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| author | Arnd Bergmann <arnd@arndb.de> | 2019-06-19 10:24:17 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab+samsung@kernel.org> | 2019-08-04 06:33:11 -0300 |
| commit | 14e3cdbb00a885eedc95c0cf8eda8fe28d26d6b4 (patch) | |
| tree | cec366785f79f0115ee334c9f7b4b559f3564458 | |
| parent | 4590c07462fbff4ecbfe1deec44431c16191bd19 (diff) | |
| download | linux-14e3cdbb00a885eedc95c0cf8eda8fe28d26d6b4.tar.bz2 | |
media: don't drop front-end reference count for ->detach
A bugfix introduce a link failure in configurations without CONFIG_MODULES:
In file included from drivers/media/usb/dvb-usb/pctv452e.c:20:0:
drivers/media/usb/dvb-usb/pctv452e.c: In function 'pctv452e_frontend_attach':
drivers/media/dvb-frontends/stb0899_drv.h:151:36: error: weak declaration of 'stb0899_attach' being applied to a already existing, static definition
The problem is that the !IS_REACHABLE() declaration of stb0899_attach()
is a 'static inline' definition that clashes with the weak definition.
I further observed that the bugfix was only done for one of the five users
of stb0899_attach(), the other four still have the problem. This reverts
the bugfix and instead addresses the problem by not dropping the reference
count when calling '->detach()', instead we call this function directly
in dvb_frontend_put() before dropping the kref on the front-end.
I first submitted this in early 2018, and after some discussion it
was apparently discarded. While there is a long-term plan in place,
that plan is obviously not nearing completion yet, and the current
kernel is still broken unless this patch is applied.
Link: https://patchwork.kernel.org/patch/10140175/
Link: https://patchwork.linuxtv.org/patch/54831/
Cc: Max Kellermann <max.kellermann@gmail.com>
Cc: Wolfgang Rohdewald <wolfgang@rohdewald.de>
Cc: stable@vger.kernel.org
Fixes: f686c14364ad ("[media] stb0899: move code to "detach" callback")
Fixes: 6cdeaed3b142 ("media: dvb_usb_pctv452e: module refcount changes were unbalanced")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
| -rw-r--r-- | drivers/media/dvb-core/dvb_frontend.c | 4 | ||||
| -rw-r--r-- | drivers/media/usb/dvb-usb/pctv452e.c | 8 |
2 files changed, 3 insertions, 9 deletions
diff --git a/drivers/media/dvb-core/dvb_frontend.c b/drivers/media/dvb-core/dvb_frontend.c index 209186c5cd9b..06ea30a689d7 100644 --- a/drivers/media/dvb-core/dvb_frontend.c +++ b/drivers/media/dvb-core/dvb_frontend.c @@ -152,6 +152,9 @@ static void dvb_frontend_free(struct kref *ref) static void dvb_frontend_put(struct dvb_frontend *fe) { + /* call detach before dropping the reference count */ + if (fe->ops.detach) + fe->ops.detach(fe); /* * Check if the frontend was registered, as otherwise * kref was not initialized yet. @@ -3040,7 +3043,6 @@ void dvb_frontend_detach(struct dvb_frontend *fe) dvb_frontend_invoke_release(fe, fe->ops.release_sec); dvb_frontend_invoke_release(fe, fe->ops.tuner_ops.release); dvb_frontend_invoke_release(fe, fe->ops.analog_ops.release); - dvb_frontend_invoke_release(fe, fe->ops.detach); dvb_frontend_put(fe); } EXPORT_SYMBOL(dvb_frontend_detach); diff --git a/drivers/media/usb/dvb-usb/pctv452e.c b/drivers/media/usb/dvb-usb/pctv452e.c index d6b36e4f33d2..441d878fc22c 100644 --- a/drivers/media/usb/dvb-usb/pctv452e.c +++ b/drivers/media/usb/dvb-usb/pctv452e.c @@ -909,14 +909,6 @@ static int pctv452e_frontend_attach(struct dvb_usb_adapter *a) &a->dev->i2c_adap); if (!a->fe_adap[0].fe) return -ENODEV; - - /* - * dvb_frontend will call dvb_detach for both stb0899_detach - * and stb0899_release but we only do dvb_attach(stb0899_attach). - * Increment the module refcount instead. - */ - symbol_get(stb0899_attach); - if ((dvb_attach(lnbp22_attach, a->fe_adap[0].fe, &a->dev->i2c_adap)) == NULL) err("Cannot attach lnbp22\n"); |