[PATCH 4/6] sfxge: add counter for Tx errors returned from if_transmit

[Andrew Rybchenko]

sfxge: add counter for Tx errors returned from if_transmit

Submitted-by:   Boris Misenov <Boris.Misenov at oktetlabs.ru>
Sponsored by:   Solarflare Communications, Inc.

diff -r 53935db50f8a -r af2586a023d8 src/driver/freebsd/sfxge_tx.c
--- a/head/sys/dev/sfxge/sfxge_tx.c    Mon Mar 10 11:37:12 2014 +0400
+++ b/head/sys/dev/sfxge/sfxge_tx.c    Mon Mar 10 11:37:12 2014 +0400
@@ -503,6 +503,11 @@
      int locked;
      int rc;

+    if (!SFXGE_LINK_UP(txq->sc)) {
+        rc = ENETDOWN;
+        goto fail;
+    }
+
      /*
       * Try to grab the txq lock.  If we are able to get the lock,
       * the packet will be appended to the "get list" of the deferred
@@ -537,6 +542,7 @@

  fail:
      m_freem(m);
+    atomic_add_long(&txq->early_drops, 1);
      return (rc);

  }
@@ -587,11 +593,6 @@

      KASSERT(ifp->if_flags & IFF_UP, ("interface not up"));

-    if (!SFXGE_LINK_UP(sc)) {
-        m_freem(m);
-        return (ENETDOWN);
-    }
-
      /* Pick the desired transmit queue. */
      if (m->m_pkthdr.csum_flags & (CSUM_DELAY_DATA | CSUM_TSO)) {
          int index = 0;
@@ -1391,6 +1392,7 @@
      SFXGE_TX_STAT(tso_long_headers, tso_long_headers),
      SFXGE_TX_STAT(tx_collapses, collapses),
      SFXGE_TX_STAT(tx_drops, drops),
+    SFXGE_TX_STAT(tx_early_drops, early_drops),
  };

  static int
diff -r 53935db50f8a -r af2586a023d8 src/driver/freebsd/sfxge_tx.h
--- a/head/sys/dev/sfxge/sfxge_tx.h    Mon Mar 10 11:37:12 2014 +0400
+++ b/head/sys/dev/sfxge/sfxge_tx.h    Mon Mar 10 11:37:12 2014 +0400
@@ -160,6 +160,7 @@
      unsigned long            tso_long_headers;
      unsigned long            collapses;
      unsigned long            drops;
+    unsigned long            early_drops;

      /* The following fields change more often, and are used mostly
       * on the completion path