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af_iucv: use paged SKBs for big outbound messages 

When an outbound message is bigger than a page, allocate and fill
a paged SKB, and subsequently use IUCV send primitive with IPBUFLST
flag. This relaxes the pressure to allocate big contiguous kernel
buffers.

Signed-off-by: Eugene Crosser <Eugene.Crosser@ru.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eugene Crosser 2016-06-13 18:46:14 +02:00 committed by David S. Miller
parent 818d49ad16
commit e53743994e
1 changed files with 76 additions and 46 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

82
net/iucv/af_iucv.c
View File

@ -1033,6 +1033,7 @@ 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;
struct sk_buff *skb;
struct iucv_message txmsg = {0};
struct cmsghdr *cmsg;
@ -1110,20 +1111,31 @@ 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 */
if (iucv->transport == AF_IUCV_TRANS_HIPER)
skb = sock_alloc_send_skb(sk,
len + sizeof(struct af_iucv_trans_hdr) + ETH_HLEN,
noblock, &err);
else
skb = sock_alloc_send_skb(sk, len, noblock, &err);
headroom = (iucv->transport == AF_IUCV_TRANS_HIPER)
? sizeof(struct af_iucv_trans_hdr) + ETH_HLEN : 0;
if (headroom + len < PAGE_SIZE) {
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;
}
skb = sock_alloc_send_pskb(sk, headroom + linear, len - linear,
noblock, &err, 0);
if (!skb)
goto out;
if (iucv->transport == AF_IUCV_TRANS_HIPER)
skb_reserve(skb, sizeof(struct af_iucv_trans_hdr) + ETH_HLEN);
if (memcpy_from_msg(skb_put(skb, len), msg, len)) {
err = -EFAULT;
if (headroom)
skb_reserve(skb, headroom);
skb_put(skb, linear);
skb->len = len;
skb->data_len = len - linear;
err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, len);
if (err)
goto fail;
}
/* wait if outstanding messages for iucv path has reached */
timeo = sock_sndtimeo(sk, noblock);
@ -1148,49 +1160,67 @@ static int iucv_sock_sendmsg(struct socket *sock, struct msghdr *msg,
atomic_dec(&iucv->msg_sent);
goto fail;
}
goto release;
}
} else { /* Classic VM IUCV transport */
skb_queue_tail(&iucv->send_skb_q, skb);
if (((iucv->path->flags & IUCV_IPRMDATA) & iucv->flags)
&& skb->len <= 7) {
if (((iucv->path->flags & IUCV_IPRMDATA) & iucv->flags) &&
skb->len <= 7) {
err = iucv_send_iprm(iucv->path, &txmsg, skb);
/* on success: there is no message_complete callback
* for an IPRMDATA msg; remove skb from send queue */
/* on success: there is no message_complete callback */
/* for an IPRMDATA msg; remove skb from send queue */
if (err == 0) {
skb_unlink(skb, &iucv->send_skb_q);
kfree_skb(skb);
}
/* this error should never happen since the
* IUCV_IPRMDATA path flag is set... sever path */
/* this error should never happen since the */
/* IUCV_IPRMDATA path flag is set... sever path */
if (err == 0x15) {
pr_iucv->path_sever(iucv->path, NULL);
skb_unlink(skb, &iucv->send_skb_q);
err = -EPIPE;
goto fail;
}
} else
err = pr_iucv->message_send(iucv->path, &txmsg, 0, 0,
(void *) skb->data, skb->len);
} else if (skb_is_nonlinear(skb)) {
struct iucv_array *iba = (struct iucv_array *)skb->head;
int i;
/* skip iucv_array lying in the headroom */
iba[0].address = (u32)(addr_t)skb->data;
iba[0].length = (u32)skb_headlen(skb);
for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
iba[i + 1].address =
(u32)(addr_t)skb_frag_address(frag);
iba[i + 1].length = (u32)skb_frag_size(frag);
}
err = pr_iucv->message_send(iucv->path, &txmsg,
IUCV_IPBUFLST, 0,
(void *)iba, skb->len);
} else { /* non-IPRM Linear skb */
err = pr_iucv->message_send(iucv->path, &txmsg,
0, 0, (void *)skb->data, skb->len);
}
if (err) {
if (err == 3) {
user_id[8] = 0;
memcpy(user_id, iucv->dst_user_id, 8);
appl_id[8] = 0;
memcpy(appl_id, iucv->dst_name, 8);
pr_err("Application %s on z/VM guest %s"
" exceeds message limit\n",
pr_err(
"Application %s on z/VM guest %s exceeds message limit\n",
appl_id, user_id);
err = -EAGAIN;
} else
} else {
err = -EPIPE;
}
skb_unlink(skb, &iucv->send_skb_q);
goto fail;
}
}
release:
release_sock(sk);
return len;