[PATCH] bio: limit bio max size.
From: Changheun Lee <hidden>
Date: 2021-01-12 08:49:08
Also in:
lkml
Subsystem:
block layer, the rest · Maintainers:
Jens Axboe, Linus Torvalds
From: "Changheun Lee" <redacted> bio size can grow up to 4GB when muli-page bvec is enabled. but sometimes it would lead to inefficient behaviors. in case of large chunk direct I/O, - 64MB chunk read in user space - all pages for 64MB would be merged to a bio structure if memory address is continued phsycally. it makes some delay to submit until merge complete. bio max size should be limited as a proper size. Signed-off-by: Changheun Lee <redacted> --- block/bio.c | 2 +- include/linux/bio.h | 3 ++- 2 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index 1f2cc1fbe283..dbe14d675f28 100644
--- a/block/bio.c
+++ b/block/bio.c@@ -877,7 +877,7 @@ bool __bio_try_merge_page(struct bio *bio, struct page *page, struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1]; if (page_is_mergeable(bv, page, len, off, same_page)) { - if (bio->bi_iter.bi_size > UINT_MAX - len) { + if (bio->bi_iter.bi_size > BIO_MAX_SIZE - len) { *same_page = false; return false; }
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 1edda614f7ce..0f49b354b1f6 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h@@ -20,6 +20,7 @@ #endif #define BIO_MAX_PAGES 256 +#define BIO_MAX_SIZE (BIO_MAX_PAGES * PAGE_SIZE) #define bio_prio(bio) (bio)->bi_ioprio #define bio_set_prio(bio, prio) ((bio)->bi_ioprio = prio)
@@ -113,7 +114,7 @@ static inline bool bio_full(struct bio *bio, unsigned len) if (bio->bi_vcnt >= bio->bi_max_vecs) return true; - if (bio->bi_iter.bi_size > UINT_MAX - len) + if (bio->bi_iter.bi_size > BIO_MAX_SIZE - len) return true; return false;
--
2.28.0