slub-enable-irqs-for-no-wait.patch

Subject: slub: Enable irqs for __GFP_WAIT
From: Thomas Gleixner <tglx@linutronix.de>
Date: Wed, 09 Jan 2013 12:08:15 +0100

SYSTEM_RUNNING might be too late for enabling interrupts. Allocations
with GFP_WAIT can happen before that. So use this as an indicator.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 mm/slub.c |   13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

Index: linux-stable/mm/slub.c
===================================================================
--- linux-stable.orig/mm/slub.c
+++ linux-stable/mm/slub.c
@@ -1280,14 +1280,15 @@ static struct page *allocate_slab(struct
 	struct page *page;
 	struct kmem_cache_order_objects oo = s->oo;
 	gfp_t alloc_gfp;
+	bool enableirqs;
 
 	flags &= gfp_allowed_mask;
 
+	enableirqs = (flags & __GFP_WAIT) != 0;
 #ifdef CONFIG_PREEMPT_RT_FULL
-	if (system_state == SYSTEM_RUNNING)
-#else
-	if (flags & __GFP_WAIT)
+	enableirqs |= system_state == SYSTEM_RUNNING;
 #endif
+	if (enableirqs)
 		local_irq_enable();
 
 	flags |= s->allocflags;
@@ -1327,11 +1328,7 @@ static struct page *allocate_slab(struct
 			kmemcheck_mark_unallocated_pages(page, pages);
 	}
 
-#ifdef CONFIG_PREEMPT_RT_FULL
-	if (system_state == SYSTEM_RUNNING)
-#else
-	if (flags & __GFP_WAIT)
-#endif
+	if (enableirqs)
 		local_irq_disable();
 	if (!page)
 		return NULL;