atm: nicstar: Replace in_interrupt() usage

push_scqe() uses in_interrupt() to figure out if it is allowed to sleep. The usage of in_interrupt() in drivers is phased out and Linus clearly requested that code which changes behaviour depending on context should either be separated or the context be conveyed in an argument passed by the caller, which usually knows the context. Aside of that in_interrupt() is not correct as it does not catch preempt disabled regions which neither can sleep. ns_send() (the only caller of push_scqe()) has the following callers: - vcc_sendmsg() used as proto_ops::sendmsg is expected to be invoked in preemtible context. -> vcc->dev->ops->send() (ns_send()) - atm_vcc::send via atmdev_ops::send either directly (pointer copied by atm_init_aal34() or atm_init_aal5()) or via atm_send_aal0(). This is invoked by drivers (like br2684, clip, pppoatm, ...) which are called from net_device_ops::ndo_start_xmit with BH disabled. Add atmdev_ops::send_bh which is used by callers from BH context (atm_send_aal*()) and if this callback missing then ::send is used instead. Implement this callback in nicstar and use it to replace in_interrupt().

Sebastian Andrzej Siewior committed 5 years ago

Commit f2bcc2f1 parent 030946f3 files · +29 −8Browse files

Unified · Split

3 files

drivers/atm/nicstar.c +18 −6
include/linux/atmdev.h +1 −0
net/atm/raw.c +10 −2

drivers/atm/nicstar.c+18−6

@@ -130,8 +130,9 @@ static int ns_open(struct atm_vcc *vcc); · 129 unmodified lines
130	130	static void ns_close(struct atm_vcc *vcc);
131	131	static void fill_tst(ns_dev * card, int n, vc_map * vc);
132	132	static int ns_send(struct atm_vcc vcc, struct sk_buff skb);
	133	+static int ns_send_bh(struct atm_vcc vcc, struct sk_buff skb);
133	134	static int push_scqe(ns_dev * card, vc_map * vc, scq_info * scq, ns_scqe * tbd,
134		− struct sk_buff *skb);
	135	+ struct sk_buff *skb, bool may_sleep);
135	136	static void process_tsq(ns_dev * card);
136	137	static void drain_scq(ns_dev * card, scq_info * scq, int pos);
137	138	static void process_rsq(ns_dev * card);
@@ -160,6 +161,7 @@ static const struct atmdev_ops atm_ops = { · 22 unmodified lines
160	161	.close = ns_close,
161	162	.ioctl = ns_ioctl,
162	163	.send = ns_send,
	164	+ .send_bh = ns_send_bh,
163	165	.phy_put = ns_phy_put,
164	166	.phy_get = ns_phy_get,
165	167	.proc_read = ns_proc_read,
@@ -1620,7 +1622,7 @@ static void fill_tst(ns_dev * card, int n, vc_map * vc) · 1454 unmodified lines
1620	1622	card->tst_addr = new_tst;
1621	1623	}
1622	1624
1623		−static int ns_send(struct atm_vcc vcc, struct sk_buff skb)
	1625	+static int _ns_send(struct atm_vcc vcc, struct sk_buff skb, bool may_sleep)
1624	1626	{
1625	1627	ns_dev *card;
1626	1628	vc_map *vc;
@@ -1704,7 +1706,7 @@ static int ns_send(struct atm_vcc vcc, struct sk_buff skb) · 77 unmodified lines
1704	1706	scq = card->scq0;
1705	1707	}
1706	1708
1707		− if (push_scqe(card, vc, scq, &scqe, skb) != 0) {
	1709	+ if (push_scqe(card, vc, scq, &scqe, skb, may_sleep) != 0) {
1708	1710	atomic_inc(&vcc->stats->tx_err);
1709	1711	dev_kfree_skb_any(skb);
1710	1712	return -EIO;
@@ -1714,8 +1716,18 @@ static int ns_send(struct atm_vcc vcc, struct sk_buff skb) · 3 unmodified lines
1714	1716	return 0;
1715	1717	}
1716	1718
	1719	+static int ns_send(struct atm_vcc vcc, struct sk_buff skb)
	1720	+{
	1721	+ return _ns_send(vcc, skb, true);
	1722	+}
	1723	+
	1724	+static int ns_send_bh(struct atm_vcc vcc, struct sk_buff skb)
	1725	+{
	1726	+ return _ns_send(vcc, skb, false);
	1727	+}
	1728	+
1717	1729	static int push_scqe(ns_dev * card, vc_map * vc, scq_info * scq, ns_scqe * tbd,
1718		− struct sk_buff *skb)
	1730	+ struct sk_buff *skb, bool may_sleep)
1719	1731	{
1720	1732	unsigned long flags;
1721	1733	ns_scqe tsr;
@@ -1726,7 +1738,7 @@ static int push_scqe(ns_dev * card, vc_map * vc, scq_info * scq, ns_scqe * tbd, · 4 unmodified lines
1726	1738
1727	1739	spin_lock_irqsave(&scq->lock, flags);
1728	1740	while (scq->tail == scq->next) {
1729		− if (in_interrupt()) {
	1741	+ if (!may_sleep) {
1730	1742	spin_unlock_irqrestore(&scq->lock, flags);
1731	1743	printk("nicstar%d: Error pushing TBD.\n", card->index);
1732	1744	return 1;
@@ -1771,7 +1783,7 @@ static int push_scqe(ns_dev * card, vc_map * vc, scq_info * scq, ns_scqe * tbd, · 38 unmodified lines
1771	1783	int has_run = 0;
1772	1784
1773	1785	while (scq->tail == scq->next) {
1774		− if (in_interrupt()) {
	1786	+ if (!may_sleep) {
1775	1787	data = scq_virt_to_bus(scq, scq->next);
1776	1788	ns_write_sram(card, scq->scd, &data, 1);
1777	1789	spin_unlock_irqrestore(&scq->lock, flags);

