mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-18 17:54:13 +08:00
642f149031
Most drivers need to set length and offset as well, so may as well fold those three lines into one. Add sg_assign_page() for those two locations that only needed to set the page, where the offset/length is set outside of the function context. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
37 lines
924 B
C
37 lines
924 B
C
#ifndef _ASM_SCATTERLIST_H
|
|
#define _ASM_SCATTERLIST_H
|
|
|
|
#include <asm/types.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_set_buf(sg, some_ptr, length);
|
|
*
|
|
* and that's it. There's no excuse for not highmem enabling YOUR driver. /jens
|
|
*/
|
|
struct scatterlist {
|
|
#ifdef CONFIG_DEBUG_SG
|
|
unsigned long sg_magic;
|
|
#endif
|
|
unsigned long page_link;
|
|
unsigned int offset; /* for highmem, page offset */
|
|
|
|
dma_addr_t dma_address;
|
|
unsigned int length;
|
|
};
|
|
|
|
#define ISA_DMA_THRESHOLD (0xffffffffUL)
|
|
|
|
#endif /* !_ASM_SCATTERLIST_H */
|