Return-Path: From: Gustavo Padovan To: linux-bluetooth@vger.kernel.org Subject: [PATCH -v3] Bluetooth: Add MSG_MORE support to L2CAP sockets Date: Fri, 18 May 2012 20:46:18 -0300 Message-Id: <1337384778-25135-1-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 is built directly in the kernel and sent only when a msg with the MSG_MORE flag not set arrives. If a send() tries to add more chan->omtu bytes -EMSGSIZE is returned. 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 --- v3: address Mat's comments from v2. include/net/bluetooth/l2cap.h | 2 + net/bluetooth/l2cap_core.c | 127 ++++++++++++++++++++++++++++++++++++++--- 2 files changed, 120 insertions(+), 9 deletions(-) diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h index 7bc4019..d6dfbf2 100644 --- a/include/net/bluetooth/l2cap.h +++ b/include/net/bluetooth/l2cap.h @@ -512,6 +512,8 @@ 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 ae69da8..bae0d17 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -549,6 +549,9 @@ static void l2cap_chan_del(struct l2cap_chan *chan, int err) if (test_bit(CONF_NOT_COMPLETE, &chan->conf_state)) return; + kfree_skb(chan->skb_more); + chan->skb_more = NULL; + switch(chan->mode) { case L2CAP_MODE_BASIC: break; @@ -1970,6 +1973,7 @@ 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; @@ -1981,7 +1985,11 @@ static inline int l2cap_skbuff_fromiovec(struct l2cap_chan *chan, while (len) { struct sk_buff *tmp; - count = min_t(unsigned int, conn->mtu, len); + if (msg->msg_flags & MSG_MORE) + count = min_t(unsigned int, conn->mtu, + chan->omtu - skb->len + L2CAP_HDR_SIZE); + else + count = min_t(unsigned int, conn->mtu, len); tmp = chan->ops->alloc_skb(chan, count, msg->msg_flags & MSG_DONTWAIT); @@ -1990,6 +1998,7 @@ static inline int l2cap_skbuff_fromiovec(struct l2cap_chan *chan, *frag = tmp; + count = min_t(unsigned int, count, len); if (memcpy_fromiovec(skb_put(*frag, count), msg->msg_iov, count)) return -EFAULT; @@ -2050,9 +2059,13 @@ 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); @@ -2197,11 +2210,84 @@ 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, *skb1; + int sent = 0; + unsigned int count; + struct l2cap_hdr *lh; + + BT_DBG("chan %p len %ld", chan, len); + + frag = &skb_shinfo(skb)->frag_list; + while (*frag && (*frag)->next) + frag = &(*frag)->next; + + if (*frag) { + skb1 = *frag; + frag = &(*frag)->next; + } else { + skb1 = skb; + } + + count = min_t(unsigned int, (conn->mtu - L2CAP_HDR_SIZE), + chan->omtu); + count = count - skb1->len + L2CAP_HDR_SIZE; + count = min_t(unsigned int, count, len); + + if (memcpy_fromiovec(skb_put(skb1, count), msg->msg_iov, count)) + return -EFAULT; + + if (skb != skb1) { + skb->len += count; + skb->data_len += count; + } + + sent += count; + len -= count; + + while (len) { + struct sk_buff *tmp; + + count = chan->omtu - skb->len + L2CAP_HDR_SIZE; + count = min_t(unsigned int, conn->mtu, count); + + tmp = chan->ops->alloc_skb(chan, count, + msg->msg_flags & MSG_DONTWAIT); + if (IS_ERR(tmp)) + return PTR_ERR(tmp); + + *frag = tmp; + + count = min_t(unsigned int, count, len); + 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; + } + + lh = (struct l2cap_hdr *) skb->data; + lh->len = cpu_to_le16(skb->len - L2CAP_HDR_SIZE); + + return sent; +} + int l2cap_chan_send(struct l2cap_chan *chan, struct msghdr *msg, size_t len, u32 priority) { struct sk_buff *skb; - int err; + int err, rem; struct sk_buff_head seg_queue; /* Connectionless channel */ @@ -2216,16 +2302,39 @@ int l2cap_chan_send(struct l2cap_chan *chan, struct msghdr *msg, size_t len, switch (chan->mode) { case L2CAP_MODE_BASIC: + skb = chan->skb_more; + /* Check outgoing MTU */ - if (len > chan->omtu) + if (skb) + rem = chan->omtu - skb->len + L2CAP_HDR_SIZE; + else + rem = chan->omtu; + + if (len > rem) return -EMSGSIZE; - /* Create a basic PDU */ - skb = l2cap_create_basic_pdu(chan, msg, len, priority); - if (IS_ERR(skb)) - return PTR_ERR(skb); + if (chan->skb_more) { + err = l2cap_append_pdu(chan, msg, len); + if (err < 0) { + kfree_skb(chan->skb_more); + chan->skb_more = NULL; + return err; + } + } else { + skb = l2cap_create_basic_pdu(chan, msg, len, priority); + if (IS_ERR(skb)) + return PTR_ERR(skb); + } + + if (msg->msg_flags & MSG_MORE) { + chan->skb_more = skb; + return len; + } l2cap_do_send(chan, skb); + + chan->skb_more = NULL; + err = len; break; -- 1.7.10.1