[PATCH v6 00/10] Read/Write with metadata/integrity

[PATCH v6 00/10] Read/Write with metadata/integrity

[Kanchan Joshi]

This adds a new io_uring interface to exchange additional integrity/pi
metadata with read/write.

The patchset is on top of block/for-next.

Interface:

Application sets up a SQE128 ring, and populates a new 'struct io_uring_meta_pi'
within the second SQE. This structure enables to pass:

* pi_flags: Three flags are exposed for integrity checks,
 namely IO_INTEGRITY_CHK_GUARD/APPTAG/REFTAG.
* len: length of the meta buffer
* addr: address of the meta buffer
* seed: seed value for reftag remapping
* app_tag: application-specific 16b value

Block path (direct IO) , NVMe and SCSI driver are modified to support
this.

Patch 1 is an enhancement patch.
Patch 2 is required to make the bounce buffer copy back work correctly.
Patch 3 to 5 are prep patches.
Patch 6 adds the io_uring support.
Patch 7 gives us unified interface for user and kernel generated
integrity.
Patch 8 adds support in SCSI and patch 9 in NVMe.
Patch 10 adds the support for block direct IO.

Testing has been done by modifying fio to use this interface.
Example program for the interface is appended below [1].

Changes since v5:
https://lore.kernel.org/linux-block/20241029162402.21400-1-anuj20.g@samsung.com/

- remove meta_type field from SQE (hch, keith)
- remove __bitwise annotation (hch)
- remove BIP_CTRL_NOCHECK from scsi (hch)

Changes since v4;
https://lore.kernel.org/linux-block/20241016112912.63542-1-anuj20.g@samsung.com/

- better variable names to describe bounce buffer copy back (hch)
- move defintion of flags in the same patch introducing uio_meta (hch)
- move uio_meta definition to include/linux/uio.h (hch)
- bump seed size in uio_meta to 8 bytes (martin)
- move flags definition to include/uapi/linux/fs.h (hch)
- s/meta/metadata in commit description of io-uring (hch)
- rearrange the meta fields in sqe for cleaner layout
- partial submission case is not applicable as, we are only plumbing for async case
- s/META_TYPE_INTEGRITY/META_TYPE_PI (hch, martin)
- remove unlikely branching (hch)
- Better formatting, misc cleanups, better commit descriptions, reordering commits(hch)

Changes since v3:
https://lore.kernel.org/linux-block/20240823103811.2421-1-anuj20.g@samsung.com/

- add reftag seed support (Martin)
- fix incorrect formatting in uio_meta (hch)
- s/IOCB_HAS_META/IOCB_HAS_METADATA (hch)
- move integrity check flags to block layer header (hch)
- add comments for BIP_CHECK_GUARD/REFTAG/APPTAG flags (hch)
- remove bio_integrity check during completion if IOCB_HAS_METADATA is set (hch)
- use goto label to get rid of duplicate error handling (hch)
- add warn_on if trying to do sync io with iocb_has_metadata flag (hch)
- remove check for disabling reftag remapping (hch)
- remove BIP_INTEGRITY_USER flag (hch)
- add comment for app_tag field introduced in bio_integrity_payload (hch)
- pass request to nvme_set_app_tag function (hch)
- right indentation at a place in scsi patch (hch)
- move IOCB_HAS_METADATA to a separate fs patch (hch)

Changes since v2:
https://lore.kernel.org/linux-block/20240626100700.3629-1-anuj20.g@samsung.com/
- io_uring error handling styling (Gabriel)
- add documented helper to get metadata bytes from data iter (hch)
- during clone specify "what flags to clone" rather than
"what not to clone" (hch)
- Move uio_meta defination to bio-integrity.h (hch)
- Rename apptag field to app_tag (hch)
- Change datatype of flags field in uio_meta to bitwise (hch)
- Don't introduce BIP_USER_CHK_FOO flags (hch, martin)
- Driver should rely on block layer flags instead of seeing if it is
user-passthrough (hch)
- update the scsi code for handling user-meta (hch, martin)

Changes since v1:
https://lore.kernel.org/linux-block/20240425183943.6319-1-joshi.k@samsung.com/
- Do not use new opcode for meta, and also add the provision to introduce new
meta types beyond integrity (Pavel)
- Stuff IOCB_HAS_META check in need_complete_io (Jens)
- Split meta handling in NVMe into a separate handler (Keith)
- Add meta handling for __blkdev_direct_IO too (Keith)
- Don't inherit BIP_COPY_USER flag for cloned bio's (Christoph)
- Better commit descriptions (Christoph)

Changes since RFC:
- modify io_uring plumbing based on recent async handling state changes
- fixes/enhancements to correctly handle the split for meta buffer
- add flags to specify guard/reftag/apptag checks
- add support to send apptag

[1]
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <linux/io_uring.h>
#include <linux/types.h>
#include "liburing.h"

/* write data/meta. read both. compare. send apptag too.
* prerequisite:
* unprotected xfer: format namespace with 4KB + 8b, pi_type = 0
* protected xfer: format namespace with 4KB + 8b, pi_type = 1
*/

