[PATCH v1 15/54] block: implement sp version of bvec iterator helpers
From: Ming Lei <tom.leiming@gmail.com>
Date: 2016-12-27 16:08:32
Also in:
lkml
Subsystem:
the rest · Maintainer:
Linus Torvalds
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 <tom.leiming@gmail.com> --- 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 307a387eb29c..d77c3cabce8c 100644
--- a/include/linux/bvec.h
+++ b/include/linux/bvec.h@@ -22,6 +22,7 @@ #include <linux/kernel.h> #include <linux/bug.h> +#include <linux/mm.h> /* * What is multipage bvecs(segment)?
@@ -95,14 +96,25 @@ 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))
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2.7.4