[PATCH 1/2] Bluetooth: set sk_sndbuf and sk_rcvbuf properly in ERTM

[PATCH 1/2] Bluetooth: set sk_sndbuf and sk_rcvbuf properly in ERTM

[Gustavo F. Padovan]

Setting both this value to MPS * TxWin * 1.2 guarantees that we are
reserving space to fit the whole txwindow in the memory, and that
sendmsg() will block when the transmission window is full avoid
overloading the system memory.
I don't have a strong reason about the 1.2 constant in the account, we
can do another tests in the future and change that value.

Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
---
 net/bluetooth/l2cap_core.c |   10 +++++++++-
 1 files changed, 9 insertions(+), 1 deletions(-)

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 44aa034..1e2ab05 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -3129,9 +3129,17 @@ static inline int l2cap_config_rsp(struct l2cap_conn *conn, struct l2cap_cmd_hdr
 		l2cap_pi(sk)->next_tx_seq = 0;
 		l2cap_pi(sk)->expected_tx_seq = 0;
 		__skb_queue_head_init(TX_QUEUE(sk));
-		if (l2cap_pi(sk)->mode ==  L2CAP_MODE_ERTM)
+		if (l2cap_pi(sk)->mode ==  L2CAP_MODE_ERTM) {
 			l2cap_ertm_init(sk);
 
+			sk->sk_sndbuf = (l2cap_pi(sk)->remote_tx_win * 1.2 *
+						(sizeof(struct l2cap_pinfo) +
+						l2cap_pi(sk)->mps));
+			sk->sk_rcvbuf = (l2cap_pi(sk)->tx_win * 1.2 *
+						(sizeof(struct l2cap_pinfo) +
+						l2cap_pi(sk)->remote_mps));
+		}
+
 		l2cap_chan_ready(sk);
 	}
 
-- 
1.7.3

[PATCH 2/2] Bluetooth: Use the proper error value from bt_skb_send_alloc()

[Gustavo F. Padovan]

&err points to the proper error set by bt_skb_send_alloc() when it
fails.

Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
---
 net/bluetooth/l2cap_core.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 1e2ab05..1510812 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -1537,7 +1537,7 @@ static inline int l2cap_skbuff_fromiovec(struct sock *sk, struct msghdr *msg, in
 
 		*frag = bt_skb_send_alloc(sk, count, msg->msg_flags & MSG_DONTWAIT, &err);
 		if (!*frag)
-			return -EFAULT;
+			return err;
 		if (memcpy_fromiovec(skb_put(*frag, count), msg->msg_iov, count))
 			return -EFAULT;
 
@@ -1563,7 +1563,7 @@ static struct sk_buff *l2cap_create_connless_pdu(struct sock *sk, struct msghdr
 	skb = bt_skb_send_alloc(sk, count + hlen,
 			msg->msg_flags & MSG_DONTWAIT, &err);
 	if (!skb)
-		return ERR_PTR(-ENOMEM);
+		return ERR_PTR(err);
 
 	/* Create L2CAP header */
 	lh = (struct l2cap_hdr *) skb_put(skb, L2CAP_HDR_SIZE);
@@ -1592,7 +1592,7 @@ static struct sk_buff *l2cap_create_basic_pdu(struct sock *sk, struct msghdr *ms
 	skb = bt_skb_send_alloc(sk, count + hlen,
 			msg->msg_flags & MSG_DONTWAIT, &err);
 	if (!skb)
-		return ERR_PTR(-ENOMEM);
+		return ERR_PTR(err);
 
 	/* Create L2CAP header */
 	lh = (struct l2cap_hdr *) skb_put(skb, L2CAP_HDR_SIZE);
@@ -1629,7 +1629,7 @@ static struct sk_buff *l2cap_create_iframe_pdu(struct sock *sk, struct msghdr *m
 	skb = bt_skb_send_alloc(sk, count + hlen,
 			msg->msg_flags & MSG_DONTWAIT, &err);
 	if (!skb)
-		return ERR_PTR(-ENOMEM);
+		return ERR_PTR(err);
 
 	/* Create L2CAP header */
 	lh = (struct l2cap_hdr *) skb_put(skb, L2CAP_HDR_SIZE);
-- 
1.7.3

Re: [PATCH 1/2] Bluetooth: set sk_sndbuf and sk_rcvbuf properly in ERTM

[Mat Martineau]

Gustavo -

On Mon, 27 Sep 2010, Gustavo F. Padovan wrote:

