[Linaro-mm-sig] [PATCHv2 3/4] mm: vmalloc: add VM_DMA flag to indicate areas used by dma-mapping framework
minchan at kernel.org
Tue May 22 07:07:45 UTC 2012
On 05/17/2012 07:54 PM, Marek Szyprowski wrote:
> Add new type of vm_area intented to be used for consisten mappings
> created by dma-mapping framework.
> Signed-off-by: Marek Szyprowski <m.szyprowski at samsung.com>
> Reviewed-by: Kyungmin Park <kyungmin.park at samsung.com>
> include/linux/vmalloc.h | 1 +
> mm/vmalloc.c | 3 +++
> 2 files changed, 4 insertions(+)
> diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
> index 6071e91..8a9555a 100644
> --- a/include/linux/vmalloc.h
> +++ b/include/linux/vmalloc.h
> @@ -14,6 +14,7 @@ struct vm_area_struct; /* vma defining user mapping in mm_types.h */
> #define VM_USERMAP 0x00000008 /* suitable for remap_vmalloc_range */
> #define VM_VPAGES 0x00000010 /* buffer for pages was vmalloc'ed */
> #define VM_UNLIST 0x00000020 /* vm_struct is not listed in vmlist */
> +#define VM_DMA 0x00000040 /* used by dma-mapping framework */
> /* bits [20..32] reserved for arch specific ioremap internals */
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 8cb7f22..9c13bab 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -2582,6 +2582,9 @@ static int s_show(struct seq_file *m, void *p)
> if (v->flags & VM_IOREMAP)
> seq_printf(m, " ioremap");
> + if (v->flags & VM_DMA)
> + seq_printf(m, " dma");
Hmm, VM_DMA would become generic flag?
AFAIU, maybe VM_DMA would be used only on ARM arch.
Of course, it isn't performance sensitive part but there in no reason to check it, either
in other architecture except ARM.
I suggest following as
#define VM_DMA 0x00000040
#define VM_DMA 0x0
Maybe it could remove check code at compile time.
> if (v->flags & VM_ALLOC)
> seq_printf(m, " vmalloc");
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