From 7d636676d2841ba5d92462dfa99a89c2f2da8919 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Mon, 21 Sep 2020 08:58:40 -0700 Subject: iomap: Convert read_count to read_bytes_pending 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) Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong Reviewed-by: Christoph Hellwig --- fs/iomap/buffered-io.c | 41 ++++++++++++----------------------------- 1 file changed, 12 insertions(+), 29 deletions(-) (limited to 'fs/iomap') diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index 9f0fa495ab69..46370cea30c8 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -26,7 +26,7 @@ * to track sub-page uptodate status and I/O completions. */ struct iomap_page { - atomic_t read_count; + atomic_t read_bytes_pending; atomic_t write_count; spinlock_t uptodate_lock; unsigned long uptodate[]; @@ -72,7 +72,7 @@ iomap_page_release(struct page *page) if (!iop) return; - WARN_ON_ONCE(atomic_read(&iop->read_count)); + WARN_ON_ONCE(atomic_read(&iop->read_bytes_pending)); WARN_ON_ONCE(atomic_read(&iop->write_count)); WARN_ON_ONCE(bitmap_full(iop->uptodate, nr_blocks) != PageUptodate(page)); @@ -167,13 +167,6 @@ 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) { @@ -187,7 +180,8 @@ 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_bytes_pending)) + unlock_page(page); } static void @@ -267,30 +261,19 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data, } ctx->cur_page_in_bio = true; + if (iop) + atomic_add(plen, &iop->read_bytes_pending); - /* - * Try to merge into a previous segment if we can. - */ + /* Try to merge into a previous segment if we can */ sector = iomap_sector(iomap, pos); - if (ctx->bio && bio_end_sector(ctx->bio) == sector) + if (ctx->bio && bio_end_sector(ctx->bio) == sector) { + if (__bio_try_merge_page(ctx->bio, page, plen, poff, + &same_page)) + goto done; 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. - */ - if (iop) - atomic_inc(&iop->read_count); - - if (!ctx->bio || !is_contig || bio_full(ctx->bio, plen)) { + if (!is_contig || bio_full(ctx->bio, plen)) { gfp_t gfp = mapping_gfp_constraint(page->mapping, GFP_KERNEL); gfp_t orig_gfp = gfp; int nr_vecs = (length + PAGE_SIZE - 1) >> PAGE_SHIFT; -- cgit v1.2.3