d5 ("base/platform: assert that dev_pm_domain callbacks are called unconditionally") had just entered the tree. That commit disconnected our platform_device and our platform_driver. These were reconnected again in v4.5-rc2 through commit 25cad69f21f5 ("base/platform: Fix platform drivers with no probe callback"). And one of the consequences of that fix was that it broke the detour via driver_data. That's because it made __device_release_driver() stop being a NOP for our struct device and actually do stuff again. One of the things it now does, is setting our driver_data to NULL. That, in turn, makes it impossible for gigaset_device_release() to get to our struct cardstate. Which has the net effect of leaking a struct ser_cardstate at every call of this driver's tty close() operation. So using container_of() has the additional benefit of actually working. Reported-by: Dmitry Vyukov <dvyukov@google.com> Tested-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Acked-by: Tilman Schmidt <tilman@imap.cc> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/isdn/gigaset/ser-gigaset.c9
1 files changed, 1 insertions, 8 deletions
diff --git a/drivers/isdn/gigaset/ser-gigaset.c b/drivers/isdn/gigaset/ser-gigaset.c
index 2a506fe0c8a4..d1f8ab915b15 100644
--- a/drivers/isdn/gigaset/ser-gigaset.c
+++ b/drivers/isdn/gigaset/ser-gigaset.c
@@ -373,13 +373,7 @@ static void gigaset_freecshw(struct cardstate *cs)
static void gigaset_device_release(struct device *dev)
{
- struct cardstate *cs = dev_get_drvdata(dev);
-
- if (!cs)
- return;
- dev_set_drvdata(dev, NULL);
- kfree(cs->hw.ser);
- cs->hw.ser = NULL;
+ kfree(container_of(dev, struct ser_cardstate, dev.dev));
}
/*
@@ -408,7 +402,6 @@ static int gigaset_initcshw(struct cardstate *cs)
cs->hw.ser = NULL;
return rc;
}
- dev_set_drvdata(&cs->hw.ser->dev.dev, cs);
tasklet_init(&cs->write_tasklet,
gigaset_modem_fill, (unsigned long) cs);