[PATCH v2 net-next 2/6] sfc: make ef100 xmit_more handling look more like ef10's

[Edward Cree]

This should cause no functional change; merely make there only be one
 design of xmit_more handling to understand.  As with the EF10/Siena
 version, we set tx_queue->xmit_pending when we queue up a TX, and
 clear it when we ring the doorbell (in ef100_notify_tx_desc).
While we're at it, make ef100_notify_tx_desc static since nothing
 outside of ef100_tx.c uses it.

Signed-off-by: Edward Cree <ec...@solarflare.com>
---
 drivers/net/ethernet/sfc/ef100_tx.c | 22 +++++++++++-----------
 drivers/net/ethernet/sfc/ef100_tx.h |  1 -
 2 files changed, 11 insertions(+), 12 deletions(-)

diff --git a/drivers/net/ethernet/sfc/ef100_tx.c 
b/drivers/net/ethernet/sfc/ef100_tx.c
index 8d478c5e720e..ce1b462efd17 100644
--- a/drivers/net/ethernet/sfc/ef100_tx.c
+++ b/drivers/net/ethernet/sfc/ef100_tx.c
@@ -117,11 +117,13 @@ static efx_oword_t *ef100_tx_desc(struct efx_tx_queue 
*tx_queue, unsigned int in
                return NULL;
 }
 
-void ef100_notify_tx_desc(struct efx_tx_queue *tx_queue)
+static void ef100_notify_tx_desc(struct efx_tx_queue *tx_queue)
 {
        unsigned int write_ptr;
        efx_dword_t reg;
 
+       tx_queue->xmit_pending = false;
+
        if (unlikely(tx_queue->notify_count == tx_queue->write_count))
                return;
 
@@ -131,7 +133,6 @@ void ef100_notify_tx_desc(struct efx_tx_queue *tx_queue)
        efx_writed_page(tx_queue->efx, &reg,
                        ER_GZ_TX_RING_DOORBELL, tx_queue->queue);
        tx_queue->notify_count = tx_queue->write_count;
-       tx_queue->xmit_pending = false;
 }
 
 static void ef100_tx_push_buffers(struct efx_tx_queue *tx_queue)
@@ -372,15 +373,14 @@ int ef100_enqueue_skb(struct efx_tx_queue *tx_queue, 
struct sk_buff *skb)
                        netif_tx_start_queue(tx_queue->core_txq);
        }
 
-       if (__netdev_tx_sent_queue(tx_queue->core_txq, skb->len, xmit_more))
-               tx_queue->xmit_pending = false; /* push doorbell */
-       else if (tx_queue->write_count - tx_queue->notify_count > 255)
-               /* Ensure we never push more than 256 packets at once */
-               tx_queue->xmit_pending = false; /* push */
-       else
-               tx_queue->xmit_pending = true; /* don't push yet */
+       tx_queue->xmit_pending = true;
 
-       if (!tx_queue->xmit_pending)
+       /* If xmit_more then we don't need to push the doorbell, unless there
+        * are 256 descriptors already queued in which case we have to push to
+        * ensure we never push more than 256 at once.
+        */
+       if (__netdev_tx_sent_queue(tx_queue->core_txq, skb->len, xmit_more) ||
+           tx_queue->write_count - tx_queue->notify_count > 255)
                ef100_tx_push_buffers(tx_queue);
 
        if (segments) {
@@ -399,7 +399,7 @@ int ef100_enqueue_skb(struct efx_tx_queue *tx_queue, struct 
sk_buff *skb)
 
        /* If we're not expecting another transmit and we had something to push
         * on this queue then we need to push here to get the previous packets
-        * out.  We only enter this branch from before the 'Update BQL' section
+        * out.  We only enter this branch from before the xmit_more handling
         * above, so xmit_pending still refers to the old state.
         */
        if (tx_queue->xmit_pending && !xmit_more)
diff --git a/drivers/net/ethernet/sfc/ef100_tx.h 
b/drivers/net/ethernet/sfc/ef100_tx.h
index fa23e430bdd7..ddc4b98fa6db 100644
--- a/drivers/net/ethernet/sfc/ef100_tx.h
+++ b/drivers/net/ethernet/sfc/ef100_tx.h
@@ -17,7 +17,6 @@
 int ef100_tx_probe(struct efx_tx_queue *tx_queue);
 void ef100_tx_init(struct efx_tx_queue *tx_queue);
 void ef100_tx_write(struct efx_tx_queue *tx_queue);
-void ef100_notify_tx_desc(struct efx_tx_queue *tx_queue);
 unsigned int ef100_tx_max_skb_descs(struct efx_nic *efx);
 
 void ef100_ev_tx(struct efx_channel *channel, const efx_qword_t *p_event);