#define DATA_LEN 4096
#define META_LEN 8

struct t10_pi_tuple {
        __be16  guard;
        __be16  apptag;
        __be32  reftag;
};

int main(int argc, char *argv[])
{
         struct io_uring ring;
         struct io_uring_sqe *sqe = NULL;
         struct io_uring_cqe *cqe = NULL;
         void *wdb,*rdb;
         char wmb[META_LEN], rmb[META_LEN];
         char *data_str = "data buffer";
         char *meta_str = "meta";
         int fd, ret, blksize;
         struct stat fstat;
         unsigned long long offset = DATA_LEN;
         struct t10_pi_tuple *pi;
         struct io_uring_meta_pi *md;

         if (argc != 2) {
                 fprintf(stderr, "Usage: %s <block-device>", argv[0]);
                 return 1;
         };

         if (stat(argv[1], &fstat) == 0) {
                 blksize = (int)fstat.st_blksize;
         } else {
                 perror("stat");
                 return 1;
         }

         if (posix_memalign(&wdb, blksize, DATA_LEN)) {
                 perror("posix_memalign failed");
                 return 1;
         }
         if (posix_memalign(&rdb, blksize, DATA_LEN)) {
                 perror("posix_memalign failed");
                 return 1;
         }

         strcpy(wdb, data_str);
         strcpy(wmb, meta_str);

         fd = open(argv[1], O_RDWR | O_DIRECT);
         if (fd < 0) {
                 printf("Error in opening device\n");
                 return 0;
         }

         ret = io_uring_queue_init(8, &ring, IORING_SETUP_SQE128);
         if (ret) {
                 fprintf(stderr, "ring setup failed: %d\n", ret);
                 return 1;
         }

         /* write data + meta-buffer to device */
         sqe = io_uring_get_sqe(&ring);
         if (!sqe) {
                 fprintf(stderr, "get sqe failed\n");
                 return 1;
         }

         io_uring_prep_write(sqe, fd, wdb, DATA_LEN, offset);

         md = (struct io_uring_meta_pi *) sqe->big_sqe;
         md->addr = (__u64)wmb;
         md->len = META_LEN;
         /* flags to ask for guard/reftag/apptag*/
         md->pi_flags = IO_INTEGRITY_CHK_APPTAG;
         md->app_tag = 0x1234;
         md->seed = 0;

         pi = (struct t10_pi_tuple *)wmb;
         pi->apptag = 0x3412;

         ret = io_uring_submit(&ring);
         if (ret <= 0) {
                 fprintf(stderr, "sqe submit failed: %d\n", ret);
                 return 1;
         }

         ret = io_uring_wait_cqe(&ring, &cqe);
         if (!cqe) {
                 fprintf(stderr, "cqe is NULL :%d\n", ret);
                 return 1;
         }
         if (cqe->res < 0) {
                 fprintf(stderr, "write cqe failure: %d", cqe->res);
                 return 1;
         }

         io_uring_cqe_seen(&ring, cqe);

         /* read data + meta-buffer back from device */
         sqe = io_uring_get_sqe(&ring);
         if (!sqe) {
                 fprintf(stderr, "get sqe failed\n");
                 return 1;
         }

         io_uring_prep_read(sqe, fd, rdb, DATA_LEN, offset);

         md = (struct io_uring_meta_pi *) sqe->big_sqe;
         md->addr = (__u64)rmb;
         md->len = META_LEN;
         md->pi_flags = IO_INTEGRITY_CHK_APPTAG;
         md->app_tag = 0x1234;
         md->seed = 0;

         ret = io_uring_submit(&ring);
         if (ret <= 0) {
                 fprintf(stderr, "sqe submit failed: %d\n", ret);
                 return 1;
         }

         ret = io_uring_wait_cqe(&ring, &cqe);
         if (!cqe) {
                 fprintf(stderr, "cqe is NULL :%d\n", ret);
                 return 1;
         }

         if (cqe->res < 0) {
                 fprintf(stderr, "read cqe failure: %d", cqe->res);
                 return 1;
         }
         io_uring_cqe_seen(&ring, cqe);

         if (strncmp(wmb, rmb, META_LEN))
                 printf("Failure: meta mismatch!, wmb=%s, rmb=%s\n", wmb, rmb);

         if (strncmp(wdb, rdb, DATA_LEN))
                 printf("Failure: data mismatch!\n");

         io_uring_queue_exit(&ring);
         free(rdb);
         free(wdb);
         return 0;
}

Anuj Gupta (7):
  block: define set of integrity flags to be inherited by cloned bip
  block: modify bio_integrity_map_user to accept iov_iter as argument
  fs, iov_iter: define meta io descriptor
  fs: introduce IOCB_HAS_METADATA for metadata
  io_uring/rw: add support to send metadata along with read/write
  block: introduce BIP_CHECK_GUARD/REFTAG/APPTAG bip_flags
  scsi: add support for user-meta interface

Christoph Hellwig (1):
  block: copy back bounce buffer to user-space correctly in case of
    split

Kanchan Joshi (2):
  nvme: add support for passing on the application tag
  block: add support to pass user meta buffer

 block/bio-integrity.c         | 84 ++++++++++++++++++++++++++++-------
 block/blk-integrity.c         | 10 ++++-
 block/fops.c                  | 42 ++++++++++++++----
 drivers/nvme/host/core.c      | 21 +++++----
 drivers/scsi/sd.c             |  4 +-
 include/linux/bio-integrity.h | 26 ++++++++---
 include/linux/fs.h            |  1 +
 include/linux/uio.h           |  9 ++++
 include/uapi/linux/fs.h       |  9 ++++
 include/uapi/linux/io_uring.h | 16 +++++++
 io_uring/io_uring.c           |  4 ++
 io_uring/rw.c                 | 71 ++++++++++++++++++++++++++++-
 io_uring/rw.h                 | 14 +++++-
 13 files changed, 266 insertions(+), 45 deletions(-)

-- 
2.25.1

[PATCH v6 01/10] block: define set of integrity flags to be inherited by cloned bip

[Kanchan Joshi]

From: Anuj Gupta <anuj20.g@samsung.com>

Introduce BIP_CLONE_FLAGS describing integrity flags that should be
inherited in the cloned bip from the parent.

Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
---
 block/bio-integrity.c         | 2 +-
 include/linux/bio-integrity.h | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/block/bio-integrity.c b/block/bio-integrity.c
index 2a4bd6611692..a448a25d13de 100644
--- a/block/bio-integrity.c
+++ b/block/bio-integrity.c
@@ -559,7 +559,7 @@ 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_BLOCK_INTEGRITY;
+	bip->bip_flags = bip_src->bip_flags & BIP_CLONE_FLAGS;
 
 	return 0;
 }
diff --git a/include/linux/bio-integrity.h b/include/linux/bio-integrity.h
index dbf0f74c1529..0f0cf10222e8 100644
--- a/include/linux/bio-integrity.h
+++ b/include/linux/bio-integrity.h
@@ -30,6 +30,9 @@ struct bio_integrity_payload {
 	struct bio_vec		bip_inline_vecs[];/* embedded bvec array */
 };
 
+#define BIP_CLONE_FLAGS (BIP_MAPPED_INTEGRITY | BIP_CTRL_NOCHECK | \
+			 BIP_DISK_NOCHECK | BIP_IP_CHECKSUM)
+
 #ifdef CONFIG_BLK_DEV_INTEGRITY
 
 #define bip_for_each_vec(bvl, bip, iter)				\
-- 
2.25.1

[PATCH v6 02/10] block: copy back bounce buffer to user-space correctly in case of split

[Kanchan Joshi]

From: Christoph Hellwig <hch@lst.de>

Copy back the bounce buffer to user-space in entirety when the parent
bio completes. The existing code uses bip_iter.bi_size for sizing the
copy, which can be modified. So move away from that and fetch it from
the vector passed to the block layer. While at it, switch to using
better variable names.

Fixes: 492c5d455969f ("block: bio-integrity: directly map user buffers")
Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
[hch: better names for variables]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
---
 block/bio-integrity.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/block/bio-integrity.c b/block/bio-integrity.c
index a448a25d13de..4341b0d4efa1 100644
--- a/block/bio-integrity.c
+++ b/block/bio-integrity.c
@@ -118,17 +118,18 @@ static void bio_integrity_unpin_bvec(struct bio_vec *bv, int nr_vecs,
 
 static void bio_integrity_uncopy_user(struct bio_integrity_payload *bip)
 {
-	unsigned short nr_vecs = bip->bip_max_vcnt - 1;
-	struct bio_vec *copy = &bip->bip_vec[1];
-	size_t bytes = bip->bip_iter.bi_size;
-	struct iov_iter iter;
+	unsigned short orig_nr_vecs = bip->bip_max_vcnt - 1;
+	struct bio_vec *orig_bvecs = &bip->bip_vec[1];
+	struct bio_vec *bounce_bvec = &bip->bip_vec[0];
+	size_t bytes = bounce_bvec->bv_len;
+	struct iov_iter orig_iter;
 	int ret;
 
-	iov_iter_bvec(&iter, ITER_DEST, copy, nr_vecs, bytes);
-	ret = copy_to_iter(bvec_virt(bip->bip_vec), bytes, &iter);
+	iov_iter_bvec(&orig_iter, ITER_DEST, orig_bvecs, orig_nr_vecs, bytes);
+	ret = copy_to_iter(bvec_virt(bounce_bvec), bytes, &orig_iter);
 	WARN_ON_ONCE(ret != bytes);
 
-	bio_integrity_unpin_bvec(copy, nr_vecs, true);
+	bio_integrity_unpin_bvec(orig_bvecs, orig_nr_vecs, true);
 }
 
 /**
-- 
2.25.1

[PATCH v6 03/10] block: modify bio_integrity_map_user to accept iov_iter as argument

[Kanchan Joshi]

From: Anuj Gupta <anuj20.g@samsung.com>

This patch refactors bio_integrity_map_user to accept iov_iter as
argument. This is a prep patch.

Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
---
 block/bio-integrity.c         | 12 +++++-------
 block/blk-integrity.c         | 10 +++++++++-
 include/linux/bio-integrity.h |  5 ++---
 3 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/block/bio-integrity.c b/block/bio-integrity.c
index 4341b0d4efa1..f56d01cec689 100644
--- a/block/bio-integrity.c
+++ b/block/bio-integrity.c
@@ -302,16 +302,15 @@ static unsigned int bvec_from_pages(struct bio_vec *bvec, struct page **pages,
 	return nr_bvecs;
 }
 
-int bio_integrity_map_user(struct bio *bio, void __user *ubuf, ssize_t bytes)
+int bio_integrity_map_user(struct bio *bio, struct iov_iter *iter)
 {
 	struct request_queue *q = bdev_get_queue(bio->bi_bdev);
 	unsigned int align = blk_lim_dma_alignment_and_pad(&q->limits);
 	struct page *stack_pages[UIO_FASTIOV], **pages = stack_pages;
 	struct bio_vec stack_vec[UIO_FASTIOV], *bvec = stack_vec;
+	size_t offset, bytes = iter->count;
 	unsigned int direction, nr_bvecs;
-	struct iov_iter iter;
 	int ret, nr_vecs;
-	size_t offset;
 	bool copy;
 
 	if (bio_integrity(bio))
@@ -324,8 +323,7 @@ int bio_integrity_map_user(struct bio *bio, void __user *ubuf, ssize_t bytes)
 	else
 		direction = ITER_SOURCE;
 
