mp_bvec_for_each_segment() is a bit big for the iteration, so introduce
a light-weight helper for iterating over pages, then 32bytes stack
space can be saved.
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
block/bio.c | 7 +++----
include/linux/bvec.h | 5 +++++
2 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index eae8b754801d..7917535123df 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -849,8 +849,7 @@ static int __bio_iov_bvec_add_pages(struct bio *bio, struct iov_iter *iter)
size = bio_add_page(bio, bv->bv_page, len,
bv->bv_offset + iter->iov_offset);
if (size == len) {
- struct bvec_iter_all iter_all;
- struct bio_vec *tmp;
+ struct page *pg;
int i;
/*
@@ -862,8 +861,8 @@ static int __bio_iov_bvec_add_pages(struct bio *bio, struct iov_iter *iter)
* get rid of the get here and the need to call
* bio_release_pages() at IO completion time.
*/
- mp_bvec_for_each_segment(tmp, bv, i, iter_all)
- get_page(tmp->bv_page);
+ mp_bvec_for_each_page(pg, bv, i)
+ get_page(pg);
iov_iter_advance(iter, size);
return 0;
}
diff --git a/include/linux/bvec.h b/include/linux/bvec.h
index 4376f683c08a..2c32e3e151a0 100644
--- a/include/linux/bvec.h
+++ b/include/linux/bvec.h
@@ -188,4 +188,9 @@ static inline void mp_bvec_last_segment(const struct bio_vec *bvec,
}
}
+#define mp_bvec_for_each_page(pg, bv, i) \
+ for (i = (bv)->bv_offset / PAGE_SIZE; \
+ (i < (((bv)->bv_offset + (bv)->bv_len) / PAGE_SIZE)) && \
+ (pg = bvec_nth_page((bv)->bv_page, i)); i += 1)
+
#endif /* __LINUX_BVEC_ITER_H */
--
2.9.5
