Instead of counting bio segments, count the number of bytes submitted.
This insulates us from the block layer's definition of what a 'same page'
is, which is not necessarily clear once THPs are involved.
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
fs/iomap/buffered-io.c | 29 ++++++++++-------------------
1 file changed, 10 insertions(+), 19 deletions(-)
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 844e95cacea8..c9b44f86d166 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -161,13 +161,6 @@ iomap_set_range_uptodate(struct page *page, unsigned off, unsigned len)
SetPageUptodate(page);
}
-static void
-iomap_read_finish(struct iomap_page *iop, struct page *page)
-{
- if (!iop || atomic_dec_and_test(&iop->read_count))
- unlock_page(page);
-}
-
static void
iomap_read_page_end_io(struct bio_vec *bvec, int error)
{
@@ -181,7 +174,8 @@ iomap_read_page_end_io(struct bio_vec *bvec, int error)
iomap_set_range_uptodate(page, bvec->bv_offset, bvec->bv_len);
}
- iomap_read_finish(iop, page);
+ if (!iop || atomic_sub_and_test(bvec->bv_len, &iop->read_count))
+ unlock_page(page);
}
static void
@@ -269,20 +263,17 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
if (ctx->bio && bio_end_sector(ctx->bio) == sector)
is_contig = true;
- if (is_contig &&
- __bio_try_merge_page(ctx->bio, page, plen, poff, &same_page)) {
- if (!same_page && iop)
- atomic_inc(&iop->read_count);
- goto done;
- }
-
/*
- * If we start a new segment we need to increase the read count, and we
- * need to do so before submitting any previous full bio to make sure
- * that we don't prematurely unlock the page.
+ * We need to increase the read count before submitting any
+ * previous bio to make sure that we don't prematurely unlock
+ * the page.
*/
if (iop)
- atomic_inc(&iop->read_count);
+ atomic_add(plen, &iop->read_count);
+
+ if (is_contig &&
+ __bio_try_merge_page(ctx->bio, page, plen, poff, &same_page))
+ goto done;
if (!ctx->bio || !is_contig || bio_full(ctx->bio, plen)) {
gfp_t gfp = mapping_gfp_constraint(page->mapping, GFP_KERNEL);
--
2.28.0
