[PATCH 3/3] block: fops: handle IOCB_USE_PI in direct IO

["Alexander V. Buev" <a.buev@yadro.com>]

Check that the size of integrity data correspond to device integrity
profile and data size. Split integrity data to the different bio's
in case of to big orginal bio (together with normal data).
Correct offset/size checking at blkdev layer in read/write_iter
functions.

Signed-off-by: Alexander V. Buev <a.buev@yadro.com>
---
 block/fops.c | 71 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)

diff --git a/block/fops.c b/block/fops.c
index 1e970c247e0e..74040314f5f3 100644
--- a/block/fops.c
+++ b/block/fops.c
@@ -197,12 +197,39 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 	struct blk_plug plug;
 	struct blkdev_dio *dio;
 	struct bio *bio;
+	struct iovec *pi_iov, _pi_iov;
 	bool is_poll = (iocb->ki_flags & IOCB_HIPRI) != 0;
 	bool is_read = (iov_iter_rw(iter) == READ), is_sync;
 	loff_t pos = iocb->ki_pos;
 	blk_qc_t qc = BLK_QC_T_NONE;
 	int ret = 0;
 
+	if (iocb->ki_flags & IOCB_USE_PI) {
+		struct blk_integrity *bi = blk_get_integrity(bdev->bd_disk);
+		unsigned int intervals;
+
+		/* Last iovec contains protection information. */
+		if (!iter->nr_segs)
+			return -EINVAL;
+
+		iter->nr_segs--;
+		pi_iov = (struct iovec *)(iter->iov + iter->nr_segs);
+
+		/* TODO: seems iter is in charge of this check ? */
+		if (pi_iov->iov_len > iter->count)
+			return -EINVAL;
+
+		iter->count -= pi_iov->iov_len;
+
+		intervals = bio_integrity_intervals(bi, iter->count >> 9);
+		if (unlikely(intervals * bi->tuple_size > pi_iov->iov_len)) {
+			pr_err("Integrity & data size mismatch data=%lu integrity=%u intervals=%u tupple=%u",
+				iter->count, (unsigned int)pi_iov->iov_len,
+				intervals, bi->tuple_size);
+				return -EINVAL;
+		}
+	}
+
 	if ((pos | iov_iter_alignment(iter)) &
 	    (bdev_logical_block_size(bdev) - 1))
 		return -EINVAL;
@@ -258,6 +285,17 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 		dio->size += bio->bi_iter.bi_size;
 		pos += bio->bi_iter.bi_size;
 
+		/* in case we can't add all data to one bio */
+		/* we must split integrity too */
+
+		if (iocb->ki_flags & IOCB_USE_PI) {
+			struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
+
+			_pi_iov.iov_base =  pi_iov->iov_base;
+			_pi_iov.iov_base += bio_integrity_bytes(bi, (dio->size-bio->bi_iter.bi_size) >> 9);
+			_pi_iov.iov_len  = bio_integrity_bytes(bi, bio->bi_iter.bi_size >> 9);
+		}
+
 		nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS);
 		if (!nr_pages) {
 			bool polled = false;
@@ -267,6 +305,16 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 				polled = true;
 			}
 
+			/* Add protection information to bio */
+			if (iocb->ki_flags & IOCB_USE_PI) {
+				ret = bio_integrity_add_pi_iovec(bio, &_pi_iov);
+				if (ret) {
+					bio->bi_status = BLK_STS_IOERR;
+					bio_endio(bio);
+					break;
+				}
+			}
+
 			qc = submit_bio(bio);
 
 			if (polled)
@@ -288,6 +336,16 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 			atomic_inc(&dio->ref);
 		}
 
+
+		if (iocb->ki_flags & IOCB_USE_PI) {
+			ret = bio_integrity_add_pi_iovec(bio, &_pi_iov);
+			if (ret) {
+				bio->bi_status = BLK_STS_IOERR;
+				bio_endio(bio);
+				break;
+			}
+		}
+
 		submit_bio(bio);
 		bio = bio_alloc(GFP_KERNEL, nr_pages);
 	}
@@ -509,6 +567,12 @@ static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	if ((iocb->ki_flags & (IOCB_NOWAIT | IOCB_DIRECT)) == IOCB_NOWAIT)
 		return -EOPNOTSUPP;
 
+	if (iocb->ki_flags & IOCB_USE_PI) {
+		if (from->nr_segs < 2)
+			return -EINVAL;
+		size += from->iov[from->nr_segs-1].iov_len;
+	}
+
 	size -= iocb->ki_pos;
 	if (iov_iter_count(from) > size) {
 		shorted = iov_iter_count(from) - size;
@@ -537,6 +601,13 @@ static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to)
 		return 0;
 
 	size -= pos;
+
+	if (iocb->ki_flags & IOCB_USE_PI) {
+		if (to->nr_segs < 2)
+			return -EINVAL;
+		size += to->iov[to->nr_segs-1].iov_len;
+	}
+
 	if (iov_iter_count(to) > size) {
 		shorted = iov_iter_count(to) - size;
 		iov_iter_truncate(to, size);
-- 
2.33.0