[PATCH v2 net-next 2/2] RDS: TCP: Call pskb_extract() helper function

[Sowmini Varadhan]

rds-stress experiments with request size 256 bytes, 8K acks,
using 16 threads show a 40% improvment when pskb_extract()
replaces the {skb_clone(..); pskb_pull(..); pskb_trim(..);}
pattern in the Rx path, so we leverage the perf gain with
this commit.

Signed-off-by: Sowmini Varadhan <sowmini.varad...@oracle.com>
---
 net/rds/tcp_recv.c |   14 +++-----------
 1 files changed, 3 insertions(+), 11 deletions(-)

diff --git a/net/rds/tcp_recv.c b/net/rds/tcp_recv.c
index 27a9921..d75d8b5 100644
--- a/net/rds/tcp_recv.c
+++ b/net/rds/tcp_recv.c
@@ -207,22 +207,14 @@ static int rds_tcp_data_recv(read_descriptor_t *desc, 
struct sk_buff *skb,
                }
 
                if (left && tc->t_tinc_data_rem) {
-                       clone = skb_clone(skb, arg->gfp);
+                       to_copy = min(tc->t_tinc_data_rem, left);
+
+                       clone = pskb_extract(skb, offset, to_copy, arg->gfp);
                        if (!clone) {
                                desc->error = -ENOMEM;
                                goto out;
                        }
 
-                       to_copy = min(tc->t_tinc_data_rem, left);
-                       if (!pskb_pull(clone, offset) ||
-                           pskb_trim(clone, to_copy)) {
-                               pr_warn("rds_tcp_data_recv: pull/trim failed "
-                                       "left %zu data_rem %zu skb_len %d\n",
-                                       left, tc->t_tinc_data_rem, skb->len);
-                               kfree_skb(clone);
-                               desc->error = -ENOMEM;
-                               goto out;
-                       }
                        skb_queue_tail(&tinc->ti_skb_list, clone);
 
                        rdsdebug("skb %p data %p len %d off %u to_copy %zu -> "
-- 
1.7.1