From 509d7648135f914a3dd64c17484b33df5dd0a19c Mon Sep 17 00:00:00 2001 From: Magnus Karlsson Date: Wed, 11 Jul 2018 10:12:49 +0200 Subject: [PATCH 1/4] xsk: do not return ENXIO from TX copy mode This patch removes the ENXIO return code from TX copy-mode when someone has forcefully changed the number of queues on the device so that the queue bound to the socket is no longer available. Just silently stop sending anything as in zero-copy mode so the error reporting gets consistent between the two modes. Fixes: 35fcde7f8deb ("xsk: support for Tx") Signed-off-by: Magnus Karlsson Signed-off-by: Daniel Borkmann --- net/xdp/xsk.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index 7d220cbd09b6a..08d09115093ed 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -244,10 +244,8 @@ static int xsk_generic_xmit(struct sock *sk, struct msghdr *m, goto out; } - if (xs->queue_id >= xs->dev->real_num_tx_queues) { - err = -ENXIO; + if (xs->queue_id >= xs->dev->real_num_tx_queues) goto out; - } skb = sock_alloc_send_skb(sk, len, 1, &err); if (unlikely(!skb)) { From 9684f5e7c8cdf076aeec81344d4893a30f7aa6a1 Mon Sep 17 00:00:00 2001 From: Magnus Karlsson Date: Wed, 11 Jul 2018 10:12:50 +0200 Subject: [PATCH 2/4] 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: 35fcde7f8deb ("xsk: support for Tx") Signed-off-by: Magnus Karlsson Signed-off-by: Daniel Borkmann --- net/xdp/xsk.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index 08d09115093ed..87567232d0f85 100644 --- 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)) { From 6efb4436f7fcc50cc3fb9a113d0f16e3968172b1 Mon Sep 17 00:00:00 2001 From: Magnus Karlsson Date: Wed, 11 Jul 2018 10:12:51 +0200 Subject: [PATCH 3/4] xsk: always return ENOBUFS from sendmsg if there is no TX queue This patch makes sure ENOBUFS is always returned from sendmsg if there is no TX queue configured. This was not the case for zero-copy mode. With this patch this error reporting is consistent between copy mode and zero-copy mode. Fixes: ac98d8aab61b ("xsk: wire upp Tx zero-copy functions") Signed-off-by: Magnus Karlsson Signed-off-by: Daniel Borkmann --- net/xdp/xsk.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index 87567232d0f85..9c784307f7b00 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -218,9 +218,6 @@ static int xsk_generic_xmit(struct sock *sk, struct msghdr *m, struct sk_buff *skb; int err = 0; - if (unlikely(!xs->tx)) - return -ENOBUFS; - mutex_lock(&xs->mutex); while (xskq_peek_desc(xs->tx, &desc)) { @@ -296,6 +293,8 @@ static int xsk_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len) return -ENXIO; if (unlikely(!(xs->dev->flags & IFF_UP))) return -ENETDOWN; + if (unlikely(!xs->tx)) + return -ENOBUFS; if (need_wait) return -EOPNOTSUPP; From 09210c4bcc065d9d91ef3c051902ad18252cd3c0 Mon Sep 17 00:00:00 2001 From: Magnus Karlsson Date: Wed, 11 Jul 2018 10:12:52 +0200 Subject: [PATCH 4/4] xsk: do not return EMSGSIZE in copy mode for packets larger than MTU This patch stops returning EMSGSIZE from sendmsg in copy mode when the size of the packet is larger than the MTU. Just send it to the device so that it will drop it as in zero-copy mode. This makes the error reporting consistent between copy mode and zero-copy mode. Fixes: 35fcde7f8deb ("xsk: support for Tx") Signed-off-by: Magnus Karlsson Signed-off-by: Daniel Borkmann --- net/xdp/xsk.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index 9c784307f7b00..72335c2e81089 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -233,15 +233,10 @@ static int xsk_generic_xmit(struct sock *sk, struct msghdr *m, if (xskq_reserve_addr(xs->umem->cq)) goto out; - len = desc.len; - if (unlikely(len > xs->dev->mtu)) { - err = -EMSGSIZE; - goto out; - } - if (xs->queue_id >= xs->dev->real_num_tx_queues) goto out; + len = desc.len; skb = sock_alloc_send_skb(sk, len, 1, &err); if (unlikely(!skb)) { err = -EAGAIN;