| #ifndef _ASM_SCATTERLIST_H | 
 | #define _ASM_SCATTERLIST_H | 
 |  | 
 | /* | 
 |  * Drivers must set either ->address or (preferred) ->page and ->offset | 
 |  * to indicate where data must be transferred to/from. | 
 |  * | 
 |  * Using ->page is recommended since it handles highmem data as well as | 
 |  * low mem. ->address is restricted to data which has a virtual mapping, and | 
 |  * it will go away in the future. Updating to ->page can be automated very | 
 |  * easily -- something like | 
 |  * | 
 |  * sg->address = some_ptr; | 
 |  * | 
 |  * can be rewritten as | 
 |  * | 
 |  * sg->page = virt_to_page(some_ptr); | 
 |  * sg->offset = (unsigned long) some_ptr & ~PAGE_MASK; | 
 |  * | 
 |  * and that's it. There's no excuse for not highmem enabling YOUR driver. /jens | 
 |  */ | 
 | struct scatterlist { | 
 | 	struct page	*page;		/* Location for highmem page, if any */ | 
 | 	unsigned int	offset;		/* for highmem, page offset */ | 
 |  | 
 | 	dma_addr_t	dma_address; | 
 | 	unsigned int	length; | 
 | }; | 
 |  | 
 | #define ISA_DMA_THRESHOLD (0xffffffffUL) | 
 |  | 
 | #endif /* !_ASM_SCATTERLIST_H */ |