On Thu, Nov 20, 2025 at 01:19:54PM +0100, Paolo Abeni wrote:

On 11/20/25 4:37 AM, Bobby Eshleman wrote:

quoted

@@ -2479,10 +2504,12 @@ static int tcp_recvmsg_dmabuf(struct sock *sk, const struct sk_buff *skb,
 			      unsigned int offset, struct msghdr *msg,
 			      int remaining_len)
 {
+	struct net_devmem_dmabuf_binding *binding = NULL;
 	struct dmabuf_cmsg dmabuf_cmsg = { 0 };
 	struct tcp_xa_pool tcp_xa_pool;
 	unsigned int start;
 	int i, copy, n;
+	int refs = 0;
 	int sent = 0;
 	int err = 0;
 

@@ -2536,6 +2563,7 @@ static int tcp_recvmsg_dmabuf(struct sock *sk, const struct sk_buff *skb,
 			skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 			struct net_iov *niov;
 			u64 frag_offset;
+			u32 token;
 			int end;
 
 			/* !skb_frags_readable() should indicate that ALL the

@@ -2568,13 +2596,32 @@ static int tcp_recvmsg_dmabuf(struct sock *sk, const struct sk_buff *skb,
 					      start;
 				dmabuf_cmsg.frag_offset = frag_offset;
 				dmabuf_cmsg.frag_size = copy;
-				err = tcp_xa_pool_refill(sk, &tcp_xa_pool,
-							 skb_shinfo(skb)->nr_frags - i);
-				if (err)
+
+				binding = net_devmem_iov_binding(niov);
+
+				if (!sk->sk_devmem_info.binding)
+					sk->sk_devmem_info.binding = binding;
+
+				if (sk->sk_devmem_info.binding != binding) {
+					err = -EFAULT;
 					goto out;
+				}
+
+				if (static_branch_unlikely(&tcp_devmem_ar_key)) {

Not a real/full review but the above is apparently causing kunit build
failures:

ERROR:root:ld: vmlinux.o: in function `tcp_recvmsg_dmabuf':
tcp.c:(.text+0x669b21): undefined reference to `tcp_devmem_ar_key'
ld: tcp.c:(.text+0x669b68): undefined reference to `tcp_devmem_ar_key'
ld: tcp.c:(.text+0x669c54): undefined reference to `tcp_devmem_ar_key'
make[3]: *** [../scripts/Makefile.vmlinux:72: vmlinux.unstripped] Error 1
make[2]: *** [/home/kunit/testing/Makefile:1242: vmlinux] Error 2
make[1]: *** [/home/kunit/testing/Makefile:248: __sub-make] Error 2
make: *** [Makefile:248: __sub-make] Error 2

see:

https://netdev-3.bots.linux.dev/kunit/results/393664/

Thanks Paolo, I'll fix that for the next rev. And I'll have to add
building kunit into my flow (currently using some custom stuff and nipa
ingest_mdir, but don't think either has kunit).

quoted

@@ -2617,6 +2664,7 @@ static int tcp_recvmsg_dmabuf(struct sock *sk,

const struct sk_buff *skb,
 
 out: tcp_xa_pool_commit(sk, &tcp_xa_pool); +

[just because I stumbled upon the above while looking for the build
issue]: please do not mix unrelated whitespace-change only with
functional change.

Don't know how I missed that line, will definitely remove.

Thanks again,
Bobby