[media] media: dmxdev: remove dvb_ringbuffer_flush() on writer side
authorSoeren Moch <smoch@web.de>
Thu, 6 Jun 2013 00:26:23 +0000 (21:26 -0300)
committerMauro Carvalho Chehab <mchehab@redhat.com>
Wed, 19 Jun 2013 14:48:09 +0000 (11:48 -0300)
commit414abbd2cd4c2618895f02ed3a76ec6647281436
tree07f702deb5fa62d94ac1fcb8820454a62c42aadf
parent6914d70ecf53e90814fd6d4c8e413b3a8f708d38
[media] media: dmxdev: remove dvb_ringbuffer_flush() on writer side

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>
CC: <stable@vger.kernel.org>
Reviewed-by: Sakari Ailus <sakari.ailus@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
drivers/media/dvb-core/dmxdev.c