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 <hch@xxxxxx>
---
block/bio.c | 34 ++++++++++------------------------
1 file changed, 10 insertions(+), 24 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index 6be22b8477ce..1db626f99bcb 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -645,25 +645,20 @@ 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);
}
/**
@@ -699,26 +694,18 @@ 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;
}
@@ -734,7 +721,6 @@ 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;
}
--
2.20.1
