1 files changed, 72 insertions, 11 deletions

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 124f90cd5a38..7cdfb4d52847 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -187,7 +187,6 @@ union skb_shared_tx {
  * the end of the header data, ie. at skb->end.
  */
 struct skb_shared_info {
-        atomic_t        dataref;
         unsigned short  nr_frags;
         unsigned short  gso_size;
         /* Warning: this field is not always filled in (UFO)! */
@@ -197,6 +196,12 @@ struct skb_shared_info {
         union skb_shared_tx tx_flags;
         struct sk_buff  *frag_list;
         struct skb_shared_hwtstamps hwtstamps;
+
+        /*
+         * Warning : all fields before dataref are cleared in __alloc_skb()
+         */
+        atomic_t        dataref;
+
         skb_frag_t      frags[MAX_SKB_FRAGS];
         /* Intermediate layers must ensure that destructor_arg
          * remains valid until skb destructor */
@@ -259,7 +264,7 @@ typedef unsigned char *sk_buff_data_t;
  *      @transport_header: Transport layer header
  *      @network_header: Network layer header
  *      @mac_header: Link layer header
- *      @_skb_dst: destination entry
+ *      @_skb_refdst: destination entry (with norefcount bit)
  *      @sp: the security path, used for xfrm
  *      @cb: Control buffer. Free for use by every layer. Put private vars here
  *      @len: Length of actual data
@@ -294,6 +299,7 @@ typedef unsigned char *sk_buff_data_t;
  *      @nfct_reasm: netfilter conntrack re-assembly pointer
  *      @nf_bridge: Saved data about a bridged frame - see br_netfilter.c
  *      @skb_iif: ifindex of device we arrived on
+ *      @rxhash: the packet hash computed on receive
  *      @queue_mapping: Queue mapping for multiqueue devices
  *      @tc_index: Traffic control index
  *      @tc_verd: traffic control verdict
@@ -322,7 +328,7 @@ struct sk_buff {
          */
         char                    cb[48] __aligned(8);
 
-        unsigned long           _skb_dst;
+        unsigned long           _skb_refdst;
 #ifdef CONFIG_XFRM
         struct  sec_path        *sp;
 #endif
@@ -369,6 +375,8 @@ struct sk_buff {
 #endif
 #endif
 
+        __u32                   rxhash;
+
         kmemcheck_bitfield_begin(flags2);
         __u16                   queue_mapping:16;
 #ifdef CONFIG_IPV6_NDISC_NODETYPE
@@ -411,14 +419,64 @@ struct sk_buff {
 
 #include <asm/system.h>
 
+/*
+ * skb might have a dst pointer attached, refcounted or not.
+ * _skb_refdst low order bit is set if refcount was _not_ taken
+ */
+#define SKB_DST_NOREF   1UL
+#define SKB_DST_PTRMASK ~(SKB_DST_NOREF)
+
+/**
+ * skb_dst - returns skb dst_entry
+ * @skb: buffer
+ *
+ * Returns skb dst_entry, regardless of reference taken or not.
+ */
 static inline struct dst_entry *skb_dst(const struct sk_buff *skb)
 {
-        return (struct dst_entry *)skb->_skb_dst;
+        /* If refdst was not refcounted, check we still are in a 
+         * rcu_read_lock section
+         */
+        WARN_ON((skb->_skb_refdst & SKB_DST_NOREF) &&
+                !rcu_read_lock_held() &&
+                !rcu_read_lock_bh_held());
+        return (struct dst_entry *)(skb->_skb_refdst & SKB_DST_PTRMASK);
 }
 
+/**
+ * skb_dst_set - sets skb dst
+ * @skb: buffer
+ * @dst: dst entry
+ *
+ * Sets skb dst, assuming a reference was taken on dst and should
+ * be released by skb_dst_drop()
+ */
 static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)
 {
-        skb->_skb_dst = (unsigned long)dst;
+        skb->_skb_refdst = (unsigned long)dst;
+}
+
+/**
+ * skb_dst_set_noref - sets skb dst, without a reference
+ * @skb: buffer
+ * @dst: dst entry
+ *
+ * Sets skb dst, assuming a reference was not taken on dst
+ * skb_dst_drop() should not dst_release() this dst
+ */
+static inline void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst)
+{
+        WARN_ON(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
+        skb->_skb_refdst = (unsigned long)dst | SKB_DST_NOREF;
+}
+
+/**
+ * skb_dst_is_noref - Test if skb dst isnt refcounted
+ * @skb: buffer
+ */
+static inline bool skb_dst_is_noref(const struct sk_buff *skb)
+{
+        return (skb->_skb_refdst & SKB_DST_NOREF) && skb_dst(skb);
 }
 
 static inline struct rtable *skb_rtable(const struct sk_buff *skb)
@@ -467,11 +525,6 @@ extern int	       skb_cow_data(struct sk_buff *skb, int tailbits,
                                     struct sk_buff **trailer);
 extern int             skb_pad(struct sk_buff *skb, int pad);
 #define dev_kfree_skb(a)        consume_skb(a)
-#define dev_consume_skb(a)      kfree_skb_clean(a)
-extern void           skb_over_panic(struct sk_buff *skb, int len,
-                                     void *here);
-extern void           skb_under_panic(struct sk_buff *skb, int len,
-                                      void *here);
 
 extern int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
                         int getfrag(void *from, char *to, int offset,
@@ -1130,6 +1183,11 @@ static inline unsigned char *__skb_pull(struct sk_buff *skb, unsigned int len)
         return skb->data += len;
 }
 
+static inline unsigned char *skb_pull_inline(struct sk_buff *skb, unsigned int len)
+{
+        return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len);
+}
+
 extern unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta);
 
 static inline unsigned char *__pskb_pull(struct sk_buff *skb, unsigned int len)
@@ -1353,9 +1411,12 @@ static inline int skb_network_offset(const struct sk_buff *skb)
  *
  * Various parts of the networking layer expect at least 32 bytes of
  * headroom, you should not reduce this.
+ * With RPS, we raised NET_SKB_PAD to 64 so that get_rps_cpus() fetches span
+ * a 64 bytes aligned block to fit modern (>= 64 bytes) cache line sizes
+ * NET_IP_ALIGN(2) + ethernet_header(14) + IP_header(20/40) + ports(8)
  */
 #ifndef NET_SKB_PAD
-#define NET_SKB_PAD     32
+#define NET_SKB_PAD     64
 #endif
 
 extern int ___pskb_trim(struct sk_buff *skb, unsigned int len);