i40e/i40evf: Break up xmit_descriptor_count from maybe_stop_tx

In an upcoming patch I would like to have access to the descriptor count
used for the data portion of the frame.  For this reason I am splitting up
the descriptor count function from the function that stops the ring.

Also in order to try and reduce unnecessary duplication of code I am moving
the slow-path portions of the code out of being inline calls so that we can
just jump to them and process them instead of having to build them into
each function that calls them.

Signed-off-by: Alexander Duyck <aduyck@mirantis.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

1 files changed, 42 insertions, 0 deletions

diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.h b/drivers/net/ethernet/intel/i40evf/i40e_txrx.h
index 6ea8701cf066..1f719d0baf7a 100644
--- a/drivers/net/ethernet/intel/i40evf/i40e_txrx.h
+++ b/drivers/net/ethernet/intel/i40evf/i40e_txrx.h
@@ -326,6 +326,7 @@ void i40evf_free_rx_resources(struct i40e_ring *rx_ring);
 int i40evf_napi_poll(struct napi_struct *napi, int budget);
 void i40evf_force_wb(struct i40e_vsi *vsi, struct i40e_q_vector *q_vector);
 u32 i40evf_get_tx_pending(struct i40e_ring *ring, bool in_sw);
+int __i40evf_maybe_stop_tx(struct i40e_ring *tx_ring, int size);
 
 /**
  * i40e_get_head - Retrieve head from head writeback
@@ -340,4 +341,45 @@ static inline u32 i40e_get_head(struct i40e_ring *tx_ring)
 
 	return le32_to_cpu(*(volatile __le32 *)head);
 }
+
+/**
+ * i40e_xmit_descriptor_count - calculate number of Tx descriptors needed
+ * @skb:     send buffer
+ * @tx_ring: ring to send buffer on
+ *
+ * Returns number of data descriptors needed for this skb. Returns 0 to indicate
+ * there is not enough descriptors available in this ring since we need at least
+ * one descriptor.
+ **/
+static inline int i40e_xmit_descriptor_count(struct sk_buff *skb)
+{
+	const struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[0];
+	unsigned int nr_frags = skb_shinfo(skb)->nr_frags;
+	int count = 0, size = skb_headlen(skb);
+
+	for (;;) {
+		count += TXD_USE_COUNT(size);
+
+		if (!nr_frags--)
+			break;
+
+		size = skb_frag_size(frag++);
+	}
+
+	return count;
+}
+
+/**
+ * i40e_maybe_stop_tx - 1st level check for Tx stop conditions
+ * @tx_ring: the ring to be checked
+ * @size:    the size buffer we want to assure is available
+ *
+ * Returns 0 if stop is not needed
+ **/
+static inline int i40e_maybe_stop_tx(struct i40e_ring *tx_ring, int size)
+{
+	if (likely(I40E_DESC_UNUSED(tx_ring) >= size))
+		return 0;
+	return __i40evf_maybe_stop_tx(tx_ring, size);
+}
 #endif /* _I40E_TXRX_H_ */