-	iov_iter_ubuf(&iter, direction, ubuf, bytes);
-	nr_vecs = iov_iter_npages(&iter, BIO_MAX_VECS + 1);
+	nr_vecs = iov_iter_npages(iter, BIO_MAX_VECS + 1);
 	if (nr_vecs > BIO_MAX_VECS)
 		return -E2BIG;
 	if (nr_vecs > UIO_FASTIOV) {
@@ -335,8 +333,8 @@ int bio_integrity_map_user(struct bio *bio, void __user *ubuf, ssize_t bytes)
 		pages = NULL;
 	}
 
-	copy = !iov_iter_is_aligned(&iter, align, align);
-	ret = iov_iter_extract_pages(&iter, &pages, bytes, nr_vecs, 0, &offset);
+	copy = !iov_iter_is_aligned(iter, align, align);
+	ret = iov_iter_extract_pages(iter, &pages, bytes, nr_vecs, 0, &offset);
 	if (unlikely(ret < 0))
 		goto free_bvec;
 
diff --git a/block/blk-integrity.c b/block/blk-integrity.c
index b180cac61a9d..4a29754f1bc2 100644
--- a/block/blk-integrity.c
+++ b/block/blk-integrity.c
@@ -115,8 +115,16 @@ EXPORT_SYMBOL(blk_rq_map_integrity_sg);
 int blk_rq_integrity_map_user(struct request *rq, void __user *ubuf,
 			      ssize_t bytes)
 {
-	int ret = bio_integrity_map_user(rq->bio, ubuf, bytes);
+	int ret;
+	struct iov_iter iter;
+	unsigned int direction;
 
+	if (op_is_write(req_op(rq)))
+		direction = ITER_DEST;
+	else
+		direction = ITER_SOURCE;
+	iov_iter_ubuf(&iter, direction, ubuf, bytes);
+	ret = bio_integrity_map_user(rq->bio, &iter);
 	if (ret)
 		return ret;
 
diff --git a/include/linux/bio-integrity.h b/include/linux/bio-integrity.h
index 0f0cf10222e8..58ff9988433a 100644
--- a/include/linux/bio-integrity.h
+++ b/include/linux/bio-integrity.h
@@ -75,7 +75,7 @@ struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio, gfp_t gfp,
 		unsigned int nr);
 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, void __user *ubuf, ssize_t len);
+int bio_integrity_map_user(struct bio *bio, struct iov_iter *iter);
 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);
@@ -101,8 +101,7 @@ static inline void bioset_integrity_free(struct bio_set *bs)
 {
 }
 
-static inline int bio_integrity_map_user(struct bio *bio, void __user *ubuf,
-					 ssize_t len)
+static int bio_integrity_map_user(struct bio *bio, struct iov_iter *iter)
 {
 	return -EINVAL;
 }
-- 
2.25.1

[PATCH v6 04/10] fs, iov_iter: define meta io descriptor

[Kanchan Joshi]

From: Anuj Gupta <anuj20.g@samsung.com>

Add flags to describe checks for integrity meta buffer. Also, introduce
a  new 'uio_meta' structure that upper layer can use to pass the
meta/integrity information.

Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
---
 include/linux/uio.h     | 9 +++++++++
 include/uapi/linux/fs.h | 9 +++++++++
 2 files changed, 18 insertions(+)

diff --git a/include/linux/uio.h b/include/linux/uio.h
index 853f9de5aa05..8ada84e85447 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -82,6 +82,15 @@ struct iov_iter {
 	};
 };
 
+typedef __u16 uio_meta_flags_t;
+
+struct uio_meta {
+	uio_meta_flags_t	flags;
+	u16			app_tag;
+	u64			seed;
+	struct iov_iter		iter;
+};
+
 static inline const struct iovec *iter_iov(const struct iov_iter *iter)
 {
 	if (iter->iter_type == ITER_UBUF)
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index 753971770733..9070ef19f0a3 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -40,6 +40,15 @@
 #define BLOCK_SIZE_BITS 10
 #define BLOCK_SIZE (1<<BLOCK_SIZE_BITS)
 
+/* flags for integrity meta */
+#define IO_INTEGRITY_CHK_GUARD		(1U << 0) /* enforce guard check */
+#define IO_INTEGRITY_CHK_REFTAG		(1U << 1) /* enforce ref check */
+#define IO_INTEGRITY_CHK_APPTAG		(1U << 2) /* enforce app check */
+
+#define IO_INTEGRITY_VALID_FLAGS (IO_INTEGRITY_CHK_GUARD | \
+				  IO_INTEGRITY_CHK_REFTAG | \
+				  IO_INTEGRITY_CHK_APPTAG)
+
 #define SEEK_SET	0	/* seek relative to beginning of file */
 #define SEEK_CUR	1	/* seek relative to current file position */
 #define SEEK_END	2	/* seek relative to end of file */
-- 
2.25.1

[PATCH v6 05/10] fs: introduce IOCB_HAS_METADATA for metadata

[Kanchan Joshi]

From: Anuj Gupta <anuj20.g@samsung.com>

Introduce an IOCB_HAS_METADATA flag for the kiocb struct, for handling
requests containing meta payload.

Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 include/linux/fs.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 4b5cad44a126..7f14675b02df 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -346,6 +346,7 @@ struct readahead_control;
 #define IOCB_DIO_CALLER_COMP	(1 << 22)
 /* kiocb is a read or write operation submitted by fs/aio.c. */
 #define IOCB_AIO_RW		(1 << 23)
+#define IOCB_HAS_METADATA	(1 << 24)
 
 /* for use in trace events */
 #define TRACE_IOCB_STRINGS \
-- 
2.25.1

[PATCH v6 06/10] io_uring/rw: add support to send metadata along with read/write

[Kanchan Joshi]

From: Anuj Gupta <anuj20.g@samsung.com>

This patch adds the capability of passing integrity metadata along with
read/write.

Introduce a new 'struct io_uring_meta_pi' that contains following:
- pi_flags: integrity check flags namely
IO_INTEGRITY_CHK_{GUARD/APPTAG/REFTAG}
- len: length of the pi/metadata buffer
- buf: address of the metadata buffer
- seed: seed value for reftag remapping
- app_tag: application defined 16b value

Application sets up a SQE128 ring, prepares io_uring_meta_pi within
the second SQE.
The patch processes this information to prepare uio_meta descriptor
and passes it down using kiocb->private.

Meta exchange is supported only for direct IO.
Also vectored read/write operations with meta are not supported
currently.

Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
---
 include/uapi/linux/io_uring.h | 16 ++++++++
 io_uring/io_uring.c           |  4 ++
 io_uring/rw.c                 | 71 ++++++++++++++++++++++++++++++++++-
 io_uring/rw.h                 | 14 ++++++-
 4 files changed, 102 insertions(+), 3 deletions(-)

diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 024745283783..48dcca125db3 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -105,6 +105,22 @@ struct io_uring_sqe {
 		 */
 		__u8	cmd[0];
 	};
+	/*
+	 * If the ring is initialized with IORING_SETUP_SQE128, then
+	 * this field is starting offset for 64 bytes of data. For meta io
+	 * this contains 'struct io_uring_meta_pi'
+	 */
+	__u8	big_sqe[0];
+};
+
+/* this is placed in SQE128 */
+struct io_uring_meta_pi {
+	__u16		pi_flags;
+	__u16		app_tag;
+	__u32		len;
+	__u64		addr;
+	__u64		seed;
+	__u64		rsvd[2];
 };
 
 /*
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 44a772013c09..c5fd74e42c04 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -3879,6 +3879,7 @@ static int __init io_uring_init(void)
 	BUILD_BUG_SQE_ELEM(48, __u64,  addr3);
 	BUILD_BUG_SQE_ELEM_SIZE(48, 0, cmd);
 	BUILD_BUG_SQE_ELEM(56, __u64,  __pad2);
+	BUILD_BUG_SQE_ELEM_SIZE(64, 0, big_sqe);
 
 	BUILD_BUG_ON(sizeof(struct io_uring_files_update) !=
 		     sizeof(struct io_uring_rsrc_update));
@@ -3902,6 +3903,9 @@ static int __init io_uring_init(void)
 	/* top 8bits are for internal use */
 	BUILD_BUG_ON((IORING_URING_CMD_MASK & 0xff000000) != 0);
 
+	BUILD_BUG_ON(sizeof(struct io_uring_meta_pi) >
+		     sizeof(struct io_uring_sqe));
+
 	io_uring_optable_init();
 
 	/*
diff --git a/io_uring/rw.c b/io_uring/rw.c
index 30448f343c7f..cbb74fcfd0d1 100644
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -257,6 +257,46 @@ static int io_prep_rw_setup(struct io_kiocb *req, int ddir, bool do_import)
 	return 0;
 }
 
+static inline void io_meta_save_state(struct io_async_rw *io)
+{
+	io->meta_state.seed = io->meta.seed;
+	iov_iter_save_state(&io->meta.iter, &io->meta_state.iter_meta);
+}
+
+static inline void io_meta_restore(struct io_async_rw *io)
+{
+	io->meta.seed = io->meta_state.seed;
+	iov_iter_restore(&io->meta.iter, &io->meta_state.iter_meta);
+}
+
+static int io_prep_rw_meta(struct io_kiocb *req, const struct io_uring_sqe *sqe,
+			   struct io_rw *rw, int ddir)
+{
+	const struct io_uring_meta_pi *md = (struct io_uring_meta_pi *)sqe->big_sqe;
+	const struct io_issue_def *def;
+	struct io_async_rw *io;
+	int ret;
+
+	if (READ_ONCE(md->rsvd[0]) || READ_ONCE(md->rsvd[1]))
+		return -EINVAL;
+
+	def = &io_issue_defs[req->opcode];
+	if (def->vectored)
+		return -EOPNOTSUPP;
+
+	io = req->async_data;
+	io->meta.flags = READ_ONCE(md->pi_flags);
+	io->meta.app_tag = READ_ONCE(md->app_tag);
+	io->meta.seed = READ_ONCE(md->seed);
+	ret = import_ubuf(ddir, u64_to_user_ptr(READ_ONCE(md->addr)),
+			  READ_ONCE(md->len), &io->meta.iter);
+	if (unlikely(ret < 0))
+		return ret;
+	rw->kiocb.ki_flags |= IOCB_HAS_METADATA;
+	io_meta_save_state(io);
+	return ret;
+}
+
 static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe,
 		      int ddir, bool do_import)
 {
@@ -279,11 +319,19 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe,
 		rw->kiocb.ki_ioprio = get_current_ioprio();
 	}
 	rw->kiocb.dio_complete = NULL;
+	rw->kiocb.ki_flags = 0;
 
