[PATCH v6 10/10] block: add support to pass user meta buffer

[Kanchan Joshi <joshi.k@samsung.com>]

If an iocb contains metadata, extract that and prepare the bip.
Based on flags specified by the user, set corresponding guard/app/ref
tags to be checked in bip.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
---
 block/bio-integrity.c         | 50 +++++++++++++++++++++++++++++++++++
 block/fops.c                  | 42 ++++++++++++++++++++++-------
 include/linux/bio-integrity.h |  7 +++++
 3 files changed, 90 insertions(+), 9 deletions(-)

diff --git a/block/bio-integrity.c b/block/bio-integrity.c
index 3bee43b87001..5d81ad9a3d20 100644
--- a/block/bio-integrity.c
+++ b/block/bio-integrity.c
@@ -364,6 +364,55 @@ int bio_integrity_map_user(struct bio *bio, struct iov_iter *iter)
 	return ret;
 }
 
+static void bio_uio_meta_to_bip(struct bio *bio, struct uio_meta *meta)
+{
+	struct bio_integrity_payload *bip = bio_integrity(bio);
+
+	if (meta->flags & IO_INTEGRITY_CHK_GUARD)
+		bip->bip_flags |= BIP_CHECK_GUARD;
+	if (meta->flags & IO_INTEGRITY_CHK_APPTAG)
+		bip->bip_flags |= BIP_CHECK_APPTAG;
+	if (meta->flags & IO_INTEGRITY_CHK_REFTAG)
+		bip->bip_flags |= BIP_CHECK_REFTAG;
+
+	bip->app_tag = meta->app_tag;
+}
+
+int bio_integrity_map_iter(struct bio *bio, struct uio_meta *meta)
+{
+	struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
+	unsigned int integrity_bytes;
+	int ret;
+	struct iov_iter it;
+
+	if (!bi)
+		return -EINVAL;
+	/*
+	 * original meta iterator can be bigger.
+	 * process integrity info corresponding to current data buffer only.
+	 */
+	it = meta->iter;
+	integrity_bytes = bio_integrity_bytes(bi, bio_sectors(bio));
+	if (it.count < integrity_bytes)
+		return -EINVAL;
+
+	/* should fit into two bytes */
+	BUILD_BUG_ON(IO_INTEGRITY_VALID_FLAGS >= (1 << 16));
+
+	if (meta->flags && (meta->flags & ~IO_INTEGRITY_VALID_FLAGS))
+		return -EINVAL;
+
+	it.count = integrity_bytes;
+	ret = bio_integrity_map_user(bio, &it);
+	if (!ret) {
+		bio_uio_meta_to_bip(bio, meta);
+		bip_set_seed(bio_integrity(bio), meta->seed);
+		iov_iter_advance(&meta->iter, integrity_bytes);
+		meta->seed += bio_integrity_intervals(bi, bio_sectors(bio));
+	}
+	return ret;
+}
+
 /**
  * bio_integrity_prep - Prepare bio for integrity I/O
  * @bio:	bio to prepare
@@ -564,6 +613,7 @@ int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
 	bip->bip_vec = bip_src->bip_vec;
 	bip->bip_iter = bip_src->bip_iter;
 	bip->bip_flags = bip_src->bip_flags & BIP_CLONE_FLAGS;
+	bip->app_tag = bip_src->app_tag;
 
 	return 0;
 }
diff --git a/block/fops.c b/block/fops.c
index 2d01c9007681..3cf7e15eabbc 100644
--- a/block/fops.c
+++ b/block/fops.c
@@ -54,6 +54,7 @@ static ssize_t __blkdev_direct_IO_simple(struct kiocb *iocb,
 	struct bio bio;
 	ssize_t ret;
 
+	WARN_ON_ONCE(iocb->ki_flags & IOCB_HAS_METADATA);
 	if (nr_pages <= DIO_INLINE_BIO_VECS)
 		vecs = inline_vecs;
 	else {
@@ -128,6 +129,9 @@ static void blkdev_bio_end_io(struct bio *bio)
 	if (bio->bi_status && !dio->bio.bi_status)
 		dio->bio.bi_status = bio->bi_status;
 
