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#ifndef __BACKPORT_SCATTERLIST_H
#define __BACKPORT_SCATTERLIST_H
#include_next <linux/scatterlist.h>
#include <linux/version.h>
#if LINUX_VERSION_CODE < KERNEL_VERSION(3,9,0)
/* Lets expect distributions might backport this */
#ifndef for_each_sg_page
/*
* sg page iterator
*
* Iterates over sg entries page-by-page. On each successful iteration,
* @piter->page points to the current page, @piter->sg to the sg holding this
* page and @piter->sg_pgoffset to the page's page offset within the sg. The
* iteration will stop either when a maximum number of sg entries was reached
* or a terminating sg (sg_last(sg) == true) was reached.
*/
struct sg_page_iter {
struct page *page; /* current page */
struct scatterlist *sg; /* sg holding the page */
unsigned int sg_pgoffset; /* page offset within the sg */
/* these are internal states, keep away */
unsigned int __nents; /* remaining sg entries */
int __pg_advance; /* nr pages to advance at the
* next step */
};
#define __sg_page_iter_next LINUX_BACKPORT(__sg_page_iter_next)
bool __sg_page_iter_next(struct sg_page_iter *piter);
#define __sg_page_iter_start LINUX_BACKPORT(__sg_page_iter_start)
void __sg_page_iter_start(struct sg_page_iter *piter,
struct scatterlist *sglist, unsigned int nents,
unsigned long pgoffset);
/**
* for_each_sg_page - iterate over the pages of the given sg list
* @sglist: sglist to iterate over
* @piter: page iterator to hold current page, sg, sg_pgoffset
* @nents: maximum number of sg entries to iterate over
* @pgoffset: starting page offset
*/
#define for_each_sg_page(sglist, piter, nents, pgoffset) \
for (__sg_page_iter_start((piter), (sglist), (nents), (pgoffset)); \
__sg_page_iter_next(piter);)
#endif /* for_each_sg_page assumption */
#endif /* version < 3.9 */
#endif /* __BACKPORT_SCATTERLIST_H */
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