[IPSEC]: Add async resume support on output

This patch adds support for async resumptions on output.  To do so,
the transform would return -EINPROGRESS and subsequently invoke the
function xfrm_output_resume to resume processing.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 41 insertions, 17 deletions

diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index ab9e747340b4..99677207a4ce 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -1119,6 +1119,7 @@ extern void xfrm_replay_notify(struct xfrm_state *x, int event);
 extern int xfrm_state_mtu(struct xfrm_state *x, int mtu);
 extern int xfrm_init_state(struct xfrm_state *x);
 extern int xfrm_prepare_input(struct xfrm_state *x, struct sk_buff *skb);
+extern int xfrm_output_resume(struct sk_buff *skb, int err);
 extern int xfrm_output(struct sk_buff *skb);
 extern int xfrm4_extract_header(struct sk_buff *skb);
 extern int xfrm4_extract_input(struct xfrm_state *x, struct sk_buff *skb);
diff --git a/net/xfrm/xfrm_output.c b/net/xfrm/xfrm_output.c
index bcb3701c5cf3..048d240c3e15 100644
--- a/net/xfrm/xfrm_output.c
+++ b/net/xfrm/xfrm_output.c
@@ -18,6 +18,8 @@
 #include <net/dst.h>
 #include <net/xfrm.h>
 
+static int xfrm_output2(struct sk_buff *skb);
+
 static int xfrm_state_check_space(struct xfrm_state *x, struct sk_buff *skb)
 {
         struct dst_entry *dst = skb->dst;
@@ -41,17 +43,13 @@ err:
         return err;
 }
 
-static int xfrm_output_one(struct sk_buff *skb)
+static int xfrm_output_one(struct sk_buff *skb, int err)
 {
         struct dst_entry *dst = skb->dst;
         struct xfrm_state *x = dst->xfrm;
-        int err;
 
-        if (skb->ip_summed == CHECKSUM_PARTIAL) {
-                err = skb_checksum_help(skb);
-                if (err)
-                        goto error_nolock;
-        }
+        if (err <= 0)
+                goto resume;
 
         do {
                 err = x->outer_mode->output(x, skb);
@@ -75,6 +73,8 @@ static int xfrm_output_one(struct sk_buff *skb)
                 spin_unlock_bh(&x->lock);
 
                 err = x->type->output(x, skb);
+
+resume:
                 if (err)
                         goto error_nolock;
 
@@ -97,18 +97,16 @@ error_nolock:
         goto out_exit;
 }
 
-static int xfrm_output2(struct sk_buff *skb)
+int xfrm_output_resume(struct sk_buff *skb, int err)
 {
-        int err;
-
-        while (likely((err = xfrm_output_one(skb)) == 0)) {
+        while (likely((err = xfrm_output_one(skb, err)) == 0)) {
                 struct xfrm_state *x;
 
                 nf_reset(skb);
 
                 err = skb->dst->ops->local_out(skb);
                 if (unlikely(err != 1))
-                        break;
+                        goto out;
 
                 x = skb->dst->xfrm;
                 if (!x)
@@ -118,18 +116,25 @@ static int xfrm_output2(struct sk_buff *skb)
                               x->inner_mode->afinfo->nf_post_routing, skb,
                               NULL, skb->dst->dev, xfrm_output2);
                 if (unlikely(err != 1))
-                        break;
+                        goto out;
         }
 
+        if (err == -EINPROGRESS)
+                err = 0;
+
+out:
         return err;
 }
+EXPORT_SYMBOL_GPL(xfrm_output_resume);
 
-int xfrm_output(struct sk_buff *skb)
+static int xfrm_output2(struct sk_buff *skb)
 {
-        struct sk_buff *segs;
+        return xfrm_output_resume(skb, 1);
+}
 
-        if (!skb_is_gso(skb))
-                return xfrm_output2(skb);
+static int xfrm_output_gso(struct sk_buff *skb)
+{
+        struct sk_buff *segs;
 
         segs = skb_gso_segment(skb, 0);
         kfree_skb(skb);
@@ -157,4 +162,22 @@ int xfrm_output(struct sk_buff *skb)
 
         return 0;
 }
+
+int xfrm_output(struct sk_buff *skb)
+{
+        int err;
+
+        if (skb_is_gso(skb))
+                return xfrm_output_gso(skb);
+
+        if (skb->ip_summed == CHECKSUM_PARTIAL) {
+                err = skb_checksum_help(skb);
+                if (err) {
+                        kfree_skb(skb);
+                        return err;
+                }
+        }
+
+        return xfrm_output2(skb);
+}
 EXPORT_SYMBOL_GPL(xfrm_output);