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Commit a11ef7be authored by Jan Kiszka's avatar Jan Kiszka Committed by David S. Miller
Browse files

CAPI: Rework capiminor RX handler 



Avoid re-queuing skbs unless the error detected in handle_recv_skb is
expected to be recoverable such as lacking memory, a full CAPI queue, a
full TTY input buffer, or a not yet existing TTY.

Signed-off-by: default avatarJan Kiszka <jan.kiszka@web.de>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b75b2eed

drivers/isdn/capi/capi.c

+38 −22
Original line number Diff line number Diff line
@@ -436,15 +436,13 @@ gen_data_b3_resp_for(struct capiminor *mp, struct sk_buff *skb) 


static int handle_recv_skb(struct capiminor *mp, struct sk_buff *skb)

{

	unsigned int datalen = skb->len - CAPIMSG_LEN(skb->data);

	struct tty_struct *tty;

	struct sk_buff *nskb;

	int datalen;

	u16 errcode, datahandle;

	struct tty_ldisc *ld;

	int ret = -1;



	datalen = skb->len - CAPIMSG_LEN(skb->data);



	tty = tty_port_tty_get(&mp->port);

	if (!tty) {

#ifdef _DEBUG_DATAFLOW
@@ -454,50 +452,68 @@ static int handle_recv_skb(struct capiminor *mp, struct sk_buff *skb) 
	}

	

	ld = tty_ldisc_ref(tty);

	if (!ld)

		goto out1;

	if (!ld) {

		/* fatal error, do not requeue */

		ret = 0;

		kfree_skb(skb);

		goto deref_tty;

	}



	if (ld->ops->receive_buf == NULL) {

#if defined(_DEBUG_DATAFLOW) || defined(_DEBUG_TTYFUNCS)

		printk(KERN_DEBUG "capi: ldisc has no receive_buf function\n");

#endif

		goto out2;

		/* fatal error, do not requeue */

		goto free_skb;

	}

	if (mp->ttyinstop) {

#if defined(_DEBUG_DATAFLOW) || defined(_DEBUG_TTYFUNCS)

		printk(KERN_DEBUG "capi: recv tty throttled\n");

#endif

		goto out2;

		goto deref_ldisc;

	}



	if (tty->receive_room < datalen) {

#if defined(_DEBUG_DATAFLOW) || defined(_DEBUG_TTYFUNCS)

		printk(KERN_DEBUG "capi: no room in tty\n");

#endif

		goto out2;

		goto deref_ldisc;

	}

	if ((nskb = gen_data_b3_resp_for(mp, skb)) == NULL) {



	nskb = gen_data_b3_resp_for(mp, skb);

	if (!nskb) {

		printk(KERN_ERR "capi: gen_data_b3_resp failed\n");

		goto out2;

		goto deref_ldisc;

	}



	datahandle = CAPIMSG_U16(skb->data, CAPIMSG_BASELEN + 4);



	errcode = capi20_put_message(mp->ap, nskb);

	if (errcode != CAPI_NOERROR) {

		printk(KERN_ERR "capi: send DATA_B3_RESP failed=%x\n",

				errcode);

		kfree_skb(nskb);

		goto out2;

	}

	(void)skb_pull(skb, CAPIMSG_LEN(skb->data));



	if (errcode == CAPI_NOERROR) {

		skb_pull(skb, CAPIMSG_LEN(skb->data));

#ifdef _DEBUG_DATAFLOW

		printk(KERN_DEBUG "capi: DATA_B3_RESP %u len=%d => ldisc\n",

					datahandle, skb->len);

#endif

		ld->ops->receive_buf(tty, skb->data, NULL, skb->len);

	kfree_skb(skb);

	} else {

		printk(KERN_ERR "capi: send DATA_B3_RESP failed=%x\n",

				errcode);

		kfree_skb(nskb);



		if (errcode == CAPI_SENDQUEUEFULL)

			goto deref_ldisc;

	}



free_skb:

	ret = 0;

out2:

	kfree_skb(skb);



deref_ldisc:

	tty_ldisc_deref(ld);

out1:



deref_tty:

	tty_kref_put(tty);

	return ret;

}