ixgbe: Roll RSC code into non-EOP code

This change moves the RSC code into the non-EOP descriptor handling
function. The main motivation behind this change is to help reduce the
overhead in the non-RSC case. Previously the non-RSC path code would
always be checking for append count even if RSC had been disabled. Now
this code is completely skipped in a single conditional check instead of
having to make two separate checks.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index 9e72ae6..aa37b84 100644 (file)
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -1320,29 +1320,6 @@ static unsigned int ixgbe_get_headlen(unsigned char *data,
                return max_len;
 }
 
-static void ixgbe_get_rsc_cnt(struct ixgbe_ring *rx_ring,
-                             union ixgbe_adv_rx_desc *rx_desc,
-                             struct sk_buff *skb)
-{
-       __le32 rsc_enabled;
-       u32 rsc_cnt;
-
-       if (!ring_is_rsc_enabled(rx_ring))
-               return;
-
-       rsc_enabled = rx_desc->wb.lower.lo_dword.data &
-                     cpu_to_le32(IXGBE_RXDADV_RSCCNT_MASK);
-
-       /* If this is an RSC frame rsc_cnt should be non-zero */
-       if (!rsc_enabled)
-               return;
-
-       rsc_cnt = le32_to_cpu(rsc_enabled);
-       rsc_cnt >>= IXGBE_RXDADV_RSCCNT_SHIFT;
-
-       IXGBE_CB(skb)->append_cnt += rsc_cnt - 1;
-}
-
 static void ixgbe_set_rsc_gso_size(struct ixgbe_ring *ring,
                                   struct sk_buff *skb)
 {
@@ -1440,16 +1417,28 @@ static bool ixgbe_is_non_eop(struct ixgbe_ring *rx_ring,
 
        prefetch(IXGBE_RX_DESC(rx_ring, ntc));
 
-       if (likely(ixgbe_test_staterr(rx_desc, IXGBE_RXD_STAT_EOP)))
-               return false;
+       /* update RSC append count if present */
+       if (ring_is_rsc_enabled(rx_ring)) {
+               __le32 rsc_enabled = rx_desc->wb.lower.lo_dword.data &
+                                    cpu_to_le32(IXGBE_RXDADV_RSCCNT_MASK);
+
+               if (unlikely(rsc_enabled)) {
+                       u32 rsc_cnt = le32_to_cpu(rsc_enabled);
+
+                       rsc_cnt >>= IXGBE_RXDADV_RSCCNT_SHIFT;
+                       IXGBE_CB(skb)->append_cnt += rsc_cnt - 1;
 
-       /* append_cnt indicates packet is RSC, if so fetch nextp */
-       if (IXGBE_CB(skb)->append_cnt) {
-               ntc = le32_to_cpu(rx_desc->wb.upper.status_error);
-               ntc &= IXGBE_RXDADV_NEXTP_MASK;
-               ntc >>= IXGBE_RXDADV_NEXTP_SHIFT;
+                       /* update ntc based on RSC value */
+                       ntc = le32_to_cpu(rx_desc->wb.upper.status_error);
+                       ntc &= IXGBE_RXDADV_NEXTP_MASK;
+                       ntc >>= IXGBE_RXDADV_NEXTP_SHIFT;
+               }
        }
 
+       /* if we are the last buffer then there is nothing else to do */
+       if (likely(ixgbe_test_staterr(rx_desc, IXGBE_RXD_STAT_EOP)))
+               return false;
+
        /* place skb in next buffer to be received */
        rx_ring->rx_buffer_info[ntc].skb = skb;
        rx_ring->rx_stats.non_eop_descs++;
@@ -1829,8 +1818,6 @@ static bool ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector,
                if (!skb)
                        break;
 
-               ixgbe_get_rsc_cnt(rx_ring, rx_desc, skb);
-
                cleaned_count++;
 
                /* place incomplete frames back on ring for completion */