include/linux/atmdev.h+1−0

@@ -186,6 +186,7 @@ struct atmdev_ops { /* only send is required */ · 185 unmodified lines
186	186	void __user *arg);
187	187	#endif
188	188	int (send)(struct atm_vcc vcc,struct sk_buff *skb);
	189	+ int (send_bh)(struct atm_vcc vcc, struct sk_buff *skb);
189	190	int (send_oam)(struct atm_vcc vcc,void *cell,int flags);
190	191	void (phy_put)(struct atm_dev dev,unsigned char value,
191	192	unsigned long addr);

net/atm/raw.c+10−2

@@ -54,6 +54,8 @@ static int atm_send_aal0(struct atm_vcc vcc, struct sk_buff skb) · 53 unmodified lines
54	54	kfree_skb(skb);
55	55	return -EADDRNOTAVAIL;
56	56	}
	57	+ if (vcc->dev->ops->send_bh)
	58	+ return vcc->dev->ops->send_bh(vcc, skb);
57	59	return vcc->dev->ops->send(vcc, skb);
58	60	}
59	61
@@ -71,7 +73,10 @@ int atm_init_aal34(struct atm_vcc *vcc) · 11 unmodified lines
71	73	vcc->push = atm_push_raw;
72	74	vcc->pop = atm_pop_raw;
73	75	vcc->push_oam = NULL;
74		− vcc->send = vcc->dev->ops->send;
	76	+ if (vcc->dev->ops->send_bh)
	77	+ vcc->send = vcc->dev->ops->send_bh;
	78	+ else
	79	+ vcc->send = vcc->dev->ops->send;
75	80	return 0;
76	81	}
77	82
@@ -80,7 +85,10 @@ int atm_init_aal5(struct atm_vcc *vcc) · 2 unmodified lines
80	85	vcc->push = atm_push_raw;
81	86	vcc->pop = atm_pop_raw;
82	87	vcc->push_oam = NULL;
83		− vcc->send = vcc->dev->ops->send;
	88	+ if (vcc->dev->ops->send_bh)
	89	+ vcc->send = vcc->dev->ops->send_bh;
	90	+ else
	91	+ vcc->send = vcc->dev->ops->send;
84	92	return 0;
85	93	}
86	94	EXPORT_SYMBOL(atm_init_aal5);