net/sctp: Replace in/out stream arrays with flex_array

This path replaces physically contiguous memory arrays
allocated using kmalloc_array() with flexible arrays.
This enables to avoid memory allocation failures on the
systems under a memory stress.

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, 5 insertions, 4 deletions

diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 6b2b8df8a1d2..28a7c8e44636 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -57,6 +57,7 @@
 #include <linux/atomic.h>               /* This gets us atomic counters.  */
 #include <linux/skbuff.h>       /* We need sk_buff_head. */
 #include <linux/workqueue.h>    /* We need tq_struct.    */
+#include <linux/flex_array.h>   /* We need flex_array.   */
 #include <linux/sctp.h>         /* We need sctp* header structs.  */
 #include <net/sctp/auth.h>      /* We need auth specific structs */
 #include <net/ip.h>             /* For inet_skb_parm */
@@ -1438,8 +1439,8 @@ struct sctp_stream_in {
 };
 
 struct sctp_stream {
-        struct sctp_stream_out *out;
-        struct sctp_stream_in *in;
+        struct flex_array *out;
+        struct flex_array *in;
         __u16 outcnt;
         __u16 incnt;
         /* Current stream being sent, if any */
@@ -1465,14 +1466,14 @@ static inline struct sctp_stream_out *sctp_stream_out(
         const struct sctp_stream *stream,
         __u16 sid)
 {
-        return ((struct sctp_stream_out *)(stream->out)) + sid;
+        return flex_array_get(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;
+        return flex_array_get(stream->in, sid);
 }
 
 #define SCTP_SO(s, i) sctp_stream_out((s), (i))