net/sctp: Make wrappers for accessing in/out streams

This patch introduces wrappers for accessing in/out streams indirectly.
This will enable to replace physically contiguous memory arrays
of streams with flexible arrays (or maybe any other appropriate
mechanism) which do memory allocation on a per-page basis.

Signed-off-by: Oleg Babin <obabin@virtuozzo.com>
Signed-off-by: Konstantin Khorenko <khorenko@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 25 insertions, 10 deletions

diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index ab869e0d8326..6b2b8df8a1d2 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -398,37 +398,35 @@ void sctp_stream_update(struct sctp_stream *stream, struct sctp_stream *new);
 
 /* What is the current SSN number for this stream? */
 #define sctp_ssn_peek(stream, type, sid) \
-        ((stream)->type[sid].ssn)
+        (sctp_stream_##type((stream), (sid))->ssn)
 
 /* Return the next SSN number for this stream.  */
 #define sctp_ssn_next(stream, type, sid) \
-        ((stream)->type[sid].ssn++)
+        (sctp_stream_##type((stream), (sid))->ssn++)
 
 /* Skip over this ssn and all below. */
 #define sctp_ssn_skip(stream, type, sid, ssn) \
-        ((stream)->type[sid].ssn = ssn + 1)
+        (sctp_stream_##type((stream), (sid))->ssn = ssn + 1)
 
 /* What is the current MID number for this stream? */
 #define sctp_mid_peek(stream, type, sid) \
-        ((stream)->type[sid].mid)
+        (sctp_stream_##type((stream), (sid))->mid)
 
 /* Return the next MID number for this stream.  */
 #define sctp_mid_next(stream, type, sid) \
-        ((stream)->type[sid].mid++)
+        (sctp_stream_##type((stream), (sid))->mid++)
 
 /* Skip over this mid and all below. */
 #define sctp_mid_skip(stream, type, sid, mid) \
-        ((stream)->type[sid].mid = mid + 1)
-
-#define sctp_stream_in(asoc, sid) (&(asoc)->stream.in[sid])
+        (sctp_stream_##type((stream), (sid))->mid = mid + 1)
 
 /* What is the current MID_uo number for this stream? */
 #define sctp_mid_uo_peek(stream, type, sid) \
-        ((stream)->type[sid].mid_uo)
+        (sctp_stream_##type((stream), (sid))->mid_uo)
 
 /* Return the next MID_uo number for this stream.  */
 #define sctp_mid_uo_next(stream, type, sid) \
-        ((stream)->type[sid].mid_uo++)
+        (sctp_stream_##type((stream), (sid))->mid_uo++)
 
 /*
  * Pointers to address related SCTP functions.
@@ -1463,6 +1461,23 @@ struct sctp_stream {
         struct sctp_stream_interleave *si;
 };
 
+static inline struct sctp_stream_out *sctp_stream_out(
+        const struct sctp_stream *stream,
+        __u16 sid)
+{
+        return ((struct sctp_stream_out *)(stream->out)) + sid;
+}
+
+static inline struct sctp_stream_in *sctp_stream_in(
+        const struct sctp_stream *stream,
+        __u16 sid)
+{
+        return ((struct sctp_stream_in *)(stream->in)) + sid;
+}
+
+#define SCTP_SO(s, i) sctp_stream_out((s), (i))
+#define SCTP_SI(s, i) sctp_stream_in((s), (i))
+
 #define SCTP_STREAM_CLOSED              0x00
 #define SCTP_STREAM_OPEN                0x01