net: simplify flags for tx timestamping

This patch removes the abstraction introduced by the union skb_shared_tx in
the shared skb data.

The access of the different union elements at several places led to some
confusion about accessing the shared tx_flags e.g. in skb_orphan_try().

    http://marc.info/?l=linux-netdev&m=128084897415886&w=2

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 19 insertions, 35 deletions

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index d8050382b189..f067c95cf18a 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -163,26 +163,19 @@ struct skb_shared_hwtstamps {
         ktime_t syststamp;
 };
 
-/**
- * struct skb_shared_tx - instructions for time stamping of outgoing packets
- * @hardware:           generate hardware time stamp
- * @software:           generate software time stamp
- * @in_progress:        device driver is going to provide
- *                      hardware time stamp
- * @prevent_sk_orphan:  make sk reference available on driver level
- * @flags:              all shared_tx flags
- *
- * These flags are attached to packets as part of the
- * &skb_shared_info. Use skb_tx() to get a pointer.
- */
-union skb_shared_tx {
-        struct {
-                __u8    hardware:1,
-                        software:1,
-                        in_progress:1,
-                        prevent_sk_orphan:1;
-        };
-        __u8 flags;
+/* Definitions for tx_flags in struct skb_shared_info */
+enum {
+        /* generate hardware time stamp */
+        SKBTX_HW_TSTAMP = 1 << 0,
+
+        /* generate software time stamp */
+        SKBTX_SW_TSTAMP = 1 << 1,
+
+        /* device driver is going to provide hardware time stamp */
+        SKBTX_IN_PROGRESS = 1 << 2,
+
+        /* ensure the originating sk reference is available on driver level */
+        SKBTX_DRV_NEEDS_SK_REF = 1 << 3,
 };
 
 /* This data is invariant across clones and lives at
@@ -195,7 +188,7 @@ struct skb_shared_info {
         unsigned short  gso_segs;
         unsigned short  gso_type;
         __be32          ip6_frag_id;
-        union skb_shared_tx tx_flags;
+        __u8            tx_flags;
         struct sk_buff  *frag_list;
         struct skb_shared_hwtstamps hwtstamps;
 
@@ -587,11 +580,6 @@ static inline struct skb_shared_hwtstamps *skb_hwtstamps(struct sk_buff *skb)
         return &skb_shinfo(skb)->hwtstamps;
 }
 
-static inline union skb_shared_tx *skb_tx(struct sk_buff *skb)
-{
-        return &skb_shinfo(skb)->tx_flags;
-}
-
 /**
  *      skb_queue_empty - check if a queue is empty
  *      @list: queue head
@@ -1996,8 +1984,8 @@ extern void skb_tstamp_tx(struct sk_buff *orig_skb,
 
 static inline void sw_tx_timestamp(struct sk_buff *skb)
 {
-        union skb_shared_tx *shtx = skb_tx(skb);
-        if (shtx->software && !shtx->in_progress)
+        if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP &&
+            !(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))
                 skb_tstamp_tx(skb, NULL);
 }
 
diff --git a/include/net/ip.h b/include/net/ip.h
index 890f9725d681..7691aca133db 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -53,7 +53,7 @@ struct ipcm_cookie {
         __be32                  addr;
         int                     oif;
         struct ip_options       *opt;
-        union skb_shared_tx     shtx;
+        __u8                    tx_flags;
 };
 
 #define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
diff --git a/include/net/sock.h b/include/net/sock.h
index ac53bfbdfe16..100e43bf95fb 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1669,17 +1669,13 @@ static inline void sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk,
 
 /**
  * sock_tx_timestamp - checks whether the outgoing packet is to be time stamped
- * @msg:        outgoing packet
  * @sk:         socket sending this packet
- * @shtx:       filled with instructions for time stamping
+ * @tx_flags:   filled with instructions for time stamping
  *
  * Currently only depends on SOCK_TIMESTAMPING* flags. Returns error code if
  * parameters are invalid.
  */
-extern int sock_tx_timestamp(struct msghdr *msg,
-                             struct sock *sk,
-                             union skb_shared_tx *shtx);
-
+extern int sock_tx_timestamp(struct sock *sk, __u8 *tx_flags);
 
 /**
  * sk_eat_skb - Release a skb if it is no longer needed