From e53743994e21d2458f0129d07b253d66f96f5742 Mon Sep 17 00:00:00 2001 From: Eugene Crosser Date: Mon, 13 Jun 2016 18:46:14 +0200 Subject: [PATCH] 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 Signed-off-by: Ursula Braun Signed-off-by: David S. Miller --- 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 fc3598a922b0..38448d17c006 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; -- 2.39.5