Le mardi 30 novembre 2010 Ã 13:26 -0600, Christoph Lameter a Ãcrit :
> 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
>
well maybe a single prototype ;)
static inline void kmap_atomic_idx_pop(void)
{
#ifdef CONFIG_DEBUG_HIGHMEM
int idx = __this_cpu_dec_return(__kmap_atomic_idx);
BUG_ON(idx < 0);
#else
__this_cpu_dec(__kmap_atomic_idx);
#endif
}
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