[NET]: Kill skb->list

Remove the "list" member of struct sk_buff, as it is entirely
redundant.  All SKB list removal callers know which list the
SKB is on, so storing this in sk_buff does nothing other than
taking up some space.

Two tricky bits were SCTP, which I took care of, and two ATM
drivers which Francois Romieu <romieu@fr.zoreil.com> fixed
up.

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>

2 files changed, 40 insertions, 27 deletions

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 091a66f06a35..4454afe4727e 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -4892,7 +4892,7 @@ static void sctp_sock_migrate(struct sock *oldsk, struct sock *newsk,
         sctp_skb_for_each(skb, &oldsk->sk_receive_queue, tmp) {
                 event = sctp_skb2event(skb);
                 if (event->asoc == assoc) {
-                        __skb_unlink(skb, skb->list);
+                        __skb_unlink(skb, &oldsk->sk_receive_queue);
                         __skb_queue_tail(&newsk->sk_receive_queue, skb);
                 }
         }
@@ -4921,7 +4921,7 @@ static void sctp_sock_migrate(struct sock *oldsk, struct sock *newsk,
                 sctp_skb_for_each(skb, &oldsp->pd_lobby, tmp) {
                         event = sctp_skb2event(skb);
                         if (event->asoc == assoc) {
-                                __skb_unlink(skb, skb->list);
+                                __skb_unlink(skb, &oldsp->pd_lobby);
                                 __skb_queue_tail(queue, skb);
                         }
                 }
diff --git a/net/sctp/ulpqueue.c b/net/sctp/ulpqueue.c
index 8bbc279d6c99..ec2c857eae7f 100644
--- a/net/sctp/ulpqueue.c
+++ b/net/sctp/ulpqueue.c
@@ -50,9 +50,9 @@
 
 /* Forward declarations for internal helpers.  */
 static struct sctp_ulpevent * sctp_ulpq_reasm(struct sctp_ulpq *ulpq,
-                                                struct sctp_ulpevent *);
+                                              struct sctp_ulpevent *);
 static struct sctp_ulpevent * sctp_ulpq_order(struct sctp_ulpq *,
-                                                struct sctp_ulpevent *);
+                                              struct sctp_ulpevent *);
 
 /* 1st Level Abstractions */
 
@@ -125,7 +125,9 @@ int sctp_ulpq_tail_data(struct sctp_ulpq *ulpq, struct sctp_chunk *chunk,
                 event = sctp_ulpq_order(ulpq, event);
         }
 
-        /* Send event to the ULP.  */
+        /* Send event to the ULP.  'event' is the sctp_ulpevent for
+         * very first SKB on the 'temp' list.
+         */
         if (event)
                 sctp_ulpq_tail_event(ulpq, event);
 
@@ -158,14 +160,18 @@ static int sctp_ulpq_clear_pd(struct sctp_ulpq *ulpq)
         return sctp_clear_pd(ulpq->asoc->base.sk);
 }
 
-
-
+/* If the SKB of 'event' is on a list, it is the first such member
+ * of that list.
+ */
 int sctp_ulpq_tail_event(struct sctp_ulpq *ulpq, struct sctp_ulpevent *event)
 {
         struct sock *sk = ulpq->asoc->base.sk;
-        struct sk_buff_head *queue;
+        struct sk_buff_head *queue, *skb_list;
+        struct sk_buff *skb = sctp_event2skb(event);
         int clear_pd = 0;
 
+        skb_list = (struct sk_buff_head *) skb->prev;
+
         /* If the socket is just going to throw this away, do not
          * even try to deliver it.
          */
@@ -197,10 +203,10 @@ int sctp_ulpq_tail_event(struct sctp_ulpq *ulpq, struct sctp_ulpevent *event)
         /* If we are harvesting multiple skbs they will be
          * collected on a list.
          */
-        if (sctp_event2skb(event)->list)
-                sctp_skb_list_tail(sctp_event2skb(event)->list, queue);
+        if (skb_list)
+                sctp_skb_list_tail(skb_list, queue);
         else
-                __skb_queue_tail(queue, sctp_event2skb(event));
+                __skb_queue_tail(queue, skb);
 
         /* Did we just complete partial delivery and need to get
          * rolling again?  Move pending data to the receive
@@ -214,10 +220,11 @@ int sctp_ulpq_tail_event(struct sctp_ulpq *ulpq, struct sctp_ulpevent *event)
         return 1;
 
 out_free:
-        if (sctp_event2skb(event)->list)
-                sctp_queue_purge_ulpevents(sctp_event2skb(event)->list);
+        if (skb_list)
+                sctp_queue_purge_ulpevents(skb_list);
         else
                 sctp_ulpevent_free(event);
+
         return 0;
 }
 
@@ -269,7 +276,7 @@ static inline void sctp_ulpq_store_reasm(struct sctp_ulpq *ulpq,
  * payload was fragmented on the way and ip had to reassemble them.
  * We add the rest of skb's to the first skb's fraglist.
  */
-static struct sctp_ulpevent *sctp_make_reassembled_event(struct sk_buff *f_frag, struct sk_buff *l_frag)
+static struct sctp_ulpevent *sctp_make_reassembled_event(struct sk_buff_head *queue, struct sk_buff *f_frag, struct sk_buff *l_frag)
 {
         struct sk_buff *pos;
         struct sctp_ulpevent *event;
@@ -294,7 +301,7 @@ static struct sctp_ulpevent *sctp_make_reassembled_event(struct sk_buff *f_frag,
                 skb_shinfo(f_frag)->frag_list = pos;
 
