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| author | Julian Wiedmann <jwi@linux.vnet.ibm.com> | 2017-01-10 17:10:34 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-01-10 21:08:29 -0500 |
| commit | dc5367bcc556e97555fc94a32cd1aadbebdff47e (patch) | |
| tree | 78778f65fe742ff199468fc3ac00e572513b89bc /net/iucv | |
| parent | 5d722b3024f6762addb8642ffddc9f275b5107ae (diff) | |
| download | lwn-dc5367bcc556e97555fc94a32cd1aadbebdff47e.tar.gz lwn-dc5367bcc556e97555fc94a32cd1aadbebdff47e.zip | |
net/af_iucv: don't use paged skbs for TX on HiperSockets
With commit e53743994e21
("af_iucv: use paged SKBs for big outbound messages"),
we transmit paged skbs for both of AF_IUCV's transport modes
(IUCV or HiperSockets).
The qeth driver for Layer 3 HiperSockets currently doesn't
support NETIF_F_SG, so these skbs would just be linearized again
by the stack.
Avoid that overhead by using paged skbs only for IUCV transport.
cc stable, since this also circumvents a significant skb leak when
sending large messages (where the skb then needs to be linearized).
Signed-off-by: Julian Wiedmann <jwi@linux.vnet.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Cc: <stable@vger.kernel.org> # v4.8+
Fixes: e53743994e21 ("af_iucv: use paged SKBs for big outbound messages")
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/iucv')
| -rw-r--r-- | net/iucv/af_iucv.c | 25 |
1 files changed, 14 insertions, 11 deletions
diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c index cfb9e5f4e28f..13190b38f22e 100644 --- a/net/iucv/af_iucv.c +++ b/net/iucv/af_iucv.c @@ -1044,7 +1044,8 @@ static int iucv_sock_sendmsg(struct socket *sock, struct msghdr *msg, { struct sock *sk = sock->sk; struct iucv_sock *iucv = iucv_sk(sk); - size_t headroom, linear; + size_t headroom = 0; + size_t linear; struct sk_buff *skb; struct iucv_message txmsg = {0}; struct cmsghdr *cmsg; @@ -1122,18 +1123,20 @@ static int iucv_sock_sendmsg(struct socket *sock, struct msghdr *msg, * this is fine for SOCK_SEQPACKET (unless we want to support * segmented records using the MSG_EOR flag), but * for SOCK_STREAM we might want to improve it in future */ - headroom = (iucv->transport == AF_IUCV_TRANS_HIPER) - ? sizeof(struct af_iucv_trans_hdr) + ETH_HLEN : 0; - if (headroom + len < PAGE_SIZE) { + if (iucv->transport == AF_IUCV_TRANS_HIPER) { + headroom = sizeof(struct af_iucv_trans_hdr) + ETH_HLEN; linear = len; } else { - /* In nonlinear "classic" iucv skb, - * reserve space for iucv_array - */ - if (iucv->transport != AF_IUCV_TRANS_HIPER) - headroom += sizeof(struct iucv_array) * - (MAX_SKB_FRAGS + 1); - linear = PAGE_SIZE - headroom; + if (len < PAGE_SIZE) { + linear = len; + } else { + /* In nonlinear "classic" iucv skb, + * reserve space for iucv_array + */ + headroom = sizeof(struct iucv_array) * + (MAX_SKB_FRAGS + 1); + linear = PAGE_SIZE - headroom; + } } skb = sock_alloc_send_pskb(sk, headroom + linear, len - linear, noblock, &err, 0); |