* [PATCH net 0/1] af_iucv: don't use paged skbs for TX on HiperSockets
@ 2017-01-10 16:10 Ursula Braun
2017-01-10 16:10 ` [PATCH net 1/1] net/af_iucv: " Ursula Braun
0 siblings, 1 reply; 3+ messages in thread
From: Ursula Braun @ 2017-01-10 16:10 UTC (permalink / raw)
To: davem; +Cc: netdev, linux-s390, schwidefsky, heiko.carstens, stable, ubraun
Dave,
here is an af_iucv patch built for the net-tree.
Thanks, Ursula
Julian Wiedmann (1):
net/af_iucv: don't use paged skbs for TX on HiperSockets
net/iucv/af_iucv.c | 25 ++++++++++++++-----------
1 file changed, 14 insertions(+), 11 deletions(-)
--
2.8.4
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH net 1/1] net/af_iucv: don't use paged skbs for TX on HiperSockets
2017-01-10 16:10 [PATCH net 0/1] af_iucv: don't use paged skbs for TX on HiperSockets Ursula Braun
@ 2017-01-10 16:10 ` Ursula Braun
2017-01-11 2:07 ` David Miller
0 siblings, 1 reply; 3+ messages in thread
From: Ursula Braun @ 2017-01-10 16:10 UTC (permalink / raw)
To: davem; +Cc: netdev, linux-s390, schwidefsky, heiko.carstens, stable, ubraun
From: Julian Wiedmann <jwi@linux.vnet.ibm.com>
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")
---
net/iucv/af_iucv.c | 25 ++++++++++++++-----------
1 file changed, 14 insertions(+), 11 deletions(-)
diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
index cfb9e5f..13190b3 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);
--
2.8.4
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH net 1/1] net/af_iucv: don't use paged skbs for TX on HiperSockets
2017-01-10 16:10 ` [PATCH net 1/1] net/af_iucv: " Ursula Braun
@ 2017-01-11 2:07 ` David Miller
0 siblings, 0 replies; 3+ messages in thread
From: David Miller @ 2017-01-11 2:07 UTC (permalink / raw)
To: ubraun; +Cc: netdev, linux-s390, schwidefsky, heiko.carstens, stable
From: Ursula Braun <ubraun@linux.vnet.ibm.com>
Date: Tue, 10 Jan 2017 17:10:34 +0100
> From: Julian Wiedmann <jwi@linux.vnet.ibm.com>
>
> 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")
Applied.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2017-01-10 16:10 [PATCH net 0/1] af_iucv: don't use paged skbs for TX on HiperSockets Ursula Braun
2017-01-10 16:10 ` [PATCH net 1/1] net/af_iucv: " Ursula Braun
2017-01-11 2:07 ` David Miller
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