From: Thomas Gleixner <tglx@linutronix.de>
Date: Wed, 26 Sep 2012 16:21:08 +0200
Subject: net: Another local_irq_disable/kmalloc headache
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.25-rt16.tar.xz

Replace it by a local lock. Though that's pretty inefficient :(

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 net/core/skbuff.c |   10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -63,6 +63,7 @@
 #include <linux/errqueue.h>
 #include <linux/prefetch.h>
 #include <linux/if_vlan.h>
+#include <linux/locallock.h>
 
 #include <net/protocol.h>
 #include <net/dst.h>
@@ -330,6 +331,7 @@ struct napi_alloc_cache {
 
 static DEFINE_PER_CPU(struct page_frag_cache, netdev_alloc_cache);
 static DEFINE_PER_CPU(struct napi_alloc_cache, napi_alloc_cache);
+static DEFINE_LOCAL_IRQ_LOCK(netdev_alloc_lock);
 
 static void *__netdev_alloc_frag(unsigned int fragsz, gfp_t gfp_mask)
 {
@@ -337,10 +339,10 @@ static void *__netdev_alloc_frag(unsigne
 	unsigned long flags;
 	void *data;
 
-	local_irq_save(flags);
+	local_lock_irqsave(netdev_alloc_lock, flags);
 	nc = this_cpu_ptr(&netdev_alloc_cache);
 	data = page_frag_alloc(nc, fragsz, gfp_mask);
-	local_irq_restore(flags);
+	local_unlock_irqrestore(netdev_alloc_lock, flags);
 	return data;
 }
 
@@ -412,13 +414,13 @@ struct sk_buff *__netdev_alloc_skb(struc
 	if (sk_memalloc_socks())
 		gfp_mask |= __GFP_MEMALLOC;
 
-	local_irq_save(flags);
+	local_lock_irqsave(netdev_alloc_lock, flags);
 
 	nc = this_cpu_ptr(&netdev_alloc_cache);
 	data = page_frag_alloc(nc, len, gfp_mask);
 	pfmemalloc = nc->pfmemalloc;
 
-	local_irq_restore(flags);
+	local_unlock_irqrestore(netdev_alloc_lock, flags);
 
 	if (unlikely(!data))
 		return NULL;