Split out the logic to allocate a new bio and only keep the fast path that adds more data to an existing bio in iomap_bio_read_folio_range.
Signed-off-by: Christoph Hellwig <[email protected]> --- fs/iomap/bio.c | 69 +++++++++++++++++++++++++++----------------------- 1 file changed, 37 insertions(+), 32 deletions(-) diff --git a/fs/iomap/bio.c b/fs/iomap/bio.c index fc045f2e4c45..578b1202e037 100644 --- a/fs/iomap/bio.c +++ b/fs/iomap/bio.c @@ -26,45 +26,50 @@ static void iomap_bio_submit_read(struct iomap_read_folio_ctx *ctx) submit_bio(bio); } -static int iomap_bio_read_folio_range(const struct iomap_iter *iter, +static void iomap_read_alloc_bio(const struct iomap_iter *iter, struct iomap_read_folio_ctx *ctx, size_t plen) { - struct folio *folio = ctx->cur_folio; const struct iomap *iomap = &iter->iomap; - loff_t pos = iter->pos; - size_t poff = offset_in_folio(folio, pos); - loff_t length = iomap_length(iter); - sector_t sector; + unsigned int nr_vecs = DIV_ROUND_UP(iomap_length(iter), PAGE_SIZE); + struct folio *folio = ctx->cur_folio; + gfp_t gfp = mapping_gfp_constraint(folio->mapping, GFP_KERNEL); + gfp_t orig_gfp = gfp; struct bio *bio = ctx->read_ctx; - sector = iomap_sector(iomap, pos); - if (!bio || bio_end_sector(bio) != sector || - !bio_add_folio(bio, folio, plen, poff)) { - gfp_t gfp = mapping_gfp_constraint(folio->mapping, GFP_KERNEL); - gfp_t orig_gfp = gfp; - unsigned int nr_vecs = DIV_ROUND_UP(length, PAGE_SIZE); + if (bio) + submit_bio(bio); + + /* Same as readahead_gfp_mask: */ + if (ctx->rac) + gfp |= __GFP_NORETRY | __GFP_NOWARN; - if (bio) - submit_bio(bio); + /* + * If the bio_alloc fails, try it again for a single page to avoid + * having to deal with partial page reads. This emulates what + * do_mpage_read_folio does. + */ + bio = bio_alloc(iomap->bdev, bio_max_segs(nr_vecs), REQ_OP_READ, gfp); + if (!bio) + bio = bio_alloc(iomap->bdev, 1, REQ_OP_READ, orig_gfp); + if (ctx->rac) + bio->bi_opf |= REQ_RAHEAD; + bio->bi_iter.bi_sector = iomap_sector(iomap, iter->pos); + bio->bi_end_io = iomap_read_end_io; + bio_add_folio_nofail(bio, folio, plen, + offset_in_folio(folio, iter->pos)); + ctx->read_ctx = bio; +} + +static int iomap_bio_read_folio_range(const struct iomap_iter *iter, + struct iomap_read_folio_ctx *ctx, size_t plen) +{ + struct folio *folio = ctx->cur_folio; + struct bio *bio = ctx->read_ctx; - if (ctx->rac) /* same as readahead_gfp_mask */ - gfp |= __GFP_NORETRY | __GFP_NOWARN; - bio = bio_alloc(iomap->bdev, bio_max_segs(nr_vecs), REQ_OP_READ, - gfp); - /* - * If the bio_alloc fails, try it again for a single page to - * avoid having to deal with partial page reads. This emulates - * what do_mpage_read_folio does. - */ - if (!bio) - bio = bio_alloc(iomap->bdev, 1, REQ_OP_READ, orig_gfp); - if (ctx->rac) - bio->bi_opf |= REQ_RAHEAD; - bio->bi_iter.bi_sector = sector; - bio->bi_end_io = iomap_read_end_io; - bio_add_folio_nofail(bio, folio, plen, poff); - ctx->read_ctx = bio; - } + if (!bio || + bio_end_sector(bio) != iomap_sector(&iter->iomap, iter->pos) || + !bio_add_folio(bio, folio, plen, offset_in_folio(folio, iter->pos))) + iomap_read_alloc_bio(iter, ctx, plen); return 0; } -- 2.47.3
