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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/dvb-core
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/dvb-core')
-rw-r--r--drivers/media/dvb-core/dvb_ca_en50221.c9
-rw-r--r--drivers/media/dvb-core/dvb_net.c71
-rw-r--r--drivers/media/dvb-core/dvb_net.h1
-rw-r--r--drivers/media/dvb-core/dvbdev.c2
4 files changed, 58 insertions, 25 deletions
diff --git a/drivers/media/dvb-core/dvb_ca_en50221.c b/drivers/media/dvb-core/dvb_ca_en50221.c
index 9be65a3b931f..190e5e0f48c7 100644
--- a/drivers/media/dvb-core/dvb_ca_en50221.c
+++ b/drivers/media/dvb-core/dvb_ca_en50221.c
@@ -156,6 +156,9 @@ struct dvb_ca_private {
/* Slot to start looking for data to read from in the next user-space read operation */
int next_read_slot;
+
+ /* mutex serializing ioctls */
+ struct mutex ioctl_mutex;
};
static void dvb_ca_en50221_thread_wakeup(struct dvb_ca_private *ca);
@@ -1191,6 +1194,9 @@ static int dvb_ca_en50221_io_do_ioctl(struct file *file,
dprintk("%s\n", __func__);
+ if (mutex_lock_interruptible(&ca->ioctl_mutex))
+ return -ERESTARTSYS;
+
switch (cmd) {
case CA_RESET:
for (slot = 0; slot < ca->slot_count; slot++) {
@@ -1241,6 +1247,7 @@ static int dvb_ca_en50221_io_do_ioctl(struct file *file,
break;
}
+ mutex_unlock(&ca->ioctl_mutex);
return err;
}
@@ -1695,6 +1702,8 @@ int dvb_ca_en50221_init(struct dvb_adapter *dvb_adapter,
mutex_init(&ca->slot_info[i].slot_lock);
}
+ mutex_init(&ca->ioctl_mutex);
+
if (signal_pending(current)) {
ret = -EINTR;
goto error;
diff --git a/drivers/media/dvb-core/dvb_net.c b/drivers/media/dvb-core/dvb_net.c
index c2117688aa23..44225b186f6d 100644
--- a/drivers/media/dvb-core/dvb_net.c
+++ b/drivers/media/dvb-core/dvb_net.c
@@ -1345,26 +1345,35 @@ static int dvb_net_do_ioctl(struct file *file,
{
struct dvb_device *dvbdev = file->private_data;
struct dvb_net *dvbnet = dvbdev->priv;
+ int ret = 0;
if (((file->f_flags&O_ACCMODE)==O_RDONLY))
return -EPERM;
+ if (mutex_lock_interruptible(&dvbnet->ioctl_mutex))
+ return -ERESTARTSYS;
+
switch (cmd) {
case NET_ADD_IF:
{
struct dvb_net_if *dvbnetif = parg;
int result;
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
+ if (!capable(CAP_SYS_ADMIN)) {
+ ret = -EPERM;
+ goto ioctl_error;
+ }
- if (!try_module_get(dvbdev->adapter->module))
- return -EPERM;
+ if (!try_module_get(dvbdev->adapter->module)) {
+ ret = -EPERM;
+ goto ioctl_error;
+ }
result=dvb_net_add_if(dvbnet, dvbnetif->pid, dvbnetif->feedtype);
if (result<0) {
module_put(dvbdev->adapter->module);
- return result;
+ ret = result;
+ goto ioctl_error;
}
dvbnetif->if_num=result;
break;
@@ -1376,8 +1385,10 @@ static int dvb_net_do_ioctl(struct file *file,
struct dvb_net_if *dvbnetif = parg;
if (dvbnetif->if_num >= DVB_NET_DEVICES_MAX ||
- !dvbnet->state[dvbnetif->if_num])
- return -EINVAL;
+ !dvbnet->state[dvbnetif->if_num]) {
+ ret = -EINVAL;
