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author | Paul Bolle <pebolle@tiscali.nl> | 2016-02-18 21:29:08 +0100 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2016-02-19 21:52:41 +0100 |
commit | 8d2c3ab4445640957d136caa3629857d63544a2a (patch) | |
tree | e72809a721c5fb5ba5e0e90ee0a9d54175aeec1e | |
parent | Merge tag 'wireless-drivers-for-davem-2016-02-18' of git://git.kernel.org/pub... (diff) | |
download | linux-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.c | 9 |
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); |