path: root/drivers
diff options
authorSoeren Moch <smoch@web.de>2013-06-05 21:26:23 -0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-07-28 16:30:21 -0700
commit61eeaa1b66e47443f27f4cf0809940fbe08142f8 (patch)
treee53df49a046094fe9bbc6e3096e3e9e783ae2cd8 /drivers
parentb534f8f9f56d5e800d4529f54e38be960fd064a2 (diff)
media: dmxdev: remove dvb_ringbuffer_flush() on writer side
commit 414abbd2cd4c2618895f02ed3a76ec6647281436 upstream. In dvb_ringbuffer lock-less synchronizationof reader and writer threads is done with separateread and write pointers. Sincedvb_ringbuffer_flush() modifies the read pointer, this function must not be called from the writer thread. This patch removes the dvb_ringbuffer_flush() calls in the dmxdev ringbuffer write functions, this fixes Oopses "Unable to handle kernel paging request" I could observe for the call chaindvb_demux_read ->dvb_dmxdev_buffer_read -> dvb_ringbuffer_read_user -> __copy_to_user (the reader side of the ringbuffer). The flush calls at the write side are not necessary anyway since ringbuffer_flush is also called in dvb_dmxdev_buffer_read() when an error condition is set in the ringbuffer. This patch should also be applied to stable kernels. Signed-off-by: Soeren Moch <smoch@web.de> Reviewed-by: Sakari Ailus <sakari.ailus@iki.fi> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
1 files changed, 2 insertions, 6 deletions
diff --git a/drivers/media/dvb-core/dmxdev.c b/drivers/media/dvb-core/dmxdev.c
index a1a3a5159d7..0b4616b8719 100644
--- a/drivers/media/dvb-core/dmxdev.c
+++ b/drivers/media/dvb-core/dmxdev.c
@@ -377,10 +377,8 @@ static int dvb_dmxdev_section_callback(const u8 *buffer1, size_t buffer1_len,
ret = dvb_dmxdev_buffer_write(&dmxdevfilter->buffer, buffer2,
- if (ret < 0) {
- dvb_ringbuffer_flush(&dmxdevfilter->buffer);
+ if (ret < 0)
dmxdevfilter->buffer.error = ret;
- }
if (dmxdevfilter->params.sec.flags & DMX_ONESHOT)
dmxdevfilter->state = DMXDEV_STATE_DONE;
@@ -416,10 +414,8 @@ static int dvb_dmxdev_ts_callback(const u8 *buffer1, size_t buffer1_len,
ret = dvb_dmxdev_buffer_write(buffer, buffer1, buffer1_len);
if (ret == buffer1_len)
ret = dvb_dmxdev_buffer_write(buffer, buffer2, buffer2_len);
- if (ret < 0) {
- dvb_ringbuffer_flush(buffer);
+ if (ret < 0)
buffer->error = ret;
- }
return 0;