[src/trunk]: src/sys/dev/pci/ixgbe Fix a problem that m_defrag() isn't called...

[msaitoh <msaitoh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/3056c3017082
branches:  trunk
changeset: 822121:3056c3017082
user:      msaitoh <msaitoh%NetBSD.org@localhost>
date:      Thu Mar 02 05:35:01 2017 +0000

description:
Fix a problem that m_defrag() isn't called in if_transmit path. Now both
if_start and if_transmit do m_defrag() correctly. This change improves the
performance of TSO.

diffstat:

 sys/dev/pci/ixgbe/ix_txrx.c |  41 +++++++++++++++++++++++------------------
 1 files changed, 23 insertions(+), 18 deletions(-)

diffs (83 lines):

diff -r 59a9577692c2 -r 3056c3017082 sys/dev/pci/ixgbe/ix_txrx.c
--- a/sys/dev/pci/ixgbe/ix_txrx.c       Thu Mar 02 05:31:04 2017 +0000
+++ b/sys/dev/pci/ixgbe/ix_txrx.c       Thu Mar 02 05:35:01 2017 +0000
@@ -59,7 +59,7 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 /*$FreeBSD: head/sys/dev/ixgbe/ix_txrx.c 301538 2016-06-07 04:51:50Z sephe $*/
-/*$NetBSD: ix_txrx.c,v 1.21 2017/03/02 04:33:56 msaitoh Exp $*/
+/*$NetBSD: ix_txrx.c,v 1.22 2017/03/02 05:35:01 msaitoh Exp $*/
 
 #include "opt_inet.h"
 #include "opt_inet6.h"
@@ -162,17 +162,6 @@
                        break;
                }
                IFQ_DEQUEUE(&ifp->if_snd, m_head);
-               if (rc == EFBIG) {
-                       struct mbuf *mtmp;
-
-                       if ((mtmp = m_defrag(m_head, M_NOWAIT)) != NULL) {
-                               m_head = mtmp;
-                               rc = ixgbe_xmit(txr, m_head);
-                               if (rc != 0)
-                                       adapter->efbig2_tx_dma_setup.ev_count++;
-                       } else
-                               adapter->mbuf_defrag_failed.ev_count++;
-               }
                if (rc != 0) {
                        m_freem(m_head);
                        continue;
@@ -348,6 +337,7 @@
        u32             olinfo_status = 0, cmd_type_len;
        int             i, j, error;
        int             first;
+       bool            remap = TRUE;
        bus_dmamap_t    map;
        struct ixgbe_tx_buf *txbuf;
        union ixgbe_adv_tx_desc *txd = NULL;
@@ -371,10 +361,12 @@
        /*
         * Map the packet for DMA.
         */
+retry:
        error = bus_dmamap_load_mbuf(txr->txtag->dt_dmat, map,
            m_head, BUS_DMA_NOWAIT);
 
        if (__predict_false(error)) {
+               struct mbuf *m;
 
                switch (error) {
                case EAGAIN:
@@ -384,12 +376,25 @@
                        adapter->enomem_tx_dma_setup.ev_count++;
                        return EAGAIN;
                case EFBIG:
-                       /*
-                        * XXX Try it again?
-                        * do m_defrag() and retry bus_dmamap_load_mbuf().
-                        */
-                       adapter->efbig_tx_dma_setup.ev_count++;
-                       return error;
+                       /* Try it again? - one try */
+                       if (remap == TRUE) {
+                               remap = FALSE;
+                               /*
+                                * XXX: m_defrag will choke on
+                                * non-MCLBYTES-sized clusters
+                                */
+                               adapter->efbig_tx_dma_setup.ev_count++;
+                               m = m_defrag(m_head, M_NOWAIT);
+                               if (m == NULL) {
+                                       adapter->mbuf_defrag_failed.ev_count++;
+                                       return ENOBUFS;
+                               }
+                               m_head = m;
+                               goto retry;
+                       } else {
+                               adapter->efbig2_tx_dma_setup.ev_count++;
+                               return error;
+                       }
                case EINVAL:
                        adapter->einval_tx_dma_setup.ev_count++;
                        return error;