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media: dmxdev: Fix the logic that enables DMA mmap support 

Some conditions required for DVB mmap support to work are reversed.
Also, the logic is not too clear.

So, improve the logic, making it easier to be handled.

PS.: I'm pretty sure that I fixed it while testing, but, somehow,
the change got lost.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
This commit is contained in:
Mauro Carvalho Chehab 2018-02-09 10:44:49 -05:00
parent a145f64c61
commit 0b23498aac
2 changed files with 44 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

75
drivers/media/dvb-core/dmxdev.c
View File

@ -128,11 +128,7 @@ static int dvb_dvr_open(struct inode *inode, struct file *file)
struct dvb_device *dvbdev = file->private_data;
struct dmxdev *dmxdev = dvbdev->priv;
struct dmx_frontend *front;
#ifndef CONFIG_DVB_MMAP
bool need_ringbuffer = false;
#else
const bool need_ringbuffer = true;
#endif
dprintk("%s\n", __func__);
@ -144,17 +140,31 @@ static int dvb_dvr_open(struct inode *inode, struct file *file)
return -ENODEV;
}
#ifndef CONFIG_DVB_MMAP
dmxdev->may_do_mmap = 0;
/*
* The logic here is a little tricky due to the ifdef.
*
* The ringbuffer is used for both read and mmap.
*
* It is not needed, however, on two situations:
* - Write devices (access with O_WRONLY);
* - For duplex device nodes, opened with O_RDWR.
*/
if ((file->f_flags & O_ACCMODE) == O_RDONLY)
need_ringbuffer = true;
#else
if ((file->f_flags & O_ACCMODE) == O_RDWR) {
else if ((file->f_flags & O_ACCMODE) == O_RDWR) {
if (!(dmxdev->capabilities & DMXDEV_CAP_DUPLEX)) {
#ifdef CONFIG_DVB_MMAP
dmxdev->may_do_mmap = 1;
need_ringbuffer = true;
#else
mutex_unlock(&dmxdev->mutex);
return -EOPNOTSUPP;
#endif
}
}
#endif
if (need_ringbuffer) {
void *mem;
@ -169,8 +179,9 @@ static int dvb_dvr_open(struct inode *inode, struct file *file)
return -ENOMEM;
}
dvb_ringbuffer_init(&dmxdev->dvr_buffer, mem, DVR_BUFFER_SIZE);
dvb_vb2_init(&dmxdev->dvr_vb2_ctx, "dvr",
file->f_flags & O_NONBLOCK);
if (dmxdev->may_do_mmap)
dvb_vb2_init(&dmxdev->dvr_vb2_ctx, "dvr",
file->f_flags & O_NONBLOCK);
dvbdev->readers--;
}
@ -200,11 +211,6 @@ static int dvb_dvr_release(struct inode *inode, struct file *file)
{
struct dvb_device *dvbdev = file->private_data;
struct dmxdev *dmxdev = dvbdev->priv;
#ifndef CONFIG_DVB_MMAP
bool need_ringbuffer = false;
#else
const bool need_ringbuffer = true;
#endif
mutex_lock(&dmxdev->mutex);
@ -213,15 +219,14 @@ static int dvb_dvr_release(struct inode *inode, struct file *file)
dmxdev->demux->connect_frontend(dmxdev->demux,
dmxdev->dvr_orig_fe);
}
#ifndef CONFIG_DVB_MMAP
if ((file->f_flags & O_ACCMODE) == O_RDONLY)
need_ringbuffer = true;
#endif
if (need_ringbuffer) {
if (dvb_vb2_is_streaming(&dmxdev->dvr_vb2_ctx))
dvb_vb2_stream_off(&dmxdev->dvr_vb2_ctx);
dvb_vb2_release(&dmxdev->dvr_vb2_ctx);
if (((file->f_flags & O_ACCMODE) == O_RDONLY) ||
dmxdev->may_do_mmap) {
if (dmxdev->may_do_mmap) {
if (dvb_vb2_is_streaming(&dmxdev->dvr_vb2_ctx))
dvb_vb2_stream_off(&dmxdev->dvr_vb2_ctx);
dvb_vb2_release(&dmxdev->dvr_vb2_ctx);
}
dvbdev->readers++;
if (dmxdev->dvr_buffer.data) {
void *mem = dmxdev->dvr_buffer.data;
@ -802,6 +807,12 @@ static int dvb_demux_open(struct inode *inode, struct file *file)
mutex_init(&dmxdevfilter->mutex);
file->private_data = dmxdevfilter;
#ifdef CONFIG_DVB_MMAP
dmxdev->may_do_mmap = 1;
#else
dmxdev->may_do_mmap = 0;
#endif
dvb_ringbuffer_init(&dmxdevfilter->buffer, NULL, 8192);
dvb_vb2_init(&dmxdevfilter->vb2_ctx, "demux_filter",
file->f_flags & O_NONBLOCK);
@ -1206,6 +1217,9 @@ static int dvb_demux_mmap(struct file *file, struct vm_area_struct *vma)
struct dmxdev *dmxdev = dmxdevfilter->dev;
int ret;
if (!dmxdev->may_do_mmap)
return -EOPNOTSUPP;
if (mutex_lock_interruptible(&dmxdev->mutex))
return -ERESTARTSYS;
@ -1322,11 +1336,6 @@ static __poll_t dvb_dvr_poll(struct file *file, poll_table *wait)
struct dvb_device *dvbdev = file->private_data;
struct dmxdev *dmxdev = dvbdev->priv;
__poll_t mask = 0;
#ifndef CONFIG_DVB_MMAP
bool need_ringbuffer = false;
#else
const bool need_ringbuffer = true;
#endif
dprintk("%s\n", __func__);
@ -1337,11 +1346,8 @@ static __poll_t dvb_dvr_poll(struct file *file, poll_table *wait)
poll_wait(file, &dmxdev->dvr_buffer.queue, wait);
#ifndef CONFIG_DVB_MMAP
if ((file->f_flags & O_ACCMODE) == O_RDONLY)
need_ringbuffer = true;
#endif
if (need_ringbuffer) {
if (((file->f_flags & O_ACCMODE) == O_RDONLY) ||
dmxdev->may_do_mmap) {
if (dmxdev->dvr_buffer.error)
mask |= (EPOLLIN | EPOLLRDNORM | EPOLLPRI | EPOLLERR);
@ -1360,6 +1366,9 @@ static int dvb_dvr_mmap(struct file *file, struct vm_area_struct *vma)
struct dmxdev *dmxdev = dvbdev->priv;
int ret;
if (!dmxdev->may_do_mmap)
return -EOPNOTSUPP;
if (dmxdev->exit)
return -ENODEV;

2
include/media/dmxdev.h
View File

@ -163,6 +163,7 @@ struct dmxdev_filter {
* @demux: pointer to &struct dmx_demux.
* @filternum: number of filters.
* @capabilities: demux capabilities as defined by &enum dmx_demux_caps.
* @may_do_mmap: flag used to indicate if the device may do mmap.
* @exit: flag to indicate that the demux is being released.
* @dvr_orig_fe: pointer to &struct dmx_frontend.
* @dvr_buffer: embedded &struct dvb_ringbuffer for DVB output.
@ -180,6 +181,7 @@ struct dmxdev {
int filternum;
int capabilities;
unsigned int may_do_mmap:1;
unsigned int exit:1;
#define DMXDEV_CAP_DUPLEX 1
struct dmx_frontend *dvr_orig_fe;