         /* Remove the first fragment from the reassembly queue.  */
-        __skb_unlink(f_frag, f_frag->list);
+        __skb_unlink(f_frag, queue);
         while (pos) {
 
                 pnext = pos->next;
@@ -304,7 +311,7 @@ static struct sctp_ulpevent *sctp_make_reassembled_event(struct sk_buff *f_frag,
                 f_frag->data_len += pos->len;
 
                 /* Remove the fragment from the reassembly queue.  */
-                __skb_unlink(pos, pos->list);
+                __skb_unlink(pos, queue);
         
                 /* Break if we have reached the last fragment.  */
                 if (pos == l_frag)
@@ -375,7 +382,7 @@ static inline struct sctp_ulpevent *sctp_ulpq_retrieve_reassembled(struct sctp_u
 done:
         return retval;
 found:
-        retval = sctp_make_reassembled_event(first_frag, pos);
+        retval = sctp_make_reassembled_event(&ulpq->reasm, first_frag, pos);
         if (retval)
                 retval->msg_flags |= MSG_EOR;
         goto done;
@@ -435,7 +442,7 @@ static inline struct sctp_ulpevent *sctp_ulpq_retrieve_partial(struct sctp_ulpq
          * further.
          */
 done:
-        retval = sctp_make_reassembled_event(first_frag, last_frag);
+        retval = sctp_make_reassembled_event(&ulpq->reasm, first_frag, last_frag);
         if (retval && is_last)
                 retval->msg_flags |= MSG_EOR;
 
@@ -527,7 +534,7 @@ static inline struct sctp_ulpevent *sctp_ulpq_retrieve_first(struct sctp_ulpq *u
          * further.
          */
 done:
-        retval = sctp_make_reassembled_event(first_frag, last_frag);
+        retval = sctp_make_reassembled_event(&ulpq->reasm, first_frag, last_frag);
         return retval;
 }
 
@@ -537,6 +544,7 @@ done:
 static inline void sctp_ulpq_retrieve_ordered(struct sctp_ulpq *ulpq,
                                               struct sctp_ulpevent *event)
 {
+        struct sk_buff_head *event_list;
         struct sk_buff *pos, *tmp;
         struct sctp_ulpevent *cevent;
         struct sctp_stream *in;
@@ -547,6 +555,8 @@ static inline void sctp_ulpq_retrieve_ordered(struct sctp_ulpq *ulpq,
         ssn = event->ssn;
         in  = &ulpq->asoc->ssnmap->in;
 
+        event_list = (struct sk_buff_head *) sctp_event2skb(event)->prev;
+
         /* We are holding the chunks by stream, by SSN.  */
         sctp_skb_for_each(pos, &ulpq->lobby, tmp) {
                 cevent = (struct sctp_ulpevent *) pos->cb;
@@ -567,10 +577,10 @@ static inline void sctp_ulpq_retrieve_ordered(struct sctp_ulpq *ulpq,
                 /* Found it, so mark in the ssnmap. */
                 sctp_ssn_next(in, sid);
 
-                __skb_unlink(pos, pos->list);
+                __skb_unlink(pos, &ulpq->lobby);
 
                 /* Attach all gathered skbs to the event.  */
-                __skb_queue_tail(sctp_event2skb(event)->list, pos);
+                __skb_queue_tail(event_list, pos);
         }
 }
 
@@ -626,7 +636,7 @@ static inline void sctp_ulpq_store_ordered(struct sctp_ulpq *ulpq,
 }
 
 static struct sctp_ulpevent *sctp_ulpq_order(struct sctp_ulpq *ulpq,
-                                                struct sctp_ulpevent *event)
+                                             struct sctp_ulpevent *event)
 {
         __u16 sid, ssn;
         struct sctp_stream *in;
@@ -667,7 +677,7 @@ static inline void sctp_ulpq_reap_ordered(struct sctp_ulpq *ulpq)
 {
         struct sk_buff *pos, *tmp;
         struct sctp_ulpevent *cevent;
-        struct sctp_ulpevent *event = NULL;
+        struct sctp_ulpevent *event;
         struct sctp_stream *in;
         struct sk_buff_head temp;
         __u16 csid, cssn;
@@ -675,6 +685,8 @@ static inline void sctp_ulpq_reap_ordered(struct sctp_ulpq *ulpq)
         in  = &ulpq->asoc->ssnmap->in;
 
         /* We are holding the chunks by stream, by SSN.  */
+        skb_queue_head_init(&temp);
+        event = NULL;
         sctp_skb_for_each(pos, &ulpq->lobby, tmp) {
                 cevent = (struct sctp_ulpevent *) pos->cb;
                 csid = cevent->stream;
@@ -686,19 +698,20 @@ static inline void sctp_ulpq_reap_ordered(struct sctp_ulpq *ulpq)
                 /* Found it, so mark in the ssnmap. */         
                 sctp_ssn_next(in, csid);
 
-                __skb_unlink(pos, pos->list);
+                __skb_unlink(pos, &ulpq->lobby);
                 if (!event) {                                           
                         /* Create a temporary list to collect chunks on.  */
                         event = sctp_skb2event(pos);
-                        skb_queue_head_init(&temp);
                         __skb_queue_tail(&temp, sctp_event2skb(event));
                 } else {
                         /* Attach all gathered skbs to the event.  */
-                        __skb_queue_tail(sctp_event2skb(event)->list, pos);
+                        __skb_queue_tail(&temp, pos);
                 }
         }
 
-        /* Send event to the ULP.  */
+        /* Send event to the ULP.  'event' is the sctp_ulpevent for
+         * very first SKB on the 'temp' list.
+         */
         if (event)
                 sctp_ulpq_tail_event(ulpq, event);
 }