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| author | Nikolaus Schulz <schulz@macnetix.de> | 2012-12-23 18:49:07 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2012-12-27 15:44:21 -0200 |
| commit | 30ad64b8ac539459f8975aa186421ef3db0bb5cb (patch) | |
| tree | 1f1024574f1e7bb1ddf25ea79f3c361acfa0f3fe /drivers/media/pci/ttpci/av7110.c | |
| parent | 6ae23224557d797439d02f6ce5d10a82ab544b21 (diff) | |
| download | linux-30ad64b8ac539459f8975aa186421ef3db0bb5cb.tar.gz linux-30ad64b8ac539459f8975aa186421ef3db0bb5cb.tar.xz | |
[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 <schulz@macnetix.de>
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'drivers/media/pci/ttpci/av7110.c')
| -rw-r--r-- | drivers/media/pci/ttpci/av7110.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/media/pci/ttpci/av7110.c b/drivers/media/pci/ttpci/av7110.c index 4bd8bd56befc..2f54e2b741f6 100644 --- a/drivers/media/pci/ttpci/av7110.c +++ b/drivers/media/pci/ttpci/av7110.c @@ -2723,6 +2723,8 @@ static int __devinit av7110_attach(struct saa7146_dev* dev, if (ret < 0) goto err_av7110_exit_v4l_12; + mutex_init(&av7110->ioctl_mutex); + #if defined(CONFIG_INPUT_EVDEV) || defined(CONFIG_INPUT_EVDEV_MODULE) av7110_ir_init(av7110); #endif |