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

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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;