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Message-Id: <1465836376-24452-2-git-send-email-ubraun@linux.vnet.ibm.com>
Date: Mon, 13 Jun 2016 18:46:14 +0200
From: Ursula Braun <ubraun@...ux.vnet.ibm.com>
To: davem@...emloft.net
Cc: netdev@...r.kernel.org, linux-s390@...r.kernel.org,
schwidefsky@...ibm.com, heiko.carstens@...ibm.com,
utz.bacher@...ibm.com
Subject: [PATCH net-next 1/3] af_iucv: use paged SKBs for big outbound messages
From: Eugene Crosser <Eugene.Crosser@...ibm.com>
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@...ibm.com>
Signed-off-by: Ursula Braun <ubraun@...ux.vnet.ibm.com>
---
net/iucv/af_iucv.c | 124 +++++++++++++++++++++++++++++++++--------------------
1 file changed, 77 insertions(+), 47 deletions(-)
diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
index fc3598a..38448d1 100644
--- a/net/iucv/af_iucv.c
+++ b/net/iucv/af_iucv.c
@@ -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;
- }
- skb_queue_tail(&iucv->send_skb_q, skb);
-
- if (((iucv->path->flags & IUCV_IPRMDATA) & iucv->flags)
- && skb->len <= 7) {
- err = iucv_send_iprm(iucv->path, &txmsg, skb);
+ } else { /* Classic VM IUCV transport */
+ skb_queue_tail(&iucv->send_skb_q, skb);
+
+ 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 */
+ if (err == 0) {
+ skb_unlink(skb, &iucv->send_skb_q);
+ kfree_skb(skb);
+ }
- /* 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 */
+ if (err == 0x15) {
+ pr_iucv->path_sever(iucv->path, NULL);
+ skb_unlink(skb, &iucv->send_skb_q);
+ err = -EPIPE;
+ goto fail;
+ }
+ } 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);
}
-
- /* 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);
+ 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",
+ appl_id, user_id);
+ err = -EAGAIN;
+ } else {
+ err = -EPIPE;
+ }
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);
- 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",
- appl_id, user_id);
- err = -EAGAIN;
- } else
- err = -EPIPE;
- skb_unlink(skb, &iucv->send_skb_q);
- goto fail;
}
-release:
release_sock(sk);
return len;
--
2.6.6
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