 	rw->addr = READ_ONCE(sqe->addr);
 	rw->len = READ_ONCE(sqe->len);
 	rw->flags = READ_ONCE(sqe->rw_flags);
-	return io_prep_rw_setup(req, ddir, do_import);
+	ret = io_prep_rw_setup(req, ddir, do_import);
+
+	if (unlikely(ret))
+		return ret;
+
+	if (req->ctx->flags & IORING_SETUP_SQE128)
+		ret = io_prep_rw_meta(req, sqe, rw, ddir);
+	return ret;
 }
 
 int io_prep_read(struct io_kiocb *req, const struct io_uring_sqe *sqe)
@@ -409,7 +457,10 @@ static inline loff_t *io_kiocb_update_pos(struct io_kiocb *req)
 static void io_resubmit_prep(struct io_kiocb *req)
 {
 	struct io_async_rw *io = req->async_data;
+	struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
 
+	if (rw->kiocb.ki_flags & IOCB_HAS_METADATA)
+		io_meta_restore(io);
 	iov_iter_restore(&io->iter, &io->iter_state);
 }
 
@@ -794,7 +845,7 @@ static int io_rw_init_file(struct io_kiocb *req, fmode_t mode, int rw_type)
 	if (!(req->flags & REQ_F_FIXED_FILE))
 		req->flags |= io_file_get_flags(file);
 
-	kiocb->ki_flags = file->f_iocb_flags;
+	kiocb->ki_flags |= file->f_iocb_flags;
 	ret = kiocb_set_rw_flags(kiocb, rw->flags, rw_type);
 	if (unlikely(ret))
 		return ret;
@@ -823,6 +874,18 @@ static int io_rw_init_file(struct io_kiocb *req, fmode_t mode, int rw_type)
 		kiocb->ki_complete = io_complete_rw;
 	}
 
+	if (kiocb->ki_flags & IOCB_HAS_METADATA) {
+		struct io_async_rw *io = req->async_data;
+
+		/*
+		 * We have a union of meta fields with wpq used for buffered-io
+		 * in io_async_rw, so fail it here.
+		 */
+		if (!(req->file->f_flags & O_DIRECT))
+			return -EOPNOTSUPP;
+		kiocb->private = &io->meta;
+	}
+
 	return 0;
 }
 
@@ -897,6 +960,8 @@ static int __io_read(struct io_kiocb *req, unsigned int issue_flags)
 	 * manually if we need to.
 	 */
 	iov_iter_restore(&io->iter, &io->iter_state);
+	if (kiocb->ki_flags & IOCB_HAS_METADATA)
+		io_meta_restore(io);
 
 	do {
 		/*
@@ -1101,6 +1166,8 @@ int io_write(struct io_kiocb *req, unsigned int issue_flags)
 	} else {
 ret_eagain:
 		iov_iter_restore(&io->iter, &io->iter_state);
+		if (kiocb->ki_flags & IOCB_HAS_METADATA)
+			io_meta_restore(io);
 		if (kiocb->ki_flags & IOCB_WRITE)
 			io_req_end_write(req);
 		return -EAGAIN;
diff --git a/io_uring/rw.h b/io_uring/rw.h
index 3f432dc75441..2d7656bd268d 100644
--- a/io_uring/rw.h
+++ b/io_uring/rw.h
@@ -2,6 +2,11 @@
 
 #include <linux/pagemap.h>
 
+struct io_meta_state {
+	u32			seed;
+	struct iov_iter_state	iter_meta;
+};
+
 struct io_async_rw {
 	size_t				bytes_done;
 	struct iov_iter			iter;
@@ -9,7 +14,14 @@ struct io_async_rw {
 	struct iovec			fast_iov;
 	struct iovec			*free_iovec;
 	int				free_iov_nr;
-	struct wait_page_queue		wpq;
+	/* wpq is for buffered io, while meta fields are used with direct io */
+	union {
+		struct wait_page_queue		wpq;
+		struct {
+			struct uio_meta			meta;
+			struct io_meta_state		meta_state;
+		};
+	};
 };
 
 int io_prep_read_fixed(struct io_kiocb *req, const struct io_uring_sqe *sqe);
-- 
2.25.1

Re: [PATCH v6 06/10] io_uring/rw: add support to send metadata along with read/write

[Keith Busch]

On Wed, Oct 30, 2024 at 11:31:08PM +0530, Kanchan Joshi wrote:
> diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
> index 024745283783..48dcca125db3 100644
> --- a/include/uapi/linux/io_uring.h
> +++ b/include/uapi/linux/io_uring.h
> @@ -105,6 +105,22 @@ struct io_uring_sqe {
>  		 */
>  		__u8	cmd[0];
>  	};
> +	/*
> +	 * If the ring is initialized with IORING_SETUP_SQE128, then
> +	 * this field is starting offset for 64 bytes of data. For meta io
> +	 * this contains 'struct io_uring_meta_pi'
> +	 */
> +	__u8	big_sqe[0];
> +};
> +
> +/* this is placed in SQE128 */
> +struct io_uring_meta_pi {
> +	__u16		pi_flags;
> +	__u16		app_tag;
> +	__u32		len;
> +	__u64		addr;
> +	__u64		seed;
> +	__u64		rsvd[2];
>  };

On the previous version, I was more questioning if it aligns with what
Pavel was trying to do here. I didn't quite get it, so I was more
confused than saying it should be this way now.

