From 384209cd5b93a926321fafe880ed05b1bca97260 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 12 Aug 2019 17:39:57 +0200 Subject: [PATCH] block: create a bio_try_merge_pc_page helper Passsthrough bio handling should be the same as normal bio handling, except that we need to take hardware limitations into account. Thus use the common try_merge implementation after checking the hardware limits. This changes behavior in that we now also check segment and dma boundary settings for same page merges, which is a little more work but has no effect as those need to be larger than the page size. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe --- block/bio.c | 34 ++++++++++------------------------ 1 file changed, 10 insertions(+), 24 deletions(-) diff --git a/block/bio.c b/block/bio.c index 537d71a30e56..c1782df36dff 100644 --- a/block/bio.c +++ b/block/bio.c @@ -646,25 +646,20 @@ static inline bool page_is_mergeable(const struct bio_vec *bv, return true; } -/* - * Check if the @page can be added to the current segment(@bv), and make - * sure to call it only if page_is_mergeable(@bv, @page) is true - */ -static bool can_add_page_to_seg(struct request_queue *q, - struct bio_vec *bv, struct page *page, unsigned len, - unsigned offset) +static bool bio_try_merge_pc_page(struct request_queue *q, struct bio *bio, + struct page *page, unsigned len, unsigned offset, + bool *same_page) { + struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1]; unsigned long mask = queue_segment_boundary(q); phys_addr_t addr1 = page_to_phys(bv->bv_page) + bv->bv_offset; phys_addr_t addr2 = page_to_phys(page) + offset + len - 1; if ((addr1 | mask) != (addr2 | mask)) return false; - if (bv->bv_len + len > queue_max_segment_size(q)) return false; - - return true; + return __bio_try_merge_page(bio, page, len, offset, same_page); } /** @@ -700,26 +695,18 @@ static int __bio_add_pc_page(struct request_queue *q, struct bio *bio, return 0; if (bio->bi_vcnt > 0) { - bvec = &bio->bi_io_vec[bio->bi_vcnt - 1]; - - if (page == bvec->bv_page && - offset == bvec->bv_offset + bvec->bv_len) { - if (put_same_page) + if (bio_try_merge_pc_page(q, bio, page, len, offset, + &same_page)) { + if (put_same_page && same_page) put_page(page); - bvec->bv_len += len; - goto done; - } - - if (page_is_mergeable(bvec, page, len, offset, &same_page) && - can_add_page_to_seg(q, bvec, page, len, offset)) { - bvec->bv_len += len; - goto done; + return len; } /* * If the queue doesn't support SG gaps and adding this segment * would create a gap, disallow it. */ + bvec = &bio->bi_io_vec[bio->bi_vcnt - 1]; if (bvec_gap_to_prev(q, bvec, offset)) return 0; } @@ -735,7 +722,6 @@ static int __bio_add_pc_page(struct request_queue *q, struct bio *bio, bvec->bv_len = len; bvec->bv_offset = offset; bio->bi_vcnt++; - done: bio->bi_iter.bi_size += len; return len; } -- 2.11.0