Return-Path: From: Gustavo Padovan To: linux-bluetooth@vger.kernel.org Subject: [PATCH 3/4] Bluetooth: Add MSG_MORE support to L2CAP sockets Date: Fri, 11 May 2012 13:16:13 -0300 Message-Id: <1336752974-7747-3-git-send-email-gustavo@padovan.org> In-Reply-To: <1336752974-7747-2-git-send-email-gustavo@padovan.org> References: <1336752974-7747-1-git-send-email-gustavo@padovan.org> <1336752974-7747-2-git-send-email-gustavo@padovan.org> Sender: linux-bluetooth-owner@vger.kernel.org List-ID: MSG_MORE enables us to save buffer space in userspace, the packet are built directly in the kernel and sent when their size reaches the Output MTU value. Only MSG_MORE for Basic Mode is supported right now. chan->skb_more keeps a pointer to the L2CAP packet that is being build through many calls to send(). Signed-off-by: Gustavo Padovan --- include/net/bluetooth/l2cap.h | 2 + net/bluetooth/l2cap_core.c | 116 ++++++++++++++++++++++++++++++++++++++--- 2 files changed, 110 insertions(+), 8 deletions(-) diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h index 1c7d1cd..5f2845d 100644 --- a/include/net/bluetooth/l2cap.h +++ b/include/net/bluetooth/l2cap.h @@ -520,6 +520,8 @@ struct l2cap_chan { struct list_head list; struct list_head global_l; + struct sk_buff *skb_more; + void *data; struct l2cap_ops *ops; struct mutex lock; diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c index e5a4fd9..73bf8a8 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -1827,6 +1827,8 @@ static inline int l2cap_skbuff_fromiovec(struct l2cap_chan *chan, struct sk_buff **frag; int sent = 0; + count = min_t(unsigned int, count, len); + if (memcpy_fromiovec(skb_put(skb, count), msg->msg_iov, count)) return -EFAULT; @@ -1903,9 +1905,13 @@ static struct sk_buff *l2cap_create_basic_pdu(struct l2cap_chan *chan, int err, count; struct l2cap_hdr *lh; - BT_DBG("chan %p len %d", chan, (int)len); + BT_DBG("chan %p len %d aclmtu %d" , chan, (int)len, conn->mtu); - count = min_t(unsigned int, (conn->mtu - L2CAP_HDR_SIZE), len); + if (msg->msg_flags & MSG_MORE) + count = min_t(unsigned int, (conn->mtu - L2CAP_HDR_SIZE), + chan->omtu); + else + count = min_t(unsigned int, (conn->mtu - L2CAP_HDR_SIZE), len); skb = chan->ops->alloc_skb(chan, count + L2CAP_HDR_SIZE, msg->msg_flags & MSG_DONTWAIT); @@ -2048,6 +2054,75 @@ static int l2cap_segment_sdu(struct l2cap_chan *chan, return err; } +static int l2cap_append_pdu(struct l2cap_chan *chan, struct msghdr *msg, + size_t len) +{ + struct l2cap_conn *conn = chan->conn; + struct sk_buff **frag, *skb = chan->skb_more; + int sent = 0; + unsigned int count; + struct l2cap_hdr *lh; + + BT_DBG("chan %p len %ld", chan, len); + + frag = &skb_shinfo(skb)->frag_list; + if (*frag) + goto frags; + + count = min_t(unsigned int, (conn->mtu - L2CAP_HDR_SIZE), + chan->omtu); + count = count - skb->len + L2CAP_HDR_SIZE; + count = min_t(unsigned int, count, len); + + if (memcpy_fromiovec(skb_put(skb, count), msg->msg_iov, count)) + return -EFAULT; + + sent += count; + len -= count; + +frags: + while (*frag) + frag = &(*frag)->next; + + while (len) { + count = chan->omtu - skb->len + L2CAP_HDR_SIZE; + count = min_t(unsigned int, count, len); + count = min_t(unsigned int, conn->mtu, count); + + *frag = chan->ops->alloc_skb(chan, count, + msg->msg_flags & MSG_DONTWAIT); + if (IS_ERR(*frag)) + return PTR_ERR(*frag); + + if (memcpy_fromiovec(skb_put(*frag, count), msg->msg_iov, + count)) + return -EFAULT; + + (*frag)->priority = skb->priority; + + sent += count; + len -= count; + + skb->len += (*frag)->len; + skb->data_len += (*frag)->len; + + frag = &(*frag)->next; + + if (skb->len == chan->omtu + L2CAP_HDR_SIZE) + break; + } + + lh = (struct l2cap_hdr *) skb->data; + lh->len = cpu_to_le16(skb->len - L2CAP_HDR_SIZE); + + if (skb->len == chan->omtu + L2CAP_HDR_SIZE) { + l2cap_do_send(chan, skb); + chan->skb_more = NULL; + } + + return sent; +} + int l2cap_chan_send(struct l2cap_chan *chan, struct msghdr *msg, size_t len, u32 priority) { @@ -2068,16 +2143,41 @@ int l2cap_chan_send(struct l2cap_chan *chan, struct msghdr *msg, size_t len, switch (chan->mode) { case L2CAP_MODE_BASIC: /* Check outgoing MTU */ - if (len > chan->omtu) + if (len > chan->omtu) { + kfree_skb(chan->skb_more); return -EMSGSIZE; + } - /* Create a basic PDU */ - skb = l2cap_create_basic_pdu(chan, msg, len, priority); - if (IS_ERR(skb)) + err = len; + if (chan->skb_more) { + int sent = l2cap_append_pdu(chan, msg, len); + + if (sent < 0) { + kfree_skb(chan->skb_more); + return sent; + } + + len -= sent; + } + + if (len) + skb = l2cap_create_basic_pdu(chan, msg, len, priority); + else + skb = chan->skb_more; + + if (IS_ERR(skb)) { + kfree_skb(chan->skb_more); return PTR_ERR(skb); + } + + if (!skb) + return err; + + if (msg->msg_flags & MSG_MORE && skb->len < chan->omtu) + chan->skb_more = skb; + else + l2cap_do_send(chan, skb); - l2cap_do_send(chan, skb); - err = len; break; case L2CAP_MODE_ERTM: -- 1.7.10.1