This patch implements singlepage version of the following 3 helpers: - bvec_iter_offset_sp() - bvec_iter_len_sp() - bvec_iter_page_sp() So that one multipage bvec can be splited to singlepage bvec, and make users of current bvec iterator happy. Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx> --- include/linux/bvec.h | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/include/linux/bvec.h b/include/linux/bvec.h index 1eaf7ca5cab3..d5f999a493de 100644 --- a/include/linux/bvec.h +++ b/include/linux/bvec.h @@ -23,6 +23,7 @@ #include <linux/kernel.h> #include <linux/bug.h> #include <linux/errno.h> +#include <linux/mm.h> /* * What is multipage bvecs(segment)? @@ -98,14 +99,25 @@ struct bvec_iter { #define bvec_iter_offset_mp(bvec, iter) \ (__bvec_iter_bvec((bvec), (iter))->bv_offset + (iter).bi_bvec_done) +#define bvec_iter_page_idx_mp(bvec, iter) \ + (bvec_iter_offset_mp((bvec), (iter)) / PAGE_SIZE) + + /* * <page, offset,length> of singlepage(sp) segment. * * This helpers will be implemented for building sp bvec in flight. */ -#define bvec_iter_offset_sp(bvec, iter) bvec_iter_offset_mp((bvec), (iter)) -#define bvec_iter_len_sp(bvec, iter) bvec_iter_len_mp((bvec), (iter)) -#define bvec_iter_page_sp(bvec, iter) bvec_iter_page_mp((bvec), (iter)) +#define bvec_iter_offset_sp(bvec, iter) \ + (bvec_iter_offset_mp((bvec), (iter)) % PAGE_SIZE) + +#define bvec_iter_len_sp(bvec, iter) \ + min_t(unsigned, bvec_iter_len_mp((bvec), (iter)), \ + (PAGE_SIZE - (bvec_iter_offset_sp((bvec), (iter))))) + +#define bvec_iter_page_sp(bvec, iter) \ + nth_page(bvec_iter_page_mp((bvec), (iter)), \ + bvec_iter_page_idx_mp((bvec), (iter))) /* current interfaces support sp style at default */ #define bvec_iter_page(bvec, iter) bvec_iter_page_sp((bvec), (iter)) -- 2.9.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>