30ad64b8ac
Since most dvb ioctls wrap their real work with dvb_usercopy, the static mutex
used in dvb_usercopy effectively is a global lock for dvb ioctls.
Unfortunately, frontend ioctls can be blocked by the frontend thread for
several seconds; this leads to unacceptable lock contention. Mitigate that by
pushing the mutex from dvb_usercopy down to the individual, device specific
ioctls.
There are 10 such ioctl functions using dvb_usercopy, either calling it
directly, or via the trivial wrapper dvb_generic_ioctl. The following already
employ their own locking and look safe:
• dvb_demux_ioctl (as per dvb_demux_do_ioctl)
• dvb_dvr_ioctl (as per dvb_dvr_do_ioctl)
• dvb_osd_ioctl (as per single non-trivial callee)
• fdtv_ca_ioctl (as per callees)
• dvb_frontend_ioctl
The following functions do not, and are thus changed to use a device specific
mutex:
• dvb_net_ioctl (as per dvb_net_do_ioctl)
• dvb_ca_en50221_io_ioctl (as per dvb_ca_en50221_io_do_ioctl)
• dvb_video_ioctl
• dvb_audio_ioctl
• dvb_ca_ioctl
Signed-off-by: Nikolaus Schulz <schulz@macnetix.de>
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
|
||
|---|---|---|
| .. | ||
| Kconfig | ||
| Makefile | ||
| demux.h | ||
| dmxdev.c | ||
| dmxdev.h | ||
| dvb-usb-ids.h | ||
| dvb_ca_en50221.c | ||
| dvb_ca_en50221.h | ||
| dvb_demux.c | ||
| dvb_demux.h | ||
| dvb_filter.c | ||
| dvb_filter.h | ||
| dvb_frontend.c | ||
| dvb_frontend.h | ||
| dvb_math.c | ||
| dvb_math.h | ||
| dvb_net.c | ||
| dvb_net.h | ||
| dvb_ringbuffer.c | ||
| dvb_ringbuffer.h | ||
| dvbdev.c | ||
| dvbdev.h | ||