Properly account for negative values when computing the consumed
value for DVB ringbuffers, by adding the size of the ring-buffer.
The modulus is unsigned so no out of bounds is possible, but
dvb_ringbuffer_pkt_next() may fail for CA's at least when the
default buffer size of 65535 bytes is used.
The current logic only works for buffer sizes that are power of two.
Signed-off-by: Yong Su Yoo <yongsuyoo0215@xxxxxxxxx>
Signed-off-by: Hans Petter Selasky <hps@xxxxxxxxxxx>
---
drivers/media/dvb-core/dvb_ringbuffer.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/media/dvb-core/dvb_ringbuffer.c
b/drivers/media/dvb-core/dvb_ringbuffer.c
index d1d471af0636..7d4558de8e83 100644
--- a/drivers/media/dvb-core/dvb_ringbuffer.c
+++ b/drivers/media/dvb-core/dvb_ringbuffer.c
@@ -335,7 +335,9 @@ ssize_t dvb_ringbuffer_pkt_next(struct
dvb_ringbuffer *rbuf, size_t idx, size_t*
idx = (idx + curpktlen + DVB_RINGBUFFER_PKTHDRSIZE) % rbuf->size;
}
- consumed = (idx - rbuf->pread) % rbuf->size;
+ consumed = (idx - rbuf->pread);
+ if (consumed < 0)
+ consumed += rbuf->size;
while((dvb_ringbuffer_avail(rbuf) - consumed) >
DVB_RINGBUFFER_PKTHDRSIZE) {
--
2.37.3
