[RESEND PATCH net-next v1 12/13] tap/tun: add skb_zcopy_init() helper for initialization.

[Jonathan Lemon]

Replace direct assignments with skb_zcopy_init() for zerocopy
cases where a new skb is initialized, without changing the
reference counts.

Signed-off-by: Jonathan Lemon <jonathan.le...@gmail.com>
---
 drivers/net/tap.c      | 3 +--
 drivers/net/tun.c      | 3 +--
 drivers/vhost/net.c    | 1 +
 include/linux/skbuff.h | 9 +++++++--
 4 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/net/tap.c b/drivers/net/tap.c
index f7a19d9b7c27..3c652c8ac5ba 100644
--- a/drivers/net/tap.c
+++ b/drivers/net/tap.c
@@ -722,8 +722,7 @@ static ssize_t tap_get_user(struct tap_queue *q, void 
*msg_control,
        tap = rcu_dereference(q->tap);
        /* copy skb_ubuf_info for callback when skb has no error */
        if (zerocopy) {
-               skb_shinfo(skb)->destructor_arg = msg_control;
-               skb_shinfo(skb)->flags |= SKBFL_ZEROCOPY_FRAG;
+               skb_zcopy_init(skb, msg_control);
        } else if (msg_control) {
                struct ubuf_info *uarg = msg_control;
                uarg->callback(NULL, uarg, false);
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index d8f1c3d34612..02a93cfdb6b1 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1814,8 +1814,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, 
struct tun_file *tfile,
 
        /* copy skb_ubuf_info for callback when skb has no error */
        if (zerocopy) {
-               skb_shinfo(skb)->destructor_arg = msg_control;
-               skb_shinfo(skb)->flags |= SKBFL_ZEROCOPY_FRAG;
+               skb_zcopy_init(skb, msg_control);
        } else if (msg_control) {
                struct ubuf_info *uarg = msg_control;
                uarg->callback(NULL, uarg, false);
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index f834a097895e..3b744031ec8f 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -903,6 +903,7 @@ static void handle_tx_zerocopy(struct vhost_net *net, 
struct socket *sock)
                        ubuf->callback = vhost_zerocopy_callback;
                        ubuf->ctx = nvq->ubufs;
                        ubuf->desc = nvq->upend_idx;
+                       ubuf->flags = SKBFL_ZEROCOPY_FRAG;
                        refcount_set(&ubuf->refcnt, 1);
                        msg.msg_control = &ctl;
                        ctl.type = TUN_MSG_UBUF;
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 58010df9d183..3ec8b83aca3e 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1448,6 +1448,12 @@ static inline void skb_zcopy_get(struct ubuf_info *uarg)
        refcount_inc(&uarg->refcnt);
 }
 
+static inline void skb_zcopy_init(struct sk_buff *skb, struct ubuf_info *uarg)
+{
+       skb_shinfo(skb)->destructor_arg = uarg;
+       skb_shinfo(skb)->flags |= uarg->flags;
+}
+
 static inline void skb_zcopy_set(struct sk_buff *skb, struct ubuf_info *uarg,
                                 bool *have_ref)
 {
@@ -1456,8 +1462,7 @@ static inline void skb_zcopy_set(struct sk_buff *skb, 
struct ubuf_info *uarg,
                        *have_ref = false;
                else
                        skb_zcopy_get(uarg);
-               skb_shinfo(skb)->destructor_arg = uarg;
-               skb_shinfo(skb)->flags |= uarg->flags;
+               skb_zcopy_init(skb, uarg);
        }
 }
 
-- 
2.24.1