But I personally think this path makes sense. I would set it up just a
little differently for extended sqe's so that the PI overlays a more
generic struct that other opcodes might find a way to use later.
Something like:

struct io_uring_sqe_ext {
	union {
		__u32	rsvd0[8];
		struct {
			__u16		pi_flags;
			__u16		app_tag;
			__u32		len;
			__u64		addr;
			__u64		seed;
		} rw_pi;
	};
	__u32	rsvd1[8];
};
  
> @@ -3902,6 +3903,9 @@ static int __init io_uring_init(void)
>  	/* top 8bits are for internal use */
>  	BUILD_BUG_ON((IORING_URING_CMD_MASK & 0xff000000) != 0);
>  
> +	BUILD_BUG_ON(sizeof(struct io_uring_meta_pi) >
> +		     sizeof(struct io_uring_sqe));

Then this check would become:

	BUILD_BUG_ON(sizeof(struct io_uring_sqe_ext) != sizeof(struct io_uring_sqe));

[PATCH v6 07/10] block: introduce BIP_CHECK_GUARD/REFTAG/APPTAG bip_flags

[Kanchan Joshi]

From: Anuj Gupta <anuj20.g@samsung.com>

This patch introduces BIP_CHECK_GUARD/REFTAG/APPTAG bip_flags which
indicate how the hardware should check the integrity payload.
BIP_CHECK_GUARD/REFTAG are conversion of existing semantics, while
BIP_CHECK_APPTAG is a new flag. The driver can now just rely on block
layer flags, and doesn't need to know the integrity source. Submitter
of PI decides which tags to check. This would also give us a unified
interface for user and kernel generated integrity.

Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
---
 block/bio-integrity.c         |  5 +++++
 drivers/nvme/host/core.c      | 11 +++--------
 include/linux/bio-integrity.h |  6 +++++-
 3 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/block/bio-integrity.c b/block/bio-integrity.c
index f56d01cec689..3bee43b87001 100644
--- a/block/bio-integrity.c
+++ b/block/bio-integrity.c
@@ -434,6 +434,11 @@ bool bio_integrity_prep(struct bio *bio)
 	if (bi->csum_type == BLK_INTEGRITY_CSUM_IP)
 		bip->bip_flags |= BIP_IP_CHECKSUM;
 
+	/* describe what tags to check in payload */
+	if (bi->csum_type)
+		bip->bip_flags |= BIP_CHECK_GUARD;
+	if (bi->flags & BLK_INTEGRITY_REF_TAG)
+		bip->bip_flags |= BIP_CHECK_REFTAG;
 	if (bio_integrity_add_page(bio, virt_to_page(buf), len,
 			offset_in_page(buf)) < len) {
 		printk(KERN_ERR "could not attach integrity payload\n");
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 3de7555a7de7..79bd6b22e88d 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1004,18 +1004,13 @@ static inline blk_status_t nvme_setup_rw(struct nvme_ns *ns,
 			control |= NVME_RW_PRINFO_PRACT;
 		}
 
-		switch (ns->head->pi_type) {
-		case NVME_NS_DPS_PI_TYPE3:
+		if (bio_integrity_flagged(req->bio, BIP_CHECK_GUARD))
 			control |= NVME_RW_PRINFO_PRCHK_GUARD;
-			break;
-		case NVME_NS_DPS_PI_TYPE1:
-		case NVME_NS_DPS_PI_TYPE2:
-			control |= NVME_RW_PRINFO_PRCHK_GUARD |
-					NVME_RW_PRINFO_PRCHK_REF;
+		if (bio_integrity_flagged(req->bio, BIP_CHECK_REFTAG)) {
+			control |= NVME_RW_PRINFO_PRCHK_REF;
 			if (op == nvme_cmd_zone_append)
 				control |= NVME_RW_APPEND_PIREMAP;
 			nvme_set_ref_tag(ns, cmnd, req);
-			break;
 		}
 	}
 
diff --git a/include/linux/bio-integrity.h b/include/linux/bio-integrity.h
index 58ff9988433a..fe2bfe122db2 100644
--- a/include/linux/bio-integrity.h
+++ b/include/linux/bio-integrity.h
@@ -11,6 +11,9 @@ enum bip_flags {
 	BIP_DISK_NOCHECK	= 1 << 3, /* disable disk integrity checking */
 	BIP_IP_CHECKSUM		= 1 << 4, /* IP checksum */
 	BIP_COPY_USER		= 1 << 5, /* Kernel bounce buffer in use */
+	BIP_CHECK_GUARD		= 1 << 6, /* guard check */
+	BIP_CHECK_REFTAG	= 1 << 7, /* reftag check */
+	BIP_CHECK_APPTAG	= 1 << 8, /* apptag check */
 };
 
 struct bio_integrity_payload {
@@ -31,7 +34,8 @@ struct bio_integrity_payload {
 };
 
 #define BIP_CLONE_FLAGS (BIP_MAPPED_INTEGRITY | BIP_CTRL_NOCHECK | \
-			 BIP_DISK_NOCHECK | BIP_IP_CHECKSUM)
+			 BIP_DISK_NOCHECK | BIP_IP_CHECKSUM | \
+			 BIP_CHECK_GUARD | BIP_CHECK_REFTAG | BIP_CHECK_APPTAG)
 
 #ifdef CONFIG_BLK_DEV_INTEGRITY
 
-- 
2.25.1

[PATCH v6 08/10] nvme: add support for passing on the application tag

[Kanchan Joshi]

With user integrity buffer, there is a way to specify the app_tag.
Set the corresponding protocol specific flags and send the app_tag down.

