net: shrink struct ubuf_info

We can benefit from a smaller struct ubuf_info, so leave only mandatory
fields and let users to decide how they want to extend it. Convert
MSG_ZEROCOPY to struct ubuf_info_msgzc and remove duplicated fields.
This reduces the size from 48 bytes to just 16.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 4 insertions, 18 deletions

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index fd7dcb977fdf..920eb6413fee 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -533,25 +533,8 @@ enum {
 struct ubuf_info {
 	void (*callback)(struct sk_buff *, struct ubuf_info *,
 			 bool zerocopy_success);
-	union {
-		struct {
-			unsigned long desc;
-			void *ctx;
-		};
-		struct {
-			u32 id;
-			u16 len;
-			u16 zerocopy:1;
-			u32 bytelen;
-		};
-	};
 	refcount_t refcnt;
 	u8 flags;
-
-	struct mmpin {
-		struct user_struct *user;
-		unsigned int num_pg;
-	} mmp;
 };
 
 struct ubuf_info_msgzc {
@@ -570,7 +553,10 @@ struct ubuf_info_msgzc {
 		};
 	};
 
-	struct mmpin mmp;
+	struct mmpin {
+		struct user_struct *user;
+		unsigned int num_pg;
+	} mmp;
 };
 
 #define skb_uarg(SKB)	((struct ubuf_info *)(skb_shinfo(SKB)->destructor_arg))