From a006353a9a8d9e28d35f94bfc97e9573d6ee28aa Mon Sep 17 00:00:00 2001 From: Eugene Crosser Date: Mon, 13 Jun 2016 18:46:16 +0200 Subject: [PATCH] af_iucv: use paged SKBs for big inbound messages When an inbound message is bigger than a page, allocate a paged SKB, and subsequently use IUCV receive 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 | 56 +++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 50 insertions(+), 6 deletions(-) diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c index 9ed2adf9e057..37d674e6f8a9 100644 --- a/net/iucv/af_iucv.c +++ b/net/iucv/af_iucv.c @@ -1231,6 +1231,34 @@ out: return err; } +static struct sk_buff *alloc_iucv_recv_skb(unsigned long len) +{ + size_t headroom, linear; + struct sk_buff *skb; + int err; + + if (len < PAGE_SIZE) { + headroom = 0; + linear = len; + } else { + headroom = sizeof(struct iucv_array) * (MAX_SKB_FRAGS + 1); + linear = PAGE_SIZE - headroom; + } + skb = alloc_skb_with_frags(headroom + linear, len - linear, + 0, &err, GFP_ATOMIC | GFP_DMA); + WARN_ONCE(!skb, + "alloc of recv iucv skb len=%lu failed with errcode=%d\n", + len, err); + if (skb) { + if (headroom) + skb_reserve(skb, headroom); + skb_put(skb, linear); + skb->len = len; + skb->data_len = len - linear; + } + return skb; +} + /* iucv_process_message() - Receive a single outstanding IUCV message * * Locking: must be called with message_q.lock held @@ -1255,16 +1283,32 @@ static void iucv_process_message(struct sock *sk, struct sk_buff *skb, skb->len = 0; } } else { - rc = pr_iucv->message_receive(path, msg, + if (skb_is_nonlinear(skb)) { + struct iucv_array *iba = (struct iucv_array *)skb->head; + int i; + + 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); + } + rc = pr_iucv->message_receive(path, msg, + IUCV_IPBUFLST, + (void *)iba, len, NULL); + } else { + rc = pr_iucv->message_receive(path, msg, msg->flags & IUCV_IPRMDATA, skb->data, len, NULL); + } if (rc) { kfree_skb(skb); return; } - skb_reset_transport_header(skb); - skb_reset_network_header(skb); - skb->len = len; + WARN_ON_ONCE(skb->len != len); } IUCV_SKB_CB(skb)->offset = 0; @@ -1283,7 +1327,7 @@ static void iucv_process_message_q(struct sock *sk) struct sock_msg_q *p, *n; list_for_each_entry_safe(p, n, &iucv->message_q.list, list) { - skb = alloc_skb(iucv_msg_length(&p->msg), GFP_ATOMIC | GFP_DMA); + skb = alloc_iucv_recv_skb(iucv_msg_length(&p->msg)); if (!skb) break; iucv_process_message(sk, skb, p->path, &p->msg); @@ -1778,7 +1822,7 @@ static void iucv_callback_rx(struct iucv_path *path, struct iucv_message *msg) if (len > sk->sk_rcvbuf) goto save_message; - skb = alloc_skb(iucv_msg_length(msg), GFP_ATOMIC | GFP_DMA); + skb = alloc_iucv_recv_skb(iucv_msg_length(msg)); if (!skb) goto save_message; -- 2.20.1