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>
---
 drivers/nvme/host/core.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 79bd6b22e88d..3b329e036d33 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -872,6 +872,12 @@ static blk_status_t nvme_setup_discard(struct nvme_ns *ns, struct request *req,
 	return BLK_STS_OK;
 }
 
+static void nvme_set_app_tag(struct request *req, struct nvme_command *cmnd)
+{
+	cmnd->rw.lbat = cpu_to_le16(bio_integrity(req->bio)->app_tag);
+	cmnd->rw.lbatm = cpu_to_le16(0xffff);
+}
+
 static void nvme_set_ref_tag(struct nvme_ns *ns, struct nvme_command *cmnd,
 			      struct request *req)
 {
@@ -1012,6 +1018,10 @@ static inline blk_status_t nvme_setup_rw(struct nvme_ns *ns,
 				control |= NVME_RW_APPEND_PIREMAP;
 			nvme_set_ref_tag(ns, cmnd, req);
 		}
+		if (bio_integrity_flagged(req->bio, BIP_CHECK_APPTAG)) {
+			control |= NVME_RW_PRINFO_PRCHK_APP;
+			nvme_set_app_tag(req, cmnd);
+		}
 	}
 
 	cmnd->rw.control = cpu_to_le16(control);
-- 
2.25.1

[PATCH v6 09/10] scsi: add support for user-meta interface

[Kanchan Joshi]

From: Anuj Gupta <anuj20.g@samsung.com>

Add support for sending user-meta buffer. Set tags to be checked
using flags specified by user/block-layer.
With this change, BIP_CTRL_NOCHECK becomes unused. Remove it.

Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/sd.c             |  4 ++--
 include/linux/bio-integrity.h | 17 ++++++++---------
 2 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index ca4bc0ac76ad..d1a2ae0d4c29 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -814,14 +814,14 @@ static unsigned char sd_setup_protect_cmnd(struct scsi_cmnd *scmd,
 		if (bio_integrity_flagged(bio, BIP_IP_CHECKSUM))
 			scmd->prot_flags |= SCSI_PROT_IP_CHECKSUM;
 
-		if (bio_integrity_flagged(bio, BIP_CTRL_NOCHECK) == false)
+		if (bio_integrity_flagged(bio, BIP_CHECK_GUARD))
 			scmd->prot_flags |= SCSI_PROT_GUARD_CHECK;
 	}
 
 	if (dif != T10_PI_TYPE3_PROTECTION) {	/* DIX/DIF Type 0, 1, 2 */
 		scmd->prot_flags |= SCSI_PROT_REF_INCREMENT;
 
-		if (bio_integrity_flagged(bio, BIP_CTRL_NOCHECK) == false)
+		if (bio_integrity_flagged(bio, BIP_CHECK_REFTAG))
 			scmd->prot_flags |= SCSI_PROT_REF_CHECK;
 	}
 
diff --git a/include/linux/bio-integrity.h b/include/linux/bio-integrity.h
index fe2bfe122db2..0046c744ea53 100644
--- a/include/linux/bio-integrity.h
+++ b/include/linux/bio-integrity.h
@@ -7,13 +7,12 @@
 enum bip_flags {
 	BIP_BLOCK_INTEGRITY	= 1 << 0, /* block layer owns integrity data */
 	BIP_MAPPED_INTEGRITY	= 1 << 1, /* ref tag has been remapped */
-	BIP_CTRL_NOCHECK	= 1 << 2, /* disable HBA integrity checking */
-	BIP_DISK_NOCHECK	= 1 << 3, /* disable disk integrity checking */
-	BIP_IP_CHECKSUM		= 1 << 4, /* IP checksum */
-	BIP_COPY_USER		= 1 << 5, /* Kernel bounce buffer in use */
-	BIP_CHECK_GUARD		= 1 << 6, /* guard check */
-	BIP_CHECK_REFTAG	= 1 << 7, /* reftag check */
-	BIP_CHECK_APPTAG	= 1 << 8, /* apptag check */
+	BIP_DISK_NOCHECK	= 1 << 2, /* disable disk integrity checking */
+	BIP_IP_CHECKSUM		= 1 << 3, /* IP checksum */
+	BIP_COPY_USER		= 1 << 4, /* Kernel bounce buffer in use */
+	BIP_CHECK_GUARD		= 1 << 5, /* guard check */
+	BIP_CHECK_REFTAG	= 1 << 6, /* reftag check */
+	BIP_CHECK_APPTAG	= 1 << 7, /* apptag check */
 };
 
 struct bio_integrity_payload {
@@ -34,8 +33,8 @@ struct bio_integrity_payload {
 };
 
 #define BIP_CLONE_FLAGS (BIP_MAPPED_INTEGRITY | BIP_CTRL_NOCHECK | \
-			 BIP_DISK_NOCHECK | BIP_IP_CHECKSUM | \
-			 BIP_CHECK_GUARD | BIP_CHECK_REFTAG | BIP_CHECK_APPTAG)
+			 BIP_IP_CHECKSUM | BIP_CHECK_GUARD | \
+			 BIP_CHECK_REFTAG | BIP_CHECK_APPTAG)
 
 #ifdef CONFIG_BLK_DEV_INTEGRITY
 
-- 
2.25.1

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

[Kanchan Joshi]

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