fq: split out backlog update logic

mac80211 (which will be the first user of the
fq.h) recently started to support software A-MSDU
aggregation. It glues skbuffs together into a
single one so the backlog accounting needs to be
more fine-grained.

To avoid backlog sorting logic duplication split
it up for re-use.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 19 insertions, 11 deletions

diff --git a/include/net/fq_impl.h b/include/net/fq_impl.h
index 02eab7c51adb..163f3ed0f05a 100644
--- a/include/net/fq_impl.h
+++ b/include/net/fq_impl.h
@@ -120,6 +120,24 @@ static struct fq_flow *fq_flow_classify(struct fq *fq,
         return flow;
 }
 
+static void fq_recalc_backlog(struct fq *fq,
+                              struct fq_tin *tin,
+                              struct fq_flow *flow)
+{
+        struct fq_flow *i;
+
+        if (list_empty(&flow->backlogchain))
+                list_add_tail(&flow->backlogchain, &fq->backlogs);
+
+        i = flow;
+        list_for_each_entry_continue_reverse(i, &fq->backlogs,
+                                             backlogchain)
+                if (i->backlog > flow->backlog)
+                        break;
+
+        list_move(&flow->backlogchain, &i->backlogchain);
+}
+
 static void fq_tin_enqueue(struct fq *fq,
                            struct fq_tin *tin,
                            struct sk_buff *skb,
@@ -127,7 +145,6 @@ static void fq_tin_enqueue(struct fq *fq,
                            fq_flow_get_default_t get_default_func)
 {
         struct fq_flow *flow;
-        struct fq_flow *i;
 
         lockdep_assert_held(&fq->lock);
 
@@ -139,16 +156,7 @@ static void fq_tin_enqueue(struct fq *fq,
         tin->backlog_packets++;
         fq->backlog++;
 
-        if (list_empty(&flow->backlogchain))
-                list_add_tail(&flow->backlogchain, &fq->backlogs);
-
-        i = flow;
-        list_for_each_entry_continue_reverse(i, &fq->backlogs,
-                                             backlogchain)
-                if (i->backlog > flow->backlog)
-                        break;
-
-        list_move(&flow->backlogchain, &i->backlogchain);
+        fq_recalc_backlog(fq, tin, flow);
 
         if (list_empty(&flow->flowchain)) {
                 flow->deficit = fq->quantum;