+ goto ioctl_error;
+ }
netdev = dvbnet->device[dvbnetif->if_num];
@@ -1388,16 +1399,18 @@ static int dvb_net_do_ioctl(struct file *file,
}
case NET_REMOVE_IF:
{
- int ret;
-
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
- if ((unsigned long) parg >= DVB_NET_DEVICES_MAX)
- return -EINVAL;
+ if (!capable(CAP_SYS_ADMIN)) {
+ ret = -EPERM;
+ goto ioctl_error;
+ }
+ if ((unsigned long) parg >= DVB_NET_DEVICES_MAX) {
+ ret = -EINVAL;
+ goto ioctl_error;
+ }
ret = dvb_net_remove_if(dvbnet, (unsigned long) parg);
if (!ret)
module_put(dvbdev->adapter->module);
- return ret;
+ break;
}
/* binary compatibility cruft */
@@ -1406,16 +1419,21 @@ static int dvb_net_do_ioctl(struct file *file,
struct __dvb_net_if_old *dvbnetif = parg;
int result;
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
+ if (!capable(CAP_SYS_ADMIN)) {
+ ret = -EPERM;
+ goto ioctl_error;
+ }
- if (!try_module_get(dvbdev->adapter->module))
- return -EPERM;
+ if (!try_module_get(dvbdev->adapter->module)) {
+ ret = -EPERM;
+ goto ioctl_error;
+ }
result=dvb_net_add_if(dvbnet, dvbnetif->pid, DVB_NET_FEEDTYPE_MPE);
if (result<0) {
module_put(dvbdev->adapter->module);
- return result;
+ ret = result;
+ goto ioctl_error;
}
dvbnetif->if_num=result;
break;
@@ -1427,8 +1445,10 @@ static int dvb_net_do_ioctl(struct file *file,
struct __dvb_net_if_old *dvbnetif = parg;
if (dvbnetif->if_num >= DVB_NET_DEVICES_MAX ||
- !dvbnet->state[dvbnetif->if_num])
- return -EINVAL;
+ !dvbnet->state[dvbnetif->if_num]) {
+ ret = -EINVAL;
+ goto ioctl_error;
+ }
netdev = dvbnet->device[dvbnetif->if_num];
@@ -1437,9 +1457,13 @@ static int dvb_net_do_ioctl(struct file *file,
break;
}
default:
- return -ENOTTY;
+ ret = -ENOTTY;
+ break;
}
- return 0;
+
+ioctl_error:
+ mutex_unlock(&dvbnet->ioctl_mutex);
+ return ret;
}
static long dvb_net_ioctl(struct file *file,
@@ -1505,6 +1529,7 @@ int dvb_net_init (struct dvb_adapter *adap, struct dvb_net *dvbnet,
{
int i;
+ mutex_init(&dvbnet->ioctl_mutex);
dvbnet->demux = dmx;
for (i=0; i<DVB_NET_DEVICES_MAX; i++)
diff --git a/drivers/media/dvb-core/dvb_net.h b/drivers/media/dvb-core/dvb_net.h
index 1e53acd50cf4..ede78e8c8aa8 100644
--- a/drivers/media/dvb-core/dvb_net.h
+++ b/drivers/media/dvb-core/dvb_net.h
@@ -40,6 +40,7 @@ struct dvb_net {
int state[DVB_NET_DEVICES_MAX];
unsigned int exit:1;
struct dmx_demux *demux;
+ struct mutex ioctl_mutex;
};
void dvb_net_release(struct dvb_net *);
diff --git a/drivers/media/dvb-core/dvbdev.c b/drivers/media/dvb-core/dvbdev.c
index d33101aaf0b5..401ef64f92c6 100644
--- a/drivers/media/dvb-core/dvbdev.c
+++ b/drivers/media/dvb-core/dvbdev.c
@@ -418,10 +418,8 @@ int dvb_usercopy(struct file *file,
}
/* call driver */
- mutex_lock(&dvbdev_mutex);
if ((err = func(file, cmd, parg)) == -ENOIOCTLCMD)
err = -ENOTTY;
- mutex_unlock(&dvbdev_mutex);
if (err < 0)
goto out;

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