[PATCH 3/3] block: Refuse adding appending a gapped integrity page to a bio

[Sagi Grimberg]

This is only theoretical at the moment given that the only
subsystems that generate integrity payloads are the block layer
itself and the scsi target. But when we will expose integrity
meta-data to user-space, we'll need to refuse appending a page
with a gap when QUEUE_FLAG_SG_GAPS flag is on.

Signed-off-by: Sagi Grimberg <sagig at mellanox.com>
---
 block/bio-integrity.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/block/bio-integrity.c b/block/bio-integrity.c
index 5cbd5d9..a18edb8 100644
--- a/block/bio-integrity.c
+++ b/block/bio-integrity.c
@@ -140,6 +140,15 @@ int bio_integrity_add_page(struct bio *bio, struct page *page,
 
 	iv = bip->bip_vec + bip->bip_vcnt;
 
+	if (bip->bip_vcnt) {
+		struct request_queue *q = bdev_get_queue(bio->bi_bdev);
+		struct bio_vec *iv_prev = &bip->bip_vec[bip->bip_vcnt - 1];
+
+		if (q->queue_flags & (1 << QUEUE_FLAG_SG_GAPS) &&
+		    bvec_gap_to_prev(iv_prev, offset))
+			return 0;
+	}
+
 	iv->bv_page = page;
 	iv->bv_len = len;
 	iv->bv_offset = offset;
-- 
1.8.4.3