[NETLINK]: Limit NLMSG_GOODSIZE to 8K.
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index 2a20f48..a9d3ad5 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -171,9 +171,16 @@
/*
* skb should fit one page. This choice is good for headerless malloc.
+ * But we should limit to 8K so that userspace does not have to
+ * use enormous buffer sizes on recvmsg() calls just to avoid
+ * MSG_TRUNC when PAGE_SIZE is very large.
*/
-#define NLMSG_GOODORDER 0
-#define NLMSG_GOODSIZE (SKB_MAX_ORDER(0, NLMSG_GOODORDER))
+#if PAGE_SIZE < 8192UL
+#define NLMSG_GOODSIZE SKB_WITH_OVERHEAD(PAGE_SIZE)
+#else
+#define NLMSG_GOODSIZE SKB_WITH_OVERHEAD(8192UL)
+#endif
+
#define NLMSG_DEFAULT_SIZE (NLMSG_GOODSIZE - NLMSG_HDRLEN)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index f9441b5..30089ad 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -39,9 +39,11 @@
#define SKB_DATA_ALIGN(X) (((X) + (SMP_CACHE_BYTES - 1)) & \
~(SMP_CACHE_BYTES - 1))
-#define SKB_MAX_ORDER(X, ORDER) (((PAGE_SIZE << (ORDER)) - (X) - \
- sizeof(struct skb_shared_info)) & \
- ~(SMP_CACHE_BYTES - 1))
+#define SKB_WITH_OVERHEAD(X) \
+ (((X) - sizeof(struct skb_shared_info)) & \
+ ~(SMP_CACHE_BYTES - 1))
+#define SKB_MAX_ORDER(X, ORDER) \
+ SKB_WITH_OVERHEAD((PAGE_SIZE << (ORDER)) - (X))
#define SKB_MAX_HEAD(X) (SKB_MAX_ORDER((X), 0))
#define SKB_MAX_ALLOC (SKB_MAX_ORDER(0, 2))