From: Nikolaus Schulz Date: Sun, 23 Dec 2012 21:49:07 +0000 (-0300) Subject: [media] dvb: push down ioctl lock in dvb_usercopy X-Git-Tag: v3.9-rc1~93^2~387 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=30ad64b8ac539459f8975aa186421ef3db0bb5cb;p=pandora-kernel.git [media] dvb: push down ioctl lock in dvb_usercopy 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 Signed-off-by: Michael Krufky Signed-off-by: Mauro Carvalho Chehab --- Reading git-diff-tree failed