- if (old_write == rbi->ring_buffer->read_index)
- return true;
-
- return false;
-}
-
-/*
- * To optimize the flow management on the send-side,
- * when the sender is blocked because of lack of
- * sufficient space in the ring buffer, potential the
- * consumer of the ring buffer can signal the producer.
- * This is controlled by the following parameters:
- *
- * 1. pending_send_sz: This is the size in bytes that the
- * producer is trying to send.
- * 2. The feature bit feat_pending_send_sz set to indicate if
- * the consumer of the ring will signal when the ring
- * state transitions from being full to a state where
- * there is room for the producer to send the pending packet.
- */
-
-static bool hv_need_to_signal_on_read(struct hv_ring_buffer_info *rbi)
-{
- u32 cur_write_sz;
- u32 r_size;
- u32 write_loc;
- u32 read_loc = rbi->ring_buffer->read_index;
- u32 pending_sz;
-
- /*
- * Issue a full memory barrier before making the signaling decision.
- * Here is the reason for having this barrier:
- * If the reading of the pend_sz (in this function)
- * were to be reordered and read before we commit the new read
- * index (in the calling function) we could
- * have a problem. If the host were to set the pending_sz after we
- * have sampled pending_sz and go to sleep before we commit the
- * read index, we could miss sending the interrupt. Issue a full
- * memory barrier to address this.
- */
- mb();
-
- pending_sz = rbi->ring_buffer->pending_send_sz;
- write_loc = rbi->ring_buffer->write_index;
- /* If the other end is not blocked on write don't bother. */
- if (pending_sz == 0)
- return false;
-
- r_size = rbi->ring_datasize;
- cur_write_sz = write_loc >= read_loc ? r_size - (write_loc - read_loc) :
- read_loc - write_loc;
-
- if (cur_write_sz >= pending_sz)