[Xen-devel] [PATCH] linux-2.6.18/netback: Re-factor net_tx_action_dealloc() slightly

["Jan Beulich" <JBeulich@xxxxxxxxxx>]

From: Paul Durrant <paul.durrant@xxxxxxxxxx>
Subject: Re-factor net_tx_action_dealloc() slightly.

There is no need for processing of the pending_inuse list to be within
the dealloc_prod/cons loop.

Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>

--- sle10sp4-2010-12-15.orig/drivers/xen/netback/netback.c
+++ sle10sp4-2010-12-15/drivers/xen/netback/netback.c
@@ -924,7 +924,6 @@ inline static void net_tx_action_dealloc
        u16 pending_idx;
        PEND_RING_IDX dc, dp;
        netif_t *netif;
-       int ret;
        LIST_HEAD(list);
 
        dc = dealloc_cons;
@@ -959,11 +958,17 @@ inline static void net_tx_action_dealloc
                        gop++;
                }
 
-               if (netbk_copy_skb_mode != NETBK_DELAYED_COPY_SKB ||
-                   list_empty(&pending_inuse_head))
-                       break;
+       } while (dp != dealloc_prod);
+
+       dealloc_cons = dc;
 
-               /* Copy any entries that have been pending for too long. */
+       if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
+                                     tx_unmap_ops, gop - tx_unmap_ops))
+               BUG();
+
+       /* Copy any entries that have been pending for too long. */
+       if (netbk_copy_skb_mode == NETBK_DELAYED_COPY_SKB &&
+           !list_empty(&pending_inuse_head)) {
                list_for_each_entry_safe(inuse, n, &pending_inuse_head, list) {
                        if (time_after(inuse->alloc_time + HZ / 2, jiffies))
                                break;
@@ -985,13 +990,7 @@ inline static void net_tx_action_dealloc
 
                        break;
                }
-       } while (dp != dealloc_prod);
-
-       dealloc_cons = dc;
-
-       ret = HYPERVISOR_grant_table_op(
-               GNTTABOP_unmap_grant_ref, tx_unmap_ops, gop - tx_unmap_ops);
-       BUG_ON(ret);
+       }
 
        list_for_each_entry_safe(inuse, n, &list, list) {
                pending_idx = inuse - pending_inuse;

Attachment: xen-netback-tx_action_dealloc-refactor.patch
Description: Text document

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