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> |
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.. | ||
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 |