On Tue, 30 Nov 2010, Eric Dumazet wrote:
> > {
> > - int idx = --__get_cpu_var(__kmap_atomic_idx);
> > + int idx = __this_cpu_dec_return(__kmap_atomic_idx);
>
> __this_cpu_dec_return() is only needed if CONFIG_DEBUG_HIGHMEM
>
> > #ifdef CONFIG_DEBUG_HIGHMEM
> > BUG_ON(idx < 0);
> > #endif
> >
>
> You could change kmap_atomic_idx_pop() to return void, and use
> __this_cpu_dec(__kmap_atomic_idx)
The following would do?
Subject: highmem: Use this_cpu_dec instead of __this_cpu_dec_return if !DEBUG_HIGHMEM
Signed-off-by: Christoph Lameter <cl@xxxxxxxxx>
---
include/linux/highmem.h | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
Index: linux-2.6/include/linux/highmem.h
===================================================================
--- linux-2.6.orig/include/linux/highmem.h 2010-11-30 13:23:44.000000000 -0600
+++ linux-2.6/include/linux/highmem.h 2010-11-30 13:24:54.000000000 -0600
@@ -95,14 +95,19 @@ static inline int kmap_atomic_idx(void)
return __this_cpu_read(__kmap_atomic_idx) - 1;
}
+#ifdef CONFIG_DEBUG_HIGHMEM
static inline int kmap_atomic_idx_pop(void)
{
int idx = __this_cpu_dec_return(__kmap_atomic_idx);
-#ifdef CONFIG_DEBUG_HIGHMEM
BUG_ON(idx < 0);
-#endif
return idx;
}
+#else
+static inline void kmap_atomic_idx_pop(void)
+{
+ __this_cpu_dec(__kmap_atomic_idx);
+}
+#endif
#endif
--
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