+	if (dio->iocb->ki_flags & IOCB_HAS_METADATA)
+		bio_integrity_unmap_user(bio);
+
 	if (atomic_dec_and_test(&dio->ref)) {
 		if (!(dio->flags & DIO_IS_SYNC)) {
 			struct kiocb *iocb = dio->iocb;
@@ -221,14 +225,16 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 			 * a retry of this from blocking context.
 			 */
 			if (unlikely(iov_iter_count(iter))) {
-				bio_release_pages(bio, false);
-				bio_clear_flag(bio, BIO_REFFED);
-				bio_put(bio);
-				blk_finish_plug(&plug);
-				return -EAGAIN;
+				ret = -EAGAIN;
+				goto fail;
 			}
 			bio->bi_opf |= REQ_NOWAIT;
 		}
+		if (!is_sync && (iocb->ki_flags & IOCB_HAS_METADATA)) {
+			ret = bio_integrity_map_iter(bio, iocb->private);
+			if (unlikely(ret))
+				goto fail;
+		}
 
 		if (is_read) {
 			if (dio->flags & DIO_SHOULD_DIRTY)
@@ -269,6 +275,12 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 
 	bio_put(&dio->bio);
 	return ret;
+fail:
+	bio_release_pages(bio, false);
+	bio_clear_flag(bio, BIO_REFFED);
+	bio_put(bio);
+	blk_finish_plug(&plug);
+	return ret;
 }
 
 static void blkdev_bio_end_io_async(struct bio *bio)
@@ -286,6 +298,9 @@ static void blkdev_bio_end_io_async(struct bio *bio)
 		ret = blk_status_to_errno(bio->bi_status);
 	}
 
+	if (iocb->ki_flags & IOCB_HAS_METADATA)
+		bio_integrity_unmap_user(bio);
+
 	iocb->ki_complete(iocb, ret);
 
 	if (dio->flags & DIO_SHOULD_DIRTY) {
@@ -330,10 +345,8 @@ static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb,
 		bio_iov_bvec_set(bio, iter);
 	} else {
 		ret = bio_iov_iter_get_pages(bio, iter);
-		if (unlikely(ret)) {
-			bio_put(bio);
-			return ret;
-		}
+		if (unlikely(ret))
+			goto out_bio_put;
 	}
 	dio->size = bio->bi_iter.bi_size;
 
@@ -346,6 +359,13 @@ static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb,
 		task_io_account_write(bio->bi_iter.bi_size);
 	}
 
+	if (iocb->ki_flags & IOCB_HAS_METADATA) {
+		ret = bio_integrity_map_iter(bio, iocb->private);
+		WRITE_ONCE(iocb->private, NULL);
+		if (unlikely(ret))
+			goto out_bio_put;
+	}
+
 	if (iocb->ki_flags & IOCB_ATOMIC)
 		bio->bi_opf |= REQ_ATOMIC;
 
@@ -360,6 +380,10 @@ static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb,
 		submit_bio(bio);
 	}
 	return -EIOCBQUEUED;
+
+out_bio_put:
+	bio_put(bio);
+	return ret;
 }
 
 static ssize_t blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
diff --git a/include/linux/bio-integrity.h b/include/linux/bio-integrity.h
index 0046c744ea53..a42b7fe0eee9 100644
--- a/include/linux/bio-integrity.h
+++ b/include/linux/bio-integrity.h
@@ -23,6 +23,7 @@ struct bio_integrity_payload {
 	unsigned short		bip_vcnt;	/* # of integrity bio_vecs */
 	unsigned short		bip_max_vcnt;	/* integrity bio_vec slots */
 	unsigned short		bip_flags;	/* control flags */
+	u16			app_tag;	/* application tag value */
 
 	struct bvec_iter	bio_iter;	/* for rewinding parent bio */
 
@@ -79,6 +80,7 @@ struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio, gfp_t gfp,
 int bio_integrity_add_page(struct bio *bio, struct page *page, unsigned int len,
 		unsigned int offset);
 int bio_integrity_map_user(struct bio *bio, struct iov_iter *iter);
+int bio_integrity_map_iter(struct bio *bio, struct uio_meta *meta);
 void bio_integrity_unmap_user(struct bio *bio);
 bool bio_integrity_prep(struct bio *bio);
 void bio_integrity_advance(struct bio *bio, unsigned int bytes_done);
@@ -109,6 +111,11 @@ static int bio_integrity_map_user(struct bio *bio, struct iov_iter *iter)
 	return -EINVAL;
 }
 
+static inline int bio_integrity_map_iter(struct bio *bio, struct uio_meta *meta)
+{
+	return -EINVAL;
+}
+
 static inline void bio_integrity_unmap_user(struct bio *bio)
 {
 }
-- 
2.25.1