From: Mike Galbraith <mgalbraith@suse.de>

Date: Wed Aug  2 10:55:41 CEST 2017

Subject: net: net dont disable irqs in netpoll_send_skb()

Patch-mainline: Never, RT specific

References: SLE Realtime Extension

RT takes sleeping locks, we can't disable irqs.

Signed-off-by: Mike Galbraith <mgalbraith@suse.de>

---

 include/linux/netpoll.h |    8 ++++++--

 net/core/netpoll.c      |    6 +++---

 2 files changed, 9 insertions(+), 5 deletions(-)

--- a/include/linux/netpoll.h

+++ b/include/linux/netpoll.h

@@ -67,9 +67,13 @@ void netpoll_send_skb_on_dev(struct netp

 static inline void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)

 {

 	unsigned long flags;

-	local_irq_save(flags);

+	local_irq_save_nort(flags);

+	if (IS_ENABLED(CONFIG_PREEMPT_RT))

+		rcu_read_lock();

 	netpoll_send_skb_on_dev(np, skb, np->dev);

-	local_irq_restore(flags);

+	if (IS_ENABLED(CONFIG_PREEMPT_RT))

+		rcu_read_unlock();

+	local_irq_restore_nort(flags);

 }

 #ifdef CONFIG_NETPOLL

--- a/net/core/netpoll.c

+++ b/net/core/netpoll.c

@@ -334,7 +334,7 @@ void netpoll_send_skb_on_dev(struct netp

 	/* It is up to the caller to keep npinfo alive. */

 	struct netpoll_info *npinfo;

-	lockdep_assert_irqs_disabled();

+	lockdep_assert_irqs_disabled_nonrt();

 	npinfo = rcu_dereference_bh(np->dev->npinfo);

 	if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {

@@ -368,7 +368,7 @@ void netpoll_send_skb_on_dev(struct netp

 			udelay(USEC_PER_POLL);

 		}

-		WARN_ONCE(!irqs_disabled(),

+		WARN_ONCE(!IS_ENABLED(CONFIG_PREEMPT_RT) && !irqs_disabled(),

 			"netpoll_send_skb_on_dev(): %s enabled interrupts in poll (%pF)\n",

 			dev->name, dev->netdev_ops->ndo_start_xmit);

@@ -391,7 +391,7 @@ void netpoll_send_udp(struct netpoll *np

 	static atomic_t ip_ident;

 	struct ipv6hdr *ip6h;

-	WARN_ON_ONCE(!irqs_disabled());

+	WARN_ON_ONCE_NONRT(!irqs_disabled());

 	udp_len = len + sizeof(*udph);

 	if (np->ipv6)