[PATCH 4.19 24/47] rpmsg: glink: Set tail pointer to 0 at end of FIFO

[Greg Kroah-Hartman]

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
@@ -105,7 +105,7 @@ 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);