[PATCH 4.14 19/36] rpmsg: glink: Set tail pointer to 0 at end of FIFO

From: Greg Kroah-Hartman
Date: Thu Dec 19 2019 - 14:01:15 EST


From: Chris Lew <clew@xxxxxxxxxxxxxx>

commit 4623e8bf1de0b86e23a56cdb39a72f054e89c3bd upstream.

When wrapping around the FIFO, the remote expects the tail pointer to
be reset to 0 on the edge case where the tail equals the FIFO length.

Fixes: caf989c350e8 ("rpmsg: glink: Introduce glink smem based transport")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Chris Lew <clew@xxxxxxxxxxxxxx>
Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/rpmsg/qcom_glink_smem.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/rpmsg/qcom_glink_smem.c
+++ b/drivers/rpmsg/qcom_glink_smem.c
@@ -119,7 +119,7 @@ static void glink_smem_rx_advance(struct
tail = le32_to_cpu(*pipe->tail);

tail += count;
- if (tail > pipe->native.length)
+ if (tail >= pipe->native.length)
tail -= pipe->native.length;

*pipe->tail = cpu_to_le32(tail);