# \[PATCH net v1 2/3\] net: devmem: return EMSGSIZE on type mismatch - From: Mina Almasry \ - Date: 2026-08-01 12:53:16 - List: netdev - Page: https://ratatoskr.run/netdev/2026/08/17352682 - Thread: https://ratatoskr.run/netdev/2026/08/17352681/t.md ```text When a devmem payload mixes with a standard page payload, return -EMSGSIZE instead of -EFAULT. This enables tcp_sendmsg to seamlessly fall back to creating a new segment instead of failing the socket send. Fixes: bd61848900bff ("net: devmem: Implement TX path") Cc: Pavel Begunkov Cc: Stanislav Fomichev Cc: Bobby Eshleman Signed-off-by: Mina Almasry --- net/core/datagram.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/core/datagram.c b/net/core/datagram.c index 173b5d97bd409..6f8ffd61bcab4 100644 --- a/net/core/datagram.c +++ b/net/core/datagram.c @@ -638,7 +638,7 @@ int zerocopy_fill_skb_from_iter(struct sk_buff *skb, int frag = skb_shinfo(skb)->nr_frags; if (!skb_frags_readable(skb)) - return -EFAULT; + return -EMSGSIZE; while (length && iov_iter_count(from)) { struct page *head, *last_head = NULL; @@ -713,7 +713,7 @@ zerocopy_fill_skb_from_devmem(struct sk_buff *skb, struct iov_iter *from, struct net_iov *niov; if (i && skb_frags_readable(skb)) - return -EFAULT; + return -EMSGSIZE; /* Devmem filling works by taking an IOVEC from the user where the * iov_addrs are interpreted as an offset in bytes into the dma-buf to -- 2.55.0.571.g244d577d93-goog ```