queue-4.19/thunderx-enable-page-recycling-for-non-xdp-case.patch

   1 From foo@baz Thu Mar 28 21:54:17 CET 2019
   2 From: Dean Nelson <dnelson@redhat.com>
   3 Date: Tue, 26 Mar 2019 11:53:19 -0400
   4 Subject: thunderx: enable page recycling for non-XDP case
   5
   6 From: Dean Nelson <dnelson@redhat.com>
   7
   8 [ Upstream commit b3e208069477588c06f4d5d986164b435bb06e6d ]
   9
  10 Commit 773225388dae15e72790 ("net: thunderx: Optimize page recycling for XDP")
  11 added code to nicvf_alloc_page() that inadvertently disables receive buffer
  12 page recycling for the non-XDP case by always NULL'ng the page pointer.
  13
  14 This patch corrects two if-conditionals to allow for the recycling of non-XDP
  15 mode pages by only setting the page pointer to NULL when the page is not ready
  16 for recycling.
  17
  18 Fixes: 773225388dae ("net: thunderx: Optimize page recycling for XDP")
  19 Signed-off-by: Dean Nelson <dnelson@redhat.com>
  20 Signed-off-by: David S. Miller <davem@davemloft.net>
  21 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  22 ---
  23  drivers/net/ethernet/cavium/thunder/nicvf_queues.c |   23 ++++++++++-----------
  24  1 file changed, 11 insertions(+), 12 deletions(-)
  25
  26 --- a/drivers/net/ethernet/cavium/thunder/nicvf_queues.c
  27 +++ b/drivers/net/ethernet/cavium/thunder/nicvf_queues.c
  28 @@ -105,20 +105,19 @@ static inline struct pgcache *nicvf_allo
  29         /* Check if page can be recycled */
  30         if (page) {
  31                 ref_count = page_ref_count(page);
  32 -               /* Check if this page has been used once i.e 'put_page'
  33 -                * called after packet transmission i.e internal ref_count
  34 -                * and page's ref_count are equal i.e page can be recycled.
  35 +               /* This page can be recycled if internal ref_count and page's
  36 +                * ref_count are equal, indicating that the page has been used
  37 +                * once for packet transmission. For non-XDP mode, internal
  38 +                * ref_count is always '1'.
  39                  */
  40 -               if (rbdr->is_xdp && (ref_count == pgcache->ref_count))
  41 -                       pgcache->ref_count--;
  42 -               else
  43 -                       page = NULL;
  44 -
  45 -               /* In non-XDP mode, page's ref_count needs to be '1' for it
  46 -                * to be recycled.
  47 -                */
  48 -               if (!rbdr->is_xdp && (ref_count != 1))
  49 +               if (rbdr->is_xdp) {
  50 +                       if (ref_count == pgcache->ref_count)
  51 +                               pgcache->ref_count--;
  52 +                       else
  53 +                               page = NULL;
  54 +               } else if (ref_count != 1) {
  55                         page = NULL;
  56 +               }
  57         }
  58
  59         if (!page) {