[RFC net-next v3 08/29] skbuff: don't mix ubuf_info of different types

[Pavel Begunkov <asml.silence@gmail.com>]

We should not append MSG_ZEROCOPY requests to skbuff with non
MSG_ZEROCOPY ubuf_info, they are not compatible.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 net/core/skbuff.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 71870def129c..7e6fcb3cd817 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1222,6 +1222,10 @@ struct ubuf_info *msg_zerocopy_realloc(struct sock *sk, size_t size,
 		const u32 byte_limit = 1 << 19;		/* limit to a few TSO */
 		u32 bytelen, next;
 
+		/* there might be non MSG_ZEROCOPY users */
+		if (uarg->callback != msg_zerocopy_callback)
+			return NULL;
+
 		/* realloc only when socket is locked (TCP, UDP cork),
 		 * so uarg->len and sk_zckey access is serialized
 		 */
-- 
2.36.1