[PATCH V11 15/19] block: enable multipage bvecs

Ming Lei
2018-11-21T03:28:41Z

This patch pulls the trigger for multi-page bvecs.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
block/bio.c | 32 +++++++++++++++++++++++++++-----
fs/iomap.c | 2 +-
fs/xfs/xfs_aops.c | 2 +-
3 files changed, 29 insertions(+), 7 deletions(-)

diff --git a/block/bio.c b/block/bio.c
index 0f1635b9ec50..854676edc438 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -823,7 +823,7 @@ EXPORT_SYMBOL(bio_add_pc_page);
* @len: length of the data to add
* @off: offset of the data in @page
*
- * Try to add the data at @page + @off to the last bvec of @bio. This is a
+ * Try to add the data at @page + @off to the last page of @bio. This is a
* a useful optimisation for file systems with a block size smaller than the
* page size.
*
@@ -836,10 +836,13 @@ bool __bio_try_merge_page(struct bio *bio, struct page *page,
return false;

if (bio->bi_vcnt > 0) {
- struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1];
+ struct bio_vec bv;
+ struct bio_vec *seg = &bio->bi_io_vec[bio->bi_vcnt - 1];

- if (page == bv->bv_page && off == bv->bv_offset + bv->bv_len) {
- bv->bv_len += len;
+ bvec_last_segment(seg, &bv);
+
+ if (page == bv.bv_page && off == bv.bv_offset + bv.bv_len) {
+ seg->bv_len += len;
bio->bi_iter.bi_size += len;
return true;
}
@@ -848,6 +851,25 @@ bool __bio_try_merge_page(struct bio *bio, struct page *page,
}
EXPORT_SYMBOL_GPL(__bio_try_merge_page);

+static bool bio_try_merge_segment(struct bio *bio, struct page *page,
+ unsigned int len, unsigned int off)
+{
+ if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)))
+ return false;
+
+ if (bio->bi_vcnt > 0) {
+ struct bio_vec *seg = &bio->bi_io_vec[bio->bi_vcnt - 1];
+
+ if (page_to_phys(seg->bv_page) + seg->bv_offset + seg->bv_len ==
+ page_to_phys(page) + off) {
+ seg->bv_len += len;
+ bio->bi_iter.bi_size += len;
+ return true;
+ }
+ }
+ return false;
+}
+
/**
* __bio_add_page - add page to a bio in a new segment
* @bio: destination bio
@@ -888,7 +910,7 @@ EXPORT_SYMBOL_GPL(__bio_add_page);
int bio_add_page(struct bio *bio, struct page *page,
unsigned int len, unsigned int offset)
{
- if (!__bio_try_merge_page(bio, page, len, offset)) {
+ if (!bio_try_merge_segment(bio, page, len, offset)) {
if (bio_full(bio))
return 0;
__bio_add_page(bio, page, len, offset);
diff --git a/fs/iomap.c b/fs/iomap.c
index f5fb8bf75cc8..ccc2ba115f4d 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -344,7 +344,7 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
ctx->bio->bi_end_io = iomap_read_end_io;
}

- __bio_add_page(ctx->bio, page, plen, poff);
+ bio_add_page(ctx->bio, page, plen, poff);
done:
/*
* Move the caller beyond our range so that it keeps making progress.
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 1f1829e506e8..5c2190216614 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -621,7 +621,7 @@ xfs_add_to_ioend(
atomic_inc(&iop->write_count);
if (bio_full(wpc->ioend->io_bio))
xfs_chain_bio(wpc->ioend, wbc, bdev, sector);
- __bio_add_page(wpc->ioend->io_bio, page, len, poff);
+ bio_add_page(wpc->ioend->io_bio, page, len, poff);
}

wpc->ioend->io_size += len;
--
2.9.5