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Subject: [PATCH v3 4/4] bio-integrity: create multi-page bvecs in
 bio_integrity_add_page()
Reply-To: j-young.choi@samsung.com
Sender: Jinyoung Choi <j-young.choi@samsung.com>
From:   Jinyoung Choi <j-young.choi@samsung.com>
To:     Christoph Hellwig <hch@infradead.org>,
        "axboe@kernel.dk" <axboe@kernel.dk>,
        "kbusch@kernel.org" <kbusch@kernel.org>,
        "chaitanya.kulkarni@wdc.com" <chaitanya.kulkarni@wdc.com>,
        "sagi@grimberg.me" <sagi@grimberg.me>,
        "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "martin.petersen@oracle.com" <martin.petersen@oracle.com>
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Date:   Thu, 03 Aug 2023 11:52:02 +0900
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Precedence: bulk

In general, the bvec data structure consists of one for physically
continuous pages. But, in the bvec configuration for bip, physically
continuous integrity pages are composed of each bvec.

Allow bio_integrity_add_page() to create multi-page bvecs, just like
the bio payloads. This simplifies adding larger payloads, and fixes
support for non-tiny workloads with nvme, which stopped using
scatterlist for metadata a while ago.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Martin K. Petersen <martin.petersen@oracle.com>

Fixes: 783b94bd9250 ("nvme-pci: do not build a scatterlist to map metadata")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jinyoung Choi <j-young.choi@samsung.com>
---
 block/bio-integrity.c | 31 ++++++++++++++++++++++++-------
 1 file changed, 24 insertions(+), 7 deletions(-)

diff --git a/block/bio-integrity.c b/block/bio-integrity.c
index c6b3bc86e1f9..ec8ac8cf6e1b 100644
--- a/block/bio-integrity.c
+++ b/block/bio-integrity.c
@@ -123,17 +123,34 @@ void bio_integrity_free(struct bio *bio)
 int bio_integrity_add_page(struct bio *bio, struct page *page,
 			   unsigned int len, unsigned int offset)
 {
+	struct request_queue *q = bdev_get_queue(bio->bi_bdev);
 	struct bio_integrity_payload *bip = bio_integrity(bio);
 
-	if (bip->bip_vcnt >= bip->bip_max_vcnt) {
-		printk(KERN_ERR "%s: bip_vec full\n", __func__);
+	if (((bip->bip_iter.bi_size + len) >> SECTOR_SHIFT) >
+	    queue_max_hw_sectors(q))
 		return 0;
-	}
 
-	if (bip->bip_vcnt &&
-	    bvec_gap_to_prev(&bdev_get_queue(bio->bi_bdev)->limits,
-			     &bip->bip_vec[bip->bip_vcnt - 1], offset))
-		return 0;
+	if (bip->bip_vcnt > 0) {
+		struct bio_vec *bv = &bip->bip_vec[bip->bip_vcnt - 1];
+		bool same_page = false;
+
+		if (bvec_try_merge_hw_page(q, bv, page, len, offset,
+					   &same_page)) {
+			bip->bip_iter.bi_size += len;
+			return len;
+		}
+
+		if (bip->bip_vcnt >=
+		    min(bip->bip_max_vcnt, queue_max_integrity_segments(q)))
+			return 0;
+
+		/*
+		 * If the queue doesn't support SG gaps and adding this segment
+		 * would create a gap, disallow it.
+		 */
+		if (bvec_gap_to_prev(&q->limits, bv, offset))
+			return 0;
+	}
 
 	bvec_set_page(&bip->bip_vec[bip->bip_vcnt], page, len, offset);
 	bip->bip_vcnt++;
-- 
2.34.1