[XFRM] Optimize SA dumping

Same comments as in "[XFRM] Optimize policy dumping"

The numbers are (20K SAs):

1 files changed, 11 insertions, 13 deletions

diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index da54a64ccfa3..a14c88bf17f0 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -1099,7 +1099,7 @@ int xfrm_state_walk(u8 proto, int (*func)(struct xfrm_state *, int, void*),
                     void *data)
 {
         int i;
-        struct xfrm_state *x;
+        struct xfrm_state *x, *last = NULL;
         struct hlist_node *entry;
         int count = 0;
         int err = 0;
@@ -1107,24 +1107,22 @@ int xfrm_state_walk(u8 proto, int (*func)(struct xfrm_state *, int, void*),
         spin_lock_bh(&xfrm_state_lock);
         for (i = 0; i <= xfrm_state_hmask; i++) {
                 hlist_for_each_entry(x, entry, xfrm_state_bydst+i, bydst) {
-                        if (xfrm_id_proto_match(x->id.proto, proto))
-                                count++;
+                        if (!xfrm_id_proto_match(x->id.proto, proto))
+                                continue;
+                        if (last) {
+                                err = func(last, count, data);
+                                if (err)
+                                        goto out;
+                        }
+                        last = x;
+                        count++;
                 }
         }
         if (count == 0) {
                 err = -ENOENT;
                 goto out;
         }
-
-        for (i = 0; i <= xfrm_state_hmask; i++) {
-                hlist_for_each_entry(x, entry, xfrm_state_bydst+i, bydst) {
-                        if (!xfrm_id_proto_match(x->id.proto, proto))
-                                continue;
-                        err = func(x, --count, data);
-                        if (err)
-                                goto out;
-                }
-        }
+        err = func(last, 0, data);
 out:
         spin_unlock_bh(&xfrm_state_lock);
         return err;