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From 681b3db2848619e907fc478bf32f95547cee9e0b Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
Date: Fri, 3 Jul 2009 08:30:37 -0500
Subject: [PATCH] sparc: Prepare decoupling of page-fault logic from preempt-count
commit ab70f1d5819af93e041cbd88dcd310f60b5d83ba in tip.
With the separation of pagefault_{disable,enable}() from the
preempt_count a previously overlooked dependancy became painfully
clear.
kmap_atomic() is per cpu and relies not only on disabling the
pagefault handler, but really needs preemption disabled too.
Make this explicit now - so that we can change pagefault_disable().
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
arch/sparc/mm/highmem.c | 4 +++-
1 files changed, 3 insertions(+), 1 deletions(-)
diff --git a/arch/sparc/mm/highmem.c b/arch/sparc/mm/highmem.c
index 7916feb..a9f414c 100644
--- a/arch/sparc/mm/highmem.c
+++ b/arch/sparc/mm/highmem.c
@@ -34,7 +34,7 @@ void *kmap_atomic(struct page *page, enum km_type type)
unsigned long idx;
unsigned long vaddr;
- /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
+ preempt_disable();
pagefault_disable();
if (!PageHighMem(page))
return page_address(page);
@@ -73,6 +73,7 @@ void kunmap_atomic(void *kvaddr, enum km_type type)
if (vaddr < FIXADDR_START) { // FIXME
pagefault_enable();
+ preempt_enable();
return;
}
@@ -99,6 +100,7 @@ void kunmap_atomic(void *kvaddr, enum km_type type)
#endif
pagefault_enable();
+ preempt_enable();
}
EXPORT_SYMBOL(kunmap_atomic);
--
1.7.0.4
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