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[media] dvb: push down ioctl lock in dvb_usercopy

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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>
This commit is contained in:
Nikolaus Schulz 2012-12-23 18:49:07 -03:00 committed by Mauro Carvalho Chehab
parent 6ae2322455
commit 30ad64b8ac
8 changed files with 87 additions and 32 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
drivers/media/dvb-core/dvb_ca_en50221.c
View File

@ -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;

71
drivers/media/dvb-core/dvb_net.c
View File

@ -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++)

1
drivers/media/dvb-core/dvb_net.h
View File

@ -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 *);

2
drivers/media/dvb-core/dvbdev.c
View File

@ -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;

2
drivers/media/pci/ttpci/av7110.c
View File

@ -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

2
drivers/media/pci/ttpci/av7110.h
View File

@ -271,6 +271,8 @@ struct av7110 {
struct dvb_frontend* fe;
fe_status_t fe_status;
struct mutex ioctl_mutex;
/* crash recovery */
void (*recover)(struct av7110* av7110);
fe_sec_voltage_t saved_voltage;

8
drivers/media/pci/ttpci/av7110_av.c
View File

@ -1109,6 +1109,9 @@ static int dvb_video_ioctl(struct file *file,
}
}
if (mutex_lock_interruptible(&av7110->ioctl_mutex))
return -ERESTARTSYS;
switch (cmd) {
case VIDEO_STOP:
av7110->videostate.play_state = VIDEO_STOPPED;
@ -1297,6 +1300,7 @@ static int dvb_video_ioctl(struct file *file,
break;
}
mutex_unlock(&av7110->ioctl_mutex);
return ret;
}
@ -1314,6 +1318,9 @@ static int dvb_audio_ioctl(struct file *file,
(cmd != AUDIO_GET_STATUS))
return -EPERM;
if (mutex_lock_interruptible(&av7110->ioctl_mutex))
return -ERESTARTSYS;
switch (cmd) {
case AUDIO_STOP:
if (av7110->audiostate.stream_source == AUDIO_SOURCE_MEMORY)
@ -1442,6 +1449,7 @@ static int dvb_audio_ioctl(struct file *file,
ret = -ENOIOCTLCMD;
}
mutex_unlock(&av7110->ioctl_mutex);
return ret;
}

24
drivers/media/pci/ttpci/av7110_ca.c
View File

@ -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,