xsk: do not return EAGAIN from sendmsg when completion queue is full

This patch stops returning EAGAIN in TX copy mode when the completion queue is full as zero-copy does not do this. Instead this situation can be detected by comparing the head and tail pointers of the completion queue in both modes. In any case, EAGAIN was not the correct error code here since no amount of calling sendmsg will solve the problem. Only consuming one or more messages on the completion queue will fix this. With this patch, the error reporting becomes consistent between copy mode and zero-copy mode. Fixes: 35fcde7 ("xsk: support for Tx") Signed-off-by: Magnus Karlsson <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]>
olifre · Jul 13, 2018 · 9684f5e · 9684f5e
1 parent 509d764
commit 9684f5e
Showing 1 changed file with 1 addition and 3 deletions.
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
@@ -233,10 +233,8 @@ static int xsk_generic_xmit(struct sock *sk, struct msghdr *m,
 			goto out;
 		}
 
-		if (xskq_reserve_addr(xs->umem->cq)) {
-			err = -EAGAIN;
+		if (xskq_reserve_addr(xs->umem->cq))
 			goto out;
-		}
 
 		len = desc.len;
 		if (unlikely(len > xs->dev->mtu)) {