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@xxxxxxxxxxxxxxxx>
---
drivers/media/dvb-core/dmxdev.c | 76 +++++++++++++++++++++++------------------
include/media/dmxdev.h | 2 ++
2 files changed, 44 insertions(+), 34 deletions(-)
diff --git a/drivers/media/dvb-core/dmxdev.c b/drivers/media/dvb-core/dmxdev.c
index 15847b64698b..ad349fe26aa2 100644
--- a/drivers/media/dvb-core/dmxdev.c
+++ b/drivers/media/dvb-core/dmxdev.c
@@ -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;
@@ -1323,12 +1337,6 @@ static unsigned int dvb_dvr_poll(struct file *file, poll_table *wait)
struct dmxdev *dmxdev = dvbdev->priv;
unsigned int mask = 0;
-#ifndef CONFIG_DVB_MMAP
- bool need_ringbuffer = false;
-#else
- const bool need_ringbuffer = true;
-#endif
-
dprintk("%s\n", __func__);
if (dmxdev->exit)
@@ -1338,11 +1346,8 @@ static unsigned int 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 |= (POLLIN | POLLRDNORM | POLLPRI | POLLERR);
@@ -1361,6 +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;
diff --git a/include/media/dmxdev.h b/include/media/dmxdev.h
index 2f5cb2c7b6a7..baafa3b8aca4 100644
--- a/include/media/dmxdev.h
+++ b/include/media/dmxdev.h
@@ -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;
--
2.14.3