> Setting both this value to MPS * TxWin * 1.2 guarantees that we are
> reserving space to fit the whole txwindow in the memory, and that
> sendmsg() will block when the transmission window is full avoid
> overloading the system memory.
> I don't have a strong reason about the 1.2 constant in the account, we
> can do another tests in the future and change that value.
>
> Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
> ---
> net/bluetooth/l2cap_core.c |   10 +++++++++-
> 1 files changed, 9 insertions(+), 1 deletions(-)
>
> diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
> index 44aa034..1e2ab05 100644
> --- a/net/bluetooth/l2cap_core.c
> +++ b/net/bluetooth/l2cap_core.c
> @@ -3129,9 +3129,17 @@ static inline int l2cap_config_rsp(struct l2cap_conn *conn, struct l2cap_cmd_hdr
> 		l2cap_pi(sk)->next_tx_seq = 0;
> 		l2cap_pi(sk)->expected_tx_seq = 0;
> 		__skb_queue_head_init(TX_QUEUE(sk));
> -		if (l2cap_pi(sk)->mode ==  L2CAP_MODE_ERTM)
> +		if (l2cap_pi(sk)->mode ==  L2CAP_MODE_ERTM) {
> 			l2cap_ertm_init(sk);
>
> +			sk->sk_sndbuf = (l2cap_pi(sk)->remote_tx_win * 1.2 *
> +						(sizeof(struct l2cap_pinfo) +
> +						l2cap_pi(sk)->mps));
> +			sk->sk_rcvbuf = (l2cap_pi(sk)->tx_win * 1.2 *
> +						(sizeof(struct l2cap_pinfo) +
> +						l2cap_pi(sk)->remote_mps));
> +		}
> +
> 		l2cap_chan_ready(sk);
> 	}
>
> -- 
> 1.7.3

I think sizeof(struct sk_buff) would be better than
sizeof(struct l2cap_pinfo), since these limits apply to data buffers, 
not per-socket overhead.

The 1.2 constant would need to be increased if we allow ERTM MPS
bigger than the HCI MTU, since there would be multiple sk_buffs per 
PDU.  However, the calculation could be updated when those MPS changes 
are made.

It would also help to enforce some limits:
SOCK_MIN_SNDBUF < sk->sk_sndbuf < sysctl_wmem_max
SOCK_MIN_RCVBUF < sk->sk_rcvbuf < sysctl_rmem_max


Regards,

--
Mat Martineau
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum

Re: [PATCH 1/2] Bluetooth: set sk_sndbuf and sk_rcvbuf properly in ERTM

[Gustavo F. Padovan]

Hi Mat,

* Mat Martineau <mathewm@codeaurora.org> [2010-09-27 14:22:07 -0700]:

> 
> Gustavo -
> 
> On Mon, 27 Sep 2010, Gustavo F. Padovan wrote:
> 
> > Setting both this value to MPS * TxWin * 1.2 guarantees that we are
> > reserving space to fit the whole txwindow in the memory, and that
> > sendmsg() will block when the transmission window is full avoid
> > overloading the system memory.
> > I don't have a strong reason about the 1.2 constant in the account, we
> > can do another tests in the future and change that value.
> >
> > Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
> > ---
> > net/bluetooth/l2cap_core.c |   10 +++++++++-
> > 1 files changed, 9 insertions(+), 1 deletions(-)
> >
> > diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
> > index 44aa034..1e2ab05 100644
> > --- a/net/bluetooth/l2cap_core.c
> > +++ b/net/bluetooth/l2cap_core.c
> > @@ -3129,9 +3129,17 @@ static inline int l2cap_config_rsp(struct l2cap_conn *conn, struct l2cap_cmd_hdr
> > 		l2cap_pi(sk)->next_tx_seq = 0;
> > 		l2cap_pi(sk)->expected_tx_seq = 0;
> > 		__skb_queue_head_init(TX_QUEUE(sk));
> > -		if (l2cap_pi(sk)->mode ==  L2CAP_MODE_ERTM)
> > +		if (l2cap_pi(sk)->mode ==  L2CAP_MODE_ERTM) {
> > 			l2cap_ertm_init(sk);
> >
> > +			sk->sk_sndbuf = (l2cap_pi(sk)->remote_tx_win * 1.2 *
> > +						(sizeof(struct l2cap_pinfo) +
> > +						l2cap_pi(sk)->mps));
> > +			sk->sk_rcvbuf = (l2cap_pi(sk)->tx_win * 1.2 *
> > +						(sizeof(struct l2cap_pinfo) +
> > +						l2cap_pi(sk)->remote_mps));
> > +		}
> > +
> > 		l2cap_chan_ready(sk);
> > 	}
> >
> > -- 
> > 1.7.3

Thanks a lot for your comments, I'll rework the patches and then resend.

> 
> I think sizeof(struct sk_buff) would be better than
> sizeof(struct l2cap_pinfo), since these limits apply to data buffers, 
> not per-socket overhead.

Sure.

> 
> The 1.2 constant would need to be increased if we allow ERTM MPS
> bigger than the HCI MTU, since there would be multiple sk_buffs per 
> PDU.  However, the calculation could be updated when those MPS changes 
> are made.

Yes, we can change that when we start to allow MPS greater than HCI MTU.

> 
> It would also help to enforce some limits:
> SOCK_MIN_SNDBUF < sk->sk_sndbuf < sysctl_wmem_max
> SOCK_MIN_RCVBUF < sk->sk_rcvbuf < sysctl_rmem_max

Sure.

-- 
Gustavo F. Padovan
ProFUSION embedded systems - http://profusion.mobi