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authorNikolaus Schulz <schulz@macnetix.de>2012-12-23 18:49:07 -0300
committerMauro Carvalho Chehab <mchehab@redhat.com>2012-12-27 15:44:21 -0200
commit30ad64b8ac539459f8975aa186421ef3db0bb5cb (patch)
tree1f1024574f1e7bb1ddf25ea79f3c361acfa0f3fe /drivers/media/pci/ttpci/av7110_ca.c
parent6ae23224557d797439d02f6ce5d10a82ab544b21 (diff)
[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_ca.c')
-rw-r--r--drivers/media/pci/ttpci/av7110_ca.c24
1 files changed, 17 insertions, 7 deletions
diff --git a/drivers/media/pci/ttpci/av7110_ca.c b/drivers/media/pci/ttpci/av7110_ca.c
index 9fc1dd0ba4c3..a6079b90252a 100644
--- a/drivers/media/pci/ttpci/av7110_ca.c
+++ b/drivers/media/pci/ttpci/av7110_ca.c
@@ -253,12 +253,17 @@ static int dvb_ca_ioctl(struct file *file, unsigned int cmd, void *parg)
struct dvb_device *dvbdev = file->private_data;
struct av7110 *av7110 = dvbdev->priv;
unsigned long arg = (unsigned long) parg;
+ int ret = 0;
dprintk(8, "av7110:%p\n",av7110);
+ if (mutex_lock_interruptible(&av7110->ioctl_mutex))
+ return -ERESTARTSYS;
+
switch (cmd) {
case CA_RESET:
- return ci_ll_reset(&av7110->ci_wbuffer, file, arg, &av7110->ci_slot[0]);
+ ret = ci_ll_reset(&av7110->ci_wbuffer, file, arg,
+ &av7110->ci_slot[0]);
break;
case CA_GET_CAP:
{
@@ -277,8 +282,10 @@ static int dvb_ca_ioctl(struct file *file, unsigned int cmd, void *parg)
{
ca_slot_info_t *info=(ca_slot_info_t *)parg;
- if (info->num < 0 || info->num > 1)
+ if (info->num < 0 || info->num > 1) {
+ mutex_unlock(&av7110->ioctl_mutex);
return -EINVAL;
+ }
av7110->ci_slot[info->num].num = info->num;
av7110->ci_slot[info->num].type = FW_CI_LL_SUPPORT(av7110->arm_app) ?
CA_CI_LINK : CA_CI;
@@ -306,10 +313,10 @@ static int dvb_ca_ioctl(struct file *file, unsigned int cmd, void *parg)
{
ca_descr_t *descr = (ca_descr_t*) parg;
- if (descr->index >= 16)
- return -EINVAL;
- if (descr->parity > 1)
+ if (descr->index >= 16 || descr->parity > 1) {
+ mutex_unlock(&av7110->ioctl_mutex);
return -EINVAL;
+ }
av7110_fw_cmd(av7110, COMTYPE_PIDFILTER, SetDescr, 5,
(descr->index<<8)|descr->parity,
(descr->cw[0]<<8)|descr->cw[1],
@@ -320,9 +327,12 @@ static int dvb_ca_ioctl(struct file *file, unsigned int cmd, void *parg)
}
default:
- return -EINVAL;
+ ret = -EINVAL;
+ break;
}
- return 0;
+
+ mutex_unlock(&av7110->ioctl_mutex);
+ return ret;
}
static ssize_t dvb_ca_write(struct file *file, const char __user *buf,

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